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**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that used to generate VDBE code
** that implements the ALTER TABLE command.
**
** $Id: alter.c,v 1.14 2006/01/05 11:34:33 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** The code in this file only exists if we are not omitting the
** ALTER TABLE logic from the build.

** table pTab has no temporary triggers, or is itself stored in the 
** temporary database, NULL is returned.
*/
static char *whereTempTriggers(Parse *pParse, Table *pTab){
  Trigger *pTrig;
  char *zWhere = 0;
  char *tmp = 0;
  const DbSchema *pTempSchema = pParse->db->aDb[1].pSchema; /* Temp db schema */

  /* If the table is not located in the temp-db (in which case NULL is 
  ** returned, loop through the tables list of triggers. For each trigger
  ** that is not part of the temp-db schema, add a clause to the WHERE 
  ** expression being built up in zWhere.
  */
  if( pTab->pSchema!=pTempSchema ){
    for( pTrig=pTab->pTrigger; pTrig; pTrig=pTrig->pNext ){
      if( pTrig->pSchema==pTempSchema ){
        if( !zWhere ){
          zWhere = sqlite3MPrintf("name=%Q", pTrig->name);
        }else{
          tmp = zWhere;
          zWhere = sqlite3MPrintf("%s OR name=%Q", zWhere, pTrig->name);
          sqliteFree(tmp);
        }

** the time the generated code is executed. This can be different from
** pTab->zName if this function is being called to code part of an 
** "ALTER TABLE RENAME TO" statement.
*/
static void reloadTableSchema(Parse *pParse, Table *pTab, const char *zName){
  Vdbe *v;
  char *zWhere;
  int iDb;                   /* Index of database containing pTab */
#ifndef SQLITE_OMIT_TRIGGER
  Trigger *pTrig;
#endif

  v = sqlite3GetVdbe(pParse);
  if( !v ) return;
  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
  assert( iDb>=0 );

#ifndef SQLITE_OMIT_TRIGGER
  /* Drop any table triggers from the internal schema. */
  for(pTrig=pTab->pTrigger; pTrig; pTrig=pTrig->pNext){
    int iTrigDb = sqlite3SchemaToIndex(pParse->db, pTrig->pSchema);
    assert( iTrigDb==iDb || iTrigDb==1 );
    sqlite3VdbeOp3(v, OP_DropTrigger, iTrigDb, 0, pTrig->name, 0);
  }
#endif

  /* Drop the table and index from the internal schema */
  sqlite3VdbeOp3(v, OP_DropTable, iDb, 0, pTab->zName, 0);

  /* Reload the table, index and permanent trigger schemas. */

#endif
  
  if( sqlite3Tsd()->mallocFailed ) goto exit_rename_table;
  assert( pSrc->nSrc==1 );

  pTab = sqlite3LocateTable(pParse, pSrc->a[0].zName, pSrc->a[0].zDatabase);
  if( !pTab ) goto exit_rename_table;
  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
  zDb = db->aDb[iDb].zName;

  /* Get a NULL terminated version of the new table name. */
  zName = sqlite3NameFromToken(pName);
  if( !zName ) goto exit_rename_table;

  /* Check that a table or index named 'zName' does not already exist

  Column *pCol;             /* The new column */
  Expr *pDflt;              /* Default value for the new column */

  if( pParse->nErr ) return;
  pNew = pParse->pNewTable;
  assert( pNew );

  iDb = sqlite3SchemaToIndex(pParse->db, pNew->pSchema);
  zDb = pParse->db->aDb[iDb].zName;
  zTab = pNew->zName;
  pCol = &pNew->aCol[pNew->nCol-1];
  pDflt = pCol->pDflt;
  pTab = sqlite3FindTable(pParse->db, zTab, zDb);
  assert( pTab );

  Table *pNew;
  Table *pTab;
  Vdbe *v;
  int iDb;
  int i;
  int nAlloc;


  /* Look up the table being altered. */
  assert( pParse->pNewTable==0 );
  if( sqlite3Tsd()->mallocFailed ) goto exit_begin_add_column;
  pTab = sqlite3LocateTable(pParse, pSrc->a[0].zName, pSrc->a[0].zDatabase);
  if( !pTab ) goto exit_begin_add_column;

  /* Make sure this is not an attempt to ALTER a view. */
  if( pTab->pSelect ){
    sqlite3ErrorMsg(pParse, "Cannot add a column to a view");
    goto exit_begin_add_column;
  }

  assert( pTab->addColOffset>0 );
  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);

  /* Put a copy of the Table struct in Parse.pNewTable for the
  ** sqlite3AddColumn() function and friends to modify.
  */
  pNew = (Table *)sqliteMalloc(sizeof(Table));
  if( !pNew ) goto exit_begin_add_column;
  pParse->pNewTable = pNew;

  memcpy(pNew->aCol, pTab->aCol, sizeof(Column)*pNew->nCol);
  for(i=0; i<pNew->nCol; i++){
    Column *pCol = &pNew->aCol[i];
    pCol->zName = sqliteStrDup(pCol->zName);
    pCol->zType = 0;
    pCol->pDflt = 0;
  }
  pNew->pSchema = pParse->db->aDb[iDb].pSchema;
  pNew->addColOffset = pTab->addColOffset;
  pNew->nRef = 1;

  /* Begin a transaction and increment the schema cookie.  */
  sqlite3BeginWriteOperation(pParse, 0, iDb);
  v = sqlite3GetVdbe(pParse);
  if( !v ) goto exit_begin_add_column;

/*
** 2005 July 8
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains code associated with the ANALYZE command.
**
** @(#) $Id: analyze.c,v 1.12 2006/01/05 11:34:33 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_ANALYZE
#include "sqliteInt.h"

/*
** This routine generates code that opens the sqlite_stat1 table on cursor
** iStatCur.

  int iIdxCur;     /* Cursor number for index being analyzed */
  int nCol;        /* Number of columns in the index */
  Vdbe *v;         /* The virtual machine being built up */
  int i;           /* Loop counter */
  int topOfLoop;   /* The top of the loop */
  int endOfLoop;   /* The end of the loop */
  int addr;        /* The address of an instruction */
  int iDb;         /* Index of database containing pTab */

  v = sqlite3GetVdbe(pParse);
  if( pTab==0 || pTab->pIndex==0 ){
    /* Do no analysis for tables that have no indices */
    return;
  }

  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
  assert( iDb>=0 );
#ifndef SQLITE_OMIT_AUTHORIZATION
  if( sqlite3AuthCheck(pParse, SQLITE_ANALYZE, pTab->zName, 0,
      pParse->db->aDb[iDb].zName ) ){
    return;
  }
#endif

  iIdxCur = pParse->nTab;
  for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
    /* Open a cursor to the index to be analyzed
    */
    assert( iDb==sqlite3SchemaToIndex(pParse->db, pIdx->pSchema) );
    sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
    VdbeComment((v, "# %s", pIdx->zName));
    sqlite3VdbeOp3(v, OP_OpenRead, iIdxCur, pIdx->tnum,
                     (char*)&pIdx->keyInfo, P3_KEYINFO);
    nCol = pIdx->nColumn;
    if( iMem+nCol*2>=pParse->nMem ){
      pParse->nMem = iMem+nCol*2+1;
    }

}

/*
** Generate code that will do an analysis of an entire database
*/
static void analyzeDatabase(Parse *pParse, int iDb){
  sqlite3 *db = pParse->db;
  DbSchema *pSchema = db->aDb[iDb].pSchema;    /* Schema of database iDb */
  HashElem *k;
  int iStatCur;
  int iMem;

  sqlite3BeginWriteOperation(pParse, 0, iDb);
  iStatCur = pParse->nTab++;
  openStatTable(pParse, iDb, iStatCur, 0);
  iMem = pParse->nMem;
  for(k=sqliteHashFirst(&pSchema->tblHash); k; k=sqliteHashNext(k)){
    Table *pTab = (Table*)sqliteHashData(k);
    analyzeOneTable(pParse, pTab, iStatCur, iMem);
  }
  loadAnalysis(pParse, iDb);
}

/*
** Generate code that will do an analysis of a single table in
** a database.
*/
static void analyzeTable(Parse *pParse, Table *pTab){
  int iDb;
  int iStatCur;

  assert( pTab!=0 );
  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
  sqlite3BeginWriteOperation(pParse, 0, iDb);
  iStatCur = pParse->nTab++;
  openStatTable(pParse, iDb, iStatCur, pTab->zName);
  analyzeOneTable(pParse, pTab, iStatCur, pParse->nMem);
  loadAnalysis(pParse, iDb);
}

*/
void sqlite3AnalysisLoad(sqlite3 *db, int iDb){
  analysisInfo sInfo;
  HashElem *i;
  char *zSql;

  /* Clear any prior statistics */
  for(i=sqliteHashFirst(&db->aDb[iDb].pSchema->idxHash);i;i=sqliteHashNext(i)){
    Index *pIdx = sqliteHashData(i);
    sqlite3DefaultRowEst(pIdx);
  }

  /* Check to make sure the sqlite_stat1 table existss */
  sInfo.db = db;
  sInfo.zDatabase = db->aDb[iDb].zName;

/*
** 2003 April 6
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains code used to implement the ATTACH and DETACH commands.
**
** $Id: attach.c,v 1.39 2006/01/05 11:34:33 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** Resolve an expression that was part of an ATTACH or DETACH statement. This
** is slightly different from resolving a normal SQL expression, because simple
** identifiers are treated as strings, not possible column names or aliases.

    if( aNew==0 ){
      return;
    } 
  }
  db->aDb = aNew;
  aNew = &db->aDb[db->nDb++];
  memset(aNew, 0, sizeof(*aNew));

  /* Open the database file. If the btree is successfully opened, use
  ** it to obtain the database schema. At this point the schema may
  ** or may not be initialised.
  */
  rc = sqlite3BtreeFactory(db, zFile, 0, MAX_PAGES, &aNew->pBt);
  if( rc==SQLITE_OK ){
    aNew->pSchema = sqlite3SchemaGet(aNew->pBt);
    if( !aNew->pSchema ){
      rc = SQLITE_NOMEM;
    }
  }
  aNew->zName = sqliteStrDup(zName);
  aNew->safety_level = 3;




#if SQLITE_HAS_CODEC
  {
    extern int sqlite3CodecAttach(sqlite3*, int, void*, int);
    extern void sqlite3CodecGetKey(sqlite3*, int, void**, int*);
    int nKey;
    char *zKey;

**
*************************************************************************
** This file contains code used to implement the sqlite3_set_authorizer()
** API.  This facility is an optional feature of the library.  Embedded
** systems that do not need this facility may omit it by recompiling
** the library with -DSQLITE_OMIT_AUTHORIZATION=1
**
** $Id: auth.c,v 1.23 2006/01/05 11:34:34 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** All of the code in this file may be omitted by defining a single
** macro.
*/

  sqlite3 *db = pParse->db;
  int rc;
  Table *pTab;          /* The table being read */
  const char *zCol;     /* Name of the column of the table */
  int iSrc;             /* Index in pTabList->a[] of table being read */
  const char *zDBase;   /* Name of database being accessed */
  TriggerStack *pStack; /* The stack of current triggers */
  int iDb;              /* The index of the database the expression refers to */

  if( db->xAuth==0 ) return;
  if( pExpr->op==TK_AS ) return;
  assert( pExpr->op==TK_COLUMN );
  iDb = sqlite3SchemaToIndex(pParse->db, pExpr->pSchema);
  for(iSrc=0; pTabList && iSrc<pTabList->nSrc; iSrc++){
    if( pExpr->iTable==pTabList->a[iSrc].iCursor ) break;
  }
  if( iSrc>=0 && pTabList && iSrc<pTabList->nSrc ){
    pTab = pTabList->a[iSrc].pTab;
  }else if( (pStack = pParse->trigStack)!=0 ){
    /* This must be an attempt to read the NEW or OLD pseudo-tables

    zCol = pTab->aCol[pExpr->iColumn].zName;
  }else if( pTab->iPKey>=0 ){
    assert( pTab->iPKey<pTab->nCol );
    zCol = pTab->aCol[pTab->iPKey].zName;
  }else{
    zCol = "ROWID";
  }
  assert( iDb<db->nDb );
  zDBase = db->aDb[iDb].zName;
  rc = db->xAuth(db->pAuthArg, SQLITE_READ, pTab->zName, zCol, zDBase, 
                 pParse->zAuthContext);
  if( rc==SQLITE_IGNORE ){
    pExpr->op = TK_NULL;
  }else if( rc==SQLITE_DENY ){
    if( db->nDb>2 || iDb!=0 ){
      sqlite3ErrorMsg(pParse, "access to %s.%s.%s is prohibited", 
         zDBase, pTab->zName, zCol);
    }else{
      sqlite3ErrorMsg(pParse, "access to %s.%s is prohibited",pTab->zName,zCol);
    }
    pParse->rc = SQLITE_AUTH;
  }else if( rc!=SQLITE_OK ){

/*
** 2004 April 6
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** $Id: btree.c,v 1.279 2006/01/05 11:34:34 danielk1977 Exp $
**
** This file implements a external (disk-based) database using BTrees.
** For a detailed discussion of BTrees, refer to
**
**     Donald E. Knuth, THE ART OF COMPUTER PROGRAMMING, Volume 3:
**     "Sorting And Searching", pages 473-480. Addison-Wesley
**     Publishing Company, Reading, Massachusetts.

  int minLeaf;          /* Minimum local payload in a LEAFDATA table */
  BusyHandler *pBusyHandler;   /* Callback for when there is lock contention */
  u8 inTransaction;     /* Transaction state */
  BtShared *pNext;      /* Next in SqliteTsd.pBtree linked list */
  int nRef;             /* Number of references to this structure */
  int nTransaction;     /* Number of open transactions (read + write) */
  BtLock *pLock;        /* List of locks held on this shared-btree struct */
  void *pSchema;
  void (*xFreeSchema)(void*);
};

/*
** An instance of the following structure is used to hold information
** about a cell.  The parseCellPtr() function fills in this structure
** based on information extract from the raw disk page.
*/

  int (*xCompare)(void*,int,const void*,int,const void*); /* Key comp func */
  void *pArg;               /* First arg to xCompare() */
  Pgno pgnoRoot;            /* The root page of this tree */
  MemPage *pPage;           /* Page that contains the entry */
  int idx;                  /* Index of the entry in pPage->aCell[] */
  CellInfo info;            /* A parse of the cell we are pointing at */
  u8 wrFlag;                /* True if writable */
  u8 eState;                /* One of the CURSOR_XXX constants (see below) */
#ifndef SQLITE_OMIT_SHARED_CACHE
  void *pKey;
  i64 nKey;
  int skip;        /* (skip<0) -> Prev() is a no-op. (skip>0) -> Next() is */
#endif
};

/*
** Potential values for BtCursor.eState. The first two values (VALID and 
** INVALID) may occur in any build. The third (REQUIRESEEK) may only occur 
** if sqlite was compiled without the OMIT_SHARED_CACHE symbol defined.
**
** CURSOR_VALID:
**   Cursor points to a valid entry. getPayload() etc. may be called.
**
** CURSOR_INVALID:
**   Cursor does not point to a valid entry. This can happen (for example) 
**   because the table is empty or because BtreeCursorFirst() has not been
**   called.
**
** CURSOR_REQUIRESEEK:
**   The table that this cursor was opened on still exists, but has been 
**   modified since the cursor was last used. The cursor position is saved
**   in variables BtCursor.pKey and BtCursor.nKey. When a cursor is in 
**   this state, restoreCursorPosition() can be called to attempt to seek 
**   the cursor to the saved position.
*/
#define CURSOR_INVALID           0
#define CURSOR_VALID             1
#define CURSOR_REQUIRESEEK       2

/*
** The TRACE macro will print high-level status information about the
** btree operation when the global variable sqlite3_btree_trace is
** enabled.
*/
#if SQLITE_TEST
# define TRACE(X)   if( sqlite3_btree_trace )\

#ifdef SQLITE_OMIT_SHARED_CACHE
  /*
  ** The functions queryTableLock(), lockTable() and unlockAllTables()
  ** manipulate entries in the BtShared.pLock linked list used to store
  ** shared-cache table level locks. If the library is compiled with the
  ** shared-cache feature disabled, then there is only ever one user
  ** of each BtShared structure and so this locking is not necessary. 
  ** So define the lock related functions as no-ops.
  */
  #define queryTableLock(a,b,c) SQLITE_OK
  #define lockTable(a,b,c) SQLITE_OK
  #define unlockAllTables(a)
  #define restoreCursorPosition(a,b) SQLITE_OK
  #define saveAllCursors(a,b,c) SQLITE_OK

#else

/*
** Save the current cursor position in the variables BtCursor.nKey 
** and BtCursor.pKey. The cursor's state is set to CURSOR_REQUIRESEEK.
*/
static int saveCursorPosition(BtCursor *pCur){
  int rc = SQLITE_OK;

  assert( CURSOR_VALID==pCur->eState|| CURSOR_INVALID==pCur->eState );
  assert( 0==pCur->pKey );

  if( pCur->eState==CURSOR_VALID ){
    rc = sqlite3BtreeKeySize(pCur, &pCur->nKey);

    /* If this is an intKey table, then the above call to BtreeKeySize()
    ** stores the integer key in pCur->nKey. In this case this value is
    ** all that is required. Otherwise, if pCur is not open on an intKey
    ** table, then malloc space for and store the pCur->nKey bytes of key 
    ** data.
    */
    if( rc==SQLITE_OK && 0==pCur->pPage->intKey){
      void *pKey = sqliteMalloc(pCur->nKey);
      if( pKey ){
        rc = sqlite3BtreeKey(pCur, 0, pCur->nKey, pKey);
        if( pKey ){
          pCur->pKey = pKey;
        }else{
          sqliteFree(pKey);
        }
      }else{
        rc = SQLITE_NOMEM;
      }
    }
    assert( !pCur->pPage->intKey || !pCur->pKey );

    /* Todo: Should we drop the reference to pCur->pPage here? */

    if( rc==SQLITE_OK ){
      pCur->eState = CURSOR_REQUIRESEEK;
    }
  }

  return rc;
}

/*
** Save the positions of all cursors except pExcept open on the table 
** with root-page iRoot. Usually, this is called just before cursor
** pExcept is used to modify the table (BtreeDelete() or BtreeInsert()).
*/
static int saveAllCursors(BtShared *pBt, Pgno iRoot, BtCursor *pExcept){
  BtCursor *p;
  if( sqlite3Tsd()->useSharedData ){
    for(p=pBt->pCursor; p; p=p->pNext){
      if( p!=pExcept && p->pgnoRoot==iRoot && p->eState==CURSOR_VALID ){
        int rc = saveCursorPosition(p);
        if( SQLITE_OK!=rc ){
          return rc;
        }
      }
    }
  }
  return SQLITE_OK;
}

/*
** Restore the cursor to the position it was in (or as close to as possible)
** when saveCursorPosition() was called. Note that this call deletes the 
** saved position info stored by saveCursorPosition(), so there can be
** at most one effective restoreCursorPosition() call after each 
** saveCursorPosition().
**
** If the second argument argument - doSeek - is false, then instead of 
** returning the cursor to it's saved position, any saved position is deleted
** and the cursor state set to CURSOR_INVALID.
*/
static int restoreCursorPosition(BtCursor *pCur, int doSeek){
  int rc = SQLITE_OK;
  if( pCur->eState==CURSOR_REQUIRESEEK ){
    assert( sqlite3Tsd()->useSharedData );
    if( doSeek ){
      rc = sqlite3BtreeMoveto(pCur, pCur->pKey, pCur->nKey, &pCur->skip);
    }else{
      pCur->eState = CURSOR_INVALID;
    }
    if( rc==SQLITE_OK ){
      sqliteFree(pCur->pKey);
      pCur->pKey = 0;
      assert( CURSOR_VALID==pCur->eState || CURSOR_INVALID==pCur->eState );
    }
  }
  return rc;
}

/*
** Query to see if btree handle p may obtain a lock of type eLock 
** (READ_LOCK or WRITE_LOCK) on the table with root-page iTab. Return
** SQLITE_OK if the lock may be obtained (by calling lockTable()), or
** SQLITE_BUSY if not.
*/
static int queryTableLock(Btree *p, Pgno iTab, u8 eLock){
  BtShared *pBt = p->pBt;
  BtLock *pIter;

  /* This is a no-op if the shared-cache is not enabled */
  if( 0==sqlite3Tsd()->useSharedData ){
    return SQLITE_OK;
  }

  /* This (along with lockTable()) is where the ReadUncommitted flag is
  ** dealt with. If the caller is querying for a read-lock and the flag is
  ** set, it is unconditionally granted - even if there are write-locks
  ** on the table. If a write-lock is requested, the ReadUncommitted flag
  ** is not considered.
  **
  ** In function lockTable(), if a read-lock is demanded and the 
  ** ReadUncommitted flag is set, no entry is added to the locks list 
  ** (BtShared.pLock).
  **
  ** To summarize: If the ReadUncommitted flag is set, then read cursors do
  ** not create or respect table locks. The locking procedure for a 
  ** write-cursor does not change.
  */
  if( 
    !p->pSqlite || 
    0==(p->pSqlite->flags&SQLITE_ReadUncommitted) || 
    eLock==WRITE_LOCK ||
    iTab==1
  ){
    for(pIter=pBt->pLock; pIter; pIter=pIter->pNext){
      if( pIter->pBtree!=p && pIter->iTable==iTab && 
          (pIter->eLock!=eLock || eLock!=READ_LOCK) ){
        return SQLITE_BUSY;
      }
    }
  }
  return SQLITE_OK;
}

/*
** Add a lock on the table with root-page iTable to the shared-btree used
** by Btree handle p. Parameter eLock must be either READ_LOCK or 
** WRITE_LOCK.
**
** SQLITE_OK is returned if the lock is added successfully. SQLITE_BUSY and
** SQLITE_NOMEM may also be returned.
*/
static int lockTable(Btree *p, Pgno iTable, u8 eLock){
  BtShared *pBt = p->pBt;
  BtLock *pLock = 0;
  BtLock *pIter;

  /* This is a no-op if the shared-cache is not enabled */
  if( 0==sqlite3Tsd()->useSharedData ){
    return SQLITE_OK;
  }

  assert( SQLITE_OK==queryTableLock(p, iTable, eLock) );

  /* If the read-uncommitted flag is set and a read-lock is requested,
  ** return early without adding an entry to the BtShared.pLock list. See
  ** comment in function queryTableLock() for more info on handling 
  ** the ReadUncommitted flag.
  */
  if( 
    (p->pSqlite) && 
    (p->pSqlite->flags&SQLITE_ReadUncommitted) && 
    (eLock==READ_LOCK) &&
    iTable!=1
  ){
    return SQLITE_OK;
  }

  /* First search the list for an existing lock on this table. */
  for(pIter=pBt->pLock; pIter; pIter=pIter->pNext){
    if( pIter->iTable==iTable && pIter->pBtree==p ){
      pLock = pIter;
      break;
    }

/*
** Release all the table locks (locks obtained via calls to the lockTable()
** procedure) held by Btree handle p.
*/
static void unlockAllTables(Btree *p){
  BtLock **ppIter = &p->pBt->pLock;

  /* If the shared-cache extension is not enabled, there should be no
  ** locks in the BtShared.pLock list, making this procedure a no-op. Assert
  ** that this is the case.
  */
  assert( sqlite3Tsd()->useSharedData || 0==*ppIter );

  while( *ppIter ){
    BtLock *pLock = *ppIter;
    if( pLock->pBtree==p ){
      *ppIter = pLock->pNext;
      sqliteFree(pLock);
    }else{
      ppIter = &pLock->pNext;

  sqlite3pager_unref(pPtrmap);
  if( *pEType<1 || *pEType>5 ) return SQLITE_CORRUPT_BKPT;
  return SQLITE_OK;
}

#endif /* SQLITE_OMIT_AUTOVACUUM */






















/*
** Given a btree page and a cell index (0 means the first cell on
** the page, 1 means the second cell, and so forth) return a pointer
** to the cell content.
**
** This routine works only for pages that do not contain overflow cells.
*/

  int flags               /* Options */
){
  BtShared *pBt;          /* Shared part of btree structure */
  Btree *p;               /* Handle to return */
  int rc;
  int nReserve;
  unsigned char zDbHeader[100];
#ifndef SQLITE_OMIT_SHARED_CACHE
  SqliteTsd *pTsd = sqlite3Tsd();
#endif

  /* Set the variable isMemdb to true for an in-memory database, or 
  ** false for a file-based database. This symbol is only required if
  ** either of the shared-data or autovacuum features are compiled 
  ** into the library.
  */
#if !defined(SQLITE_OMIT_SHARED_CACHE) || !defined(SQLITE_OMIT_AUTOVACUUM)

#ifndef SQLITE_OMIT_SHARED_CACHE
  /* Add the new btree to the linked list starting at SqliteTsd.pBtree */
  if( pTsd->useSharedData && zFilename && !isMemdb ){
    pBt->pNext = pTsd->pBtree;
    pTsd->pBtree = pBt;
  }

#endif
  pBt->nRef = 1;
  *ppBtree = p;
  return SQLITE_OK;
}

/*
** Close an open database and invalidate all cursors.
*/
int sqlite3BtreeClose(Btree *p){

  BtShared *pBt = p->pBt;
  BtCursor *pCur;

#ifndef SQLITE_OMIT_SHARED_CACHE
  SqliteTsd *pTsd = sqlite3Tsd();
#endif

  /* Drop any table-locks */
  unlockAllTables(p);

  /* Close all cursors opened via this handle.  */
  pCur = pBt->pCursor;
  while( pCur ){

    }
  }
#endif

  /* Close the pager and free the shared-btree structure */
  assert( !pBt->pCursor );
  sqlite3pager_close(pBt->pPager);
  if( pBt->xFreeSchema && pBt->pSchema ){
    pBt->xFreeSchema(pBt->pSchema);
  }
  sqliteFree(pBt);
  return SQLITE_OK;
}

/*
** Change the busy handler callback function.
*/

  BtShared *pBt = p->pBt;
  for(pCur=pBt->pCursor; pCur; pCur=pCur->pNext){
    MemPage *pPage = pCur->pPage;
    char *zMode = pCur->wrFlag ? "rw" : "ro";
    sqlite3DebugPrintf("CURSOR %p rooted at %4d(%s) currently at %d.%d%s\n",
       pCur, pCur->pgnoRoot, zMode,
       pPage ? pPage->pgno : 0, pCur->idx,
       (pCur->eState==CURSOR_VALID) ? "" : " eof"
    );
  }
}
#endif

/*
** Rollback the transaction in progress.  All cursors will be

  if( pBt->pPage1==0 ){
    rc = lockBtreeWithRetry(p);
    if( rc!=SQLITE_OK ){
      return rc;
    }
  }
  pCur = sqliteMalloc( sizeof(*pCur) );
  if( pCur==0 ){
    rc = SQLITE_NOMEM;
    goto create_cursor_exception;
  }
  pCur->pgnoRoot = (Pgno)iTable;
  pCur->pPage = 0;  /* For exit-handler, in case getAndInitPage() fails. */
  if( iTable==1 && sqlite3pager_pagecount(pBt->pPager)==0 ){

  memset(&pCur->info, 0, sizeof(pCur->info));
  pCur->pNext = pBt->pCursor;
  if( pCur->pNext ){
    pCur->pNext->pPrev = pCur;
  }
  pCur->pPrev = 0;
  pBt->pCursor = pCur;
  pCur->eState = CURSOR_INVALID;
  *ppCur = pCur;

  return SQLITE_OK;
create_cursor_exception:
  if( pCur ){
    releasePage(pCur->pPage);
    sqliteFree(pCur);

/*
** Close a cursor.  The read lock on the database file is released
** when the last cursor is closed.
*/
int sqlite3BtreeCloseCursor(BtCursor *pCur){
  BtShared *pBt = pCur->pBtree->pBt;
  restoreCursorPosition(pCur, 0);
  if( pCur->pPrev ){
    pCur->pPrev->pNext = pCur->pNext;
  }else{
    pBt->pCursor = pCur->pNext;
  }
  if( pCur->pNext ){
    pCur->pNext->pPrev = pCur->pPrev;

** the key for the current entry.  If the cursor is not pointing
** to a valid entry, *pSize is set to 0. 
**
** For a table with the INTKEY flag set, this routine returns the key
** itself, not the number of bytes in the key.
*/
int sqlite3BtreeKeySize(BtCursor *pCur, i64 *pSize){
  int rc = restoreCursorPosition(pCur, 1);
  if( rc==SQLITE_OK ){
    assert( pCur->eState==CURSOR_INVALID || pCur->eState==CURSOR_VALID );
    if( pCur->eState==CURSOR_INVALID ){
      *pSize = 0;
    }else{
      getCellInfo(pCur);
      *pSize = pCur->info.nKey;
    }
  }
  return rc;
}

/*
** Set *pSize to the number of bytes of data in the entry the
** cursor currently points to.  Always return SQLITE_OK.
** Failure is not possible.  If the cursor is not currently
** pointing to an entry (which can happen, for example, if
** the database is empty) then *pSize is set to 0.
*/
int sqlite3BtreeDataSize(BtCursor *pCur, u32 *pSize){
  int rc = restoreCursorPosition(pCur, 1);
  if( rc==SQLITE_OK ){
    assert( pCur->eState==CURSOR_INVALID || pCur->eState==CURSOR_VALID );
    if( pCur->eState==CURSOR_INVALID ){
      /* Not pointing at a valid entry - set *pSize to 0. */
      *pSize = 0;
    }else{
      getCellInfo(pCur);
      *pSize = pCur->info.nData;
    }
  }
  return rc;
}

/*
** Read payload information from the entry that the pCur cursor is
** pointing to.  Begin reading the payload at "offset" and read
** a total of "amt" bytes.  Put the result in zBuf.
**

  int rc;
  MemPage *pPage;
  BtShared *pBt;
  int ovflSize;
  u32 nKey;

  assert( pCur!=0 && pCur->pPage!=0 );
  assert( pCur->eState==CURSOR_VALID );
  pBt = pCur->pBtree->pBt;
  pPage = pCur->pPage;
  pageIntegrity(pPage);
  assert( pCur->idx>=0 && pCur->idx<pPage->nCell );
  getCellInfo(pCur);
  aPayload = pCur->info.pCell;
  aPayload += pCur->info.nHeader;

** begins at "offset".
**
** Return SQLITE_OK on success or an error code if anything goes
** wrong.  An error is returned if "offset+amt" is larger than
** the available payload.
*/
int sqlite3BtreeKey(BtCursor *pCur, u32 offset, u32 amt, void *pBuf){
  int rc = restoreCursorPosition(pCur, 1);
  if( rc==SQLITE_OK ){
    assert( pCur->eState==CURSOR_VALID );
    assert( pCur->pPage!=0 );
    if( pCur->pPage->intKey ){
      return SQLITE_CORRUPT_BKPT;
    }
    assert( pCur->pPage->intKey==0 );
    assert( pCur->idx>=0 && pCur->idx<pCur->pPage->nCell );
    rc = getPayload(pCur, offset, amt, (unsigned char*)pBuf, 0);
  }
  return rc;
}

/*
** Read part of the data associated with cursor pCur.  Exactly
** "amt" bytes will be transfered into pBuf[].  The transfer
** begins at "offset".
**
** Return SQLITE_OK on success or an error code if anything goes
** wrong.  An error is returned if "offset+amt" is larger than
** the available payload.
*/
int sqlite3BtreeData(BtCursor *pCur, u32 offset, u32 amt, void *pBuf){
  int rc = restoreCursorPosition(pCur, 1);
  if( rc==SQLITE_OK ){
    assert( pCur->eState==CURSOR_VALID );
    assert( pCur->pPage!=0 );
    assert( pCur->idx>=0 && pCur->idx<pCur->pPage->nCell );
    rc = getPayload(pCur, offset, amt, pBuf, 1);
  }
  return rc;
}

/*
** Return a pointer to payload information from the entry that the 
** pCur cursor is pointing to.  The pointer is to the beginning of
** the key if skipKey==0 and it points to the beginning of data if
** skipKey==1.  The number of bytes of available key/data is written

){
  unsigned char *aPayload;
  MemPage *pPage;
  u32 nKey;
  int nLocal;

  assert( pCur!=0 && pCur->pPage!=0 );
  assert( pCur->eState==CURSOR_VALID );
  pPage = pCur->pPage;
  pageIntegrity(pPage);
  assert( pCur->idx>=0 && pCur->idx<pPage->nCell );
  getCellInfo(pCur);
  aPayload = pCur->info.pCell;
  aPayload += pCur->info.nHeader;
  if( pPage->intKey ){

** The pointer returned is ephemeral.  The key/data may move
** or be destroyed on the next call to any Btree routine.
**
** These routines is used to get quick access to key and data
** in the common case where no overflow pages are used.
*/
const void *sqlite3BtreeKeyFetch(BtCursor *pCur, int *pAmt){
  if( pCur->eState==CURSOR_VALID ){
    return (const void*)fetchPayload(pCur, pAmt, 0);
  }
  return 0;
}
const void *sqlite3BtreeDataFetch(BtCursor *pCur, int *pAmt){
  if( pCur->eState==CURSOR_VALID ){
    return (const void*)fetchPayload(pCur, pAmt, 1);
  }
  return 0;
}


/*
** Move the cursor down to a new child page.  The newPgno argument is the
** page number of the child page to move to.
*/
static int moveToChild(BtCursor *pCur, u32 newPgno){
  int rc;
  MemPage *pNewPage;
  MemPage *pOldPage;
  BtShared *pBt = pCur->pBtree->pBt;

  assert( pCur->eState==CURSOR_VALID );
  rc = getAndInitPage(pBt, newPgno, &pNewPage, pCur->pPage);
  if( rc ) return rc;
  pageIntegrity(pNewPage);
  pNewPage->idxParent = pCur->idx;
  pOldPage = pCur->pPage;
  pOldPage->idxShift = 0;
  releasePage(pOldPage);

** the largest cell index.
*/
static void moveToParent(BtCursor *pCur){
  MemPage *pParent;
  MemPage *pPage;
  int idxParent;

  assert( pCur->eState==CURSOR_VALID );
  pPage = pCur->pPage;
  assert( pPage!=0 );
  assert( !isRootPage(pPage) );
  pageIntegrity(pPage);
  pParent = pPage->pParent;
  assert( pParent!=0 );
  pageIntegrity(pParent);

** Move the cursor to the root page
*/
static int moveToRoot(BtCursor *pCur){
  MemPage *pRoot;
  int rc;
  BtShared *pBt = pCur->pBtree->pBt;

  restoreCursorPosition(pCur, 0);
  rc = getAndInitPage(pBt, pCur->pgnoRoot, &pRoot, 0);
  if( rc ){
    pCur->eState = CURSOR_INVALID;
    return rc;
  }
  releasePage(pCur->pPage);
  pageIntegrity(pRoot);
  pCur->pPage = pRoot;
  pCur->idx = 0;
  pCur->info.nSize = 0;
  if( pRoot->nCell==0 && !pRoot->leaf ){
    Pgno subpage;
    assert( pRoot->pgno==1 );
    subpage = get4byte(&pRoot->aData[pRoot->hdrOffset+8]);
    assert( subpage>0 );
    pCur->eState = CURSOR_VALID;
    rc = moveToChild(pCur, subpage);
  }
  pCur->eState = ((pCur->pPage->nCell>0)?CURSOR_VALID:CURSOR_INVALID);
  return rc;
}

/*
** Move the cursor down to the left-most leaf entry beneath the
** entry to which it is currently pointing.
*/
static int moveToLeftmost(BtCursor *pCur){
  Pgno pgno;
  int rc;
  MemPage *pPage;

  assert( pCur->eState==CURSOR_VALID );
  while( !(pPage = pCur->pPage)->leaf ){
    assert( pCur->idx>=0 && pCur->idx<pPage->nCell );
    pgno = get4byte(findCell(pPage, pCur->idx));
    rc = moveToChild(pCur, pgno);
    if( rc ) return rc;
  }
  return SQLITE_OK;

** finds the right-most entry beneath the *page*.
*/
static int moveToRightmost(BtCursor *pCur){
  Pgno pgno;
  int rc;
  MemPage *pPage;

  assert( pCur->eState==CURSOR_VALID );
  while( !(pPage = pCur->pPage)->leaf ){
    pgno = get4byte(&pPage->aData[pPage->hdrOffset+8]);
    pCur->idx = pPage->nCell;
    rc = moveToChild(pCur, pgno);
    if( rc ) return rc;
  }
  pCur->idx = pPage->nCell - 1;
  pCur->info.nSize = 0;
  return SQLITE_OK;
}

/* Move the cursor to the first entry in the table.  Return SQLITE_OK
** on success.  Set *pRes to 0 if the cursor actually points to something
** or set *pRes to 1 if the table is empty.
*/
int sqlite3BtreeFirst(BtCursor *pCur, int *pRes){
  int rc;
  rc = moveToRoot(pCur);
  if( rc ) return rc;
  if( pCur->eState==CURSOR_INVALID ){
    assert( pCur->pPage->nCell==0 );
    *pRes = 1;
    return SQLITE_OK;
  }
  assert( pCur->pPage->nCell>0 );
  *pRes = 0;
  rc = moveToLeftmost(pCur);
  return rc;
}

/* Move the cursor to the last entry in the table.  Return SQLITE_OK
** on success.  Set *pRes to 0 if the cursor actually points to something
** or set *pRes to 1 if the table is empty.
*/
int sqlite3BtreeLast(BtCursor *pCur, int *pRes){
  int rc;
  rc = moveToRoot(pCur);
  if( rc ) return rc;
  if( CURSOR_INVALID==pCur->eState ){
    assert( pCur->pPage->nCell==0 );
    *pRes = 1;
    return SQLITE_OK;
  }
  assert( pCur->eState==CURSOR_VALID );
  *pRes = 0;
  rc = moveToRightmost(pCur);
  return rc;
}

/* Move the cursor so that it points to an entry near pKey/nKey.
** Return a success code.

*/
int sqlite3BtreeMoveto(BtCursor *pCur, const void *pKey, i64 nKey, int *pRes){
  int rc;
  rc = moveToRoot(pCur);
  if( rc ) return rc;
  assert( pCur->pPage );
  assert( pCur->pPage->isInit );
  if( pCur->eState==CURSOR_INVALID ){
    *pRes = -1;
    assert( pCur->pPage->nCell==0 );
    return SQLITE_OK;
  }
   for(;;){
    int lwr, upr;
    Pgno chldPg;

** Return TRUE if the cursor is not pointing at an entry of the table.
**
** TRUE will be returned after a call to sqlite3BtreeNext() moves
** past the last entry in the table or sqlite3BtreePrev() moves past
** the first entry.  TRUE is also returned if the table is empty.
*/
int sqlite3BtreeEof(BtCursor *pCur){
  /* TODO: What if the cursor is in CURSOR_REQUIRESEEK but all table entries
  ** have been deleted? This API will need to change to return an error code
  ** as well as the boolean result value.
  */
  return (CURSOR_VALID!=pCur->eState);
}

/*
** Advance the cursor to the next entry in the database.  If
** successful then set *pRes=0.  If the cursor
** was already pointing to the last entry in the database before
** this routine was called, then set *pRes=1.
*/
int sqlite3BtreeNext(BtCursor *pCur, int *pRes){
  int rc;
  MemPage *pPage = pCur->pPage;

#ifndef SQLITE_OMIT_SHARED_CACHE
  rc = restoreCursorPosition(pCur, 1);
  if( rc!=SQLITE_OK ){
    return rc;
  }
  if( pCur->skip>0 ){
    pCur->skip = 0;
    *pRes = 0;
    return SQLITE_OK;
  }
  pCur->skip = 0;
#endif

  assert( pRes!=0 );
  if( CURSOR_INVALID==pCur->eState ){
    *pRes = 1;
    return SQLITE_OK;
  }
  assert( pPage->isInit );
  assert( pCur->idx<pPage->nCell );

  pCur->idx++;
  pCur->info.nSize = 0;
  if( pCur->idx>=pPage->nCell ){
    if( !pPage->leaf ){
      rc = moveToChild(pCur, get4byte(&pPage->aData[pPage->hdrOffset+8]));
      if( rc ) return rc;
      rc = moveToLeftmost(pCur);
      *pRes = 0;
      return rc;
    }
    do{
      if( isRootPage(pPage) ){
        *pRes = 1;
        pCur->eState = CURSOR_INVALID;
        return SQLITE_OK;
      }
      moveToParent(pCur);
      pPage = pCur->pPage;
    }while( pCur->idx>=pPage->nCell );
    *pRes = 0;
    if( pPage->leafData ){

** was already pointing to the first entry in the database before
** this routine was called, then set *pRes=1.
*/
int sqlite3BtreePrevious(BtCursor *pCur, int *pRes){
  int rc;
  Pgno pgno;
  MemPage *pPage;

#ifndef SQLITE_OMIT_SHARED_CACHE
  rc = restoreCursorPosition(pCur, 1);
  if( rc!=SQLITE_OK ){
    return rc;
  }
  if( pCur->skip<0 ){
    pCur->skip = 0;
    *pRes = 0;
    return SQLITE_OK;
  }
  pCur->skip = 0;
#endif

  if( CURSOR_INVALID==pCur->eState ){
    *pRes = 1;
    return SQLITE_OK;
  }

  pPage = pCur->pPage;
  assert( pPage->isInit );
  assert( pCur->idx>=0 );
  if( !pPage->leaf ){
    pgno = get4byte( findCell(pPage, pCur->idx) );
    rc = moveToChild(pCur, pgno);
    if( rc ) return rc;
    rc = moveToRightmost(pCur);
  }else{
    while( pCur->idx==0 ){
      if( isRootPage(pPage) ){
        pCur->eState = CURSOR_INVALID;
        *pRes = 1;
        return SQLITE_OK;
      }
      moveToParent(pCur);
      pPage = pCur->pPage;
    }
    pCur->idx--;

** or delete might change the number of cells on a page or delete
** a page entirely and we do not want to leave any cursors 
** pointing to non-existant pages or cells.
*/
static int checkReadLocks(BtShared *pBt, Pgno pgnoRoot, BtCursor *pExclude){
  BtCursor *p;
  for(p=pBt->pCursor; p; p=p->pNext){
    u32 flags = (p->pBtree->pSqlite ? p->pBtree->pSqlite->flags : 0);
    if( p->pgnoRoot!=pgnoRoot || p==pExclude ) continue;
    if( p->wrFlag==0 && flags&SQLITE_ReadUncommitted ) continue;
    if( p->wrFlag==0 ) return SQLITE_LOCKED;
    if( p->pPage->pgno!=p->pgnoRoot ){
      moveToRoot(p);
    }
  }
  return SQLITE_OK;
}

  assert( !pBt->readOnly );
  if( !pCur->wrFlag ){
    return SQLITE_PERM;   /* Cursor not open for writing */
  }
  if( checkReadLocks(pBt, pCur->pgnoRoot, pCur) ){
    return SQLITE_LOCKED; /* The table pCur points to has a read lock */
  }

  /* Save the positions of any other cursors open on this table */
  restoreCursorPosition(pCur, 0);
  rc = saveAllCursors(pBt, pCur->pgnoRoot, pCur);
  if( rc ){
    return rc;
  }

  rc = sqlite3BtreeMoveto(pCur, pKey, nKey, &loc);
  if( rc ) return rc;
  pPage = pCur->pPage;
  assert( pPage->intKey || nKey>=0 );
  assert( pPage->leaf || !pPage->leafData );
  TRACE(("INSERT: table=%d nkey=%lld ndata=%d page=%d %s\n",
          pCur->pgnoRoot, nKey, nData, pPage->pgno,
          loc==0 ? "overwrite" : "new entry"));
  assert( pPage->isInit );
  rc = sqlite3pager_write(pPage->aData);
  if( rc ) return rc;
  newCell = sqliteMallocRaw( MX_CELL_SIZE(pBt) );
  if( newCell==0 ) return SQLITE_NOMEM;
  rc = fillInCell(pPage, newCell, pKey, nKey, pData, nData, &szNew);
  if( rc ) goto end_insert;
  assert( szNew==cellSizePtr(pPage, newCell) );
  assert( szNew<=MX_CELL_SIZE(pBt) );
  if( loc==0 && CURSOR_VALID==pCur->eState ){
    int szOld;
    assert( pCur->idx>=0 && pCur->idx<pPage->nCell );
    oldCell = findCell(pPage, pCur->idx);
    if( !pPage->leaf ){
      memcpy(newCell, oldCell, 4);
    }
    szOld = cellSizePtr(pPage, oldCell);

  }
  if( !pCur->wrFlag ){
    return SQLITE_PERM;   /* Did not open this cursor for writing */
  }
  if( checkReadLocks(pBt, pCur->pgnoRoot, pCur) ){
    return SQLITE_LOCKED; /* The table pCur points to has a read lock */
  }

  /* Restore the current cursor position (a no-op if the cursor is not in 
  ** CURSOR_REQUIRESEEK state) and save the positions of any other cursors 
  ** open on the same table. Then call sqlite3pager_write() on the page
  ** that the entry will be deleted from.
  */
  if( 
    (rc = restoreCursorPosition(pCur, 1)) ||
    (rc = saveAllCursors(pBt, pCur->pgnoRoot, pCur)) ||
    (rc = sqlite3pager_write(pPage->aData))
  ){
    return rc;
  }

  /* Locate the cell within it's page and leave pCell pointing to the
  ** data. The clearCell() call frees any overflow pages associated with the
  ** cell. The cell itself is still intact.
  */
  pCell = findCell(pPage, pCur->idx);
  if( !pPage->leaf ){

** layer (and the SetCookie and ReadCookie opcodes) the number of
** free pages is not visible.  So Cookie[0] is the same as Meta[1].
*/
int sqlite3BtreeGetMeta(Btree *p, int idx, u32 *pMeta){
  int rc;
  unsigned char *pP1;
  BtShared *pBt = p->pBt;

  /* Reading a meta-data value requires a read-lock on page 1 (and hence
  ** the sqlite_master table. We grab this lock regardless of whether or
  ** not the SQLITE_ReadUncommitted flag is set (the table rooted at page
  ** 1 is treated as a special case by queryTableLock() and lockTable()).
  */
  rc = queryTableLock(p, 1, READ_LOCK);
  if( rc!=SQLITE_OK ){
    return rc;
  }

  assert( idx>=0 && idx<=15 );
  rc = sqlite3pager_get(pBt->pPager, 1, (void**)&pP1);
  if( rc ) return rc;
  *pMeta = get4byte(&pP1[36 + idx*4]);
  sqlite3pager_unref(pP1);

  /* If autovacuumed is disabled in this build but we are trying to 
  ** access an autovacuumed database, then make the database readonly. 
  */
#ifdef SQLITE_OMIT_AUTOVACUUM
  if( idx==4 && *pMeta>0 ) pBt->readOnly = 1;
#endif

  /* Grab the read-lock on page 1. */
  rc = lockTable(p, 1, READ_LOCK);
  return rc;
}

/*
** Write meta-information back into the database.  Meta[0] is
** read-only and may not be written.
*/
int sqlite3BtreeUpdateMeta(Btree *p, int idx, u32 iMeta){

}

/*
** Return the flag byte at the beginning of the page that the cursor
** is currently pointing to.
*/
int sqlite3BtreeFlags(BtCursor *pCur){
  /* TODO: What about CURSOR_REQUIRESEEK state? Probably need to call
  ** restoreCursorPosition() here.
  */
  MemPage *pPage = pCur->pPage;
  return pPage ? pPage->aData[pPage->hdrOffset] : 0;
}

#ifdef SQLITE_DEBUG
/*
** Print a disassembly of the given page on standard output.  This routine

**
** This routine is used for testing and debugging only.
*/
int sqlite3BtreeCursorInfo(BtCursor *pCur, int *aResult, int upCnt){
  int cnt, idx;
  MemPage *pPage = pCur->pPage;
  BtCursor tmpCur;

  int rc = restoreCursorPosition(pCur, 1);
  if( rc!=SQLITE_OK ){
    return rc;
  }

  pageIntegrity(pPage);
  assert( pPage->isInit );
  getTempCursor(pCur, &tmpCur);
  while( upCnt-- ){
    moveToParent(&tmpCur);
  }

    }
    return sqlite3pager_sync(pBt->pPager, zMaster, nTrunc);
#endif
    return sqlite3pager_sync(pBt->pPager, zMaster, 0);
  }
  return SQLITE_OK;
}

/*
** This function returns a pointer to a blob of memory associated with
** a single shared-btree. The memory is used by client code for it's own
** purposes (for example, to store a high-level schema associated with 
** the shared-btree). The btree layer manages reference counting issues.
**
** The first time this is called on a shared-btree, nBytes bytes of memory
** are allocated, zeroed, and returned to the caller. For each subsequent 
** call the nBytes parameter is ignored and a pointer to the same blob
** of memory returned. 
**
** Just before the shared-btree is closed, the function passed as the 
** xFree argument when the memory allocation was made is invoked on the 
** blob of allocated memory. This function should not call sqliteFree()
** on the memory, the btree layer does that.
*/
void *sqlite3BtreeSchema(Btree *p, int nBytes, void(*xFree)(void *)){
  BtShared *pBt = p->pBt;
  if( !pBt->pSchema ){
    pBt->pSchema = sqliteMalloc(nBytes);
    pBt->xFreeSchema = xFree;
  }
  return pBt->pSchema;
}

#ifndef SQLITE_OMIT_SHARED_CACHE
/*
** Enable the shared pager and schema features.
*/
int sqlite3_enable_shared_cache(int enable){
  SqliteTsd *pTsd = sqlite3Tsd();

**    May you share freely, never taking more than you give.
**
*************************************************************************
** This header file defines the interface that the sqlite B-Tree file
** subsystem.  See comments in the source code for a detailed description
** of what each interface routine does.
**
** @(#) $Id: btree.h,v 1.67 2006/01/05 11:34:34 danielk1977 Exp $
*/
#ifndef _BTREE_H_
#define _BTREE_H_

/* TODO: This definition is just included so other modules compile. It
** needs to be revisited.
*/

int sqlite3BtreeBeginStmt(Btree*);
int sqlite3BtreeCommitStmt(Btree*);
int sqlite3BtreeRollbackStmt(Btree*);
int sqlite3BtreeCreateTable(Btree*, int*, int flags);
int sqlite3BtreeIsInTrans(Btree*);
int sqlite3BtreeIsInStmt(Btree*);
int sqlite3BtreeSync(Btree*, const char *zMaster);
void *sqlite3BtreeSchema(Btree *, int, void(*)(void *));

const char *sqlite3BtreeGetFilename(Btree *);
const char *sqlite3BtreeGetDirname(Btree *);
const char *sqlite3BtreeGetJournalname(Btree *);
int sqlite3BtreeCopyFile(Btree *, Btree *);

/* The flags parameter to sqlite3BtreeCreateTable can be the bitwise OR

**     CREATE INDEX
**     DROP INDEX
**     creating ID lists
**     BEGIN TRANSACTION
**     COMMIT
**     ROLLBACK
**
** $Id: build.c,v 1.367 2006/01/05 11:34:34 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** This routine is called when a new SQL statement is beginning to
** be parsed.  Initialize the pParse structure as needed.

  Table *p = 0;
  int i;
  assert( zName!=0 );
  assert( (db->flags & SQLITE_Initialized) || db->init.busy );
  for(i=OMIT_TEMPDB; i<db->nDb; i++){
    int j = (i<2) ? i^1 : i;   /* Search TEMP before MAIN */
    if( zDatabase!=0 && sqlite3StrICmp(zDatabase, db->aDb[j].zName) ) continue;
    p = sqlite3HashFind(&db->aDb[j].pSchema->tblHash, zName, strlen(zName)+1);
    if( p ) break;
  }
  return p;
}

/*
** Locate the in-memory structure that describes a particular database

*/
Index *sqlite3FindIndex(sqlite3 *db, const char *zName, const char *zDb){
  Index *p = 0;
  int i;
  assert( (db->flags & SQLITE_Initialized) || db->init.busy );
  for(i=OMIT_TEMPDB; i<db->nDb; i++){
    int j = (i<2) ? i^1 : i;  /* Search TEMP before MAIN */
    DbSchema *pSchema = db->aDb[j].pSchema;
    if( zDb && sqlite3StrICmp(zDb, db->aDb[j].zName) ) continue;
    assert( pSchema || (j==1 && !db->aDb[1].pBt) );
    if( pSchema ){
      p = sqlite3HashFind(&pSchema->idxHash, zName, strlen(zName)+1);
    }
    if( p ) break;
  }
  return p;
}

/*
** Reclaim the memory used by an index

**
** The index is removed from the database hash tables but
** it is not unlinked from the Table that it indexes.
** Unlinking from the Table must be done by the calling function.
*/
static void sqliteDeleteIndex(sqlite3 *db, Index *p){
  Index *pOld;
  const char *zName = p->zName;

  assert( db!=0 && zName!=0 );
  pOld = sqlite3HashInsert(&p->pSchema->idxHash, zName, strlen( zName)+1, 0);

  assert( pOld==0 || pOld==p );
  freeIndex(p);
}

/*
** For the index called zIdxName which is found in the database iDb,
** unlike that index from its Table then remove the index from
** the index hash table and free all memory structures associated
** with the index.
*/
void sqlite3UnlinkAndDeleteIndex(sqlite3 *db, int iDb, const char *zIdxName){
  Index *pIndex;
  int len;
  Hash *pHash = &db->aDb[iDb].pSchema->idxHash;

  len = strlen(zIdxName);
  pIndex = sqlite3HashInsert(pHash, zIdxName, len+1, 0);
  if( pIndex ){
    if( pIndex->pTable->pIndex==pIndex ){
      pIndex->pTable->pIndex = pIndex->pNext;
    }else{
      Index *p;
      for(p=pIndex->pTable->pIndex; p && p->pNext!=pIndex; p=p->pNext){}
      if( p && p->pNext==pIndex ){

  Hash temp2;
  int i, j;

  assert( iDb>=0 && iDb<db->nDb );
  db->flags &= ~SQLITE_Initialized;
  for(i=iDb; i<db->nDb; i++){
    Db *pDb = &db->aDb[i];
    if( pDb->pSchema ){
      temp1 = pDb->pSchema->tblHash;
      temp2 = pDb->pSchema->trigHash;
      sqlite3HashInit(&pDb->pSchema->trigHash, SQLITE_HASH_STRING, 0);
      sqlite3HashClear(&pDb->pSchema->aFKey);
      sqlite3HashClear(&pDb->pSchema->idxHash);
      for(pElem=sqliteHashFirst(&temp2); pElem; pElem=sqliteHashNext(pElem)){
        sqlite3DeleteTrigger((Trigger*)sqliteHashData(pElem));
      }
      sqlite3HashClear(&temp2);
      sqlite3HashInit(&pDb->pSchema->tblHash, SQLITE_HASH_STRING, 0);
      for(pElem=sqliteHashFirst(&temp1); pElem; pElem=sqliteHashNext(pElem)){
        Table *pTab = sqliteHashData(pElem);
        sqlite3DeleteTable(db, pTab);
      }
      sqlite3HashClear(&temp1);
      pDb->pSchema->pSeqTab = 0;
      DbClearProperty(db, i, DB_SchemaLoaded);
    }
    if( iDb>0 ) return;
  }
  assert( iDb==0 );
  db->flags &= ~SQLITE_InternChanges;

  /* If one or more of the auxiliary database files has been closed,
  ** then remove then from the auxiliary database list.  We take the

  }
  assert( pTable->nRef==0 );

  /* Delete all indices associated with this table
  */
  for(pIndex = pTable->pIndex; pIndex; pIndex=pNext){
    pNext = pIndex->pNext;
    assert( pIndex->pSchema==pTable->pSchema );
    sqliteDeleteIndex(db, pIndex);
  }

#ifndef SQLITE_OMIT_FOREIGN_KEY
  /* Delete all foreign keys associated with this table.  The keys
  ** should have already been unlinked from the db->aFKey hash table 
  */
  for(pFKey=pTable->pFKey; pFKey; pFKey=pNextFKey){
    pNextFKey = pFKey->pNextFrom;
    assert( sqlite3SchemaToIndex(db, pTable->pSchema)<db->nDb );
    assert( sqlite3HashFind(&pTable->pSchema->aFKey,
                           pFKey->zTo, strlen(pFKey->zTo)+1)!=pFKey );
    sqliteFree(pFKey);
  }
#endif

  /* Delete the Table structure itself.
  */

  FKey *pF1, *pF2;
  Db *pDb;

  assert( db!=0 );
  assert( iDb>=0 && iDb<db->nDb );
  assert( zTabName && zTabName[0] );
  pDb = &db->aDb[iDb];
  p = sqlite3HashInsert(&pDb->pSchema->tblHash, zTabName, strlen(zTabName)+1,0);
  if( p ){
#ifndef SQLITE_OMIT_FOREIGN_KEY
    for(pF1=p->pFKey; pF1; pF1=pF1->pNextFrom){
      int nTo = strlen(pF1->zTo) + 1;
      pF2 = sqlite3HashFind(&pDb->pSchema->aFKey, pF1->zTo, nTo);
      if( pF2==pF1 ){
        sqlite3HashInsert(&pDb->pSchema->aFKey, pF1->zTo, nTo, pF1->pNextTo);
      }else{
        while( pF2 && pF2->pNextTo!=pF1 ){ pF2=pF2->pNextTo; }
        if( pF2 ){
          pF2->pNextTo = pF1->pNextTo;
        }
      }
    }

    goto begin_table_error;
  }
  pTable->zName = zName;
  pTable->nCol = 0;
  pTable->aCol = 0;
  pTable->iPKey = -1;
  pTable->pIndex = 0;
  pTable->pSchema = db->aDb[iDb].pSchema;
  pTable->nRef = 1;
  if( pParse->pNewTable ) sqlite3DeleteTable(db, pParse->pNewTable);
  pParse->pNewTable = pTable;

  /* If this is the magic sqlite_sequence table used by autoincrement,
  ** then record a pointer to this table in the main database structure
  ** so that INSERT can find the table easily.
  */
#ifndef SQLITE_OMIT_AUTOINCREMENT
  if( !pParse->nested && strcmp(zName, "sqlite_sequence")==0 ){
    pTable->pSchema->pSeqTab = pTable;
  }
#endif

  /* Begin generating the code that will insert the table record into
  ** the SQLITE_MASTER table.  Note in particular that we must go ahead
  ** and allocate the record number for the table entry now.  Before any
  ** PRIMARY KEY or UNIQUE keywords are parsed.  Those keywords will cause

** This plan is not completely bullet-proof.  It is possible for
** the schema to change multiple times and for the cookie to be
** set back to prior value.  But schema changes are infrequent
** and the probability of hitting the same cookie value is only
** 1 chance in 2^32.  So we're safe enough.
*/
void sqlite3ChangeCookie(sqlite3 *db, Vdbe *v, int iDb){
  sqlite3VdbeAddOp(v, OP_Integer, db->aDb[iDb].pSchema->schema_cookie+1, 0);
  sqlite3VdbeAddOp(v, OP_SetCookie, iDb, 0);
}

/*
** Measure the number of characters needed to output the given
** identifier.  The number returned includes any quotes used
** but does not include the null terminator.

}

/*
** Generate a CREATE TABLE statement appropriate for the given
** table.  Memory to hold the text of the statement is obtained
** from sqliteMalloc() and must be freed by the calling function.
*/
static char *createTableStmt(Table *p, int isTemp){
  int i, k, n;
  char *zStmt;
  char *zSep, *zSep2, *zEnd, *z;
  Column *pCol;
  n = 0;
  for(pCol = p->aCol, i=0; i<p->nCol; i++, pCol++){
    n += identLength(pCol->zName);

    zSep = "\n  ";
    zSep2 = ",\n  ";
    zEnd = "\n)";
  }
  n += 35 + 6*p->nCol;
  zStmt = sqliteMallocRaw( n );
  if( zStmt==0 ) return 0;
  strcpy(zStmt, !OMIT_TEMPDB&&isTemp ? "CREATE TEMP TABLE ":"CREATE TABLE ");
  k = strlen(zStmt);
  identPut(zStmt, &k, p->zName);
  zStmt[k++] = '(';
  for(pCol=p->aCol, i=0; i<p->nCol; i++, pCol++){
    strcpy(&zStmt[k], zSep);
    k += strlen(&zStmt[k]);
    zSep = zSep2;

  Parse *pParse,          /* Parse context */
  Token *pCons,           /* The ',' token after the last column defn. */
  Token *pEnd,            /* The final ')' token in the CREATE TABLE */
  Select *pSelect         /* Select from a "CREATE ... AS SELECT" */
){
  Table *p;
  sqlite3 *db = pParse->db;
  int iDb;

  if( (pEnd==0 && pSelect==0) || pParse->nErr || sqlite3Tsd()->mallocFailed ) {
    return;
  }
  p = pParse->pNewTable;
  if( p==0 ) return;

  assert( !db->init.busy || !pSelect );

  iDb = sqlite3SchemaToIndex(pParse->db, p->pSchema);

#ifndef SQLITE_OMIT_CHECK
  /* Resolve names in all CHECK constraint expressions.
  */
  if( p->pCheck ){
    SrcList sSrc;                   /* Fake SrcList for pParse->pNewTable */
    NameContext sNC;                /* Name context for pParse->pNewTable */

    ** Once the SELECT has been coded by sqlite3Select(), it is in a
    ** suitable state to query for the column names and types to be used
    ** by the new table.
    */
    if( pSelect ){
      Table *pSelTab;
      sqlite3VdbeAddOp(v, OP_Dup, 0, 0);
      sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
      sqlite3VdbeAddOp(v, OP_OpenWrite, 1, 0);
      pParse->nTab = 2;
      sqlite3Select(pParse, pSelect, SRT_Table, 1, 0, 0, 0, 0);
      sqlite3VdbeAddOp(v, OP_Close, 1, 0);
      if( pParse->nErr==0 ){
        pSelTab = sqlite3ResultSetOfSelect(pParse, 0, pSelect);
        if( pSelTab==0 ) return;
        assert( p->aCol==0 );
        p->nCol = pSelTab->nCol;
        p->aCol = pSelTab->aCol;
        pSelTab->nCol = 0;
        pSelTab->aCol = 0;
        sqlite3DeleteTable(0, pSelTab);
      }
    }

    /* Compute the complete text of the CREATE statement */
    if( pSelect ){
      zStmt = createTableStmt(p, p->pSchema==pParse->db->aDb[1].pSchema);
    }else{
      n = pEnd->z - pParse->sNameToken.z + 1;
      zStmt = sqlite3MPrintf("CREATE %s %.*s", zType2, n, pParse->sNameToken.z);
    }

    /* A slot for the record has already been allocated in the 
    ** SQLITE_MASTER table.  We just need to update that slot with all
    ** the information we've collected.  The rowid for the preallocated
    ** slot is the 2nd item on the stack.  The top of the stack is the
    ** root page for the new table (or a 0 if this is a view).
    */
    sqlite3NestedParse(pParse,
      "UPDATE %Q.%s "
         "SET type='%s', name=%Q, tbl_name=%Q, rootpage=#0, sql=%Q "
       "WHERE rowid=#1",
      db->aDb[iDb].zName, SCHEMA_TABLE(iDb),
      zType,
      p->zName,
      p->zName,
      zStmt
    );
    sqliteFree(zStmt);
    sqlite3ChangeCookie(db, v, iDb);

#ifndef SQLITE_OMIT_AUTOINCREMENT
    /* Check to see if we need to create an sqlite_sequence table for
    ** keeping track of autoincrement keys.
    */
    if( p->autoInc ){
      Db *pDb = &db->aDb[iDb];
      if( pDb->pSchema->pSeqTab==0 ){
        sqlite3NestedParse(pParse,
          "CREATE TABLE %Q.sqlite_sequence(name,seq)",
          pDb->zName
        );
      }
    }
#endif

    /* Reparse everything to update our internal data structures */
    sqlite3VdbeOp3(v, OP_ParseSchema, iDb, 0,
        sqlite3MPrintf("tbl_name='%q'",p->zName), P3_DYNAMIC);
  }


  /* Add the table to the in-memory representation of the database.
  */
  if( db->init.busy && pParse->nErr==0 ){
    Table *pOld;
    FKey *pFKey; 
    DbSchema *pSchema = p->pSchema;
    pOld = sqlite3HashInsert(&pSchema->tblHash, p->zName, strlen(p->zName)+1,p);
    if( pOld ){
      assert( p==pOld );  /* Malloc must have failed inside HashInsert() */
      return;
    }
#ifndef SQLITE_OMIT_FOREIGN_KEY
    for(pFKey=p->pFKey; pFKey; pFKey=pFKey->pNextFrom){
      int nTo = strlen(pFKey->zTo) + 1;
      pFKey->pNextTo = sqlite3HashFind(&pSchema->aFKey, pFKey->zTo, nTo);
      sqlite3HashInsert(&pSchema->aFKey, pFKey->zTo, nTo, pFKey);
    }
#endif
    pParse->pNewTable = 0;
    db->nTable++;
    db->flags |= SQLITE_InternChanges;

#ifndef SQLITE_OMIT_ALTERTABLE

){
  Table *p;
  int n;
  const unsigned char *z;
  Token sEnd;
  DbFixer sFix;
  Token *pName;
  int iDb;

  if( pParse->nVar>0 ){
    sqlite3ErrorMsg(pParse, "parameters are not allowed in views");
    sqlite3SelectDelete(pSelect);
    return;
  }
  sqlite3StartTable(pParse, pBegin, pName1, pName2, isTemp, 1, 0);
  p = pParse->pNewTable;
  if( p==0 || pParse->nErr ){
    sqlite3SelectDelete(pSelect);
    return;
  }
  sqlite3TwoPartName(pParse, pName1, pName2, &pName);
  iDb = sqlite3SchemaToIndex(pParse->db, p->pSchema);
  if( sqlite3FixInit(&sFix, pParse, iDb, "view", pName)
    && sqlite3FixSelect(&sFix, pSelect)
  ){
    sqlite3SelectDelete(pSelect);
    return;
  }

  /* Make a copy of the entire SELECT statement that defines the view.

    if( pSelTab ){
      assert( pTable->aCol==0 );
      pTable->nCol = pSelTab->nCol;
      pTable->aCol = pSelTab->aCol;
      pSelTab->nCol = 0;
      pSelTab->aCol = 0;
      sqlite3DeleteTable(0, pSelTab);
      pTable->pSchema->flags |= DB_UnresetViews;
    }else{
      pTable->nCol = 0;
      nErr++;
    }
    sqlite3SelectDelete(pSel);
  } else {
    nErr++;
  }
  return nErr;  
}
#endif /* SQLITE_OMIT_VIEW */

#ifndef SQLITE_OMIT_VIEW
/*
** Clear the column names from every VIEW in database idx.
*/
static void sqliteViewResetAll(sqlite3 *db, int idx){
  HashElem *i;
  if( !DbHasProperty(db, idx, DB_UnresetViews) ) return;
  for(i=sqliteHashFirst(&db->aDb[idx].pSchema->tblHash); i;i=sqliteHashNext(i)){
    Table *pTab = sqliteHashData(i);
    if( pTab->pSelect ){
      sqliteResetColumnNames(pTab);
    }
  }
  DbClearProperty(db, idx, DB_UnresetViews);
}
#else
# define sqliteViewResetAll(A,B)
#endif /* SQLITE_OMIT_VIEW */

/*
** This function is called by the VDBE to adjust the internal schema
** used by SQLite when the btree layer moves a table root page. The
** root-page of a table or index in database iDb has changed from iFrom
** to iTo.
*/
#ifndef SQLITE_OMIT_AUTOVACUUM
void sqlite3RootPageMoved(Db *pDb, int iFrom, int iTo){
  HashElem *pElem;
  Hash *pHash;

  pHash = &pDb->pSchema->tblHash;
  for(pElem=sqliteHashFirst(pHash); pElem; pElem=sqliteHashNext(pElem)){
    Table *pTab = sqliteHashData(pElem);
    if( pTab->tnum==iFrom ){
      pTab->tnum = iTo;
      return;
    }
  }
  pHash = &pDb->pSchema->idxHash;
  for(pElem=sqliteHashFirst(pHash); pElem; pElem=sqliteHashNext(pElem)){
    Index *pIdx = sqliteHashData(pElem);
    if( pIdx->tnum==iFrom ){
      pIdx->tnum = iTo;
      return;
    }
  }
  assert(0);

    int iLargest = 0;

    if( iDestroyed==0 || iTab<iDestroyed ){
      iLargest = iTab;
    }
    for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
      int iIdx = pIdx->tnum;
      assert( pIdx->pSchema==pTab->pSchema );
      if( (iDestroyed==0 || (iIdx<iDestroyed)) && iIdx>iLargest ){
        iLargest = iIdx;
      }
    }
    if( iLargest==0 ){
      return;
    }else{
      int iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
      destroyRootPage(pParse, iLargest, iDb);
      iDestroyed = iLargest;
    }
  }
#endif
}

/*
** This routine is called to do the work of a DROP TABLE statement.
** pName is the name of the table to be dropped.

  if( pTab==0 ){
    if( noErr ){
      sqlite3ErrorClear(pParse);
    }
    goto exit_drop_table;
  }
  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
  assert( iDb>=0 && iDb<db->nDb );
#ifndef SQLITE_OMIT_AUTHORIZATION
  {
    int code;
    const char *zTab = SCHEMA_TABLE(iDb);
    const char *zDb = db->aDb[iDb].zName;
    if( sqlite3AuthCheck(pParse, SQLITE_DELETE, zTab, 0, zDb)){
      goto exit_drop_table;
    }
    if( isView ){
      if( !OMIT_TEMPDB && iDb==1 ){
        code = SQLITE_DROP_TEMP_VIEW;
      }else{

      goto exit_drop_table;
    }
    if( sqlite3AuthCheck(pParse, SQLITE_DELETE, pTab->zName, 0, zDb) ){
      goto exit_drop_table;
    }
  }
#endif
  if( pTab->readOnly || pTab==db->aDb[iDb].pSchema->pSeqTab ){
    sqlite3ErrorMsg(pParse, "table %s may not be dropped", pTab->zName);
    goto exit_drop_table;
  }

#ifndef SQLITE_OMIT_VIEW
  /* Ensure DROP TABLE is not used on a view, and DROP VIEW is not used
  ** on a table.

  /* Generate code to remove the table from the master table
  ** on disk.
  */
  v = sqlite3GetVdbe(pParse);
  if( v ){
    Trigger *pTrigger;

    Db *pDb = &db->aDb[iDb];
    sqlite3BeginWriteOperation(pParse, 0, iDb);

    /* Drop all triggers associated with the table being dropped. Code
    ** is generated to remove entries from sqlite_master and/or
    ** sqlite_temp_master if required.
    */
    pTrigger = pTab->pTrigger;
    while( pTrigger ){
      assert( pTrigger->pSchema==pTab->pSchema || 
          pTrigger->pSchema==db->aDb[1].pSchema );
      sqlite3DropTriggerPtr(pParse, pTrigger, 1);
      pTrigger = pTrigger->pNext;
    }

#ifndef SQLITE_OMIT_AUTOINCREMENT
    /* Remove any entries of the sqlite_sequence table associated with
    ** the table being dropped. This is done before the table is dropped

static void sqlite3RefillIndex(Parse *pParse, Index *pIndex, int memRootPage){
  Table *pTab = pIndex->pTable;  /* The table that is indexed */
  int iTab = pParse->nTab;       /* Btree cursor used for pTab */
  int iIdx = pParse->nTab+1;     /* Btree cursor used for pIndex */
  int addr1;                     /* Address of top of loop */
  int tnum;                      /* Root page of index */
  Vdbe *v;                       /* Generate code into this virtual machine */
  int iDb = sqlite3SchemaToIndex(pParse->db, pIndex->pSchema);

#ifndef SQLITE_OMIT_AUTHORIZATION
  if( sqlite3AuthCheck(pParse, SQLITE_REINDEX, pIndex->zName, 0,
      pParse->db->aDb[iDb].zName ) ){
    return;
  }
#endif

  /* Ensure all the required collation sequences are available. This
  ** routine will invoke the collation-needed callback if necessary (and
  ** if one has been registered).
  */
  if( sqlite3CheckIndexCollSeq(pParse, pIndex) ){
    return;
  }

  v = sqlite3GetVdbe(pParse);
  if( v==0 ) return;
  if( memRootPage>=0 ){
    sqlite3VdbeAddOp(v, OP_MemLoad, memRootPage, 0);
    tnum = 0;
  }else{
    tnum = pIndex->tnum;
    sqlite3VdbeAddOp(v, OP_Clear, tnum, iDb);
  }
  sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
  sqlite3VdbeOp3(v, OP_OpenWrite, iIdx, tnum,
                    (char*)&pIndex->keyInfo, P3_KEYINFO);
  sqlite3OpenTableForReading(v, iTab, iDb, pTab);
  addr1 = sqlite3VdbeAddOp(v, OP_Rewind, iTab, 0);
  sqlite3GenerateIndexKey(v, pIndex, iTab);
  if( pIndex->onError!=OE_None ){
    int curaddr = sqlite3VdbeCurrentAddr(v);
    int addr2 = curaddr+4;
    sqlite3VdbeChangeP2(v, curaddr-1, addr2);
    sqlite3VdbeAddOp(v, OP_Rowid, iTab, 0);

    if( iDb<0 ) goto exit_create_index;

#ifndef SQLITE_OMIT_TEMPDB
    /* If the index name was unqualified, check if the the table
    ** is a temp table. If so, set the database to 1.
    */
    pTab = sqlite3SrcListLookup(pParse, pTblName);
    if( pName2 && pName2->n==0 && pTab && pTab->pSchema==db->aDb[1].pSchema ){
      iDb = 1;
    }
#endif

    if( sqlite3FixInit(&sFix, pParse, iDb, "index", pName) &&
        sqlite3FixSrcList(&sFix, pTblName)
    ){
      /* Because the parser constructs pTblName from a single identifier,
      ** sqlite3FixSrcList can never fail. */
      assert(0);
    }
    pTab = sqlite3LocateTable(pParse, pTblName->a[0].zName, 
        pTblName->a[0].zDatabase);
    if( !pTab ) goto exit_create_index;
    assert( db->aDb[iDb].pSchema==pTab->pSchema );
  }else{
    assert( pName==0 );
    pTab = pParse->pNewTable;
    if( !pTab ) goto exit_create_index;
    iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
  }
  pDb = &db->aDb[iDb];

  if( pTab==0 || pParse->nErr ) goto exit_create_index;
  if( pTab->readOnly ){
    sqlite3ErrorMsg(pParse, "table %s may not be indexed", pTab->zName);
    goto exit_create_index;

  pIndex->zName = (char*)&pIndex->aiRowEst[pList->nExpr+1];
  pIndex->keyInfo.aSortOrder = &pIndex->zName[nName+1];
  strcpy(pIndex->zName, zName);
  pIndex->pTable = pTab;
  pIndex->nColumn = pList->nExpr;
  pIndex->onError = onError;
  pIndex->autoIndex = pName==0;
  pIndex->pSchema = db->aDb[iDb].pSchema;

  /* Check to see if we should honor DESC requests on index columns
  */
  if( pDb->pSchema->file_format>=4 ){
    sortOrderMask = -1;   /* Honor DESC */
  }else{
    sortOrderMask = 0;    /* Ignore DESC */
  }

  /* Scan the names of the columns of the table to be indexed and
  ** load the column indices into the Index structure.  Report an error

  }

  /* Link the new Index structure to its table and to the other
  ** in-memory database structures. 
  */
  if( db->init.busy ){
    Index *p;
    p = sqlite3HashInsert(&pIndex->pSchema->idxHash, 
                         pIndex->zName, strlen(pIndex->zName)+1, pIndex);
    if( p ){
      assert( p==pIndex );  /* Malloc must have failed */
      goto exit_create_index;
    }
    db->flags |= SQLITE_InternChanges;
    if( pTblName!=0 ){

** This routine will drop an existing named index.  This routine
** implements the DROP INDEX statement.
*/
void sqlite3DropIndex(Parse *pParse, SrcList *pName, int ifExists){
  Index *pIndex;
  Vdbe *v;
  sqlite3 *db = pParse->db;
  int iDb;

  if( pParse->nErr || sqlite3Tsd()->mallocFailed ){
    goto exit_drop_index;
  }
  assert( pName->nSrc==1 );
  if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
    goto exit_drop_index;

    goto exit_drop_index;
  }
  if( pIndex->autoIndex ){
    sqlite3ErrorMsg(pParse, "index associated with UNIQUE "
      "or PRIMARY KEY constraint cannot be dropped", 0);
    goto exit_drop_index;
  }
  iDb = sqlite3SchemaToIndex(db, pIndex->pSchema);
#ifndef SQLITE_OMIT_AUTHORIZATION
  {
    int code = SQLITE_DROP_INDEX;
    Table *pTab = pIndex->pTable;
    const char *zDb = db->aDb[iDb].zName;
    const char *zTab = SCHEMA_TABLE(iDb);
    if( sqlite3AuthCheck(pParse, SQLITE_DELETE, zTab, 0, zDb) ){
      goto exit_drop_index;
    }
    if( !OMIT_TEMPDB && iDb ) code = SQLITE_DROP_TEMP_INDEX;
    if( sqlite3AuthCheck(pParse, code, pIndex->zName, pTab->zName, zDb) ){
      goto exit_drop_index;
    }
  }
#endif

  /* Generate code to remove the index and from the master table */
  v = sqlite3GetVdbe(pParse);
  if( v ){

    sqlite3NestedParse(pParse,
       "DELETE FROM %Q.%s WHERE name=%Q",
       db->aDb[iDb].zName, SCHEMA_TABLE(iDb),
       pIndex->zName
    );
    sqlite3ChangeCookie(db, v, iDb);
    destroyRootPage(pParse, pIndex->tnum, iDb);

    int rc = sqlite3BtreeFactory(db, 0, 0, MAX_PAGES, &db->aDb[1].pBt);
    if( rc!=SQLITE_OK ){
      sqlite3ErrorMsg(pParse, "unable to open a temporary database "
        "file for storing temporary tables");
      pParse->rc = rc;
      return 1;
    }
/*
    db->aDb[1].pSchema = sqlite3SchemaGet(db->aDb[1].pBt);
    if( !db->aDb[1].pSchema ){
      return SQLITE_NOMEM;
    }
*/
    if( db->flags & !db->autoCommit ){
      rc = sqlite3BtreeBeginTrans(db->aDb[1].pBt, 1);
      if( rc!=SQLITE_OK ){
        sqlite3ErrorMsg(pParse, "unable to get a write lock on "
          "the temporary database file");
        pParse->rc = rc;
        return 1;

  if( iDb>=0 ){
    assert( iDb<db->nDb );
    assert( db->aDb[iDb].pBt!=0 || iDb==1 );
    assert( iDb<32 );
    mask = 1<<iDb;
    if( (pParse->cookieMask & mask)==0 ){
      pParse->cookieMask |= mask;
      pParse->cookieValue[iDb] = db->aDb[iDb].pSchema->schema_cookie;
      if( !OMIT_TEMPDB && iDb==1 ){
        sqlite3OpenTempDatabase(pParse);
      }
    }
  }
}

*/
#ifndef SQLITE_OMIT_REINDEX
static void reindexTable(Parse *pParse, Table *pTab, CollSeq *pColl){
  Index *pIndex;              /* An index associated with pTab */

  for(pIndex=pTab->pIndex; pIndex; pIndex=pIndex->pNext){
    if( pColl==0 || collationMatch(pColl,pIndex) ){
      int iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
      sqlite3BeginWriteOperation(pParse, 0, iDb);
      sqlite3RefillIndex(pParse, pIndex, -1);
    }
  }
}
#endif

/*

  int iDb;                    /* The database index number */
  sqlite3 *db = pParse->db;   /* The database connection */
  HashElem *k;                /* For looping over tables in pDb */
  Table *pTab;                /* A table in the database */

  for(iDb=0, pDb=db->aDb; iDb<db->nDb; iDb++, pDb++){
    if( pDb==0 ) continue;
    for(k=sqliteHashFirst(&pDb->pSchema->tblHash);  k; k=sqliteHashNext(k)){
      pTab = (Table*)sqliteHashData(k);
      reindexTable(pParse, pTab, pColl);
    }
  }
}
#endif

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** in order to generate code for DELETE FROM statements.
**
** $Id: delete.c,v 1.114 2006/01/05 11:34:34 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** Look up every table that is named in pSrc.  If any table is not found,
** add an error message to pParse->zErrMsg and return NULL.  If all tables
** are found, return a pointer to the last table.

/*
** Generate code that will open a table for reading.
*/
void sqlite3OpenTableForReading(
  Vdbe *v,        /* Generate code into this VDBE */
  int iCur,       /* The cursor number of the table */
  int iDb,        /* The database index in sqlite3.aDb[] */
  Table *pTab     /* The table to be opened */
){
  sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
  VdbeComment((v, "# %s", pTab->zName));
  sqlite3VdbeAddOp(v, OP_OpenRead, iCur, pTab->tnum);
  sqlite3VdbeAddOp(v, OP_SetNumColumns, iCur, pTab->nCol);
}


/*

  WhereInfo *pWInfo;     /* Information about the WHERE clause */
  Index *pIdx;           /* For looping over indices of the table */
  int iCur;              /* VDBE Cursor number for pTab */
  sqlite3 *db;           /* Main database structure */
  AuthContext sContext;  /* Authorization context */
  int oldIdx = -1;       /* Cursor for the OLD table of AFTER triggers */
  NameContext sNC;       /* Name context to resolve expressions in */
  int iDb;

#ifndef SQLITE_OMIT_TRIGGER
  int isView;                  /* True if attempting to delete from a view */
  int triggers_exist = 0;      /* True if any triggers exist */
#endif

  sContext.pParse = 0;

# undef isView
# define isView 0
#endif

  if( sqlite3IsReadOnly(pParse, pTab, triggers_exist) ){
    goto delete_from_cleanup;
  }
  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
  assert( iDb<db->nDb );
  zDb = db->aDb[iDb].zName;
  if( sqlite3AuthCheck(pParse, SQLITE_DELETE, pTab->zName, 0, zDb) ){
    goto delete_from_cleanup;
  }

  /* If pTab is really a view, make sure it has been initialized.
  */
  if( isView && sqlite3ViewGetColumnNames(pParse, pTab) ){

  /* Begin generating code.
  */
  v = sqlite3GetVdbe(pParse);
  if( v==0 ){
    goto delete_from_cleanup;
  }
  if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
  sqlite3BeginWriteOperation(pParse, triggers_exist, iDb);

  /* If we are trying to delete from a view, realize that view into
  ** a ephemeral table.
  */
  if( isView ){
    Select *pView = sqlite3SelectDup(pTab->pSelect);
    sqlite3Select(pParse, pView, SRT_VirtualTab, iCur, 0, 0, 0, 0);

  if( pWhere==0 && !triggers_exist ){
    if( db->flags & SQLITE_CountRows ){
      /* If counting rows deleted, just count the total number of
      ** entries in the table. */
      int endOfLoop = sqlite3VdbeMakeLabel(v);
      int addr;
      if( !isView ){
        sqlite3OpenTableForReading(v, iCur, iDb, pTab);
      }
      sqlite3VdbeAddOp(v, OP_Rewind, iCur, sqlite3VdbeCurrentAddr(v)+2);
      addr = sqlite3VdbeAddOp(v, OP_AddImm, 1, 0);
      sqlite3VdbeAddOp(v, OP_Next, iCur, addr);
      sqlite3VdbeResolveLabel(v, endOfLoop);
      sqlite3VdbeAddOp(v, OP_Close, iCur, 0);
    }
    if( !isView ){
      sqlite3VdbeAddOp(v, OP_Clear, pTab->tnum, iDb);
      if( !pParse->nested ){
        sqlite3VdbeChangeP3(v, -1, pTab->zName, P3_STATIC);
      }
      for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
        assert( pIdx->pSchema==pTab->pSchema );
        sqlite3VdbeAddOp(v, OP_Clear, pIdx->tnum, iDb);
      }
    }
  }

  /* The usual case: There is a WHERE clause so we have to scan through
  ** the table and pick which records to delete.
  */

    /* This is the beginning of the delete loop when there are
    ** row triggers.
    */
    if( triggers_exist ){
      addr = sqlite3VdbeAddOp(v, OP_FifoRead, 0, end);
      if( !isView ){
        sqlite3VdbeAddOp(v, OP_Dup, 0, 0);
        sqlite3OpenTableForReading(v, iCur, iDb, pTab);
      }
      sqlite3VdbeAddOp(v, OP_MoveGe, iCur, 0);
      sqlite3VdbeAddOp(v, OP_Rowid, iCur, 0);
      sqlite3VdbeAddOp(v, OP_RowData, iCur, 0);
      sqlite3VdbeAddOp(v, OP_Insert, oldIdx, 0);
      if( !isView ){
        sqlite3VdbeAddOp(v, OP_Close, iCur, 0);

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.244 2006/01/05 11:34:34 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Return the 'affinity' of the expression pExpr if any.
**

  while( pNC && cnt==0 ){
    ExprList *pEList;
    SrcList *pSrcList = pNC->pSrcList;

    if( pSrcList ){
      for(i=0, pItem=pSrcList->a; i<pSrcList->nSrc; i++, pItem++){
        Table *pTab = pItem->pTab;
        int iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
        Column *pCol;
  
        if( pTab==0 ) continue;
        assert( pTab->nCol>0 );
        if( zTab ){
          if( pItem->zAlias ){
            char *zTabName = pItem->zAlias;
            if( sqlite3StrICmp(zTabName, zTab)!=0 ) continue;
          }else{
            char *zTabName = pTab->zName;
            if( zTabName==0 || sqlite3StrICmp(zTabName, zTab)!=0 ) continue;
            if( zDb!=0 && sqlite3StrICmp(db->aDb[iDb].zName, zDb)!=0 ){
              continue;
            }
          }
        }
        if( 0==(cntTab++) ){
          pExpr->iTable = pItem->iCursor;
          pExpr->pSchema = pTab->pSchema;
          pMatch = pItem;
        }
        for(j=0, pCol=pTab->aCol; j<pTab->nCol; j++, pCol++){
          if( sqlite3StrICmp(pCol->zName, zCol)==0 ){
            IdList *pUsing;
            cnt++;
            pExpr->iTable = pItem->iCursor;
            pMatch = pItem;
            pExpr->pSchema = pTab->pSchema;
            /* Substitute the rowid (column -1) for the INTEGER PRIMARY KEY */
            pExpr->iColumn = j==pTab->iPKey ? -1 : j;
            pExpr->affinity = pTab->aCol[j].affinity;
            pExpr->pColl = pTab->aCol[j].pColl;
            if( pItem->jointype & JT_NATURAL ){
              /* If this match occurred in the left table of a natural join,
              ** then skip the right table to avoid a duplicate match */

        pTab = pTriggerStack->pTab;
      }

      if( pTab ){ 
        int j;
        Column *pCol = pTab->aCol;

        pExpr->pSchema = pTab->pSchema;
        cntTab++;
        for(j=0; j < pTab->nCol; j++, pCol++) {
          if( sqlite3StrICmp(pCol->zName, zCol)==0 ){
            cnt++;
            pExpr->iColumn = j==pTab->iPKey ? -1 : j;
            pExpr->affinity = pTab->aCol[j].affinity;
            pExpr->pColl = pTab->aCol[j].pColl;

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle INSERT statements in SQLite.
**
** $Id: insert.c,v 1.152 2006/01/05 11:34:34 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** Set P3 of the most recently inserted opcode to a column affinity
** string for index pIdx. A column affinity string has one character
** for each column in the table, according to the affinity of the column:

** Return non-zero if SELECT statement p opens the table with rootpage
** iTab in database iDb.  This is used to see if a statement of the form 
** "INSERT INTO <iDb, iTab> SELECT ..." can run without using temporary
** table for the results of the SELECT. 
**
** No checking is done for sub-selects that are part of expressions.
*/
static int selectReadsTable(Select *p, DbSchema *pSchema, int iTab){
  int i;
  struct SrcList_item *pItem;
  if( p->pSrc==0 ) return 0;
  for(i=0, pItem=p->pSrc->a; i<p->pSrc->nSrc; i++, pItem++){
    if( pItem->pSelect ){
      if( selectReadsTable(pItem->pSelect, pSchema, iTab) ) return 1;
    }else{
      if( pItem->pTab->pSchema==pSchema && pItem->pTab->tnum==iTab ) return 1;
    }
  }
  return 0;
}

/*
** This routine is call to handle SQL of the following forms:

  int iSelectLoop = 0;  /* Address of code that implements the SELECT */
  int iCleanup = 0;     /* Address of the cleanup code */
  int iInsertBlock = 0; /* Address of the subroutine used to insert data */
  int iCntMem = 0;      /* Memory cell used for the row counter */
  int newIdx = -1;      /* Cursor for the NEW table */
  Db *pDb;              /* The database containing table being inserted into */
  int counterMem = 0;   /* Memory cell holding AUTOINCREMENT counter */
  int iDb;

#ifndef SQLITE_OMIT_TRIGGER
  int isView;                 /* True if attempting to insert into a view */
  int triggers_exist = 0;     /* True if there are FOR EACH ROW triggers */
#endif

#ifndef SQLITE_OMIT_AUTOINCREMENT

  assert( pTabList->nSrc==1 );
  zTab = pTabList->a[0].zName;
  if( zTab==0 ) goto insert_cleanup;
  pTab = sqlite3SrcListLookup(pParse, pTabList);
  if( pTab==0 ){
    goto insert_cleanup;
  }
  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
  assert( iDb<db->nDb );
  pDb = &db->aDb[iDb];
  zDb = pDb->zName;
  if( sqlite3AuthCheck(pParse, SQLITE_INSERT, pTab->zName, 0, zDb) ){
    goto insert_cleanup;
  }

  /* Figure out if we have any triggers and if the table being
  ** inserted into is a view

  }

  /* Allocate a VDBE
  */
  v = sqlite3GetVdbe(pParse);
  if( v==0 ) goto insert_cleanup;
  if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
  sqlite3BeginWriteOperation(pParse, pSelect || triggers_exist, iDb);

  /* if there are row triggers, allocate a temp table for new.* references. */
  if( triggers_exist ){
    newIdx = pParse->nTab++;
  }

#ifndef SQLITE_OMIT_AUTOINCREMENT
  /* If this is an AUTOINCREMENT table, look up the sequence number in the
  ** sqlite_sequence table and store it in memory cell counterMem.  Also
  ** remember the rowid of the sqlite_sequence table entry in memory cell
  ** counterRowid.
  */
  if( pTab->autoInc ){
    int iCur = pParse->nTab;
    int base = sqlite3VdbeCurrentAddr(v);
    counterRowid = pParse->nMem++;
    counterMem = pParse->nMem++;
    sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
    sqlite3VdbeAddOp(v, OP_OpenRead, iCur, pDb->pSchema->pSeqTab->tnum);
    sqlite3VdbeAddOp(v, OP_SetNumColumns, iCur, 2);
    sqlite3VdbeAddOp(v, OP_Rewind, iCur, base+13);
    sqlite3VdbeAddOp(v, OP_Column, iCur, 0);
    sqlite3VdbeOp3(v, OP_String8, 0, 0, pTab->zName, 0);
    sqlite3VdbeAddOp(v, OP_Ne, 0x100, base+12);
    sqlite3VdbeAddOp(v, OP_Rowid, iCur, 0);
    sqlite3VdbeAddOp(v, OP_MemStore, counterRowid, 1);

    ** should be written into a temporary table.  Set to FALSE if each
    ** row of the SELECT can be written directly into the result table.
    **
    ** A temp table must be used if the table being updated is also one
    ** of the tables being read by the SELECT statement.  Also use a 
    ** temp table in the case of row triggers.
    */
    if( triggers_exist || selectReadsTable(pSelect,pTab->pSchema,pTab->tnum) ){
      useTempTable = 1;
    }

    if( useTempTable ){
      /* Generate the subroutine that SELECT calls to process each row of
      ** the result.  Store the result in a temporary table
      */

  /* Update the sqlite_sequence table by storing the content of the
  ** counter value in memory counterMem back into the sqlite_sequence
  ** table.
  */
  if( pTab->autoInc ){
    int iCur = pParse->nTab;
    int base = sqlite3VdbeCurrentAddr(v);
    sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
    sqlite3VdbeAddOp(v, OP_OpenWrite, iCur, pDb->pSchema->pSeqTab->tnum);
    sqlite3VdbeAddOp(v, OP_SetNumColumns, iCur, 2);
    sqlite3VdbeAddOp(v, OP_MemLoad, counterRowid, 0);
    sqlite3VdbeAddOp(v, OP_NotNull, -1, base+7);
    sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
    sqlite3VdbeAddOp(v, OP_NewRowid, iCur, 0);
    sqlite3VdbeOp3(v, OP_String8, 0, 0, pTab->zName, 0);
    sqlite3VdbeAddOp(v, OP_MemLoad, counterMem, 0);

void sqlite3OpenTableAndIndices(
  Parse *pParse,   /* Parsing context */
  Table *pTab,     /* Table to be opened */
  int base,        /* Cursor number assigned to the table */
  int op           /* OP_OpenRead or OP_OpenWrite */
){
  int i;
  int iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
  Index *pIdx;
  Vdbe *v = sqlite3GetVdbe(pParse);
  assert( v!=0 );
  sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
  VdbeComment((v, "# %s", pTab->zName));
  sqlite3VdbeAddOp(v, op, base, pTab->tnum);
  sqlite3VdbeAddOp(v, OP_SetNumColumns, base, pTab->nCol);
  for(i=1, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
    assert( pIdx->pSchema==pTab->pSchema );
    sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
    VdbeComment((v, "# %s", pIdx->zName));
    sqlite3VdbeOp3(v, op, i+base, pIdx->tnum,
                   (char*)&pIdx->keyInfo, P3_KEYINFO);
  }
  if( pParse->nTab<=base+i ){
    pParse->nTab = base+i;
  }
}

**
*************************************************************************
** Main file for the SQLite library.  The routines in this file
** implement the programmer interface to the library.  Routines in
** other files are for internal use by SQLite and should not be
** accessed by users of the library.
**
** $Id: main.c,v 1.314 2006/01/05 11:34:34 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

/*
** The following constant value is used by the SQLITE_BIGENDIAN and

/*
** Return the number of changes since the database handle was opened.
*/
int sqlite3_total_changes(sqlite3 *db){
  return db->nTotalChange;
}

/*
** Free a schema structure.
*/
void sqlite3SchemaFree(void *p){
  sqliteFree(p);
}

DbSchema *sqlite3SchemaGet(Btree *pBt){
  DbSchema * p;
  if( pBt ){
    p = (DbSchema *)sqlite3BtreeSchema(pBt,sizeof(DbSchema),sqlite3SchemaFree);
  }else{
    p = (DbSchema *)sqliteMalloc(sizeof(DbSchema));
  }
  if( p ){
    sqlite3HashInit(&p->tblHash, SQLITE_HASH_STRING, 0);
    sqlite3HashInit(&p->idxHash, SQLITE_HASH_STRING, 0);
    sqlite3HashInit(&p->trigHash, SQLITE_HASH_STRING, 0);
    sqlite3HashInit(&p->aFKey, SQLITE_HASH_STRING, 1);
  }
  return p;
}

int sqlite3SchemaToIndex(sqlite3 *db, DbSchema *pSchema){
  int i = -1000000;

  /* If pSchema is NULL, then return -1000000. This happens when code in 
  ** expr.c is trying to resolve a reference to a transient table (i.e. one
  ** created by a sub-select). In this case the return value of this 
  ** function should never be used.
  **
  ** We return -1000000 instead of the more usual -1 simply because using
  ** -1000000 as incorrectly using -1000000 index into db->aDb[] is much 
  ** more likely to cause a segfault than -1 (of course there are assert()
  ** statements too, but it never hurts to play the odds).
  */
  if( pSchema ){
    for(i=0; i<db->nDb; i++){
      if( db->aDb[i].pSchema==pSchema ){
        break;
      }
    }
    assert( i>=0 &&i>=0 &&  i<db->nDb );
  }
  return i;
}

/*
** Close an existing SQLite database
*/
int sqlite3_close(sqlite3 *db){
  HashElem *i;
  int j;

    }
    sqlite3Os.xLeaveMutex();
  }
#endif
#endif

  db->magic = SQLITE_MAGIC_ERROR;
  sqliteFree(db->aDb[1].pSchema);
  sqliteFree(db);
  sqlite3MallocAllow();
  return SQLITE_OK;
}

/*
** Rollback all database files.

#endif
#if TEMP_STORE==3
    zFilename = ":memory:";
#endif
#endif /* SQLITE_OMIT_MEMORYDB */
  }

  rc = sqlite3BtreeOpen(zFilename, (sqlite3 *)db, ppBtree, btree_flags);
  if( rc==SQLITE_OK ){
    sqlite3BtreeSetBusyHandler(*ppBtree, (void*)&db->busyHandler);
    sqlite3BtreeSetCacheSize(*ppBtree, nCache);
  }
  return rc;
}

** is UTF-8 encoded.
*/
static int openDatabase(
  const char *zFilename, /* Database filename UTF-8 encoded */
  sqlite3 **ppDb         /* OUT: Returned database handle */
){
  sqlite3 *db;
  int rc;
  CollSeq *pColl;

  assert( !sqlite3Tsd()->mallocFailed );

  /* Allocate the sqlite data structure */
  db = sqliteMalloc( sizeof(sqlite3) );
  if( db==0 ) goto opendb_out;
  db->priorNewRowid = 0;
  db->magic = SQLITE_MAGIC_BUSY;
  db->nDb = 2;
  db->aDb = db->aDbStatic;
  db->enc = SQLITE_UTF8;
  db->autoCommit = 1;
  db->flags |= SQLITE_ShortColNames;
  sqlite3HashInit(&db->aFunc, SQLITE_HASH_STRING, 0);
  sqlite3HashInit(&db->aCollSeq, SQLITE_HASH_STRING, 0);

#if 0
  for(i=0; i<db->nDb; i++){
    sqlite3HashInit(&db->aDb[i].tblHash, SQLITE_HASH_STRING, 0);
    sqlite3HashInit(&db->aDb[i].idxHash, SQLITE_HASH_STRING, 0);
    sqlite3HashInit(&db->aDb[i].trigHash, SQLITE_HASH_STRING, 0);
    sqlite3HashInit(&db->aDb[i].aFKey, SQLITE_HASH_STRING, 1);
  }
#endif
  
  /* Add the default collation sequence BINARY. BINARY works for both UTF-8
  ** and UTF-16, so add a version for each to avoid any unnecessary
  ** conversions. The only error that can occur here is a malloc() failure.
  */
  if( sqlite3_create_collation(db, "BINARY", SQLITE_UTF8, 0,binCollFunc) ||
      sqlite3_create_collation(db, "BINARY", SQLITE_UTF16, 0,binCollFunc) ||

  /* Open the backend database driver */
  rc = sqlite3BtreeFactory(db, zFilename, 0, MAX_PAGES, &db->aDb[0].pBt);
  if( rc!=SQLITE_OK ){
    sqlite3Error(db, rc, 0);
    db->magic = SQLITE_MAGIC_CLOSED;
    goto opendb_out;
  }
  db->aDb[0].pSchema = sqlite3SchemaGet(db->aDb[0].pBt);
  db->aDb[1].pSchema = sqlite3SchemaGet(0);

  /* The default safety_level for the main database is 'full'; for the temp
  ** database it is 'NONE'. This matches the pager layer defaults.  
  */
  db->aDb[0].zName = "main";
  db->aDb[0].safety_level = 3;
#ifndef SQLITE_OMIT_TEMPDB
  db->aDb[1].zName = "temp";
  db->aDb[1].safety_level = 1;
#endif


  /* Register all built-in functions, but do not attempt to read the
  ** database schema yet. This is delayed until the first time the database
  ** is accessed.
  */
  sqlite3RegisterBuiltinFunctions(db);
  sqlite3Error(db, SQLITE_OK, 0);

/*
** 2003 April 6
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains code used to implement the PRAGMA command.
**
** $Id: pragma.c,v 1.108 2006/01/05 11:34:34 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

/* Ignore this whole file if pragmas are disabled
*/

    { "empty_result_callbacks",   SQLITE_NullCallback  },
#ifndef SQLITE_OMIT_CHECK
    { "ignore_check_constraints", SQLITE_IgnoreChecks  },
#endif
    /* The following is VERY experimental */
    { "writable_schema",          SQLITE_WriteSchema   },
    { "omit_readlock",            SQLITE_NoReadlock    },

    /* TODO: Maybe it shouldn't be possible to change the ReadUncommitted
    ** flag if there are any active statements. */
    { "read_uncommitted",         SQLITE_ReadUncommitted },
  };
  int i;
  const struct sPragmaType *p;
  for(i=0, p=aPragma; i<sizeof(aPragma)/sizeof(aPragma[0]); i++, p++){
    if( sqlite3StrICmp(zLeft, p->zName)==0 ){
      sqlite3 *db = pParse->db;
      Vdbe *v;

    sqlite3VdbeSetNumCols(v, 1);
    sqlite3VdbeSetColName(v, 0, "integrity_check", P3_STATIC);
    sqlite3VdbeAddOp(v, OP_MemInt, 0, 0);  /* Initialize error count to 0 */

    /* Do an integrity check on each database file */
    for(i=0; i<db->nDb; i++){
      HashElem *x;
      Hash *pTbls;
      int cnt = 0;

      if( OMIT_TEMPDB && i==1 ) continue;

      sqlite3CodeVerifySchema(pParse, i);

      /* Do an integrity check of the B-Tree
      */
      pTbls = &db->aDb[i].pSchema->tblHash;
      for(x=sqliteHashFirst(pTbls); x; x=sqliteHashNext(x)){
        Table *pTab = sqliteHashData(x);
        Index *pIdx;
        sqlite3VdbeAddOp(v, OP_Integer, pTab->tnum, 0);
        cnt++;
        for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
          if( sqlite3CheckIndexCollSeq(pParse, pIdx) ) goto pragma_out;
          sqlite3VdbeAddOp(v, OP_Integer, pIdx->tnum, 0);

      sqlite3VdbeAddOp(v, OP_Concat, 0, 1);
      sqlite3VdbeAddOp(v, OP_Callback, 1, 0);
      sqlite3VdbeAddOp(v, OP_MemIncr, 0, 0);

      /* Make sure all the indices are constructed correctly.
      */
      sqlite3CodeVerifySchema(pParse, i);
      for(x=sqliteHashFirst(pTbls); x; x=sqliteHashNext(x)){
        Table *pTab = sqliteHashData(x);
        Index *pIdx;
        int loopTop;

        if( pTab->pIndex==0 ) continue;
        sqlite3OpenTableAndIndices(pParse, pTab, 1, OP_OpenRead);
        sqlite3VdbeAddOp(v, OP_MemInt, 0, 1);

**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains the implementation of the sqlite3_prepare()
** interface, and routines that contribute to loading the database schema
** from disk.
**
** $Id: prepare.c,v 1.13 2006/01/05 11:34:34 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

/*
** Fill the InitData structure with an error message that indicates

**               for auxiliary database files.
**
*/
int sqlite3InitCallback(void *pInit, int argc, char **argv, char **azColName){
  InitData *pData = (InitData*)pInit;
  sqlite3 *db = pData->db;
  int iDb;

  if( sqlite3Tsd()->mallocFailed ){
    return SQLITE_NOMEM;
  }

  assert( argc==4 );
  if( argv==0 ) return 0;   /* Might happen if EMPTY_RESULT_CALLBACKS are on */
  if( argv[1]==0 || argv[3]==0 ){
    corruptSchema(pData, 0);
    return 1;
  }

     ")"
  ;
#else
  #define temp_master_schema 0
#endif

  assert( iDb>=0 && iDb<db->nDb );

  if( 0==db->aDb[iDb].pSchema ){
    DbSchema *pS = sqlite3BtreeSchema(db->aDb[iDb].pBt, sizeof(DbSchema), 
        sqlite3SchemaFree);
    db->aDb[iDb].pSchema = pS;
    if( !pS ){
      return SQLITE_NOMEM;
    }else if( pS->file_format!=0 ){
      return SQLITE_OK;
    }else{
      sqlite3HashInit(&pS->tblHash, SQLITE_HASH_STRING, 0);
      sqlite3HashInit(&pS->idxHash, SQLITE_HASH_STRING, 0);
      sqlite3HashInit(&pS->trigHash, SQLITE_HASH_STRING, 0);
      sqlite3HashInit(&pS->aFKey, SQLITE_HASH_STRING, 1);
    }
  }

  /* zMasterSchema and zInitScript are set to point at the master schema
  ** and initialisation script appropriate for the database being
  ** initialised. zMasterName is the name of the master table.
  */
  if( !OMIT_TEMPDB && iDb==1 ){
    zMasterSchema = temp_master_schema;

      sqlite3SetString(pzErrMsg, sqlite3ErrStr(rc), (char*)0);
      sqlite3BtreeCloseCursor(curMain);
      return rc;
    }
  }else{
    memset(meta, 0, sizeof(meta));
  }
  pDb->pSchema->schema_cookie = meta[0];

  /* If opening a non-empty database, check the text encoding. For the
  ** main database, set sqlite3.enc to the encoding of the main database.
  ** For an attached db, it is an error if the encoding is not the same
  ** as sqlite3.enc.
  */
  if( meta[4] ){  /* text encoding */

  /*
  ** file_format==1    Version 3.0.0.
  ** file_format==2    Version 3.1.3.  // ALTER TABLE ADD COLUMN
  ** file_format==3    Version 3.1.4.  // ditto but with non-NULL defaults
  ** file_format==4    Version 3.3.0.  // DESC indices.  Boolean constants
  */
  pDb->pSchema->file_format = meta[1];
  if( pDb->pSchema->file_format==0 ){
    pDb->pSchema->file_format = 1;
  }
  if( pDb->pSchema->file_format>SQLITE_MAX_FILE_FORMAT ){
    sqlite3BtreeCloseCursor(curMain);
    sqlite3SetString(pzErrMsg, "unsupported file format", (char*)0);
    return SQLITE_ERROR;
  }


  /* Read the schema information out of the schema tables

  for(iDb=0; allOk && iDb<db->nDb; iDb++){
    Btree *pBt;
    pBt = db->aDb[iDb].pBt;
    if( pBt==0 ) continue;
    rc = sqlite3BtreeCursor(pBt, MASTER_ROOT, 0, 0, 0, &curTemp);
    if( rc==SQLITE_OK ){
      rc = sqlite3BtreeGetMeta(pBt, 1, (u32 *)&cookie);
      if( rc==SQLITE_OK && cookie!=db->aDb[iDb].pSchema->schema_cookie ){
        allOk = 0;
      }
      sqlite3BtreeCloseCursor(curTemp);
    }
  }
  return allOk;
}

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
**
** $Id: select.c,v 1.284 2006/01/05 11:34:34 danielk1977 Exp $
*/
#include "sqliteInt.h"


/*
** Allocate a new Select structure and return a pointer to that
** structure.

  int base;
  Vdbe *v;
  int seekOp;
  ExprList *pEList, *pList, eList;
  struct ExprList_item eListItem;
  SrcList *pSrc;
  int brk;
  int iDb;

  /* Check to see if this query is a simple min() or max() query.  Return
  ** zero if it is  not.
  */
  if( p->pGroupBy || p->pHaving || p->pWhere ) return 0;
  pSrc = p->pSrc;
  if( pSrc->nSrc!=1 ) return 0;

  }

  /* Generating code to find the min or the max.  Basically all we have
  ** to do is find the first or the last entry in the chosen index.  If
  ** the min() or max() is on the INTEGER PRIMARY KEY, then find the first
  ** or last entry in the main table.
  */
  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
  sqlite3CodeVerifySchema(pParse, iDb);
  base = pSrc->a[0].iCursor;
  brk = sqlite3VdbeMakeLabel(v);
  computeLimitRegisters(pParse, p, brk);
  if( pSrc->a[0].pSelect==0 ){
    sqlite3OpenTableForReading(v, base, iDb, pTab);
  }
  if( pIdx==0 ){
    sqlite3VdbeAddOp(v, seekOp, base, 0);
  }else{
    /* Even though the cursor used to open the index here is closed
    ** as soon as a single value has been read from it, allocate it
    ** using (pParse->nTab++) to prevent the cursor id from being 
    ** reused. This is important for statements of the form 
    ** "INSERT INTO x SELECT max() FROM x".
    */
    int iIdx;
    iIdx = pParse->nTab++;
    assert( pIdx->pSchema==pTab->pSchema );
    sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
    sqlite3VdbeOp3(v, OP_OpenRead, iIdx, pIdx->tnum,
                   (char*)&pIdx->keyInfo, P3_KEYINFO);
    if( seekOp==OP_Rewind ){
      sqlite3VdbeAddOp(v, OP_Null, 0, 0);
      sqlite3VdbeAddOp(v, OP_MakeRecord, 1, 0);
      seekOp = OP_MoveGt;
    }

/*
** 2001 September 15
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.448 2006/01/05 11:34:34 danielk1977 Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** Many people are failing to set -DNDEBUG=1 when compiling SQLite.
** Setting NDEBUG makes the code smaller and run faster.  So the following

** Forward references to structures
*/
typedef struct AggInfo AggInfo;
typedef struct AuthContext AuthContext;
typedef struct CollSeq CollSeq;
typedef struct Column Column;
typedef struct Db Db;
typedef struct DbSchema DbSchema;
typedef struct Expr Expr;
typedef struct ExprList ExprList;
typedef struct FKey FKey;
typedef struct FuncDef FuncDef;
typedef struct IdList IdList;
typedef struct Index Index;
typedef struct KeyClass KeyClass;

** in the sqlite.aDb[] array.  aDb[0] is the main database file and
** aDb[1] is the database file used to hold temporary tables.  Additional
** databases may be attached.
*/
struct Db {
  char *zName;         /* Name of this database */
  Btree *pBt;          /* The B*Tree structure for this database file */
  u8 inTrans;          /* 0: not writable.  1: Transaction.  2: Checkpoint */
  u8 safety_level;     /* How aggressive at synching data to disk */
  int cache_size;      /* Number of pages to use in the cache */
  void *pAux;               /* Auxiliary data.  Usually NULL */
  void (*xFreeAux)(void*);  /* Routine to free pAux */
  DbSchema *pSchema;   /* Pointer to database schema (possibly shared) */
};

/*
** An instance of the following structure stores a database schema.
*/
struct DbSchema {
  int schema_cookie;   /* Database schema version number for this file */
  Hash tblHash;        /* All tables indexed by name */
  Hash idxHash;        /* All (named) indices indexed by name */
  Hash trigHash;       /* All triggers indexed by name */
  Hash aFKey;          /* Foreign keys indexed by to-table */
  Table *pSeqTab;      /* The sqlite_sequence table used by AUTOINCREMENT */


  u8 file_format;      /* Schema format version for this file */


  u16 flags;           /* Flags associated with this schema */

};

/*
** These macros can be used to test, set, or clear bits in the 
** Db.flags field.
*/
#define DbHasProperty(D,I,P)     (((D)->aDb[I].pSchema->flags&(P))==(P))
#define DbHasAnyProperty(D,I,P)  (((D)->aDb[I].pSchema->flags&(P))!=0)
#define DbSetProperty(D,I,P)     (D)->aDb[I].pSchema->flags|=(P)
#define DbClearProperty(D,I,P)   (D)->aDb[I].pSchema->flags&=~(P)

/*
** Allowed values for the DB.flags field.
**
** The DB_SchemaLoaded flag is set after the database schema has been
** read into internal hash tables.
**

                                          /*   result set is empty */
#define SQLITE_SqlTrace       0x00000200  /* Debug print SQL as it executes */
#define SQLITE_VdbeListing    0x00000400  /* Debug listings of VDBE programs */
#define SQLITE_WriteSchema    0x00000800  /* OK to update SQLITE_MASTER */
#define SQLITE_NoReadlock     0x00001000  /* Readlocks are omitted when 
                                          ** accessing read-only databases */
#define SQLITE_IgnoreChecks   0x00002000  /* Do not enforce check constraints */
#define SQLITE_ReadUncommitted 0x00004000  /* For shared-cache mode */

/*
** Possible values for the sqlite.magic field.
** The numbers are obtained at random and have no special meaning, other
** than being distinct from one another.
*/
#define SQLITE_MAGIC_OPEN     0xa029a697  /* Database is open */

  int nCol;        /* Number of columns in this table */
  Column *aCol;    /* Information about each column */
  int iPKey;       /* If not less then 0, use aCol[iPKey] as the primary key */
  Index *pIndex;   /* List of SQL indexes on this table. */
  int tnum;        /* Root BTree node for this table (see note above) */
  Select *pSelect; /* NULL for tables.  Points to definition if a view. */
  u8 readOnly;     /* True if this table should not be written by the user */
// u8 iDb;          /* Index into sqlite.aDb[] of the backend for this table */
  u8 isTransient;  /* True if automatically deleted when VDBE finishes */
  u8 hasPrimKey;   /* True if there exists a primary key */
  u8 keyConf;      /* What to do in case of uniqueness conflict on iPKey */
  u8 autoInc;      /* True if the integer primary key is autoincrement */
  int nRef;          /* Number of pointers to this Table */
  Trigger *pTrigger; /* List of SQL triggers on this table */
  FKey *pFKey;       /* Linked list of all foreign keys in this table */
  char *zColAff;     /* String defining the affinity of each column */
#ifndef SQLITE_OMIT_CHECK
  Expr *pCheck;      /* The AND of all CHECK constraints */
#endif
#ifndef SQLITE_OMIT_ALTERTABLE
  int addColOffset;  /* Offset in CREATE TABLE statement to add a new column */
#endif
  DbSchema *pSchema;
};

/*
** Each foreign key constraint is an instance of the following structure.
**
** A foreign key is associated with two tables.  The "from" table is
** the table that contains the REFERENCES clause that creates the foreign

  int nColumn;     /* Number of columns in the table used by this index */
  int *aiColumn;   /* Which columns are used by this index.  1st is 0 */
  unsigned *aiRowEst; /* Result of ANALYZE: Est. rows selected by each column */
  Table *pTable;   /* The SQL table being indexed */
  int tnum;        /* Page containing root of this index in database file */
  u8 onError;      /* OE_Abort, OE_Ignore, OE_Replace, or OE_None */
  u8 autoIndex;    /* True if is automatically created (ex: by UNIQUE) */
  // u8 iDb;          /* Index in sqlite.aDb[] of where this index is stored */
  char *zColAff;   /* String defining the affinity of each column */
  Index *pNext;    /* The next index associated with the same table */
  DbSchema *pSchema;
  KeyInfo keyInfo; /* Info on how to order keys.  MUST BE LAST */
};

/*
** Each token coming out of the lexer is an instance of
** this structure.  Tokens are also used as part of an expression.
**

** If the Expr is of type OP_Column, and the table it is selecting from
** is a disk table or the "old.*" pseudo-table, then pTab points to the
** corresponding table definition.
*/
struct Expr {
  u8 op;                 /* Operation performed by this node */
  char affinity;         /* The affinity of the column or 0 if not a column */
//u8 iDb;                /* Database referenced by this expression */
  u8 flags;              /* Various flags.  See below */
  CollSeq *pColl;        /* The collation type of the column or 0 */
  Expr *pLeft, *pRight;  /* Left and right subnodes */
  ExprList *pList;       /* A list of expressions used as function arguments
                         ** or in "<expr> IN (<expr-list)" */
  Token token;           /* An operand token */
  Token span;            /* Complete text of the expression */
  int iTable, iColumn;   /* When op==TK_COLUMN, then this expr node means the
                         ** iColumn-th field of the iTable-th table. */
  AggInfo *pAggInfo;     /* Used by TK_AGG_COLUMN and TK_AGG_FUNCTION */
  int iAgg;              /* Which entry in pAggInfo->aCol[] or ->aFunc[] */
  int iRightJoinTable;   /* If EP_FromJoin, the right table of the join */
  Select *pSelect;       /* When the expression is a sub-select.  Also the
                         ** right side of "<expr> IN (<select>)" */
  Table *pTab;           /* Table for OP_Column expressions. */
  DbSchema *pSchema;
};

/*
** The following are the meanings of bits in the Expr.flags field.
*/
#define EP_FromJoin     0x01  /* Originated in ON or USING clause of a join */
#define EP_Agg          0x02  /* Contains one or more aggregate functions */

 *
 * The "step_list" member points to the first element of a linked list
 * containing the SQL statements specified as the trigger program.
 */
struct Trigger {
  char *name;             /* The name of the trigger                        */
  char *table;            /* The table or view to which the trigger applies */
//u8 iDb;                 /* Database containing this trigger               */
  u8 iTabDb;              /* Database containing Trigger.table              */
  u8 op;                  /* One of TK_DELETE, TK_UPDATE, TK_INSERT         */
  u8 tr_tm;               /* One of TRIGGER_BEFORE, TRIGGER_AFTER */
  Expr *pWhen;            /* The WHEN clause of the expresion (may be NULL) */
  IdList *pColumns;       /* If this is an UPDATE OF <column-list> trigger,
                             the <column-list> is stored here */
  int foreach;            /* One of TK_ROW or TK_STATEMENT */
  Token nameToken;        /* Token containing zName. Use during parsing only */
  DbSchema *pSchema;
  TriggerStep *step_list; /* Link list of trigger program steps             */
  Trigger *pNext;         /* Next trigger associated with the table */
};

/*
** A trigger is either a BEFORE or an AFTER trigger.  The following constants
** determine which. 

int sqlite3Select(Parse*, Select*, int, int, Select*, int, int*, char *aff);
Select *sqlite3SelectNew(ExprList*,SrcList*,Expr*,ExprList*,Expr*,ExprList*,
                        int,Expr*,Expr*);
void sqlite3SelectDelete(Select*);
void sqlite3SelectUnbind(Select*);
Table *sqlite3SrcListLookup(Parse*, SrcList*);
int sqlite3IsReadOnly(Parse*, Table*, int);
void sqlite3OpenTableForReading(Vdbe*, int iCur, int iDb, Table*);
void sqlite3OpenTable(Vdbe*, int iCur, Table*, int);
void sqlite3DeleteFrom(Parse*, SrcList*, Expr*);
void sqlite3Update(Parse*, SrcList*, ExprList*, Expr*, int);
WhereInfo *sqlite3WhereBegin(Parse*, SrcList*, Expr*, ExprList**);
void sqlite3WhereEnd(WhereInfo*);
void sqlite3ExprCode(Parse*, Expr*);
void sqlite3ExprCodeAndCache(Parse*, Expr*);

void sqlite3AnalysisLoad(sqlite3*,int iDB);
void sqlite3DefaultRowEst(Index*);
void sqlite3RegisterLikeFunctions(sqlite3*, int);
int sqlite3IsLikeFunction(sqlite3*,Expr*,int*,char*);
SqliteTsd *sqlite3Tsd();
void sqlite3AttachFunctions(sqlite3 *);
void sqlite3MinimumFileFormat(Parse*, int, int);
void sqlite3SchemaFree(void *);
DbSchema *sqlite3SchemaGet(Btree *);
int sqlite3SchemaToIndex(sqlite3 *db, DbSchema *);

void sqlite3MallocClearFailed();
#ifdef NDEBUG
  #define sqlite3MallocDisallow()
  #define sqlite3MallocAllow()
#else
  void sqlite3MallocDisallow();

  Trigger *pTrigger = 0;
  Table *pTab;
  char *zName = 0;        /* Name of the trigger */
  sqlite3 *db = pParse->db;
  int iDb;                /* The database to store the trigger in */
  Token *pName;           /* The unqualified db name */
  DbFixer sFix;
  int iTabDb;

  if( isTemp ){
    /* If TEMP was specified, then the trigger name may not be qualified. */
    if( pName2 && pName2->n>0 ){
      sqlite3ErrorMsg(pParse, "temporary trigger may not have qualified name");
      goto trigger_cleanup;
    }

  /* If the trigger name was unqualified, and the table is a temp table,
  ** then set iDb to 1 to create the trigger in the temporary database.
  ** If sqlite3SrcListLookup() returns 0, indicating the table does not
  ** exist, the error is caught by the block below.
  */
  if( !pTableName || sqlite3Tsd()->mallocFailed ) goto trigger_cleanup;
  pTab = sqlite3SrcListLookup(pParse, pTableName);
  if( pName2->n==0 && pTab && pTab->pSchema==db->aDb[1].pSchema ){
    iDb = 1;
  }

  /* Ensure the table name matches database name and that the table exists */
  if( sqlite3Tsd()->mallocFailed ) goto trigger_cleanup;
  assert( pTableName->nSrc==1 );
  if( sqlite3FixInit(&sFix, pParse, iDb, "trigger", pName) && 

  /* Check that the trigger name is not reserved and that no trigger of the
  ** specified name exists */
  zName = sqlite3NameFromToken(pName);
  if( !zName || SQLITE_OK!=sqlite3CheckObjectName(pParse, zName) ){
    goto trigger_cleanup;
  }
  if( sqlite3HashFind(&(db->aDb[iDb].pSchema->trigHash), zName,pName->n+1) ){
    sqlite3ErrorMsg(pParse, "trigger %T already exists", pName);
    goto trigger_cleanup;
  }

  /* Do not create a trigger on a system table */
  if( sqlite3StrNICmp(pTab->zName, "sqlite_", 7)==0 ){
    sqlite3ErrorMsg(pParse, "cannot create trigger on system table");

    goto trigger_cleanup;
  }
  if( !pTab->pSelect && tr_tm==TK_INSTEAD ){
    sqlite3ErrorMsg(pParse, "cannot create INSTEAD OF"
        " trigger on table: %S", pTableName, 0);
    goto trigger_cleanup;
  }
  iTabDb = sqlite3SchemaToIndex(db, pTab->pSchema);

#ifndef SQLITE_OMIT_AUTHORIZATION
  {
    int code = SQLITE_CREATE_TRIGGER;
    const char *zDb = db->aDb[iTabDb].zName;
    const char *zDbTrig = isTemp ? db->aDb[1].zName : zDb;
    if( iTabDb==1 || isTemp ) code = SQLITE_CREATE_TEMP_TRIGGER;
    if( sqlite3AuthCheck(pParse, code, zName, pTab->zName, zDbTrig) ){
      goto trigger_cleanup;
    }
    if( sqlite3AuthCheck(pParse, SQLITE_INSERT, SCHEMA_TABLE(iTabDb),0,zDb)){
      goto trigger_cleanup;
    }
  }
#endif

  /* INSTEAD OF triggers can only appear on views and BEFORE triggers
  ** cannot appear on views.  So we might as well translate every
  ** INSTEAD OF trigger into a BEFORE trigger.  It simplifies code
  ** elsewhere.
  */
  if (tr_tm == TK_INSTEAD){
    tr_tm = TK_BEFORE;
  }

  /* Build the Trigger object */
  pTrigger = (Trigger*)sqliteMalloc(sizeof(Trigger));
  if( pTrigger==0 ) goto trigger_cleanup;
  pTrigger->name = zName;
  zName = 0;
  pTrigger->table = sqliteStrDup(pTableName->a[0].zName);
  pTrigger->pSchema = db->aDb[iDb].pSchema;
  pTrigger->iTabDb = iTabDb;
  pTrigger->op = op;
  pTrigger->tr_tm = tr_tm==TK_BEFORE ? TRIGGER_BEFORE : TRIGGER_AFTER;
  pTrigger->pWhen = sqlite3ExprDup(pWhen);
  pTrigger->pColumns = sqlite3IdListDup(pColumns);
  pTrigger->foreach = foreach;
  sqlite3TokenCopy(&pTrigger->nameToken,pName);
  assert( pParse->pNewTrigger==0 );

  Parse *pParse,          /* Parser context */
  TriggerStep *pStepList, /* The triggered program */
  Token *pAll             /* Token that describes the complete CREATE TRIGGER */
){
  Trigger *pTrig = 0;     /* The trigger whose construction is finishing up */
  sqlite3 *db = pParse->db;  /* The database */
  DbFixer sFix;
  int iDb;                   /* Database containing the trigger */

  pTrig = pParse->pNewTrigger;
  pParse->pNewTrigger = 0;
  if( pParse->nErr || !pTrig ) goto triggerfinish_cleanup;
  iDb = sqlite3SchemaToIndex(pParse->db, pTrig->pSchema);
  pTrig->step_list = pStepList;
  while( pStepList ){
    pStepList->pTrig = pTrig;
    pStepList = pStepList->pNext;
  }
  if( sqlite3FixInit(&sFix, pParse, iDb, "trigger", &pTrig->nameToken) 
          && sqlite3FixTriggerStep(&sFix, pTrig->step_list) ){
    goto triggerfinish_cleanup;
  }

  /* if we are not initializing, and this trigger is not on a TEMP table, 
  ** build the sqlite_master entry
  */

    };
    int addr;
    Vdbe *v;

    /* Make an entry in the sqlite_master table */
    v = sqlite3GetVdbe(pParse);
    if( v==0 ) goto triggerfinish_cleanup;
    sqlite3BeginWriteOperation(pParse, 0, iDb);
    sqlite3OpenMasterTable(v, iDb);
    addr = sqlite3VdbeAddOpList(v, ArraySize(insertTrig), insertTrig);
    sqlite3VdbeChangeP3(v, addr+2, pTrig->name, 0); 
    sqlite3VdbeChangeP3(v, addr+3, pTrig->table, 0); 
    sqlite3VdbeChangeP3(v, addr+6, (char*)pAll->z, pAll->n);
    sqlite3ChangeCookie(db, v, iDb);
    sqlite3VdbeAddOp(v, OP_Close, 0, 0);
    sqlite3VdbeOp3(v, OP_ParseSchema, iDb, 0, 
       sqlite3MPrintf("type='trigger' AND name='%q'", pTrig->name), P3_DYNAMIC);
  }

  if( db->init.busy ){
    Table *pTab;
    Trigger *pDel;
    pDel = sqlite3HashInsert(&db->aDb[iDb].pSchema->trigHash, 
                     pTrig->name, strlen(pTrig->name)+1, pTrig);
    if( pDel ){
      assert( sqlite3Tsd()->mallocFailed && pDel==pTrig );
      goto triggerfinish_cleanup;
    }
    pTab = sqlite3LocateTable(pParse,pTrig->table,db->aDb[pTrig->iTabDb].zName);
    assert( pTab!=0 );

  assert( pName->nSrc==1 );
  zDb = pName->a[0].zDatabase;
  zName = pName->a[0].zName;
  nName = strlen(zName);
  for(i=OMIT_TEMPDB; i<db->nDb; i++){
    int j = (i<2) ? i^1 : i;  /* Search TEMP before MAIN */
    if( zDb && sqlite3StrICmp(db->aDb[j].zName, zDb) ) continue;
    pTrigger = sqlite3HashFind(&(db->aDb[j].pSchema->trigHash), zName, nName+1);
    if( pTrigger ) break;
  }
  if( !pTrigger ){
    sqlite3ErrorMsg(pParse, "no such trigger: %S", pName, 0);
    goto drop_trigger_cleanup;
  }
  sqlite3DropTriggerPtr(pParse, pTrigger, 0);

*/
void sqlite3DropTriggerPtr(Parse *pParse, Trigger *pTrigger, int nested){
  Table   *pTable;
  Vdbe *v;
  sqlite3 *db = pParse->db;
  int iDb;

  iDb = sqlite3SchemaToIndex(pParse->db, pTrigger->pSchema);
  assert( iDb>=0 && iDb<db->nDb );
  pTable = tableOfTrigger(db, pTrigger);
  assert(pTable);
  assert( pTable->pSchema==pTrigger->pSchema || iDb==1 );
#ifndef SQLITE_OMIT_AUTHORIZATION
  {
    int code = SQLITE_DROP_TRIGGER;
    const char *zDb = db->aDb[iDb].zName;
    const char *zTab = SCHEMA_TABLE(iDb);
    if( iDb==1 ) code = SQLITE_DROP_TEMP_TRIGGER;
    if( sqlite3AuthCheck(pParse, code, pTrigger->name, pTable->zName, zDb) ||

/*
** Remove a trigger from the hash tables of the sqlite* pointer.
*/
void sqlite3UnlinkAndDeleteTrigger(sqlite3 *db, int iDb, const char *zName){
  Trigger *pTrigger;
  int nName = strlen(zName);
  pTrigger = sqlite3HashInsert(&(db->aDb[iDb].pSchema->trigHash), zName, nName+1, 0);
  if( pTrigger ){
    Table *pTable = tableOfTrigger(db, pTrigger);
    assert( pTable!=0 );
    if( pTable->pTrigger == pTrigger ){
      pTable->pTrigger = pTrigger->pNext;
    }else{
      Trigger *cc = pTable->pTrigger;

  Parse *pParse,       /* The parsing context */
  TriggerStep *pStep   /* The trigger containing the target token */
){
  Token sDb;           /* Dummy database name token */
  int iDb;             /* Index of the database to use */
  SrcList *pSrc;       /* SrcList to be returned */

  iDb = sqlite3SchemaToIndex(pParse->db, pStep->pTrig->pSchema);
  if( iDb==0 || iDb>=2 ){
    assert( iDb<pParse->db->nDb );
    sDb.z = (u8*)pParse->db->aDb[iDb].zName;
    sDb.n = strlen((char*)sDb.z);
    pSrc = sqlite3SrcListAppend(0, &sDb, &pStep->target);
  } else {
    pSrc = sqlite3SrcListAppend(0, &pStep->target, 0);

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle UPDATE statements.
**
** $Id: update.c,v 1.115 2006/01/05 11:34:34 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** The most recently coded instruction was an OP_Column to retrieve the
** i-th column of table pTab. This routine sets the P3 parameter of the 
** OP_Column to the default value, if any.

                         ** an expression for the i-th column of the table.
                         ** aXRef[i]==-1 if the i-th column is not changed. */
  int chngRowid;         /* True if the record number is being changed */
  Expr *pRowidExpr = 0;  /* Expression defining the new record number */
  int openAll = 0;       /* True if all indices need to be opened */
  AuthContext sContext;  /* The authorization context */
  NameContext sNC;       /* The name-context to resolve expressions in */
  int iDb;               /* Database containing the table being updated */

#ifndef SQLITE_OMIT_TRIGGER
  int isView;                  /* Trying to update a view */
  int triggers_exist = 0;      /* True if any row triggers exist */
#endif

  int newIdx      = -1;  /* index of trigger "new" temp table       */
  int oldIdx      = -1;  /* index of trigger "old" temp table       */

  sContext.pParse = 0;
  if( pParse->nErr || sqlite3Tsd()->mallocFailed ) goto update_cleanup;
  db = pParse->db;
  assert( pTabList->nSrc==1 );

  /* Locate the table which we want to update. 
  */
  pTab = sqlite3SrcListLookup(pParse, pTabList);
  if( pTab==0 ) goto update_cleanup;
  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);

  /* Figure out if we have any triggers and if the table being
  ** updated is a view
  */
#ifndef SQLITE_OMIT_TRIGGER
  triggers_exist = sqlite3TriggersExist(pParse, pTab, TK_UPDATE, pChanges);
  isView = pTab->pSelect!=0;

        goto update_cleanup;
      }
    }
#ifndef SQLITE_OMIT_AUTHORIZATION
    {
      int rc;
      rc = sqlite3AuthCheck(pParse, SQLITE_UPDATE, pTab->zName,
                           pTab->aCol[j].zName, db->aDb[iDb].zName);
      if( rc==SQLITE_DENY ){
        goto update_cleanup;
      }else if( rc==SQLITE_IGNORE ){
        aXRef[j] = -1;
      }
    }
#endif

  }

  /* Begin generating code.
  */
  v = sqlite3GetVdbe(pParse);
  if( v==0 ) goto update_cleanup;
  if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
  sqlite3BeginWriteOperation(pParse, 1, iDb);

  /* If we are trying to update a view, realize that view into
  ** a ephemeral table.
  */
  if( isView ){
    Select *pView;
    pView = sqlite3SelectDup(pTab->pSelect);

    if( !isView ){
      sqlite3VdbeAddOp(v, OP_Dup, 0, 0);
      sqlite3VdbeAddOp(v, OP_Dup, 0, 0);
      /* Open a cursor and make it point to the record that is
      ** being updated.
      */
      sqlite3OpenTableForReading(v, iCur, iDb, pTab);
    }
    sqlite3VdbeAddOp(v, OP_MoveGe, iCur, 0);

    /* Generate the OLD table
    */
    sqlite3VdbeAddOp(v, OP_Rowid, iCur, 0);
    sqlite3VdbeAddOp(v, OP_RowData, iCur, 0);

  if( !isView ){
    /* 
    ** Open every index that needs updating.  Note that if any
    ** index could potentially invoke a REPLACE conflict resolution 
    ** action, then we need to open all indices because we might need
    ** to be deleting some records.
    */
    sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
    sqlite3VdbeAddOp(v, OP_OpenWrite, iCur, pTab->tnum);
    sqlite3VdbeAddOp(v, OP_SetNumColumns, iCur, pTab->nCol);
    if( onError==OE_Replace ){
      openAll = 1;
    }else{
      openAll = 0;
      for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
        if( pIdx->onError==OE_Replace ){
          openAll = 1;
          break;
        }
      }
    }
    for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
      if( openAll || aIdxUsed[i] ){
        sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
        sqlite3VdbeOp3(v, OP_OpenWrite, iCur+i+1, pIdx->tnum,
                       (char*)&pIdx->keyInfo, P3_KEYINFO);
        assert( pParse->nTab>iCur+i+1 );
      }
    }

    /* Loop over every record that needs updating.  We have to load

**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.511 2006/01/05 11:34:34 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*

  assert( pDb->pBt!=0 );
  assert( pTos>=p->aStack );
  sqlite3VdbeMemIntegerify(pTos);
  /* See note about index shifting on OP_ReadCookie */
  rc = sqlite3BtreeUpdateMeta(pDb->pBt, 1+pOp->p2, (int)pTos->i);
  if( pOp->p2==0 ){
    /* When the schema cookie changes, record the new cookie internally */
    pDb->pSchema->schema_cookie = pTos->i;
    db->flags |= SQLITE_InternChanges;
  }else if( pOp->p2==1 ){
    /* Record changes in the file format */
    pDb->pSchema->file_format = pTos->i;
  }
  assert( (pTos->flags & MEM_Dyn)==0 );
  pTos--;
  break;
}

/* Opcode: VerifyCookie P1 P2 *

  pTos--;
  assert( iDb>=0 && iDb<db->nDb );
  pDb = &db->aDb[iDb];
  pX = pDb->pBt;
  assert( pX!=0 );
  if( pOp->opcode==OP_OpenWrite ){
    wrFlag = 1;
    if( pDb->pSchema->file_format < p->minWriteFileFormat ){
      p->minWriteFileFormat = pDb->pSchema->file_format;
    }
  }else{
    wrFlag = 0;
  }
  if( p2<=0 ){
    assert( pTos>=p->aStack );
    sqlite3VdbeMemIntegerify(pTos);

** This module contains C code that generates VDBE code used to process
** the WHERE clause of SQL statements.  This module is reponsible for
** generating the code that loops through a table looking for applicable
** rows.  Indices are selected and used to speed the search when doing
** so is applicable.  Because this module is responsible for selecting
** indices, you might also think of this module as the "query optimizer".
**
** $Id: where.c,v 1.190 2006/01/05 11:34:34 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** The number of bits in a Bitmask.  "BMS" means "BitMask Size".
*/
#define BMS  (sizeof(Bitmask)*8)

  /* Open all tables in the pTabList and any indices selected for
  ** searching those tables.
  */
  sqlite3CodeVerifySchema(pParse, -1); /* Insert the cookie verifier Goto */
  pLevel = pWInfo->a;
  for(i=0, pLevel=pWInfo->a; i<pTabList->nSrc; i++, pLevel++){
    Table *pTab;     /* Table to open */
    Index *pIx;      /* Index used to access pTab (if any) */
    int iDb;         /* Index of database containing table/index */
    int iIdxCur = pLevel->iIdxCur;

#ifndef SQLITE_OMIT_EXPLAIN
    if( pParse->explain==2 ){
      char *zMsg;
      struct SrcList_item *pItem = &pTabList->a[pLevel->iFrom];
      zMsg = sqlite3MPrintf("TABLE %s", pItem->zName);
      if( pItem->zAlias ){
        zMsg = sqlite3MPrintf("%z AS %s", zMsg, pItem->zAlias);
      }
      if( (pIx = pLevel->pIdx)!=0 ){
        zMsg = sqlite3MPrintf("%z WITH INDEX %s", zMsg, pIx->zName);
      }else if( pLevel->flags & (WHERE_ROWID_EQ|WHERE_ROWID_RANGE) ){
        zMsg = sqlite3MPrintf("%z USING PRIMARY KEY", zMsg);
      }
      sqlite3VdbeOp3(v, OP_Explain, i, pLevel->iFrom, zMsg, P3_DYNAMIC);
    }
#endif /* SQLITE_OMIT_EXPLAIN */
    pTabItem = &pTabList->a[pLevel->iFrom];
    pTab = pTabItem->pTab;
    iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
    if( pTab->isTransient || pTab->pSelect ) continue;
    if( (pLevel->flags & WHERE_IDX_ONLY)==0 ){
      sqlite3OpenTableForReading(v, pTabItem->iCursor, iDb, pTab);
    }
    pLevel->iTabCur = pTabItem->iCursor;
    if( (pIx = pLevel->pIdx)!=0 ){
      assert( pIx->pSchema==pTab->pSchema );
      sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
      VdbeComment((v, "# %s", pIx->zName));
      sqlite3VdbeOp3(v, OP_OpenRead, iIdxCur, pIx->tnum,
                     (char*)&pIx->keyInfo, P3_KEYINFO);
    }
    if( (pLevel->flags & WHERE_IDX_ONLY)!=0 ){
      sqlite3VdbeAddOp(v, OP_SetNumColumns, iIdxCur, pIx->nColumn+1);
    }
    sqlite3CodeVerifySchema(pParse, iDb);
  }
  pWInfo->iTop = sqlite3VdbeCurrentAddr(v);

  /* Generate the code to do the search.  Each iteration of the for
  ** loop below generates code for a single nested loop of the VM
  ** program.
  */

# 2001 September 15
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file runs all tests.
#
# $Id: all.test,v 1.32 2006/01/05 11:34:34 danielk1977 Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl
rename finish_test really_finish_test
proc finish_test {} {memleak_check}

if {[file exists ./sqlite_test_count]} {

  async.test
  crash.test
  autovacuum_crash.test
  quick.test
  malloc.test
  misuse.test
  memleak.test

  malloc2.test
  malloc3.test
  malloc4.test
  malloc5.test
}

# Test files btree2.test and btree4.test don't work if the 
# SQLITE_DEFAULT_AUTOVACUUM macro is defined to true (because they depend
# on tables being allocated starting at page 2).
#
ifcapable default_autovacuum {

# Both tests leak memory. Currently, misuse.test also leaks a handful of
# file descriptors. This is not considered a problem, but can cause tests
# in malloc.test to fail. So set the open-file count to zero before running
# malloc.test to get around this.
#
catch {source $testdir/misuse.test}
set sqlite_open_file_count 0
# catch {source $testdir/malloc.test}

catch {db close}
set sqlite_open_file_count 0
really_finish_test

# index entry was deleted first, before the table entry.  And the index
# delete worked.  Thus an entry was deleted from the index but not from
# the table.
#
# The solution to the problem was to detect that the table is locked
# before the index entry is deleted.
#
# $Id: delete2.test,v 1.6 2006/01/05 11:34:34 danielk1977 Exp $
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl

# Create a table that has an index.
#

  set STMT [sqlite3_prepare $DB {SELECT * FROM q} -1 TAIL]
  sqlite3_step $STMT
} SQLITE_ROW
integrity_check delete2-1.5

# Try to delete a row from the table. The delete should fail.
#
breakpoint
do_test delete2-1.6 {
  catchsql {
    DELETE FROM q WHERE rowid=1
  }
} {1 {database table is locked}}
integrity_check delete2-1.7
do_test delete2-1.8 {

# 2005 December 30
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing the SELECT statement.
#
# $Id: shared.test,v 1.2 2006/01/05 11:34:34 danielk1977 Exp $



set testdir [file dirname $argv0]
source $testdir/tester.tcl
db close

ifcapable !shared_cache {
  finish_test
  return
}
set ::enable_shared_cache [sqlite3_enable_shared_cache 1]

# Test organization:
#
# shared-1.*: Simple test to verify basic sanity of table level locking when
#             two connections share a pager cache.
# shared-2.*: Test that a read transaction can co-exist with a 
#             write-transaction, including a simple test to ensure the 
#             external locking protocol is still working.
# shared-3.*: Simple test of read-uncommitted mode.
#

do_test shared-1.1 {
  # Open a second database on the file test.db. It should use the same pager
  # cache and schema as the original connection. Verify that only 1 file is 
  # opened.
  sqlite3 db2 test.db

  # of the read-lock connection 1 is holding on table abc (obtained in the
  # previous test case).
  catchsql {
    INSERT INTO abc VALUES(4, 5, 6);
  } db2
} {1 {database is locked}}
do_test shared-1.5 {
  # Using connection 2 (the one without the open transaction), try to create
  # a new table. This should fail because of the open read transaction 
  # held by connection 1.
  catchsql {
    CREATE TABLE def(d, e, f);

  } db2
} {1 {database is locked}}
do_test shared-1.6 {
  # Upgrade connection 1's transaction to a write transaction. Create
  # a new table - def - and insert a row into it. Because the connection 1


  # transaction modifies the schema, it should not be possible for 

  # connection 2 to access the database at all until the connection 1 


  # has finished the transaction.


  execsql {


    CREATE TABLE def(d, e, f);

    INSERT INTO def VALUES('IV', 'V', 'VI');
  }
} {}
do_test shared-1.7 {
  # Read from the sqlite_master table with connection 1 (inside the 
  # transaction). Then test that we can not do this with connection 2. This
  # is because of the schema-modified lock established by connection 1 
  # in the previous test case.
  execsql {
    SELECT * FROM sqlite_master;
  }
  catchsql {
    SELECT * FROM sqlite_master;
  } db2
} {1 {database is locked}}
do_test shared-1.8 {















  # Commit the connection 1 transaction.
  execsql {
    COMMIT;
  }
} {}

do_test shared-2.1 {

    INSERT INTO def VALUES('VII', 'VIII', 'IX');
  }
  concat [
    catchsql { SELECT * FROM def; } db3
  ] [
    catchsql { SELECT * FROM def; } db2
  ]
} {0 {IV V VI} 1 {database is locked}}
do_test shared-2.4 {
  # Commit the open transaction on db. db2 still holds a read-transaction.
  # This should prevent db3 from writing to the database, but not from 
  # reading.
  execsql {
    COMMIT;
  }
  concat [
    catchsql { SELECT * FROM def; } db3
  ] [
    catchsql { INSERT INTO def VALUES('X', 'XI', 'XII'); } db3
  ]
} {0 {IV V VI VII VIII IX} 1 {database is locked}}

catchsql COMMIT db2

do_test shared-3.1.1 {
  # This test case starts a linear scan of table 'seq' using a 
  # read-uncommitted connection. In the middle of the scan, rows are added
  # to the end of the seq table (ahead of the current cursor position).
  # The uncommitted rows should be included in the results of the scan.
  execsql "
    CREATE TABLE seq(i, x);
    INSERT INTO seq VALUES(1, '[string repeat X 500]');
    INSERT INTO seq VALUES(2, '[string repeat X 500]');
  "
  execsql {SELECT * FROM sqlite_master} db2
  execsql {PRAGMA read_uncommitted = 1} db2

  set ret [list]
  db2 eval {SELECT i FROM seq} {
    if {$i < 4} {
      execsql {
        INSERT INTO seq SELECT i + (SELECT max(i) FROM seq), x FROM seq;
      }
    }
    lappend ret $i
  }
  set ret
} {1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16}
do_test shared-3.1.2 {
  # Another linear scan through table seq using a read-uncommitted connection.
  # This time, delete each row as it is read. Should not affect the results of
  # the scan, but the table should be empty after the scan is concluded 
  # (test 3.1.3 verifies this).
  set ret [list]
  db2 eval {SELECT i FROM seq} {
    db eval {DELETE FROM seq WHERE i = $i}
    lappend ret $i
  }
  set ret
} {1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16}
do_test shared-3.1.3 {
  execsql {
    SELECT * FROM seq;
  }
} {}

catch {db close}
catch {db2 close}
catch {db3 close}

finish_test
sqlite3_enable_shared_cache $::enable_shared_cache

# 2001 September 15
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements some common TCL routines used for regression
# testing the SQLite library
#
# $Id: tester.tcl,v 1.57 2006/01/05 11:34:34 danielk1977 Exp $

# Make sure tclsqlite3 was compiled correctly.  Abort now with an
# error message if not.
#
if {[sqlite3 -tcl-uses-utf]} {
  if {"\u1234"=="u1234"} {
    puts stderr "***** BUILD PROBLEM *****"

  foreach alloc [sqlite_malloc_outstanding] {
    foreach {nBytes file iLine userstring backtrace} $alloc {}
    set stack [list]
    set skip 0

    # The first command in this block will probably fail on windows. This
    # means there will be no stack dump available.
    if {$cnt < 25 && $backtrace!=""} {
      catch {
        set stuff [eval "exec addr2line -e ./testfixture -f $backtrace"]
        foreach {func line} $stuff {
          if {$func != "??" || $line != "??:0"} {
            regexp {.*/(.*)} $line dummy line
            lappend stack "${func}() $line"
          } else {

#
# Run this script to generated a sharedcache.html output file
#
set rcsid {$Id: }
source common.tcl
header {SQLite Shared-Cache Mode}

proc HEADING {level title} {
  global pnum
  incr pnum($level)
  foreach i [array names pnum] {
    if {$i>$level} {set pnum($i) 0}
  }
  set h [expr {$level+1}]
  if {$h>6} {set h 6}
  set n $pnum(1).$pnum(2)
  for {set i 3} {$i<=$level} {incr i} {
    append n .$pnum($i)
  }
  puts "<h$h>$n $title</h$h>"
}
set pnum(1) 0
set pnum(2) 0
set pnum(3) 0
set pnum(4) 0
set pnum(5) 0
set pnum(6) 0
set pnum(7) 0
set pnum(8) 0

HEADING 1 {SQLite Shared-Cache Mode}

puts {
<p>Starting with version 3.3.0, SQLite includes a special "shared-cache"
mode (disabled by default) intended for use in embedded servers. If
shared-cache mode is enabled and a thread establishes multiple connections
to the same database, the connections share a single data and schema cache.
This can significantly reduce the quantity of memory and IO required by
the system.</p>

<p>Using shared-cache mode imposes some extra restrictions on 
passing database handles between threads and also changes the semantics
of the locking model in some cases. These details are described in full by
this document. A basic understanding of the normal SQLite locking model (see
<a href="lockingv3.html">File Locking And Concurrency In SQLite Version 3</a>
for details) is assumed.
</p>
}

HEADING 1 {Shared-Cache Locking Model}

puts {
<p>Externally, from the point of view of another process or thread, two
or more database connections using a shared-cache appear as a single 
connection. The locking protocol used to arbitrate between multiple 
shared-caches or regular database users is described elsewhere.
</p>

<table style="margin:auto">
<tr><td>
<pre>
            +--------------+      +--------------+
            | Connection 2 |      | Connection 3 |
            +--------------+      +--------------+
                         |          |
                         V          V
+--------------+       +--------------+
| Connection 1 |       | Shared cache |
+--------------+       +--------------+
            |            |
            V            V
          +----------------+
          |    Database    |
          +----------------+
</pre>
</table>
<p style="font-style:italic;text-align:center">Figure 1</p>

<p>Figure 1 depicts an example runtime configuration where three 
database connections have been established. Connection 1 is a normal
SQLite database connection. Connections 2 and 3 share a cache (and so must
have been established by the same process thread). The normal locking
protocol is used to serialize database access between connection 1 and
the shared cache. The internal protocol used to serialize (or not, see
"Read-Uncommitted Isolation Mode" below) access to the shared-cache by
connections 2 and 3 is described in the remainder of this section.
</p>

<p>There are three levels to the shared-cache locking model, 
transaction level locking, table level locking and schema level locking. 
They are described in the following three sub-sections.</p>

}

HEADING 2 {Transaction Level Locking}

puts {
<p>SQLite connections can open two kinds of transactions, read and write
transactions. This is not done explicitly, a transaction is implicitly a
read-transaction until it first writes to a database table, at which point
it becomes a write-transaction.
</p>
<p>At most one connection to a single shared cache may open a 
write transaction at any one time. This may co-exist with any number of read 
transactions. 
</p>
}

HEADING 2 {Table Level Locking}

puts {
<p>When two or more connections use a shared-cache, locks are used to 
serialize concurrent access attempts on a per-table basis. Tables support 
two types of locks, "read-locks" and "write-locks". Locks are granted to
connections - at any one time, each database connection has either a
read-lock, write-lock or no lock on each database table.
</p>

<p>At any one time, a single table may have any number of active read-locks
or a single active write lock. To read data a table, a connection must 
first obtain a read-lock. To write to a table, a connection must obtain a 
write-lock on that table. If a required table lock cannot be obtained,
the query fails and SQLITE_BUSY is returned to the caller.
</p> 

<p><b>TODO: Should we be invoking the busy-handler here? Just waiting won't do
any good, but something else might...  </b></p>

<p>Once a connection obtains a table lock, it is not released until the
current transaction (read or write) is concluded.
</p>
}

HEADING 3 {Read-Uncommitted Isolation Mode}

puts {
<p>The behaviour described above may be modified slightly by using the 
<i>read_uncommitted</i> pragma to change the isolation level from serialized 
(the default), to read-uncommitted.</p>

<p> A database connection in read-uncommitted mode does not attempt 
to obtain read-locks before reading from database tables as described 
above. This can lead to inconsistent query results if another database
connection modifies a table while it is being read, but it also means that
a read-transaction opened by a connection in read-uncommitted mode can
neither block nor be blocked by any other connection.</p>

<p>Read-uncommitted mode has no effect on the locks required to write to
database tables (i.e. read-uncommitted connections must still obtain 
write-locks and hence database writes may still block or be blocked). 
Also, read-uncommitted mode has no effect on the <i>sqlite_master</i> 
locks required by the rules enumerated below (see section 
"Schema (sqlite_master) Level Locking").
</p>

<pre>
  /* Set the value of the read-uncommitted flag:
  **
  **   True  -> Set the connection to read-uncommitted mode.
  **   False -> Set the connectino to serialized (the default) mode.
  */
  PRAGMA read_uncommitted = &lt;boolean&gt;;

  /* Retrieve the current value of the read-uncommitted flag */
  PRAGMA read_uncommitted;
</pre>
}

HEADING 2 {Schema (sqlite_master) Level Locking}

puts {
<p>The <i>sqlite_master</i> table supports shared-cache read and write 
locks in the same way as all other database tables (see description 
above). The following special rules also apply:
</p>

<ul>
<li>A connection must obtain a read-lock on <i>sqlite_master</i> before 
accessing any database tables or obtaining any other read or write locks.</li>
<li>Before executing a statement that modifies the database schema (i.e. 
a CREATE or DROP TABLE statement), a connection must obtain a write-lock on 
<i>sqlite_master</i>.
</li>
<li>A connection may not compile an SQL statement that refers to database
tables if any other connection is holding a write-lock on <i>sqlite_master</i>.
</li>
</ul>
}

HEADING 1 {Thread Related Issues}

puts {
<p>When shared-cache mode is enabled, a database connection may only be
used by the thread that called sqlite3_open() to create it. If another 
thread attempts to use the database connection, in most cases an 
SQLITE_MISUSE error is returned. However this is not guaranteed and 
programs should not depend on this behaviour, in some cases a segfault 
may result.
</p>
}

HEADING 1 {Enabling Shared-Cache Mode}

puts {
<p>Shared-cache mode is enabled on a thread-wide basis. Using the C 
interface, the following API can be used to enable or disable shared-cache
mode for the calling thread:
</p>

<pre>
int sqlite3_enable_shared_cache(int);
</pre>

<p>It is illegal to call sqlite3_enable_shared_cache() if one or more 
open database connections were opened by the calling thread. If the argument
is non-zero, shared-cache mode is enabled. If the argument is zero,
shared-cache mode is disabled. The return value is either SQLITE_OK (if the
operation was successful), SQLITE_NOMEM (if a malloc() failed), or
SQLITE_MISUSE (if the thread has open database connections).
</p>
}

footer $rcsid