SQLite

2.5.6

/*
** 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.
**
*************************************************************************
** $Id: btree.c,v 1.65 2002/07/07 16:52:47 drh 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.

  MemPage *pMemPage;

  if( pgno==0 ){
    assert( pOvfl!=0 );
    pgno = sqlitepager_pagenumber(pOvfl);
  }
  assert( pgno>2 );
  pMemPage = (MemPage*)pPage;
  pMemPage->isInit = 0;
  if( pMemPage->pParent ){
    sqlitepager_unref(pMemPage->pParent);
    pMemPage->pParent = 0;
  }
  rc = sqlitepager_write(pPage1);
  if( rc ){
    return rc;
  }
  pPage1->nFree++;
  if( pPage1->nFree>0 && pPage1->freeList ){
    OverflowPage *pFreeIdx;

  if( rc ){
    if( needUnref ) sqlitepager_unref(pOvfl);
    return rc;
  }
  pOvfl->iNext = pPage1->freeList;
  pPage1->freeList = pgno;
  memset(pOvfl->aPayload, 0, OVERFLOW_SIZE);






  if( needUnref ) rc = sqlitepager_unref(pOvfl);
  return rc;
}

/*
** Erase all the data out of a cell.  This involves returning overflow
** pages back the freelist.

** This file contains the C functions that implement various SQL
** functions of SQLite.  
**
** There is only one exported symbol in this file - the function
** sqliteRegisterBuildinFunctions() found at the bottom of the file.
** All other code has file scope.
**
** $Id: func.c,v 1.22 2002/07/07 16:52:47 drh Exp $
*/
#include <ctype.h>
#include <math.h>
#include <stdlib.h>
#include <assert.h>
#include "sqliteInt.h"

*/
static void nullifFunc(sqlite_func *context, int argc, const char **argv){
  if( argv[0]!=0 && sqliteCompare(argv[0],argv[1])!=0 ){
    sqlite_set_result_string(context, argv[0], -1);
  }
}

#ifdef SQLITE_TEST
/*
** This function generates a string of random characters.  Used for
** generating test data.
*/
static void randStr(sqlite_func *context, int argc, const char **argv){
  static const char zSrc[] = 
     "abcdefghijklmnopqrstuvwxyz"
     "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
     "0123456789"
     ".-!,:*^+=_|?/<> ";
  int iMin, iMax, n, r, i;
  char zBuf[1000];
  if( argc>=1 ){
    iMin = atoi(argv[0]);
    if( iMin<0 ) iMin = 0;
    if( iMin>=sizeof(zBuf) ) iMin = sizeof(zBuf)-1;
  }else{
    iMin = 1;
  }
  if( argc>=2 ){
    iMax = atoi(argv[1]);
    if( iMax<iMin ) iMax = iMin;
    if( iMax>=sizeof(zBuf) ) iMax = sizeof(zBuf);
  }else{
    iMax = 50;
  }
  n = iMin;
  if( iMax>iMin ){
    r = sqliteRandomInteger();
    if( r<0 ) r = -r;
    n += r%(iMax + 1 - iMin);
  }
  r = 0;
  for(i=0; i<n; i++){
    r = (r + sqliteRandomByte())% (sizeof(zSrc)-1);
    zBuf[i] = zSrc[r];
  }
  zBuf[n] = 0;
  sqlite_set_result_string(context, zBuf, n);
}
#endif

/*
** An instance of the following structure holds the context of a
** sum() or avg() aggregate computation.
*/
typedef struct SumCtx SumCtx;
struct SumCtx {
  double sum;     /* Sum of terms */

    { "coalesce",   0, 0,              0          },
    { "coalesce",   1, 0,              0          },
    { "ifnull",     2, SQLITE_ARGS,    ifnullFunc },
    { "random",    -1, SQLITE_NUMERIC, randomFunc },
    { "like",       2, SQLITE_NUMERIC, likeFunc   },
    { "glob",       2, SQLITE_NUMERIC, globFunc   },
    { "nullif",     2, SQLITE_ARGS,    nullifFunc },
#ifdef SQLITE_TEST
    { "randstr",    2, SQLITE_TEXT,    randStr    },
#endif
  };
  static struct {
    char *zName;
    int nArg;
    int dataType;
    void (*xStep)(sqlite_func*,int,const char**);
    void (*xFinalize)(sqlite_func*);

}

/*
** Get information to seed the random number generator.
*/
int sqliteOsRandomSeed(char *zBuf){
  static int once = 1;
#ifdef SQLITE_TEST
  /* When testing, always use the same random number sequence.
  ** This makes the tests repeatable.
  */
  memset(zBuf, 0, 256);
#endif
#if OS_UNIX && !defined(SQLITE_TEST)
  int pid;
  time((time_t*)zBuf);
  pid = getpid();
  memcpy(&zBuf[sizeof(time_t)], &pid, sizeof(pid));
#endif
#if OS_WIN && !defined(SQLITE_TEST)
  GetSystemTime((LPSYSTEMTIME)zBuf);
#endif
  if( once ){
    int seed;
    memcpy(&seed, zBuf, sizeof(seed));
    srand(seed);
    once = 0;

** The pager is used to access a database disk file.  It implements
** atomic commit and rollback through the use of a journal file that
** is separate from the database file.  The pager also implements file
** locking to prevent two processes from writing the same database
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.49 2002/07/07 16:52:47 drh Exp $
*/
#include "sqliteInt.h"
#include "pager.h"
#include "os.h"
#include <assert.h>
#include <string.h>

struct PgHdr {
  Pager *pPager;                 /* The pager to which this page belongs */
  Pgno pgno;                     /* The page number for this page */
  PgHdr *pNextHash, *pPrevHash;  /* Hash collision chain for PgHdr.pgno */
  int nRef;                      /* Number of users of this page */
  PgHdr *pNextFree, *pPrevFree;  /* Freelist of pages where nRef==0 */
  PgHdr *pNextAll, *pPrevAll;    /* A list of all pages */
  u8 inJournal;                  /* TRUE if has been written to journal */
  u8 inCkpt;                     /* TRUE if written to the checkpoint journal */
  u8 dirty;                      /* TRUE if we need to write back changes */
  u8 alwaysRollback;             /* Disable dont_rollback() for this page */
  /* SQLITE_PAGE_SIZE bytes of page data follow this header */
  /* Pager.nExtra bytes of local data follow the page data */
};

/*
** Convert a pointer to a PgHdr into a pointer to its data
** and back again.

  u8 noSync;                  /* Do not sync the journal if true */
  u8 state;                   /* SQLITE_UNLOCK, _READLOCK or _WRITELOCK */
  u8 errMask;                 /* One of several kinds of errors */
  u8 tempFile;                /* zFilename is a temporary file */
  u8 readOnly;                /* True for a read-only database */
  u8 needSync;                /* True if an fsync() is needed on the journal */
  u8 dirtyFile;               /* True if database file has changed in any way */
  u8 alwaysRollback;          /* Disable dont_rollback() for all pages */
  u8 *aInJournal;             /* One bit for each page in the database file */
  u8 *aInCkpt;                /* One bit for each page in the database */
  PgHdr *pFirst, *pLast;      /* List of free pages */
  PgHdr *pAll;                /* List of all pages */
  PgHdr *aHash[N_PG_HASH];    /* Hash table to map page number of PgHdr */
};

          *ppPage = 0;
          return SQLITE_IOERR;
        }
        pPg = pPager->pFirst;
      }
      assert( pPg->nRef==0 );
      assert( pPg->dirty==0 );

      /* If the page we are recyclying is marked as alwaysRollback, then
      ** set the global alwaysRollback flag, thus disabling the
      ** sqlite_dont_rollback() optimization for the rest of this transaction.
      ** It is necessary to do this because the page marked alwaysRollback
      ** might be reloaded at a later time but at that point we won't remember
      ** that is was marked alwaysRollback.  This means that all pages must
      ** be marked as alwaysRollback from here on out.
      */
      if( pPg->alwaysRollback ){
        pPager->alwaysRollback = 1;
      }

      /* Unlink the old page from the free list and the hash table
      */
      if( pPg->pPrevFree ){
        pPg->pPrevFree->pNextFree = pPg->pNextFree;
      }else{
        assert( pPager->pFirst==pPg );

      pPager->aInJournal = 0;
      sqliteOsReadLock(&pPager->fd);
      return SQLITE_CANTOPEN;
    }
    pPager->journalOpen = 1;
    pPager->needSync = 0;
    pPager->dirtyFile = 0;
    pPager->alwaysRollback = 0;
    pPager->state = SQLITE_WRITELOCK;
    sqlitepager_pagecount(pPager);
    pPager->origDbSize = pPager->dbSize;
    rc = sqliteOsWrite(&pPager->jfd, aJournalMagic, sizeof(aJournalMagic));
    if( rc==SQLITE_OK ){
      rc = sqliteOsWrite(&pPager->jfd, &pPager->dbSize, sizeof(Pgno));
    }

** rollback journal.
*/
void sqlitepager_dont_rollback(void *pData){
  PgHdr *pPg = DATA_TO_PGHDR(pData);
  Pager *pPager = pPg->pPager;

  if( pPager->state!=SQLITE_WRITELOCK || pPager->journalOpen==0 ) return;
  if( pPg->alwaysRollback || pPager->alwaysRollback ) return;
  if( !pPg->inJournal && (int)pPg->pgno <= pPager->origDbSize ){
    assert( pPager->aInJournal!=0 );
    pPager->aInJournal[pPg->pgno/8] |= 1<<(pPg->pgno&7);
    pPg->inJournal = 1;
    if( pPager->ckptInUse ){
      pPager->aInCkpt[pPg->pgno/8] |= 1<<(pPg->pgno&7);
      pPg->inCkpt = 1;

# 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 1.15 2002/07/07 16:52:47 drh 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]} {

set LeakList {}

set EXCLUDE {
  all.test
  quick.test
  malloc.test
  misuse.test

}
#  btree2.test

for {set Counter 0} {$Counter<$COUNT && $nErr==0} {incr Counter} {
  if {$Counter%2} {
    set ::SETUP_SQL {PRAGMA default_synchronous=off;}
  } else {
    catch {unset ::SETUP_SQL}
  }

# 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: quick.test,v 1.3 2002/07/07 16:52:47 drh Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl
rename finish_test really_finish_test
proc finish_test {} {}
set ISQUICK 1

set EXCLUDE {
  all.test
  quick.test
  btree2.test
  malloc.test
}

# 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 regression tests for SQLite library.  The
# focus of this script is database locks.
#
# $Id: trans.test,v 1.13 2002/07/07 16:52:47 drh Exp $


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


# Create several tables to work with.

  execsql {SELECT md5sum(x,y,z) FROM t2}
} $checksum
do_test trans-8.2 {
  execsql {SELECT md5sum(type,name,tbl_name,rootpage,sql) FROM sqlite_master}
} $checksum2
integrity_check trans-8.3

# In the following sequence of tests, compute the MD5 sum of the content
# of a table, make lots of modifications to that table, then do a rollback.
# Verify that after the rollback, the MD5 checksum is unchanged.
#
do_test trans-9.1 {
  execsql {
    PRAGMA cache_size=10;
    BEGIN;
    CREATE TABLE t3(x TEXT);
    INSERT INTO t3 VALUES(randstr(10,400));
    INSERT INTO t3 VALUES(randstr(10,400));
    INSERT INTO t3 SELECT randstr(10,400) FROM t3;
    INSERT INTO t3 SELECT randstr(10,400) FROM t3;
    INSERT INTO t3 SELECT randstr(10,400) FROM t3;
    INSERT INTO t3 SELECT randstr(10,400) FROM t3;
    INSERT INTO t3 SELECT randstr(10,400) FROM t3;
    INSERT INTO t3 SELECT randstr(10,400) FROM t3;
    INSERT INTO t3 SELECT randstr(10,400) FROM t3;
    INSERT INTO t3 SELECT randstr(10,400) FROM t3;
    INSERT INTO t3 SELECT randstr(10,400) FROM t3;
    COMMIT;
    SELECT count(*) FROM t3;
  }
} {1024}

# The following procedure computes a "signature" for table "t3".  If
# T3 changes in any way, the signature should change.  
#
# This is used to test ROLLBACK.  We gather a signature for t3, then
# make lots of changes to t3, then rollback and take another signature.
# The two signatures should be the same.
#
proc signature {} {
  return [db eval {SELECT count(*), md5sum(x) FROM t3}]
}

# Repeat the following group of tests 20 times for quick testing and
# 40 times for full testing.  Each iteration of the test makes table
# t3 a little larger, and thus takes a little longer, so doing 40 tests
# is more than 2.0 times slower than doing 20 tests.  Considerably more.
#
if {[info exists ISQUICK]} {
  set limit 20
} else {
  set limit 40
}

# Do rollbacks.  Make sure the signature does not change.
#
for {set i 2} {$i<=$limit} {incr i} {
  set ::sig [signature]
  set cnt [lindex $::sig 0]
  do_test trans-9.$i.1-$cnt {
     execsql {
       BEGIN;
       DELETE FROM t3 WHERE random()%10!=0;
       INSERT INTO t3 SELECT randstr(10,10)||x FROM t3;
       INSERT INTO t3 SELECT randstr(10,10)||x FROM t3;
       ROLLBACK;
     }
     signature
  } $sig
  do_test trans-9.$i.2-$cnt {
     execsql {
       BEGIN;
       DELETE FROM t3 WHERE random()%10!=0;
       INSERT INTO t3 SELECT randstr(10,10)||x FROM t3;
       DELETE FROM t3 WHERE random()%10!=0;
       INSERT INTO t3 SELECT randstr(10,10)||x FROM t3;
       ROLLBACK;
     }
     signature
  } $sig
  if {$i<$limit} {
    do_test trans-9.$i.9-$cnt {
       execsql {
         INSERT INTO t3 SELECT randstr(10,400) FROM t3 WHERE random()%10==0;
       }
    } {}
  }
}
   
finish_test

}


proc chng {date desc} {
  puts "<DT><B>$date</B></DT>"
  puts "<DD><P><UL>$desc</UL></P></DD>"
}

chng {2002 Jly 7 (2.5.6)} {
<li>Fix more problems with rollback.  Enhance the test suite to exercise
    the rollback logic extensively in order to prevent any future problems.
    </li>
}

chng {2002 Jly 6 (2.5.5)} {
<li>Fix a bug which could cause database corruption during a rollback.
    This bugs was introduced in version 2.4.0 by the freelist
    optimization of checking [410].</li>
<li>Fix a bug in aggregate functions for VIEWs.</li>
<li>Other minor changes and enhancements.</li>