SQLite

  sqlite3BtreeLeave(p);
  return rc;
}

/*
** This routine is called prior to sqlite3PagerCommit when a transaction
** is committed for an auto-vacuum database.





*/
static int autoVacuumCommit(Btree *p){
  int rc = SQLITE_OK;
  Pager *pPager;
  BtShared *pBt;
  sqlite3 *db;
  VVA_ONLY( int nRef );

  assert( p!=0 );
  pBt = p->pBt;  
  pPager = pBt->pPager;
  VVA_ONLY( nRef = sqlite3PagerRefcount(pPager); )

  assert( sqlite3_mutex_held(pBt->mutex) );
  invalidateAllOverflowCache(pBt);
  assert(pBt->autoVacuum);
  if( !pBt->incrVacuum ){
    Pgno nFin;         /* Number of pages in database after autovacuuming */
    Pgno nFree;        /* Number of pages on the freelist initially */
    Pgno nVac;         /* Number of pages to vacuum */
    Pgno iFree;        /* The next page to be freed */
    Pgno nOrig;        /* Database size before freeing */

    nOrig = btreePagecount(pBt);
    if( PTRMAP_ISPAGE(pBt, nOrig) || nOrig==PENDING_BYTE_PAGE(pBt) ){
      /* It is not possible to create a database for which the final page
      ** is either a pointer-map page or the pending-byte page. If one
      ** is encountered, this indicates corruption.
      */
      return SQLITE_CORRUPT_BKPT;
    }

    nFree = get4byte(&pBt->pPage1->aData[36]);
    db = p->db;
    if( db->xAutovacPages ){
      int iDb;
      for(iDb=0; ALWAYS(iDb<db->nDb); iDb++){
        if( db->aDb[iDb].pBt==p ) break;
      }
      nVac = db->xAutovacPages(
        db->pAutovacPagesArg,
        db->aDb[iDb].zDbSName,
        nOrig,
        nFree,
        pBt->pageSize
      );
      if( nVac>nFree ){
        nVac = nFree;
      }
      if( nVac==0 ){
        return SQLITE_OK;
      }
    }else{
      nVac = nFree;
    }
    nFin = finalDbSize(pBt, nOrig, nVac);
    if( nFin>nOrig ) return SQLITE_CORRUPT_BKPT;
    if( nFin<nOrig ){
      rc = saveAllCursors(pBt, 0, 0);
    }
    for(iFree=nOrig; iFree>nFin && rc==SQLITE_OK; iFree--){
      rc = incrVacuumStep(pBt, nFin, iFree, nVac==nFree);
    }
    if( (rc==SQLITE_DONE || rc==SQLITE_OK) && nFree>0 ){
      rc = sqlite3PagerWrite(pBt->pPage1->pDbPage);
      if( nVac==nFree ){
        put4byte(&pBt->pPage1->aData[32], 0);
        put4byte(&pBt->pPage1->aData[36], 0);
      }
      put4byte(&pBt->pPage1->aData[28], nFin);
      pBt->bDoTruncate = 1;
      pBt->nPage = nFin;
    }
    if( rc!=SQLITE_OK ){
      sqlite3PagerRollback(pPager);
    }

int sqlite3BtreeCommitPhaseOne(Btree *p, const char *zSuperJrnl){
  int rc = SQLITE_OK;
  if( p->inTrans==TRANS_WRITE ){
    BtShared *pBt = p->pBt;
    sqlite3BtreeEnter(p);
#ifndef SQLITE_OMIT_AUTOVACUUM
    if( pBt->autoVacuum ){
      rc = autoVacuumCommit(p);
      if( rc!=SQLITE_OK ){
        sqlite3BtreeLeave(p);
        return rc;
      }
    }
    if( pBt->bDoTruncate ){
      sqlite3PagerTruncateImage(pBt->pPager, pBt->nPage);

  sqlite3_free_filename,
  sqlite3_database_file_object,
  /* Version 3.34.0 and later */
  sqlite3_txn_state,
  /* Version 3.36.1 and later */
  sqlite3_changes64,
  sqlite3_total_changes64,
  /* Version 3.37.0 and later */
  sqlite3_autovacuum_pages,
};

/* True if x is the directory separator character
*/
#if SQLITE_OS_WIN
# define DirSep(X)  ((X)=='/'||(X)=='\\')
#else

  /* The temp-database schema is allocated differently from the other schema
  ** objects (using sqliteMalloc() directly, instead of sqlite3BtreeSchema()).
  ** So it needs to be freed here. Todo: Why not roll the temp schema into
  ** the same sqliteMalloc() as the one that allocates the database 
  ** structure?
  */
  sqlite3DbFree(db, db->aDb[1].pSchema);
  if( db->xAutovacDestr ){
    db->xAutovacDestr(db->pAutovacPagesArg);
  }
  sqlite3_mutex_leave(db->mutex);
  db->eOpenState = SQLITE_STATE_CLOSED;
  sqlite3_mutex_free(db->mutex);
  assert( sqlite3LookasideUsed(db,0)==0 );
  if( db->lookaside.bMalloced ){
    sqlite3_free(db->lookaside.pStart);
  }

  pRet = db->pPreUpdateArg;
  db->xPreUpdateCallback = xCallback;
  db->pPreUpdateArg = pArg;
  sqlite3_mutex_leave(db->mutex);
  return pRet;
}
#endif /* SQLITE_ENABLE_PREUPDATE_HOOK */

/*
** Register a function to be invoked prior to each autovacuum that
** determines the number of pages to vacuum.
*/
int sqlite3_autovacuum_pages(
  sqlite3 *db,                 /* Attach the hook to this database */
  unsigned int (*xCallback)(void*,const char*,u32,u32,u32), 
  void *pArg,                  /* Argument to the function */
  void (*xDestructor)(void*)   /* Destructor for pArg */
){
#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ){
    if( xDestructor ) xDestructor(pArg);
    return SQLITE_MISUSE_BKPT;
  }
#endif
  sqlite3_mutex_enter(db->mutex);
  if( db->xAutovacDestr ){
    db->xAutovacDestr(db->pAutovacPagesArg);
  }
  db->xAutovacPages = xCallback;
  db->pAutovacPagesArg = pArg;
  db->xAutovacDestr = xDestructor;
  sqlite3_mutex_leave(db->mutex);
  return SQLITE_OK;
}


#ifndef SQLITE_OMIT_WAL
/*
** The sqlite3_wal_hook() callback registered by sqlite3_wal_autocheckpoint().
** Invoke sqlite3_wal_checkpoint if the number of frames in the log file
** is greater than sqlite3.pWalArg cast to an integer (the value configured by
** wal_autocheckpoint()).

** ^The rollback callback is not invoked if a transaction is
** automatically rolled back because the database connection is closed.
**
** See also the [sqlite3_update_hook()] interface.
*/
void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);

/*
** CAPI3REF: Autovacuum Compaction Amount Callback
** METHOD: sqlite3
**
** ^The sqlite3_autovacuum_pages(D,C,P,X) interface registers a callback 
** function C that is invoked prior to each autovacuum of the database
** file.  ^The callback is passed a copy of the generic data pointer (P),
** the schema-name of the attached database that is being autovacuumed,
** the the size of the database file in pages, the number of free pages,
** and the number of bytes per page, respectively.  The callback should
** return the number of free pages that should be removed by the
** autovacuum.  ^If the callback returns zero, then no autovacuum happens.
** ^If the value returned is greater than or equal to the number of
** free pages, then a complete autovacuum happens.
**
** <p>^If there are multiple ATTACH-ed database files that are being
** modified as part of a transaction commit, then the autovacuum pages
** callback is invoked separately for each file.
**
** <p><b>The callback is not reentrant.</b> The callback function should
** not attempt to invoke any other SQLite interface.  If it does, bad
** things may happen, including segmentation faults and corrupt database
** files.  The callback function should be a simple function that
** does some arithmetic on its input parameters and returns a result.
**
** ^The X parameter to sqlite3_autovacuum_pages(D,C,P,X) is an optional
** destructor for the P parameter.  ^If X is not NULL, then X(P) is
** invoked whenever the database connection closes or when the callback
** is overwritten by another invocation of sqlite3_autovacuum_pages().
**
** <p>^There is only one autovacuum pages callback per database connection.
** ^Each call to the sqlite3_autovacuum_pages() interface overrides all
** previous invocations for that database connection.  ^If the callback
** argument (C) to sqlite3_autovacuum_pages(D,C,P,X) is a NULL pointer,
** then the autovacuum steps callback is cancelled.  The return value
** from sqlite3_autovacuum_pages() is normally SQLITE_OK, but might
** be some other error code if something goes wrong.  The current
** implementation will only return SQLITE_OK or SQLITE_MISUSE, but other
** return codes might be added in future releases.
**
** <p>If no autovacuum pages callback is specified (the usual case) or
** a NULL pointer is provided for the callback,
** then the default behavior is to vacuum all free pages.  So, in other
** words, the default behavior is the same as if the callback function
** were something like this:
**
** <blockquote><pre>
** &nbsp;   unsigned int demonstration_autovac_pages_callback(
** &nbsp;     void *pClientData,
** &nbsp;     const char *zSchema,
** &nbsp;     unsigned int nDbPage,
** &nbsp;     unsigned int nFreePage,
** &nbsp;     unsigned int nBytePerPage
** &nbsp;   ){
** &nbsp;     return nFreePage;
** &nbsp;   }
** </pre></blockquote>
*/
int sqlite3_autovacuum_pages(
  sqlite3 *db,
  unsigned int(*)(void*,const char*,unsigned int,unsigned int,unsigned int),
  void*,
  void(*)(void*)
);


/*
** CAPI3REF: Data Change Notification Callbacks
** METHOD: sqlite3
**
** ^The sqlite3_update_hook() interface registers a callback function
** with the [database connection] identified by the first argument

  void (*free_filename)(char*);
  sqlite3_file *(*database_file_object)(const char*);
  /* Version 3.34.0 and later */
  int (*txn_state)(sqlite3*,const char*);
  /* Version 3.36.1 and later */
  sqlite3_int64 (*changes64)(sqlite3*);
  sqlite3_int64 (*total_changes64)(sqlite3*);
  /* Version 3.37.0 and later */
  int (*autovacuum_pages)(sqlite3*,
     unsigned int(*)(void*,const char*,unsigned int,unsigned int,unsigned int),
     void*, void(*)(void*));
};

/*
** This is the function signature used for all extension entry points.  It
** is also defined in the file "loadext.c".
*/
typedef int (*sqlite3_loadext_entry)(

#define sqlite3_filename_wal           sqlite3_api->filename_wal
/* Version 3.32.0 and later */
#define sqlite3_create_filename        sqlite3_api->create_filename
#define sqlite3_free_filename          sqlite3_api->free_filename
#define sqlite3_database_file_object   sqlite3_api->database_file_object
/* Version 3.34.0 and later */
#define sqlite3_txn_state              sqlite3_api->txn_state
/* Version 3.36.1 and later */
#define sqlite3_changes64              sqlite3_api->changes64
#define sqlite3_total_changes64        sqlite3_api->total_changes64
* Version 3.37.0 and later */
#define sqlite3_autovacuum_pages       sqlite3_api->autovacuum_pages
#endif /* !defined(SQLITE_CORE) && !defined(SQLITE_OMIT_LOAD_EXTENSION) */

#if !defined(SQLITE_CORE) && !defined(SQLITE_OMIT_LOAD_EXTENSION)
  /* This case when the file really is being compiled as a loadable 
  ** extension */
# define SQLITE_EXTENSION_INIT1     const sqlite3_api_routines *sqlite3_api=0;
# define SQLITE_EXTENSION_INIT2(v)  sqlite3_api=v;

#endif
  void *pCommitArg;                 /* Argument to xCommitCallback() */
  int (*xCommitCallback)(void*);    /* Invoked at every commit. */
  void *pRollbackArg;               /* Argument to xRollbackCallback() */
  void (*xRollbackCallback)(void*); /* Invoked at every commit. */
  void *pUpdateArg;
  void (*xUpdateCallback)(void*,int, const char*,const char*,sqlite_int64);
  void *pAutovacPagesArg;           /* Client argument to autovac_pages */
  void (*xAutovacDestr)(void*);     /* Destructor for pAutovacPAgesArg */
  unsigned int (*xAutovacPages)(void*,const char*,u32,u32,u32);
  Parse *pParse;                /* Current parse */
#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
  void *pPreUpdateArg;          /* First argument to xPreUpdateCallback */
  void (*xPreUpdateCallback)(   /* Registered using sqlite3_preupdate_hook() */
    void*,sqlite3*,int,char const*,char const*,sqlite3_int64,sqlite3_int64
  );
  PreUpdate *pPreUpdate;        /* Context for active pre-update callback */

    }
  }
  Tcl_SetObjResult(interp, Tcl_NewByteArrayObj(a, n));
  free(a);
  return TCL_OK;
}

/*
** Client data for the autovacuum_pages callback.
*/
struct AutovacPageData {
  Tcl_Interp *interp;
  char *zScript;
};
typedef struct AutovacPageData AutovacPageData;

/*
** Callback functions for sqlite3_autovacuum_pages
*/
static unsigned int test_autovacuum_pages_callback(
  void *pClientData,
  const char *zSchema,
  unsigned int nFilePages,
  unsigned int nFreePages,
  unsigned int nBytePerPage
){
  AutovacPageData *pData = (AutovacPageData*)pClientData;
  Tcl_DString str;
  unsigned int x;
  char zBuf[100];
  Tcl_DStringInit(&str);
  Tcl_DStringAppend(&str, pData->zScript, -1);
  Tcl_DStringAppendElement(&str, zSchema);
  sqlite3_snprintf(sizeof(zBuf), zBuf, "%u", nFilePages);
  Tcl_DStringAppendElement(&str, zBuf);
  sqlite3_snprintf(sizeof(zBuf), zBuf, "%u", nFreePages);
  Tcl_DStringAppendElement(&str, zBuf);
  sqlite3_snprintf(sizeof(zBuf), zBuf, "%u", nBytePerPage);
  Tcl_DStringAppendElement(&str, zBuf);
  Tcl_ResetResult(pData->interp);
  Tcl_Eval(pData->interp, Tcl_DStringValue(&str));
  Tcl_DStringFree(&str);
  x = nFreePages;
  (void)Tcl_GetIntFromObj(0, Tcl_GetObjResult(pData->interp), (int*)&x);
  return x;
}

/*
** Usage:  sqlite3_autovacuum_pages DB SCRIPT
**
** Add an autovacuum-pages callback to database connection DB.  The callback
** will invoke SCRIPT, after appending parameters.
**
** If SCRIPT is an empty string or is omitted, then the callback is
** cancelled.
*/
static int SQLITE_TCLAPI test_autovacuum_pages(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  AutovacPageData *pData;
  sqlite3 *db;
  int rc;
  const char *zScript;
  if( objc!=2 && objc!=3 ){
    Tcl_WrongNumArgs(interp, 1, objv, "DB ?SCRIPT?");
    return TCL_ERROR;
  }
  if( getDbPointer(interp, Tcl_GetString(objv[1]), &db) ) return TCL_ERROR;
  zScript = objc==3 ? Tcl_GetString(objv[2]) : 0;
  if( zScript ){
    size_t nScript = strlen(zScript);
    pData = sqlite3_malloc64( sizeof(*pData) + nScript + 1 );
    if( pData==0 ){
      Tcl_AppendResult(interp, "out of memory", (void*)0);
      return TCL_ERROR;
    }
    pData->interp = interp;
    pData->zScript = (char*)&pData[1];
    memcpy(pData->zScript, zScript, nScript+1);
    rc = sqlite3_autovacuum_pages(db,test_autovacuum_pages_callback,
                                  pData, sqlite3_free);
  }else{
    rc = sqlite3_autovacuum_pages(db, 0, 0, 0);
  }
  if( rc ){
    char zBuf[1000];
    sqlite3_snprintf(sizeof(zBuf), zBuf,
       "sqlite3_autovacuum_pages() returns %d", rc);
    Tcl_AppendResult(interp, zBuf, (void*)0);
    return TCL_ERROR;
  }
  return TCL_OK;
}


/*
** Register commands with the TCL interpreter.
*/
int Sqlitetest1_Init(Tcl_Interp *interp){
  extern int sqlite3_search_count;
  extern int sqlite3_found_count;

     { "sqlite3_snapshot_open_blob", test_snapshot_open_blob, 0 },
     { "sqlite3_snapshot_cmp_blob", test_snapshot_cmp_blob, 0 },
#endif
     { "sqlite3_delete_database", test_delete_database,    0 },
     { "atomic_batch_write",      test_atomic_batch_write, 0 },
     { "sqlite3_mmap_warm",       test_mmap_warm,          0 },
     { "sqlite3_config_sorterref", test_config_sorterref,   0 },
     { "sqlite3_autovacuum_pages", test_autovacuum_pages,   0 },
     { "decode_hexdb",             test_decode_hexdb,       0 },
     { "test_write_db",            test_write_db,           0 },
     { "sqlite3_register_cksumvfs", test_register_cksumvfs,  0 },
     { "sqlite3_unregister_cksumvfs", test_unregister_cksumvfs,  0 },
  };
  static int bitmask_size = sizeof(Bitmask)*8;
  static int longdouble_size = sizeof(LONGDOUBLE_TYPE);

# 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 file is testing the autovacuum feature.
#


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

# If this build of the library does not support auto-vacuum, omit this
# whole file.
ifcapable {!autovacuum || !pragma} {

# 2021-10-15
#
# 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 file is testing the sqlite3_autovacuum_pages() interface
#

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

# If this build of the library does not support auto-vacuum, omit this
# whole file.
ifcapable {!autovacuum || !pragma} {
  finish_test
  return
}

# Demonstrate basic sqlite3_autovacuum_pages functionality
#
do_execsql_test autovacuum2-1.0 {
  PRAGMA page_size=1024;
  PRAGMA auto_vacuum=FULL;
  CREATE TABLE t1(x);
  VACUUM;
  INSERT INTO t1(x) VALUES(zeroblob(10000));
  PRAGMA page_count;
} {12}
proc autovac_page_callback {schema filesize freesize pagesize} {
  global autovac_callback_data
  lappend autovac_callback_data $schema $filesize $freesize $pagesize
  return [expr {$freesize/2}]
}
sqlite3_autovacuum_pages db autovac_page_callback
set autovac_callback_data {}
do_execsql_test autovacuum2-1.1 {
  BEGIN;
  DELETE FROM t1;
  PRAGMA freelist_count;
  PRAGMA page_count;
} {9 12}
do_execsql_test autovacuum2-1.2 {
  COMMIT;
} {}
do_test autovacuum2-1.3 {
  set autovac_callback_data
} {main 12 9 1024}
do_execsql_test autovacuum2-1.4 {
  PRAGMA freelist_count;
  PRAGMA page_count;
} {5 8}
do_execsql_test autovacuum2-1.5 {
  PRAGMA integrity_check;
} {ok}

# Disable the autovacuum-pages callback.  Then do any transaction.
# The database should shrink to minimal size
#
sqlite3_autovacuum_pages db
do_execsql_test autovacuum2-1.10 {
  CREATE TABLE t2(x);
  PRAGMA freelist_count;
} {0}

# Rig the autovacuum-pages callback to always return zero.  No
# autovacuum will happen.
#
proc autovac_page_callback_off {schema filesize freesize pagesize} {
  return 0
}
sqlite3_autovacuum_pages db autovac_page_callback_off
do_execsql_test autovacuum2-1.20 {
  BEGIN;
  INSERT INTO t1(x) VALUES(zeroblob(10000));
  DELETE FROM t1;
  PRAGMA freelist_count;
  COMMIT;
  PRAGMA freelist_count;
} {9 9}

finish_test