/*
** Check that there is no open read-transaction on the b-tree passed as the
** second argument. If there is not, return SQLITE_OK. Otherwise, if there
** is an open read-transaction, return SQLITE_ERROR and leave an error
** message in database handle db.
*/
static int checkReadTransaction(sqlite3 *db, Btree *p){
if( sqlite3BtreeIsInReadTrans(p) ){
sqlite3ErrorWithMsg(db, SQLITE_ERROR, "destination database is in use");
return SQLITE_ERROR;
}
return SQLITE_OK;
}
/*
** Invalidate temp storage, either when the temp storage is changed
** from default, or when 'file' and the temp_store_directory has changed
*/
static int invalidateTempStorage(Parse *pParse){
sqlite3 *db = pParse->db;
if( db->aDb[1].pBt!=0 ){
if( !db->autoCommit || sqlite3BtreeIsInReadTrans(db->aDb[1].pBt) ){
sqlite3ErrorMsg(pParse, "temporary storage cannot be changed "
"from within a transaction");
return SQLITE_ERROR;
}
sqlite3BtreeClose(db->aDb[1].pBt);
db->aDb[1].pBt = 0;
sqlite3ResetInternalSchema(db, 0);
}
return SQLITE_OK;
}
/*
** An SQL user-function registered to do the work of an DETACH statement. The
** three arguments to the function come directly from a detach statement:
**
** DETACH DATABASE x
**
** SELECT sqlite_detach(x)
*/
static void detachFunc(
sqlite3_context *context,
int NotUsed,
sqlite3_value **argv
){
const char *zName = (const char *)sqlite3_value_text(argv[0]);
sqlite3 *db = sqlite3_context_db_handle(context);
int i;
Db *pDb = 0;
char zErr[128];
UNUSED_PARAMETER(NotUsed);
if( zName==0 ) zName = "";
for(i=0; i<db->nDb; i++){
pDb = &db->aDb[i];
if( pDb->pBt==0 ) continue;
if( sqlite3StrICmp(pDb->zName, zName)==0 ) break;
}
if( i>=db->nDb ){
sqlite3_snprintf(sizeof(zErr),zErr, "no such database: %s", zName);
goto detach_error;
}
if( i<2 ){
sqlite3_snprintf(sizeof(zErr),zErr, "cannot detach database %s", zName);
goto detach_error;
}
if( !db->autoCommit ){
sqlite3_snprintf(sizeof(zErr), zErr,
"cannot DETACH database within transaction");
goto detach_error;
}
if( sqlite3BtreeIsInReadTrans(pDb->pBt) || sqlite3BtreeIsInBackup(pDb->pBt) ){
sqlite3_snprintf(sizeof(zErr),zErr, "database %s is locked", zName);
goto detach_error;
}
sqlite3BtreeClose(pDb->pBt);
pDb->pBt = 0;
pDb->pSchema = 0;
sqlite3ResetInternalSchema(db, 0);
return;
detach_error:
sqlite3_result_error(context, zErr, -1);
}
/*
** Check schema cookies in all databases. If any cookie is out
** of date set pParse->rc to SQLITE_SCHEMA. If all schema cookies
** make no changes to pParse->rc.
*/
static void schemaIsValid(Parse *pParse){
sqlite3 *db = pParse->db;
int iDb;
int rc;
int cookie;
assert( pParse->checkSchema );
assert( sqlite3_mutex_held(db->mutex) );
for(iDb=0; iDb<db->nDb; iDb++){
int openedTransaction = 0; /* True if a transaction is opened */
Btree *pBt = db->aDb[iDb].pBt; /* Btree database to read cookie from */
if( pBt==0 ) continue;
/* If there is not already a read-only (or read-write) transaction opened
** on the b-tree database, open one now. If a transaction is opened, it
** will be closed immediately after reading the meta-value. */
if( !sqlite3BtreeIsInReadTrans(pBt) ){
rc = sqlite3BtreeBeginTrans(pBt, 0);
if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ){
db->mallocFailed = 1;
}
if( rc!=SQLITE_OK ) return;
openedTransaction = 1;
}
/* Read the schema cookie from the database. If it does not match the
** value stored as part of the in the in-memory schema representation,
** set Parse.rc to SQLITE_SCHEMA. */
sqlite3BtreeGetMeta(pBt, BTREE_SCHEMA_VERSION, (u32 *)&cookie);
if( cookie!=db->aDb[iDb].pSchema->schema_cookie ){
pParse->rc = SQLITE_SCHEMA;
}
/* Close the transaction, if one was opened. */
if( openedTransaction ){
sqlite3BtreeCommit(pBt);
}
}
}
/*
** Copy nPage pages from the source b-tree to the destination.
*/
int sqlite3_backup_step(sqlite3_backup *p, int nPage){
int rc;
int destMode; /* Destination journal mode */
int pgszSrc = 0; /* Source page size */
int pgszDest = 0; /* Destination page size */
#ifdef SQLITE_ENABLE_API_ARMOR
if( p==0 ) return SQLITE_MISUSE_BKPT;
#endif
sqlite3_mutex_enter(p->pSrcDb->mutex);
sqlite3BtreeEnter(p->pSrc);
if( p->pDestDb ){
sqlite3_mutex_enter(p->pDestDb->mutex);
}
rc = p->rc;
if( !isFatalError(rc) ){
Pager * const pSrcPager = sqlite3BtreePager(p->pSrc); /* Source pager */
Pager * const pDestPager = sqlite3BtreePager(p->pDest); /* Dest pager */
int ii; /* Iterator variable */
int nSrcPage = -1; /* Size of source db in pages */
int bCloseTrans = 0; /* True if src db requires unlocking */
/* If the source pager is currently in a write-transaction, return
** SQLITE_BUSY immediately.
*/
if( p->pDestDb && p->pSrc->pBt->inTransaction==TRANS_WRITE ){
rc = SQLITE_BUSY;
}else{
rc = SQLITE_OK;
}
/* If there is no open read-transaction on the source database, open
** one now. If a transaction is opened here, then it will be closed
** before this function exits.
*/
if( rc==SQLITE_OK && 0==sqlite3BtreeIsInReadTrans(p->pSrc) ){
rc = sqlite3BtreeBeginTrans(p->pSrc, 0, 0);
bCloseTrans = 1;
}
/* If the destination database has not yet been locked (i.e. if this
** is the first call to backup_step() for the current backup operation),
** try to set its page size to the same as the source database. This
** is especially important on ZipVFS systems, as in that case it is
** not possible to create a database file that uses one page size by
** writing to it with another. */
if( p->bDestLocked==0 && rc==SQLITE_OK && setDestPgsz(p)==SQLITE_NOMEM ){
rc = SQLITE_NOMEM;
}
/* Lock the destination database, if it is not locked already. */
if( SQLITE_OK==rc && p->bDestLocked==0
&& SQLITE_OK==(rc = sqlite3BtreeBeginTrans(p->pDest, 2,
(int*)&p->iDestSchema))
){
p->bDestLocked = 1;
}
/* Do not allow backup if the destination database is in WAL mode
** and the page sizes are different between source and destination */
pgszSrc = sqlite3BtreeGetPageSize(p->pSrc);
pgszDest = sqlite3BtreeGetPageSize(p->pDest);
destMode = sqlite3PagerGetJournalMode(sqlite3BtreePager(p->pDest));
if( SQLITE_OK==rc && destMode==PAGER_JOURNALMODE_WAL && pgszSrc!=pgszDest ){
rc = SQLITE_READONLY;
}
/* Now that there is a read-lock on the source database, query the
** source pager for the number of pages in the database.
*/
nSrcPage = (int)sqlite3BtreeLastPage(p->pSrc);
assert( nSrcPage>=0 );
for(ii=0; (nPage<0 || ii<nPage) && p->iNext<=(Pgno)nSrcPage && !rc; ii++){
const Pgno iSrcPg = p->iNext; /* Source page number */
if( iSrcPg!=PENDING_BYTE_PAGE(p->pSrc->pBt) ){
DbPage *pSrcPg; /* Source page object */
rc = sqlite3PagerGet(pSrcPager, iSrcPg, &pSrcPg,PAGER_GET_READONLY);
if( rc==SQLITE_OK ){
rc = backupOnePage(p, iSrcPg, sqlite3PagerGetData(pSrcPg), 0);
sqlite3PagerUnref(pSrcPg);
}
}
p->iNext++;
}
if( rc==SQLITE_OK ){
p->nPagecount = nSrcPage;
p->nRemaining = nSrcPage+1-p->iNext;
if( p->iNext>(Pgno)nSrcPage ){
rc = SQLITE_DONE;
}else if( !p->isAttached ){
attachBackupObject(p);
}
}
/* Update the schema version field in the destination database. This
** is to make sure that the schema-version really does change in
** the case where the source and destination databases have the
** same schema version.
*/
if( rc==SQLITE_DONE ){
if( nSrcPage==0 ){
rc = sqlite3BtreeNewDb(p->pDest);
nSrcPage = 1;
}
if( rc==SQLITE_OK || rc==SQLITE_DONE ){
rc = sqlite3BtreeUpdateMeta(p->pDest,1,p->iDestSchema+1);
}
if( rc==SQLITE_OK ){
if( p->pDestDb ){
sqlite3ResetAllSchemasOfConnection(p->pDestDb);
}
if( destMode==PAGER_JOURNALMODE_WAL ){
rc = sqlite3BtreeSetVersion(p->pDest, 2);
}
}
if( rc==SQLITE_OK ){
int nDestTruncate;
/* Set nDestTruncate to the final number of pages in the destination
** database. The complication here is that the destination page
** size may be different to the source page size.
**
** If the source page size is smaller than the destination page size,
** round up. In this case the call to sqlite3OsTruncate() below will
** fix the size of the file. However it is important to call
** sqlite3PagerTruncateImage() here so that any pages in the
** destination file that lie beyond the nDestTruncate page mark are
** journalled by PagerCommitPhaseOne() before they are destroyed
** by the file truncation.
*/
assert( pgszSrc==sqlite3BtreeGetPageSize(p->pSrc) );
assert( pgszDest==sqlite3BtreeGetPageSize(p->pDest) );
if( pgszSrc<pgszDest ){
int ratio = pgszDest/pgszSrc;
nDestTruncate = (nSrcPage+ratio-1)/ratio;
if( nDestTruncate==(int)PENDING_BYTE_PAGE(p->pDest->pBt) ){
nDestTruncate--;
}
}else{
nDestTruncate = nSrcPage * (pgszSrc/pgszDest);
}
assert( nDestTruncate>0 );
if( pgszSrc<pgszDest ){
/* If the source page-size is smaller than the destination page-size,
** two extra things may need to happen:
**
** * The destination may need to be truncated, and
**
** * Data stored on the pages immediately following the
** pending-byte page in the source database may need to be
** copied into the destination database.
*/
const i64 iSize = (i64)pgszSrc * (i64)nSrcPage;
sqlite3_file * const pFile = sqlite3PagerFile(pDestPager);
Pgno iPg;
int nDstPage;
i64 iOff;
i64 iEnd;
assert( pFile );
assert( nDestTruncate==0
|| (i64)nDestTruncate*(i64)pgszDest >= iSize || (
nDestTruncate==(int)(PENDING_BYTE_PAGE(p->pDest->pBt)-1)
&& iSize>=PENDING_BYTE && iSize<=PENDING_BYTE+pgszDest
));
/* This block ensures that all data required to recreate the original
** database has been stored in the journal for pDestPager and the
** journal synced to disk. So at this point we may safely modify
** the database file in any way, knowing that if a power failure
** occurs, the original database will be reconstructed from the
** journal file. */
sqlite3PagerPagecount(pDestPager, &nDstPage);
for(iPg=nDestTruncate; rc==SQLITE_OK && iPg<=(Pgno)nDstPage; iPg++){
if( iPg!=PENDING_BYTE_PAGE(p->pDest->pBt) ){
DbPage *pPg;
rc = sqlite3PagerGet(pDestPager, iPg, &pPg, 0);
if( rc==SQLITE_OK ){
rc = sqlite3PagerWrite(pPg);
sqlite3PagerUnref(pPg);
}
}
}
if( rc==SQLITE_OK ){
rc = sqlite3PagerCommitPhaseOne(pDestPager, 0, 1);
}
/* Write the extra pages and truncate the database file as required */
iEnd = MIN(PENDING_BYTE + pgszDest, iSize);
for(
iOff=PENDING_BYTE+pgszSrc;
rc==SQLITE_OK && iOff<iEnd;
iOff+=pgszSrc
){
PgHdr *pSrcPg = 0;
const Pgno iSrcPg = (Pgno)((iOff/pgszSrc)+1);
rc = sqlite3PagerGet(pSrcPager, iSrcPg, &pSrcPg, 0);
if( rc==SQLITE_OK ){
u8 *zData = sqlite3PagerGetData(pSrcPg);
rc = sqlite3OsWrite(pFile, zData, pgszSrc, iOff);
}
sqlite3PagerUnref(pSrcPg);
}
if( rc==SQLITE_OK ){
rc = backupTruncateFile(pFile, iSize);
}
/* Sync the database file to disk. */
if( rc==SQLITE_OK ){
rc = sqlite3PagerSync(pDestPager, 0);
}
}else{
sqlite3PagerTruncateImage(pDestPager, nDestTruncate);
rc = sqlite3PagerCommitPhaseOne(pDestPager, 0, 0);
}
/* Finish committing the transaction to the destination database. */
if( SQLITE_OK==rc
&& SQLITE_OK==(rc = sqlite3BtreeCommitPhaseTwo(p->pDest, 0))
){
rc = SQLITE_DONE;
}
}
}
/* If bCloseTrans is true, then this function opened a read transaction
** on the source database. Close the read transaction here. There is
** no need to check the return values of the btree methods here, as
** "committing" a read-only transaction cannot fail.
*/
if( bCloseTrans ){
TESTONLY( int rc2 );
TESTONLY( rc2 = ) sqlite3BtreeCommitPhaseOne(p->pSrc, 0);
TESTONLY( rc2 |= ) sqlite3BtreeCommitPhaseTwo(p->pSrc, 0);
assert( rc2==SQLITE_OK );
}
if( rc==SQLITE_IOERR_NOMEM ){
rc = SQLITE_NOMEM_BKPT;
}
p->rc = rc;
}
/*
** Attempt to read the database schema and initialize internal
** data structures for a single database file. The index of the
** database file is given by iDb. iDb==0 is used for the main
** database. iDb==1 should never be used. iDb>=2 is used for
** auxiliary databases. Return one of the SQLITE_ error codes to
** indicate success or failure.
*/
static int sqlite3InitOne(sqlite3 *db, int iDb, char **pzErrMsg){
int rc;
int i;
int size;
Table *pTab;
Db *pDb;
char const *azArg[4];
int meta[5];
InitData initData;
char const *zMasterSchema;
char const *zMasterName = SCHEMA_TABLE(iDb);
int openedTransaction = 0;
/*
** The master database table has a structure like this
*/
static const char master_schema[] =
"CREATE TABLE sqlite_master(\n"
" type text,\n"
" name text,\n"
" tbl_name text,\n"
" rootpage integer,\n"
" sql text\n"
")"
;
#ifndef SQLITE_OMIT_TEMPDB
static const char temp_master_schema[] =
"CREATE TEMP TABLE sqlite_temp_master(\n"
" type text,\n"
" name text,\n"
" tbl_name text,\n"
" rootpage integer,\n"
" sql text\n"
")"
;
#else
#define temp_master_schema 0
#endif
assert( iDb>=0 && iDb<db->nDb );
assert( db->aDb[iDb].pSchema );
assert( sqlite3_mutex_held(db->mutex) );
assert( iDb==1 || sqlite3BtreeHoldsMutex(db->aDb[iDb].pBt) );
/* 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;
}else{
zMasterSchema = master_schema;
}
zMasterName = SCHEMA_TABLE(iDb);
/* Construct the schema tables. */
azArg[0] = zMasterName;
azArg[1] = "1";
azArg[2] = zMasterSchema;
azArg[3] = 0;
initData.db = db;
initData.iDb = iDb;
initData.rc = SQLITE_OK;
initData.pzErrMsg = pzErrMsg;
(void)sqlite3SafetyOff(db);
sqlite3InitCallback(&initData, 3, (char **)azArg, 0);
(void)sqlite3SafetyOn(db);
if( initData.rc ){
rc = initData.rc;
goto error_out;
}
pTab = sqlite3FindTable(db, zMasterName, db->aDb[iDb].zName);
if( ALWAYS(pTab) ){
pTab->tabFlags |= TF_Readonly;
}
/* Create a cursor to hold the database open
*/
pDb = &db->aDb[iDb];
if( pDb->pBt==0 ){
if( !OMIT_TEMPDB && ALWAYS(iDb==1) ){
DbSetProperty(db, 1, DB_SchemaLoaded);
}
return SQLITE_OK;
}
/* If there is not already a read-only (or read-write) transaction opened
** on the b-tree database, open one now. If a transaction is opened, it
** will be closed before this function returns. */
sqlite3BtreeEnter(pDb->pBt);
if( !sqlite3BtreeIsInReadTrans(pDb->pBt) ){
rc = sqlite3BtreeBeginTrans(pDb->pBt, 0);
if( rc!=SQLITE_OK ){
sqlite3SetString(pzErrMsg, db, "%s", sqlite3ErrStr(rc));
goto initone_error_out;
}
openedTransaction = 1;
}
/* Get the database meta information.
**
** Meta values are as follows:
** meta[0] Schema cookie. Changes with each schema change.
** meta[1] File format of schema layer.
** meta[2] Size of the page cache.
** meta[3] Largest rootpage (auto/incr_vacuum mode)
** meta[4] Db text encoding. 1:UTF-8 2:UTF-16LE 3:UTF-16BE
** meta[5] User version
** meta[6] Incremental vacuum mode
** meta[7] unused
** meta[8] unused
** meta[9] unused
**
** Note: The #defined SQLITE_UTF* symbols in sqliteInt.h correspond to
** the possible values of meta[4].
*/
for(i=0; i<ArraySize(meta); i++){
sqlite3BtreeGetMeta(pDb->pBt, i+1, (u32 *)&meta[i]);
}
pDb->pSchema->schema_cookie = meta[BTREE_SCHEMA_VERSION-1];
/* 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[BTREE_TEXT_ENCODING-1] ){ /* text encoding */
if( iDb==0 ){
u8 encoding;
/* If opening the main database, set ENC(db). */
encoding = (u8)meta[BTREE_TEXT_ENCODING-1] & 3;
if( encoding==0 ) encoding = SQLITE_UTF8;
ENC(db) = encoding;
db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, "BINARY", 0);
}else{
/* If opening an attached database, the encoding much match ENC(db) */
if( meta[BTREE_TEXT_ENCODING-1]!=ENC(db) ){
sqlite3SetString(pzErrMsg, db, "attached databases must use the same"
" text encoding as main database");
rc = SQLITE_ERROR;
goto initone_error_out;
}
}
}else{
DbSetProperty(db, iDb, DB_Empty);
}
pDb->pSchema->enc = ENC(db);
if( pDb->pSchema->cache_size==0 ){
size = meta[BTREE_DEFAULT_CACHE_SIZE-1];
if( size==0 ){ size = SQLITE_DEFAULT_CACHE_SIZE; }
if( size<0 ) size = -size;
pDb->pSchema->cache_size = size;
sqlite3BtreeSetCacheSize(pDb->pBt, pDb->pSchema->cache_size);
}
/*
** 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 = (u8)meta[BTREE_FILE_FORMAT-1];
if( pDb->pSchema->file_format==0 ){
pDb->pSchema->file_format = 1;
}
if( pDb->pSchema->file_format>SQLITE_MAX_FILE_FORMAT ){
sqlite3SetString(pzErrMsg, db, "unsupported file format");
rc = SQLITE_ERROR;
goto initone_error_out;
}
/* Ticket #2804: When we open a database in the newer file format,
** clear the legacy_file_format pragma flag so that a VACUUM will
** not downgrade the database and thus invalidate any descending
** indices that the user might have created.
*/
if( iDb==0 && meta[BTREE_FILE_FORMAT-1]>=4 ){
db->flags &= ~SQLITE_LegacyFileFmt;
}
/* Read the schema information out of the schema tables
*/
assert( db->init.busy );
{
char *zSql;
zSql = sqlite3MPrintf(db,
"SELECT name, rootpage, sql FROM '%q'.%s",
db->aDb[iDb].zName, zMasterName);
(void)sqlite3SafetyOff(db);
#ifndef SQLITE_OMIT_AUTHORIZATION
{
int (*xAuth)(void*,int,const char*,const char*,const char*,const char*);
xAuth = db->xAuth;
db->xAuth = 0;
#endif
rc = sqlite3_exec(db, zSql, sqlite3InitCallback, &initData, 0);
#ifndef SQLITE_OMIT_AUTHORIZATION
db->xAuth = xAuth;
}
#endif
if( rc==SQLITE_OK ) rc = initData.rc;
(void)sqlite3SafetyOn(db);
sqlite3DbFree(db, zSql);
#ifndef SQLITE_OMIT_ANALYZE
if( rc==SQLITE_OK ){
sqlite3AnalysisLoad(db, iDb);
}
#endif
}
if( db->mallocFailed ){
rc = SQLITE_NOMEM;
sqlite3ResetInternalSchema(db, 0);
}
if( rc==SQLITE_OK || (db->flags&SQLITE_RecoveryMode)){
/* Black magic: If the SQLITE_RecoveryMode flag is set, then consider
** the schema loaded, even if errors occurred. In this situation the
** current sqlite3_prepare() operation will fail, but the following one
** will attempt to compile the supplied statement against whatever subset
** of the schema was loaded before the error occurred. The primary
** purpose of this is to allow access to the sqlite_master table
** even when its contents have been corrupted.
*/
DbSetProperty(db, iDb, DB_SchemaLoaded);
rc = SQLITE_OK;
}
/* Jump here for an error that occurs after successfully allocating
** curMain and calling sqlite3BtreeEnter(). For an error that occurs
** before that point, jump to error_out.
*/
initone_error_out:
if( openedTransaction ){
sqlite3BtreeCommit(pDb->pBt);
}
sqlite3BtreeLeave(pDb->pBt);
error_out:
if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ){
db->mallocFailed = 1;
}
return rc;
}
/*
** Copy nPage pages from the source b-tree to the destination.
*/
int sqlite3_backup_step(sqlite3_backup *p, int nPage){
int rc;
int destMode; /* Destination journal mode */
int pgszSrc = 0; /* Source page size */
int pgszDest = 0; /* Destination page size */
sqlite3_mutex_enter(p->pSrcDb->mutex);
sqlite3BtreeEnter(p->pSrc);
if( p->pDestDb ){
sqlite3_mutex_enter(p->pDestDb->mutex);
}
rc = p->rc;
if( !isFatalError(rc) ){
Pager * const pSrcPager = sqlite3BtreePager(p->pSrc); /* Source pager */
Pager * const pDestPager = sqlite3BtreePager(p->pDest); /* Dest pager */
int ii; /* Iterator variable */
int nSrcPage = -1; /* Size of source db in pages */
int bCloseTrans = 0; /* True if src db requires unlocking */
/* If the source pager is currently in a write-transaction, return
** SQLITE_BUSY immediately.
*/
if( p->pDestDb && p->pSrc->pBt->inTransaction==TRANS_WRITE ){
rc = SQLITE_BUSY;
}else{
rc = SQLITE_OK;
}
/* Lock the destination database, if it is not locked already. */
if( SQLITE_OK==rc && p->bDestLocked==0
&& SQLITE_OK==(rc = sqlite3BtreeBeginTrans(p->pDest, 2))
){
p->bDestLocked = 1;
sqlite3BtreeGetMeta(p->pDest, BTREE_SCHEMA_VERSION, &p->iDestSchema);
}
/* If there is no open read-transaction on the source database, open
** one now. If a transaction is opened here, then it will be closed
** before this function exits.
*/
if( rc==SQLITE_OK && 0==sqlite3BtreeIsInReadTrans(p->pSrc) ){
rc = sqlite3BtreeBeginTrans(p->pSrc, 0);
bCloseTrans = 1;
}
/* Do not allow backup if the destination database is in WAL mode
** and the page sizes are different between source and destination */
pgszSrc = sqlite3BtreeGetPageSize(p->pSrc);
pgszDest = sqlite3BtreeGetPageSize(p->pDest);
destMode = sqlite3PagerGetJournalMode(sqlite3BtreePager(p->pDest));
if( SQLITE_OK==rc && destMode==PAGER_JOURNALMODE_WAL && pgszSrc!=pgszDest ){
rc = SQLITE_READONLY;
}
/* Now that there is a read-lock on the source database, query the
** source pager for the number of pages in the database.
*/
nSrcPage = (int)sqlite3BtreeLastPage(p->pSrc);
assert( nSrcPage>=0 );
for(ii=0; (nPage<0 || ii<nPage) && p->iNext<=(Pgno)nSrcPage && !rc; ii++){
const Pgno iSrcPg = p->iNext; /* Source page number */
if( iSrcPg!=PENDING_BYTE_PAGE(p->pSrc->pBt) ){
DbPage *pSrcPg; /* Source page object */
rc = sqlite3PagerGet(pSrcPager, iSrcPg, &pSrcPg);
if( rc==SQLITE_OK ){
rc = backupOnePage(p, iSrcPg, sqlite3PagerGetData(pSrcPg));
sqlite3PagerUnref(pSrcPg);
}
}
p->iNext++;
}
if( rc==SQLITE_OK ){
p->nPagecount = nSrcPage;
p->nRemaining = nSrcPage+1-p->iNext;
if( p->iNext>(Pgno)nSrcPage ){
rc = SQLITE_DONE;
}else if( !p->isAttached ){
attachBackupObject(p);
}
}
/* Update the schema version field in the destination database. This
** is to make sure that the schema-version really does change in
** the case where the source and destination databases have the
** same schema version.
*/
if( rc==SQLITE_DONE
&& (rc = sqlite3BtreeUpdateMeta(p->pDest,1,p->iDestSchema+1))==SQLITE_OK
){
int nDestTruncate;
if( p->pDestDb ){
sqlite3ResetInternalSchema(p->pDestDb, 0);
}
/* Set nDestTruncate to the final number of pages in the destination
** database. The complication here is that the destination page
** size may be different to the source page size.
**
** If the source page size is smaller than the destination page size,
** round up. In this case the call to sqlite3OsTruncate() below will
** fix the size of the file. However it is important to call
** sqlite3PagerTruncateImage() here so that any pages in the
** destination file that lie beyond the nDestTruncate page mark are
** journalled by PagerCommitPhaseOne() before they are destroyed
** by the file truncation.
*/
assert( pgszSrc==sqlite3BtreeGetPageSize(p->pSrc) );
assert( pgszDest==sqlite3BtreeGetPageSize(p->pDest) );
if( pgszSrc<pgszDest ){
int ratio = pgszDest/pgszSrc;
nDestTruncate = (nSrcPage+ratio-1)/ratio;
if( nDestTruncate==(int)PENDING_BYTE_PAGE(p->pDest->pBt) ){
nDestTruncate--;
}
}else{
nDestTruncate = nSrcPage * (pgszSrc/pgszDest);
}
sqlite3PagerTruncateImage(pDestPager, nDestTruncate);
if( pgszSrc<pgszDest ){
/* If the source page-size is smaller than the destination page-size,
** two extra things may need to happen:
**
** * The destination may need to be truncated, and
**
** * Data stored on the pages immediately following the
** pending-byte page in the source database may need to be
** copied into the destination database.
*/
const i64 iSize = (i64)pgszSrc * (i64)nSrcPage;
sqlite3_file * const pFile = sqlite3PagerFile(pDestPager);
assert( pFile );
assert( (i64)nDestTruncate*(i64)pgszDest >= iSize || (
nDestTruncate==(int)(PENDING_BYTE_PAGE(p->pDest->pBt)-1)
&& iSize>=PENDING_BYTE && iSize<=PENDING_BYTE+pgszDest
));
if( SQLITE_OK==(rc = sqlite3PagerCommitPhaseOne(pDestPager, 0, 1))
&& SQLITE_OK==(rc = backupTruncateFile(pFile, iSize))
&& SQLITE_OK==(rc = sqlite3PagerSync(pDestPager))
){
i64 iOff;
i64 iEnd = MIN(PENDING_BYTE + pgszDest, iSize);
for(
iOff=PENDING_BYTE+pgszSrc;
rc==SQLITE_OK && iOff<iEnd;
iOff+=pgszSrc
){
PgHdr *pSrcPg = 0;
const Pgno iSrcPg = (Pgno)((iOff/pgszSrc)+1);
rc = sqlite3PagerGet(pSrcPager, iSrcPg, &pSrcPg);
if( rc==SQLITE_OK ){
u8 *zData = sqlite3PagerGetData(pSrcPg);
rc = sqlite3OsWrite(pFile, zData, pgszSrc, iOff);
}
sqlite3PagerUnref(pSrcPg);
}
}
}else{
rc = sqlite3PagerCommitPhaseOne(pDestPager, 0, 0);
}
/* Finish committing the transaction to the destination database. */
if( SQLITE_OK==rc
&& SQLITE_OK==(rc = sqlite3BtreeCommitPhaseTwo(p->pDest))
){
rc = SQLITE_DONE;
}
}
/* If bCloseTrans is true, then this function opened a read transaction
** on the source database. Close the read transaction here. There is
** no need to check the return values of the btree methods here, as
** "committing" a read-only transaction cannot fail.
*/
if( bCloseTrans ){
TESTONLY( int rc2 );
TESTONLY( rc2 = ) sqlite3BtreeCommitPhaseOne(p->pSrc, 0);
TESTONLY( rc2 |= ) sqlite3BtreeCommitPhaseTwo(p->pSrc);
assert( rc2==SQLITE_OK );
}
if( rc==SQLITE_IOERR_NOMEM ){
rc = SQLITE_NOMEM;
}
p->rc = rc;
}
