/*
** Usage: page_write PAGE DATA
**
** Write something into a page.
*/
static int page_write(
void *NotUsed,
Tcl_Interp *interp, /* The TCL interpreter that invoked this command */
int argc, /* Number of arguments */
const char **argv /* Text of each argument */
){
DbPage *pPage;
char *pData;
int rc;
if( argc!=3 ){
Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
" PAGE DATA\"", 0);
return TCL_ERROR;
}
pPage = (DbPage *)sqlite3TestTextToPtr(argv[1]);
rc = sqlite3PagerWrite(pPage);
if( rc!=SQLITE_OK ){
Tcl_AppendResult(interp, errorName(rc), 0);
return TCL_ERROR;
}
pData = sqlite3PagerGetData(pPage);
strncpy(pData, argv[2], test_pagesize-1);
pData[test_pagesize-1] = 0;
return TCL_OK;
}
static int page_write(
void *NotUsed,
Tcl_Interp *interp,
int argc,
const char **argv
){
DbPage *pPage;
char *pData;
int rc;
if( argc!=3 ){
Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
" PAGE DATA\"", 0);
return TCL_ERROR;
}
pPage = (DbPage *)sqlite3TestTextToPtr(argv[1]);
rc = sqlite3PagerWrite(pPage);
if( rc!=SQLITE_OK ){
Tcl_AppendResult(interp, errorName(rc), 0);
return TCL_ERROR;
}
pData = sqlite3PagerGetData(pPage);
strncpy(pData, argv[2], test_pagesize-1);
pData[test_pagesize-1] = 0;
return TCL_OK;
}
static int dbpageColumn(
sqlite3_vtab_cursor *pCursor,
sqlite3_context *ctx,
int i
){
DbpageCursor *pCsr = (DbpageCursor *)pCursor;
DbpageTable *pTab = (DbpageTable *)pCursor->pVtab;
int rc = SQLITE_OK;
switch( i ){
case 0: { /* pgno */
sqlite3_result_int(ctx, pCsr->pgno);
break;
}
case 1: { /* data */
DbPage *pDbPage = 0;
rc = sqlite3PagerGet(pTab->pPager, pCsr->pgno, (DbPage**)&pDbPage, 0);
if( rc==SQLITE_OK ){
sqlite3_result_blob(ctx, sqlite3PagerGetData(pDbPage), pTab->szPage,
SQLITE_TRANSIENT);
}
sqlite3PagerUnref(pDbPage);
break;
}
default: { /* schema */
sqlite3 *db = sqlite3_context_db_handle(ctx);
sqlite3_result_text(ctx, db->aDb[pTab->iDb].zDbSName, -1, SQLITE_STATIC);
break;
}
}
return SQLITE_OK;
}
/*
** Parameter zSrcData points to a buffer containing the data for
** page iSrcPg from the source database. Copy this data into the
** destination database.
*/
static int backupOnePage(sqlite3_backup *p, Pgno iSrcPg, const u8 *zSrcData){
Pager * const pDestPager = sqlite3BtreePager(p->pDest);
const int nSrcPgsz = sqlite3BtreeGetPageSize(p->pSrc);
int nDestPgsz = sqlite3BtreeGetPageSize(p->pDest);
const int nCopy = MIN(nSrcPgsz, nDestPgsz);
const i64 iEnd = (i64)iSrcPg*(i64)nSrcPgsz;
int rc = SQLITE_OK;
i64 iOff;
assert( p->bDestLocked );
assert( !isFatalError(p->rc) );
assert( iSrcPg!=PENDING_BYTE_PAGE(p->pSrc->pBt) );
assert( zSrcData );
/* Catch the case where the destination is an in-memory database and the
** page sizes of the source and destination differ.
*/
if( nSrcPgsz!=nDestPgsz && sqlite3PagerIsMemdb(sqlite3BtreePager(p->pDest)) ){
rc = SQLITE_READONLY;
}
/* This loop runs once for each destination page spanned by the source
** page. For each iteration, variable iOff is set to the byte offset
** of the destination page.
*/
for(iOff=iEnd-(i64)nSrcPgsz; rc==SQLITE_OK && iOff<iEnd; iOff+=nDestPgsz){
DbPage *pDestPg = 0;
Pgno iDest = (Pgno)(iOff/nDestPgsz)+1;
if( iDest==PENDING_BYTE_PAGE(p->pDest->pBt) ) continue;
if( SQLITE_OK==(rc = sqlite3PagerGet(pDestPager, iDest, &pDestPg))
&& SQLITE_OK==(rc = sqlite3PagerWrite(pDestPg))
){
const u8 *zIn = &zSrcData[iOff%nSrcPgsz];
u8 *zDestData = sqlite3PagerGetData(pDestPg);
u8 *zOut = &zDestData[iOff%nDestPgsz];
/* Copy the data from the source page into the destination page.
** Then clear the Btree layer MemPage.isInit flag. Both this module
** and the pager code use this trick (clearing the first byte
** of the page 'extra' space to invalidate the Btree layers
** cached parse of the page). MemPage.isInit is marked
** "MUST BE FIRST" for this purpose.
*/
memcpy(zOut, zIn, nCopy);
((u8 *)sqlite3PagerGetExtra(pDestPg))[0] = 0;
}
sqlite3PagerUnref(pDestPg);
}
return rc;
}
static int dbpageUpdate(
sqlite3_vtab *pVtab,
int argc,
sqlite3_value **argv,
sqlite_int64 *pRowid
){
DbpageTable *pTab = (DbpageTable *)pVtab;
int pgno;
DbPage *pDbPage = 0;
int rc = SQLITE_OK;
char *zErr = 0;
if( argc==1 ){
zErr = "cannot delete";
goto update_fail;
}
pgno = sqlite3_value_int(argv[0]);
if( pgno<1 || pgno>pTab->nPage ){
zErr = "bad page number";
goto update_fail;
}
if( sqlite3_value_int(argv[1])!=pgno ){
zErr = "cannot insert";
goto update_fail;
}
if( sqlite3_value_type(argv[3])!=SQLITE_BLOB
|| sqlite3_value_bytes(argv[3])!=pTab->szPage
){
zErr = "bad page value";
goto update_fail;
}
rc = sqlite3PagerGet(pTab->pPager, pgno, (DbPage**)&pDbPage, 0);
if( rc==SQLITE_OK ){
rc = sqlite3PagerWrite(pDbPage);
if( rc==SQLITE_OK ){
memcpy(sqlite3PagerGetData(pDbPage),
sqlite3_value_blob(argv[3]),
pTab->szPage);
}
}
sqlite3PagerUnref(pDbPage);
return rc;
update_fail:
sqlite3_free(pVtab->zErrMsg);
pVtab->zErrMsg = sqlite3_mprintf("%s", zErr);
return SQLITE_ERROR;
}
/*
** Usage: page_read PAGE
**
** Return the content of a page
*/
static int page_read(
void *NotUsed,
Tcl_Interp *interp, /* The TCL interpreter that invoked this command */
int argc, /* Number of arguments */
const char **argv /* Text of each argument */
){
char zBuf[100];
DbPage *pPage;
if( argc!=2 ){
Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
" PAGE\"", 0);
return TCL_ERROR;
}
pPage = sqlite3TestTextToPtr(argv[1]);
memcpy(zBuf, sqlite3PagerGetData(pPage), sizeof(zBuf));
Tcl_AppendResult(interp, zBuf, 0);
return TCL_OK;
}
static int page_read(
void *NotUsed,
Tcl_Interp *interp,
int argc,
const char **argv
){
char zBuf[100];
DbPage *pPage;
if( argc!=2 ){
Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
" PAGE\"", 0);
return TCL_ERROR;
}
pPage = sqlite3TestTextToPtr(argv[1]);
memcpy(zBuf, sqlite3PagerGetData(pPage), sizeof(zBuf));
Tcl_AppendResult(interp, zBuf, 0);
return TCL_OK;
}
static int statDecodePage(Btree *pBt, StatPage *p){
int nUnused;
int iOff;
int nHdr;
int isLeaf;
int szPage;
u8 *aData = sqlite3PagerGetData(p->pPg);
u8 *aHdr = &aData[p->iPgno==1 ? 100 : 0];
p->flags = aHdr[0];
p->nCell = get2byte(&aHdr[3]);
p->nMxPayload = 0;
isLeaf = (p->flags==0x0A || p->flags==0x0D);
nHdr = 12 - isLeaf*4 + (p->iPgno==1)*100;
nUnused = get2byte(&aHdr[5]) - nHdr - 2*p->nCell;
nUnused += (int)aHdr[7];
iOff = get2byte(&aHdr[1]);
while( iOff ){
nUnused += get2byte(&aData[iOff+2]);
iOff = get2byte(&aData[iOff]);
}
p->nUnused = nUnused;
p->iRightChildPg = isLeaf ? 0 : sqlite3Get4byte(&aHdr[8]);
szPage = sqlite3BtreeGetPageSize(pBt);
if( p->nCell ){
int i; /* Used to iterate through cells */
int nUsable; /* Usable bytes per page */
sqlite3BtreeEnter(pBt);
nUsable = szPage - sqlite3BtreeGetReserveNoMutex(pBt);
sqlite3BtreeLeave(pBt);
p->aCell = sqlite3_malloc64((p->nCell+1) * sizeof(StatCell));
if( p->aCell==0 ) return SQLITE_NOMEM_BKPT;
memset(p->aCell, 0, (p->nCell+1) * sizeof(StatCell));
for(i=0; i<p->nCell; i++){
StatCell *pCell = &p->aCell[i];
iOff = get2byte(&aData[nHdr+i*2]);
if( !isLeaf ){
pCell->iChildPg = sqlite3Get4byte(&aData[iOff]);
iOff += 4;
}
if( p->flags==0x05 ){
/* A table interior node. nPayload==0. */
}else{
u32 nPayload; /* Bytes of payload total (local+overflow) */
int nLocal; /* Bytes of payload stored locally */
iOff += getVarint32(&aData[iOff], nPayload);
if( p->flags==0x0D ){
u64 dummy;
iOff += sqlite3GetVarint(&aData[iOff], &dummy);
}
if( nPayload>(u32)p->nMxPayload ) p->nMxPayload = nPayload;
getLocalPayload(nUsable, p->flags, nPayload, &nLocal);
pCell->nLocal = nLocal;
assert( nLocal>=0 );
assert( nPayload>=(u32)nLocal );
assert( nLocal<=(nUsable-35) );
if( nPayload>(u32)nLocal ){
int j;
int nOvfl = ((nPayload - nLocal) + nUsable-4 - 1) / (nUsable - 4);
pCell->nLastOvfl = (nPayload-nLocal) - (nOvfl-1) * (nUsable-4);
pCell->nOvfl = nOvfl;
pCell->aOvfl = sqlite3_malloc64(sizeof(u32)*nOvfl);
if( pCell->aOvfl==0 ) return SQLITE_NOMEM_BKPT;
pCell->aOvfl[0] = sqlite3Get4byte(&aData[iOff+nLocal]);
for(j=1; j<nOvfl; j++){
int rc;
u32 iPrev = pCell->aOvfl[j-1];
DbPage *pPg = 0;
rc = sqlite3PagerGet(sqlite3BtreePager(pBt), iPrev, &pPg, 0);
if( rc!=SQLITE_OK ){
assert( pPg==0 );
return rc;
}
pCell->aOvfl[j] = sqlite3Get4byte(sqlite3PagerGetData(pPg));
sqlite3PagerUnref(pPg);
}
}
}
}
}
return SQLITE_OK;
}
/*
** 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;
}
/*
** Parameter zSrcData points to a buffer containing the data for
** page iSrcPg from the source database. Copy this data into the
** destination database.
*/
static int backupOnePage(
sqlite3_backup *p, /* Backup handle */
Pgno iSrcPg, /* Source database page to backup */
const u8 *zSrcData, /* Source database page data */
int bUpdate /* True for an update, false otherwise */
){
Pager * const pDestPager = sqlite3BtreePager(p->pDest);
const int nSrcPgsz = sqlite3BtreeGetPageSize(p->pSrc);
int nDestPgsz = sqlite3BtreeGetPageSize(p->pDest);
const int nCopy = MIN(nSrcPgsz, nDestPgsz);
const i64 iEnd = (i64)iSrcPg*(i64)nSrcPgsz;
#ifdef SQLITE_HAS_CODEC
/* Use BtreeGetReserveNoMutex() for the source b-tree, as although it is
** guaranteed that the shared-mutex is held by this thread, handle
** p->pSrc may not actually be the owner. */
int nSrcReserve = sqlite3BtreeGetReserveNoMutex(p->pSrc);
int nDestReserve = sqlite3BtreeGetOptimalReserve(p->pDest);
#endif
int rc = SQLITE_OK;
i64 iOff;
assert( sqlite3BtreeGetReserveNoMutex(p->pSrc)>=0 );
assert( p->bDestLocked );
assert( !isFatalError(p->rc) );
assert( iSrcPg!=PENDING_BYTE_PAGE(p->pSrc->pBt) );
assert( zSrcData );
/* Catch the case where the destination is an in-memory database and the
** page sizes of the source and destination differ.
*/
if( nSrcPgsz!=nDestPgsz && sqlite3PagerIsMemdb(pDestPager) ){
rc = SQLITE_READONLY;
}
#ifdef SQLITE_HAS_CODEC
/* Backup is not possible if the page size of the destination is changing
** and a codec is in use.
*/
if( nSrcPgsz!=nDestPgsz && sqlite3PagerGetCodec(pDestPager)!=0 ){
rc = SQLITE_READONLY;
}
/* Backup is not possible if the number of bytes of reserve space differ
** between source and destination. If there is a difference, try to
** fix the destination to agree with the source. If that is not possible,
** then the backup cannot proceed.
*/
if( nSrcReserve!=nDestReserve ){
u32 newPgsz = nSrcPgsz;
rc = sqlite3PagerSetPagesize(pDestPager, &newPgsz, nSrcReserve);
if( rc==SQLITE_OK && newPgsz!=nSrcPgsz ) rc = SQLITE_READONLY;
}
#endif
/* This loop runs once for each destination page spanned by the source
** page. For each iteration, variable iOff is set to the byte offset
** of the destination page.
*/
for(iOff=iEnd-(i64)nSrcPgsz; rc==SQLITE_OK && iOff<iEnd; iOff+=nDestPgsz){
DbPage *pDestPg = 0;
Pgno iDest = (Pgno)(iOff/nDestPgsz)+1;
if( iDest==PENDING_BYTE_PAGE(p->pDest->pBt) ) continue;
if( SQLITE_OK==(rc = sqlite3PagerGet(pDestPager, iDest, &pDestPg, 0))
&& SQLITE_OK==(rc = sqlite3PagerWrite(pDestPg))
){
const u8 *zIn = &zSrcData[iOff%nSrcPgsz];
u8 *zDestData = sqlite3PagerGetData(pDestPg);
u8 *zOut = &zDestData[iOff%nDestPgsz];
/* Copy the data from the source page into the destination page.
** Then clear the Btree layer MemPage.isInit flag. Both this module
** and the pager code use this trick (clearing the first byte
** of the page 'extra' space to invalidate the Btree layers
** cached parse of the page). MemPage.isInit is marked
** "MUST BE FIRST" for this purpose.
*/
memcpy(zOut, zIn, nCopy);
((u8 *)sqlite3PagerGetExtra(pDestPg))[0] = 0;
if( iOff==0 && bUpdate==0 ){
sqlite3Put4byte(&zOut[28], sqlite3BtreeLastPage(p->pSrc));
}
}
sqlite3PagerUnref(pDestPg);
}
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;
}
/*
** Return the serialization of a database
*/
unsigned char *sqlite3_serialize(
sqlite3 *db, /* The database connection */
const char *zSchema, /* Which database within the connection */
sqlite3_int64 *piSize, /* Write size here, if not NULL */
unsigned int mFlags /* Maybe SQLITE_SERIALIZE_NOCOPY */
){
MemFile *p;
int iDb;
Btree *pBt;
sqlite3_int64 sz;
int szPage = 0;
sqlite3_stmt *pStmt = 0;
unsigned char *pOut;
char *zSql;
int rc;
#ifdef SQLITE_ENABLE_API_ARMOR
if( !sqlite3SafetyCheckOk(db) ){
(void)SQLITE_MISUSE_BKPT;
return 0;
}
#endif
if( zSchema==0 ) zSchema = db->aDb[0].zDbSName;
p = memdbFromDbSchema(db, zSchema);
iDb = sqlite3FindDbName(db, zSchema);
if( piSize ) *piSize = -1;
if( iDb<0 ) return 0;
if( p ){
if( piSize ) *piSize = p->sz;
if( mFlags & SQLITE_SERIALIZE_NOCOPY ){
pOut = p->aData;
}else{
pOut = sqlite3_malloc64( p->sz );
if( pOut ) memcpy(pOut, p->aData, p->sz);
}
return pOut;
}
pBt = db->aDb[iDb].pBt;
if( pBt==0 ) return 0;
szPage = sqlite3BtreeGetPageSize(pBt);
zSql = sqlite3_mprintf("PRAGMA \"%w\".page_count", zSchema);
rc = zSql ? sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0) : SQLITE_NOMEM;
sqlite3_free(zSql);
if( rc ) return 0;
rc = sqlite3_step(pStmt);
if( rc!=SQLITE_ROW ){
pOut = 0;
}else{
sz = sqlite3_column_int64(pStmt, 0)*szPage;
if( piSize ) *piSize = sz;
if( mFlags & SQLITE_SERIALIZE_NOCOPY ){
pOut = 0;
}else{
pOut = sqlite3_malloc64( sz );
if( pOut ){
int nPage = sqlite3_column_int(pStmt, 0);
Pager *pPager = sqlite3BtreePager(pBt);
int pgno;
for(pgno=1; pgno<=nPage; pgno++){
DbPage *pPage = 0;
unsigned char *pTo = pOut + szPage*(sqlite3_int64)(pgno-1);
rc = sqlite3PagerGet(pPager, pgno, (DbPage**)&pPage, 0);
if( rc==SQLITE_OK ){
memcpy(pTo, sqlite3PagerGetData(pPage), szPage);
}else{
memset(pTo, 0, szPage);
}
sqlite3PagerUnref(pPage);
}
}
}
}
sqlite3_finalize(pStmt);
return pOut;
}
