-C Convert\sseveral\s5-year-old\sand\solder\sNEVER()\smacros\sinto\sassert().
-D 2015-06-30T01:25:52.068
+C Put\sBtCursor\sobjects\son\sa\ssingly-linked\slist\sinstead\sof\sa\sdoubly-linked\slist.\nAdd\sthe\sBTCF_Multiple\sflag.\s\sOnly\sinvoke\ssaveAllCursors()\swhen\susing\sa\scursor\nthat\shas\sBTCF_Multiple\sset.
+D 2015-06-30T02:47:36.537
F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
F Makefile.in 285a0a234ed7610d431d91671c136098c2bd86a9
F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
F src/backup.c ff743689c4d6c5cb55ad42ed9d174b2b3e71f1e3
F src/bitvec.c d1f21d7d91690747881f03940584f4cc548c9d3d
F src/btmutex.c 45a968cc85afed9b5e6cf55bf1f42f8d18107f79
-F src/btree.c 5d5d48461b3838988bd1f5b197c145df66786805
+F src/btree.c 08ae64b0387e72b8201981a2d7b0f58b92fdff29
F src/btree.h 969adc948e89e449220ff0ff724c94bb2a52e9f1
-F src/btreeInt.h 8ca7124af9ee2ce27747a4e5500c27a254dea8eb
+F src/btreeInt.h e4eabc722b1ae017ac9c266a75769d4c6a9afde6
F src/build.c b3f15255d5b16e42dafeaa638fd4f8a47c94ed70
F src/callback.c 7b44ce59674338ad48b0e84e7b72f935ea4f68b0
F src/complete.c a5cf5b4b56390cfb7b8636e8f7ddef90258dd575
F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
F tool/warnings.sh 48bd54594752d5be3337f12c72f28d2080cb630b
F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P 53fe685d56368af78238c8981cc41704929f7660
-R 0ca8cb603f507b8c27049a9ebf015fe3
+P ed54c14ea8a72d69d69e0c0d7f6936f54efc04c2
+R f3f8b025f26bf8ce4de670023e83b4e0
U drh
-Z e0e6efeb2c6c43faed874d1e7ab03448
+Z aa2cb7c94aea3021edb11ed06abf028f
** routine is called just before cursor pExcept is used to modify the
** table, for example in BtreeDelete() or BtreeInsert().
**
+** If there are two or more cursors on the same btree, then all such
+** cursors should have their BTCF_Multiple flag set. The btreeCursor()
+** routine enforces that rule. This routine only needs to be called in
+** the uncommon case when pExpect has the BTCF_Multiple flag set.
+**
+** If pExpect!=NULL and if no other cursors are found on the same root-page,
+** then the BTCF_Multiple flag on pExpect is cleared, to avoid another
+** pointless call to this routine.
+**
** Implementation note: This routine merely checks to see if any cursors
** need to be saved. It calls out to saveCursorsOnList() in the (unusual)
** event that cursors are in need to being saved.
for(p=pBt->pCursor; p; p=p->pNext){
if( p!=pExcept && (0==iRoot || p->pgnoRoot==iRoot) ) break;
}
- return p ? saveCursorsOnList(p, iRoot, pExcept) : SQLITE_OK;
+ if( p ) return saveCursorsOnList(p, iRoot, pExcept);
+ if( pExcept ) pExcept->curFlags &= ~BTCF_Multiple;
+ return SQLITE_OK;
}
/* This helper routine to saveAllCursors does the actual work of saving
BtCursor *pCur /* Space for new cursor */
){
BtShared *pBt = p->pBt; /* Shared b-tree handle */
+ BtCursor *pX; /* Looping over other all cursors */
assert( sqlite3BtreeHoldsMutex(p) );
assert( wrFlag==0 || wrFlag==1 );
assert( wrFlag==0 || wrFlag==BTCF_WriteFlag );
pCur->curFlags = wrFlag;
pCur->curPagerFlags = wrFlag ? 0 : PAGER_GET_READONLY;
- pCur->pNext = pBt->pCursor;
- if( pCur->pNext ){
- pCur->pNext->pPrev = pCur;
+ /* If there are two or more cursors on the same btree, then all such
+ ** cursors *must* have the BTCF_Multiple flag set. */
+ for(pX=pBt->pCursor; pX; pX=pX->pNext){
+ if( pX->pgnoRoot==(Pgno)iTable ){
+ pX->curFlags |= BTCF_Multiple;
+ pCur->curFlags |= BTCF_Multiple;
+ }
}
+ pCur->pNext = pBt->pCursor;
pBt->pCursor = pCur;
pCur->eState = CURSOR_INVALID;
return SQLITE_OK;
BtShared *pBt = pCur->pBt;
sqlite3BtreeEnter(pBtree);
sqlite3BtreeClearCursor(pCur);
- if( pCur->pPrev ){
- pCur->pPrev->pNext = pCur->pNext;
- }else{
+ assert( pBt->pCursor!=0 );
+ if( pBt->pCursor==pCur ){
pBt->pCursor = pCur->pNext;
- }
- if( pCur->pNext ){
- pCur->pNext->pPrev = pCur->pPrev;
+ }else{
+ BtCursor *pPrev = pBt->pCursor;
+ do{
+ if( pPrev->pNext==pCur ){
+ pPrev->pNext = pCur->pNext;
+ break;
+ }
+ pPrev = pPrev->pNext;
+ }while( ALWAYS(pPrev) );
}
for(i=0; i<=pCur->iPage; i++){
releasePage(pCur->apPage[i]);
** doing any work. To avoid thwarting these optimizations, it is important
** not to clear the cursor here.
*/
- rc = saveAllCursors(pBt, pCur->pgnoRoot, pCur);
- if( rc ) return rc;
+ if( pCur->curFlags & BTCF_Multiple ){
+ rc = saveAllCursors(pBt, pCur->pgnoRoot, pCur);
+ if( rc ) return rc;
+ }
if( pCur->pKeyInfo==0 ){
assert( pKey==0 );
** deleted writable. Then free any overflow pages associated with the
** entry and finally remove the cell itself from within the page.
*/
- rc = saveAllCursors(pBt, pCur->pgnoRoot, pCur);
- if( rc ) return rc;
+ if( pCur->curFlags & BTCF_Multiple ){
+ rc = saveAllCursors(pBt, pCur->pgnoRoot, pCur);
+ if( rc ) return rc;
+ }
/* If this is a delete operation to remove a row from a table b-tree,
** invalidate any incrblob cursors open on the row being deleted. */
struct BtCursor {
Btree *pBtree; /* The Btree to which this cursor belongs */
BtShared *pBt; /* The BtShared this cursor points to */
- BtCursor *pNext, *pPrev; /* Forms a linked list of all cursors */
+ BtCursor *pNext; /* Forms a linked list of all cursors */
Pgno *aOverflow; /* Cache of overflow page locations */
CellInfo info; /* A parse of the cell we are pointing at */
i64 nKey; /* Size of pKey, or last integer key */
i8 iPage; /* Index of current page in apPage */
u8 curIntKey; /* Value of apPage[0]->intKey */
struct KeyInfo *pKeyInfo; /* Argument passed to comparison function */
+ void *padding1; /* Make object size a multiple of 16 */
u16 aiIdx[BTCURSOR_MAX_DEPTH]; /* Current index in apPage[i] */
MemPage *apPage[BTCURSOR_MAX_DEPTH]; /* Pages from root to current page */
};
#define BTCF_ValidOvfl 0x04 /* True if aOverflow is valid */
#define BTCF_AtLast 0x08 /* Cursor is pointing ot the last entry */
#define BTCF_Incrblob 0x10 /* True if an incremental I/O handle */
+#define BTCF_Multiple 0x20 /* Maybe another cursor on the same btree */
/*
** Potential values for BtCursor.eState.
projects / thirdparty / sqlite.git / commitdiff
