diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/rowset.c | 21 | ||||
| -rw-r--r-- | src/sqliteInt.h | 27 |
2 files changed, 41 insertions, 7 deletions
diff --git a/src/rowset.c b/src/rowset.c index bf4382ddd..5420ab991 100644 --- a/src/rowset.c +++ b/src/rowset.c @@ -179,7 +179,9 @@ void sqlite3RowSetClear(RowSet *p){ */ static struct RowSetEntry *rowSetEntryAlloc(RowSet *p){ assert( p!=0 ); - if( p->nFresh==0 ){ + if( p->nFresh==0 ){ /*OPTIMIZATION-IF-FALSE*/ + /* We could allocate a fresh RowSetEntry each time one is needed, but it + ** is more efficient to pull a preallocated entry from the pool */ struct RowSetChunk *pNew; pNew = sqlite3DbMallocRawNN(p->db, sizeof(*pNew)); if( pNew==0 ){ @@ -213,7 +215,9 @@ void sqlite3RowSetInsert(RowSet *p, i64 rowid){ pEntry->pRight = 0; pLast = p->pLast; if( pLast ){ - if( (p->rsFlags & ROWSET_SORTED)!=0 && rowid<=pLast->v ){ + if( rowid<=pLast->v ){ /*OPTIMIZATION-IF-FALSE*/ + /* Avoid unnecessary sorts by preserving the ROWSET_SORTED flags + ** where possible */ p->rsFlags &= ~ROWSET_SORTED; } pLast->pRight = pEntry; @@ -335,16 +339,19 @@ static struct RowSetEntry *rowSetNDeepTree( ){ struct RowSetEntry *p; /* Root of the new tree */ struct RowSetEntry *pLeft; /* Left subtree */ - if( *ppList==0 ){ - return 0; + if( *ppList==0 ){ /*OPTIMIZATION-IF-TRUE*/ + /* Prevent unnecessary deep recursion when we run out of entries */ + return 0; } if( iDepth>1 ){ /*OPTIMIZATION-IF-TRUE*/ /* This branch causes a *balanced* tree to be generated. A valid tree - ** is still generated without this branch, but it is wildly unbalanced - ** and inefficient. */ + ** is still generated without this branch, but the tree is wildly + ** unbalanced and inefficient. */ pLeft = rowSetNDeepTree(ppList, iDepth-1); p = *ppList; - if( p==0 ){ + if( p==0 ){ /*OPTIMIZATION-IF-FALSE*/ + /* It is safe to always return here, but the resulting tree + ** would be unbalanced */ return pLeft; } p->pLeft = pLeft; diff --git a/src/sqliteInt.h b/src/sqliteInt.h index 7bb15d0bf..76bf80962 100644 --- a/src/sqliteInt.h +++ b/src/sqliteInt.h @@ -15,6 +15,33 @@ #ifndef _SQLITEINT_H_ #define _SQLITEINT_H_ +/* Special Comments: +** +** Some comments have special meaning to the tools that measure test +** coverage: +** +** NO_TEST - The branches on this line are not +** measured by branch coverage. This is +** used on lines of code that actually +** implement parts of coverage testing. +** +** OPTIMIZATION-IF-TRUE - This branch is allowed to alway be false +** and the correct answer is still obtained, +** though perhaps more slowly. +** +** OPTIMIZATION-IF-FALSE - This branch is allowed to alway be true +** and the correct answer is still obtained, +** though perhaps more slowly. +** +** PREVENTS-HARMLESS-OVERREAD - This branch prevents a buffer overread +** that would be harmless and undetectable +** if it did occur. +** +** In all cases, the special comment must be enclosed in the usual +** slash-asterisk...asterisk-slash comment marks, with no spaces between the +** asterisks and the comment text. +*/ + /* ** Make sure that rand_s() is available on Windows systems with MSVC 2005 ** or higher. |