paulhorn/sqlite
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Tighter checking of access constraints on union members in SrcItem.

Browse Source 
Improved invariant checking.

FossilOrigin-Name: fd72d3400a8fe5747f494eee81654698acee350bb95b9db269e87d857af03492
This commit is contained in:
drh
2024-08-20 19:09:59 +00:00
parent ff176231da
commit 692c160360
9 changed files with 51 additions and 31 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/sqliteInt.h
+17 -13
View File
@@ -3298,26 +3298,30 @@ struct Subquery {
** In the colUsed field, the high-order bit (bit 63) is set if the table
** contains more than 63 columns and the 64-th or later column is used.
**
** Intenstive use of "union" helps keep the size of the object small. This
** has been shown to boost performance due to less time spend initializing
** fields to zero when a new instance of this object is allocated. The unions
** also help SrcItem, and hence SrcList and Select, use less memory.
**
** Union member validity:
** Aggressive use of "union" helps keep the size of the object small. This
** has been shown to boost performance, in addition to saving memory.
** Access to union elements is gated by the following rules which should
** always be checked, either by an if-statement or by an assert().
**
** Field Only access if this is true
** --------------- -----------------------------------
** u1.zIndexedBy fg.isIndexedBy
** u1.pFuncArg fg.isTabFunc
** u1.nRow !fg.isTabFunc && !fg.isIndexedBy
**
** u2.pIBIndex fg.isIndexedBy && !fg.isCte
** u2.pCteUse fg.isCte && !fg.isIndexedBy
** u2.pIBIndex fg.isIndexedBy
** u2.pCteUse fg.isCte
**
** u3.pOn fg.isUsing==0
** u3.pUsing fg.isUsing==1
** u3.pOn !fg.isUsing
** u3.pUsing fg.isUsing
**
** u4.zDatabase fg.fixedSchema==0 && !fg.isSubquery
** u4.pSchema fg.fixedSchema==1
** u4.zDatabase !fg.fixedSchema && !fg.isSubquery
** u4.pSchema fg.fixedSchema
** u4.pSubq fg.isSubquery
**
** See also the sqlite3SrcListDelete() routine for assert() statements that
** check invariants on the fields of this object, especially the flags
** inside the fg struct.
*/
struct SrcItem {
char *zName; /* Name of the table */
@@ -3342,7 +3346,7 @@ struct SrcItem {
unsigned isNestedFrom :1; /* pSelect is a SF_NestedFrom subquery */
unsigned rowidUsed :1; /* The ROWID of this table is referenced */
unsigned fixedSchema :1; /* Uses u4.pSchema, not u4.zDatabase */
unsigned hadSchema :1; /* Has u4.zDatabase before u4.pSchema */
unsigned hadSchema :1; /* Had u4.zDatabase before u4.pSchema */
} fg;
int iCursor; /* The VDBE cursor number used to access this table */
Bitmask colUsed; /* Bit N set if column N used. Details above for N>62 */