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Add some assert() statements to querySharedCacheTableLock(). (CVS 6421)

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FossilOrigin-Name: 3e3b5e861aeff2e4ef568c422236fdf7fa22bed3
This commit is contained in:
danielk1977
2009-04-01 09:41:54 +00:00
parent faa68dbb7d
commit 5b413d785f
4 changed files with 167 additions and 11 deletions
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23
src/btree.c
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@@ -9,7 +9,7 @@
** May you share freely, never taking more than you give.
**
*************************************************************************
** $Id: btree.c,v 1.582 2009/03/30 18:50:05 danielk1977 Exp $
** $Id: btree.c,v 1.583 2009/04/01 09:41:54 danielk1977 Exp $
**
** This file implements a external (disk-based) database using BTrees.
** See the header comment on "btreeInt.h" for additional information.
@@ -103,6 +103,13 @@ static int querySharedCacheTableLock(Btree *p, Pgno iTab, u8 eLock){
assert( eLock==READ_LOCK || eLock==WRITE_LOCK );
assert( p->db!=0 );
/* If requesting a write-lock, then the Btree must have an open write
** transaction on this file. And, obviously, for this to be so there
** must be an open write transaction on the file itself.
*/
assert( eLock==READ_LOCK || (p==pBt->pWriter && p->inTrans==TRANS_WRITE) );
assert( eLock==READ_LOCK || pBt->inTransaction==TRANS_WRITE );
/* This is a no-op if the shared-cache is not enabled */
if( !p->sharable ){
return SQLITE_OK;
@@ -138,8 +145,18 @@ static int querySharedCacheTableLock(Btree *p, Pgno iTab, u8 eLock){
iTab==MASTER_ROOT
){
for(pIter=pBt->pLock; pIter; pIter=pIter->pNext){
if( pIter->pBtree!=p && pIter->iTable==iTab &&
(pIter->eLock!=eLock || eLock!=READ_LOCK) ){
/* The condition (pIter->eLock!=eLock) in the following if(...)
** statement is a simplification of:
**
** (eLock==WRITE_LOCK || pIter->eLock==WRITE_LOCK)
**
** since we know that if eLock==WRITE_LOCK, then no other connection
** may hold a WRITE_LOCK on any table in this file (since there can
** only be a single writer).
*/
assert( pIter->eLock==READ_LOCK || pIter->eLock==WRITE_LOCK );
assert( eLock==READ_LOCK || pIter->pBtree==p || pIter->eLock==READ_LOCK);
if( pIter->pBtree!=p && pIter->iTable==iTab && pIter->eLock!=eLock ){
sqlite3ConnectionBlocked(p->db, pIter->pBtree->db);
if( eLock==WRITE_LOCK ){
assert( p==pBt->pWriter );