database/sqlite
1
0
Fork 0
mirror of https://github.com/sqlite/sqlite.git synced 2025-08-07 02:42:48 +03:00
Code Activity

Ensure tables cannot be created/dropped when btree cursors are open. (CVS 2085)

Browse Source 
FossilOrigin-Name: 8e5c2e5df8b824f7efb27e776240f005c6f1f0ff
This commit is contained in:
danielk1977
2004-11-10 11:55:10 +00:00
parent 2a03c3a326
commit e6efa74b9f
9 changed files with 142 additions and 43 deletions
Download Patch File Download Diff File Expand all files Collapse all files

33
src/btree.c
View File

@@ -9,7 +9,7 @@
** May you share freely, never taking more than you give.
**
*************************************************************************
** $Id: btree.c,v 1.215 2004/11/08 09:26:09 danielk1977 Exp $
** $Id: btree.c,v 1.216 2004/11/10 11:55:11 danielk1977 Exp $
**
** This file implements a external (disk-based) database using BTrees.
** For a detailed discussion of BTrees, refer to
@@ -4304,11 +4304,17 @@ int sqlite3BtreeDelete(BtCursor *pCur){
}
rc = sqlite3pager_write(pPage->aData);
if( rc ) return rc;
/* Locate the cell within it's page and leave pCell pointing to the
** data. The clearCell() call frees any overflow pages associated with the
** cell. The cell itself is still intact.
*/
pCell = findCell(pPage, pCur->idx);
if( !pPage->leaf ){
pgnoChild = get4byte(pCell);
}
clearCell(pPage, pCell);
if( !pPage->leaf ){
/*
** The entry we are about to delete is not a leaf so if we do not
@@ -4375,7 +4381,6 @@ int sqlite3BtreeCreateTable(Btree *pBt, int *piTable, int flags){
MemPage *pRoot;
Pgno pgnoRoot;
int rc;
/* TODO: Disallow schema modifications if there are open cursors */
if( pBt->inTrans!=TRANS_WRITE ){
/* Must start a transaction first */
return pBt->readOnly ? SQLITE_READONLY : SQLITE_ERROR;
@@ -4383,6 +4388,16 @@ int sqlite3BtreeCreateTable(Btree *pBt, int *piTable, int flags){
if( pBt->readOnly ){
return SQLITE_READONLY;
}
/* It is illegal to create a table if any cursors are open on the
** database. This is because in auto-vacuum mode the backend may
** need to move a database page to make room for the new root-page.
** If an open cursor was using the page a problem would occur.
*/
if( pBt->pCursor ){
return SQLITE_LOCKED;
}
#ifdef SQLITE_OMIT_AUTOVACUUM
rc = allocatePage(pBt, &pRoot, &pgnoRoot, 1, 0);
if( rc ) return rc;
@@ -4565,17 +4580,19 @@ int sqlite3BtreeClearTable(Btree *pBt, int iTable){
int sqlite3BtreeDropTable(Btree *pBt, int iTable, int *piMoved){
int rc;
MemPage *pPage = 0;
BtCursor *pCur;
if( pBt->inTrans!=TRANS_WRITE ){
return pBt->readOnly ? SQLITE_READONLY : SQLITE_ERROR;
}
/* TODO: Disallow schema modifications if there are open cursors */
for(pCur=pBt->pCursor; pCur; pCur=pCur->pNext){
if( pCur->pgnoRoot==(Pgno)iTable ){
return SQLITE_LOCKED; /* Cannot drop a table that has a cursor */
}
/* It is illegal to drop a table if any cursors are open on the
** database. This is because in auto-vacuum mode the backend may
** need to move another root-page to fill a gap left by the deleted
** root page. If an open cursor was using this page a problem would
** occur.
*/
if( pBt->pCursor ){
return SQLITE_LOCKED;
}
rc = getPage(pBt, (Pgno)iTable, &pPage);