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Overview
Comment:Ensure that kvmemSeek() does not come to rest on a deleted node.
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SHA1: 21991a932a63fa8b97a693efe792d34e83dfa703
User & Date: dan 2012-04-13 05:50:33
Context
2012-04-13
10:35
Add placeholder code to make ROLLBACK (and OR ROLLBACK constraints) work a bit. check-in: 367fdc8463 user: dan tags: primary-keys
05:50
Ensure that kvmemSeek() does not come to rest on a deleted node. check-in: 21991a932a user: dan tags: primary-keys
2012-04-12
19:52
Further fixes to things. check-in: 81fab25002 user: dan tags: primary-keys
Changes
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Changes to src/kvmem.c.

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    pCur->pOwner->nCursor--;
    kvmemReset(pKVCursor);
    memset(pCur, 0, sizeof(*pCur));
    sqlite4_free(pCur);
  }
  return SQLITE_OK;
}











































/*
** Seek a cursor.
*/
static int kvmemSeek(
  KVCursor *pKVCursor, 
  const KVByteArray *aKey,
................................................................................
    }
  }
  kvmemNodeUnref(pCur->pNode);
  kvmemDataUnref(pCur->pData);
  if( pBest ){
    pCur->pNode = kvmemNodeRef(pBest);
    pCur->pData = kvmemDataRef(pBest->pData);

















  }else{
    pCur->pNode = 0;
    pCur->pData = 0;
  }
  assert( rc!=SQLITE_DONE );
  return rc;
}
................................................................................
  }else{
    kvmemDataUnref(pNode->pData);
    pNode->pData = 0;
  }
  return SQLITE_OK;
}

/*
** Move a cursor to the next non-deleted node.
*/
static int kvmemNextEntry(KVCursor *pKVCursor){
  KVMemCursor *pCur;
  KVMemNode *pNode;

  pCur = (KVMemCursor*)pKVCursor;
  assert( pCur->iMagicKVMemCur==SQLITE_KVMEMCUR_MAGIC );
  pNode = pCur->pNode;
  kvmemReset(pKVCursor);
  do{
    pNode = kvmemNext(pNode);
  }while( pNode && pNode->pData==0 );
  if( pNode ){
    pCur->pNode = kvmemNodeRef(pNode);
    pCur->pData = kvmemDataRef(pNode->pData);
  }
  return pNode ? SQLITE_OK : SQLITE_NOTFOUND;
}

/*
** Move a cursor to the previous non-deleted node.
*/
static int kvmemPrevEntry(KVCursor *pKVCursor){
  KVMemCursor *pCur;
  KVMemNode *pNode;

  pCur = (KVMemCursor*)pKVCursor;
  assert( pCur->iMagicKVMemCur==SQLITE_KVMEMCUR_MAGIC );
  pNode = pCur->pNode;
  kvmemReset(pKVCursor);
  do{
    pNode = kvmemPrev(pNode);
  }while( pNode && pNode->pData==0 );
  if( pNode ){
    pCur->pNode = kvmemNodeRef(pNode);
    pCur->pData = kvmemDataRef(pNode->pData);
  }
  return pNode ? SQLITE_OK : SQLITE_NOTFOUND;
}

/*
** Return the key of the node the cursor is pointing to.
*/
static int kvmemKey(
  KVCursor *pKVCursor,         /* The cursor whose key is desired */
  const KVByteArray **paKey,   /* Make this point to the key */
  KVSize *pN                   /* Make this point to the size of the key */







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    pCur->pOwner->nCursor--;
    kvmemReset(pKVCursor);
    memset(pCur, 0, sizeof(*pCur));
    sqlite4_free(pCur);
  }
  return SQLITE_OK;
}

/*
** Move a cursor to the next non-deleted node.
*/
static int kvmemNextEntry(KVCursor *pKVCursor){
  KVMemCursor *pCur;
  KVMemNode *pNode;

  pCur = (KVMemCursor*)pKVCursor;
  assert( pCur->iMagicKVMemCur==SQLITE_KVMEMCUR_MAGIC );
  pNode = pCur->pNode;
  kvmemReset(pKVCursor);
  do{
    pNode = kvmemNext(pNode);
  }while( pNode && pNode->pData==0 );
  if( pNode ){
    pCur->pNode = kvmemNodeRef(pNode);
    pCur->pData = kvmemDataRef(pNode->pData);
  }
  return pNode ? SQLITE_OK : SQLITE_NOTFOUND;
}

/*
** Move a cursor to the previous non-deleted node.
*/
static int kvmemPrevEntry(KVCursor *pKVCursor){
  KVMemCursor *pCur;
  KVMemNode *pNode;

  pCur = (KVMemCursor*)pKVCursor;
  assert( pCur->iMagicKVMemCur==SQLITE_KVMEMCUR_MAGIC );
  pNode = pCur->pNode;
  kvmemReset(pKVCursor);
  do{
    pNode = kvmemPrev(pNode);
  }while( pNode && pNode->pData==0 );
  if( pNode ){
    pCur->pNode = kvmemNodeRef(pNode);
    pCur->pData = kvmemDataRef(pNode->pData);
  }
  return pNode ? SQLITE_OK : SQLITE_NOTFOUND;
}

/*
** Seek a cursor.
*/
static int kvmemSeek(
  KVCursor *pKVCursor, 
  const KVByteArray *aKey,
................................................................................
    }
  }
  kvmemNodeUnref(pCur->pNode);
  kvmemDataUnref(pCur->pData);
  if( pBest ){
    pCur->pNode = kvmemNodeRef(pBest);
    pCur->pData = kvmemDataRef(pBest->pData);

    /* The cursor currently points to a deleted node. If parameter 'direction'
    ** was zero (exact matches only), then the search has failed - return
    ** SQLITE_NOTFOUND. Otherwise, advance to the next (if direction is +ve)
    ** or the previous (if direction is -ve) undeleted node in the tree.  */
    if( pCur->pData==0 ){
      if( direction==0 ){
        rc = SQLITE_NOTFOUND;
      }else{ 
        if( (direction>0 ? kvmemNextEntry : kvmemPrevEntry)(pCur) ){
          rc = SQLITE_NOTFOUND;
        }else{
          rc = SQLITE_INEXACT;
        }
      }
    }

  }else{
    pCur->pNode = 0;
    pCur->pData = 0;
  }
  assert( rc!=SQLITE_DONE );
  return rc;
}
................................................................................
  }else{
    kvmemDataUnref(pNode->pData);
    pNode->pData = 0;
  }
  return SQLITE_OK;
}











































/*
** Return the key of the node the cursor is pointing to.
*/
static int kvmemKey(
  KVCursor *pKVCursor,         /* The cursor whose key is desired */
  const KVByteArray **paKey,   /* Make this point to the key */
  KVSize *pN                   /* Make this point to the size of the key */

Changes to test/simple.test.

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do_execsql_test 8.1 {
  CREATE TABLE t1(a PRIMARY KEY, b);
  INSERT INTO t1 VALUES('a', 'b');
}

do_execsql_test 8.2 { DELETE FROM t1 WHERE b = 'b' }

execsql {PRAGMA vdbe_trace = 1}
breakpoint
do_execsql_test 8.3 { SELECT * FROM t1 } {}
finish_test

do_execsql_test 8.4 {
  INSERT INTO t1 VALUES('a', 'A');
  INSERT INTO t1 VALUES('b', 'B');
  INSERT INTO t1 VALUES('c', 'A');
  INSERT INTO t1 VALUES('d', 'B');
  INSERT INTO t1 VALUES('e', 'A');







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do_execsql_test 8.1 {
  CREATE TABLE t1(a PRIMARY KEY, b);
  INSERT INTO t1 VALUES('a', 'b');
}

do_execsql_test 8.2 { DELETE FROM t1 WHERE b = 'b' }



do_execsql_test 8.3 { SELECT * FROM t1 } {}


do_execsql_test 8.4 {
  INSERT INTO t1 VALUES('a', 'A');
  INSERT INTO t1 VALUES('b', 'B');
  INSERT INTO t1 VALUES('c', 'A');
  INSERT INTO t1 VALUES('d', 'B');
  INSERT INTO t1 VALUES('e', 'A');