/*
** Open a new cursor handle.
**
** If there are currently no other open cursor handles, and no open write
** transaction, open a read transaction here.
*/
int lsm_csr_open(lsm_db *pDb, lsm_cursor **ppCsr){
int rc = LSM_OK; /* Return code */
MultiCursor *pCsr = 0; /* New cursor object */
/* Open a read transaction if one is not already open. */
assert_db_state(pDb);
if( pDb->pShmhdr==0 ){
assert( pDb->bReadonly );
rc = lsmBeginRoTrans(pDb);
}else if( pDb->iReader<0 ){
rc = lsmBeginReadTrans(pDb);
}
/* Allocate the multi-cursor. */
if( rc==LSM_OK ){
rc = lsmMCursorNew(pDb, &pCsr);
}
/* If an error has occured, set the output to NULL and delete any partially
** allocated cursor. If this means there are no open cursors, release the
** client snapshot. */
if( rc!=LSM_OK ){
lsmMCursorClose(pCsr, 0);
dbReleaseClientSnapshot(pDb);
}
assert_db_state(pDb);
*ppCsr = (lsm_cursor *)pCsr;
return rc;
}
int lsm_commit(lsm_db *pDb, int iLevel){
int rc = LSM_OK;
assert_db_state( pDb );
/* A value less than zero means close the innermost nested transaction. */
if( iLevel<0 ) iLevel = LSM_MAX(0, pDb->nTransOpen - 1);
if( iLevel<pDb->nTransOpen ){
if( iLevel==0 ){
/* Commit the transaction to disk. */
if( pDb->pTV && lsmTreeSize(pDb->pTV)>pDb->nTreeLimit ){
rc = lsmFlushToDisk(pDb);
}
if( rc==LSM_OK ) rc = lsmLogCommit(pDb);
if( rc==LSM_OK && pDb->eSafety==LSM_SAFETY_FULL ){
rc = lsmFsSyncLog(pDb->pFS);
}
lsmFinishWriteTrans(pDb, (rc==LSM_OK));
}
pDb->nTransOpen = iLevel;
}
dbReleaseClientSnapshot(pDb);
return rc;
}
/*
** Close a cursor opened using lsm_csr_open().
*/
int lsm_csr_close(lsm_cursor *p){
if( p ){
lsm_db *pDb = lsmMCursorDb((MultiCursor *)p);
assert_db_state(pDb);
lsmMCursorClose((MultiCursor *)p, 1);
dbReleaseClientSnapshot(pDb);
assert_db_state(pDb);
}
return LSM_OK;
}
int lsm_get_user_version(lsm_db *pDb, unsigned int *piUsr){
int rc = LSM_OK; /* Return code */
/* Open a read transaction if one is not already open. */
assert_db_state(pDb);
if( pDb->pShmhdr==0 ){
assert( pDb->bReadonly );
rc = lsmBeginRoTrans(pDb);
}else if( pDb->iReader<0 ){
rc = lsmBeginReadTrans(pDb);
}
/* Allocate the multi-cursor. */
if( rc==LSM_OK ){
*piUsr = pDb->treehdr.iUsrVersion;
}
dbReleaseClientSnapshot(pDb);
assert_db_state(pDb);
return rc;
}
int lsm_rollback(lsm_db *pDb, int iLevel){
int rc = LSM_OK;
assert_db_state( pDb );
if( pDb->nTransOpen ){
/* A value less than zero means close the innermost nested transaction. */
if( iLevel<0 ) iLevel = LSM_MAX(0, pDb->nTransOpen - 1);
if( iLevel<=pDb->nTransOpen ){
TransMark *pMark = &pDb->aTrans[(iLevel==0 ? 0 : iLevel-1)];
lsmTreeRollback(pDb, &pMark->tree);
if( iLevel ) lsmLogSeek(pDb, &pMark->log);
pDb->nTransOpen = iLevel;
}
if( pDb->nTransOpen==0 ){
lsmFinishWriteTrans(pDb, 0);
}
dbReleaseClientSnapshot(pDb);
}
return rc;
}
