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Further simplifications to the SHM locking logic. Remove the SQLITE_SHM_QUERY

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option.  Unify the WRITE to READ and RECOVER to READ transitions.

FossilOrigin-Name: e9bfa6e4ce7d1edc6be8b9173ac3b6bfd180632a
This commit is contained in:
drh
2010-05-05 19:09:49 +00:00
parent c7991bdf29
commit ccd13d1f80
4 changed files with 25 additions and 24 deletions
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15
src/os_unix.c
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@@ -5266,8 +5266,7 @@ static int unixShmLock(
** directly requested; they are side effects from requesting
** SQLITE_SHM_READ and SQLITE_SHM_CHECKPOINT, respectively.
*/
assert( desiredLock==SQLITE_SHM_QUERY
|| desiredLock==SQLITE_SHM_UNLOCK
assert( desiredLock==SQLITE_SHM_UNLOCK
|| desiredLock==SQLITE_SHM_READ
|| desiredLock==SQLITE_SHM_WRITE
|| desiredLock==SQLITE_SHM_CHECKPOINT
@@ -5276,8 +5275,7 @@ static int unixShmLock(
/* Return directly if this is just a lock state query, or if
** the connection is already in the desired locking state.
*/
if( desiredLock==SQLITE_SHM_QUERY
|| desiredLock==p->lockState
if( desiredLock==p->lockState
|| (desiredLock==SQLITE_SHM_READ && p->lockState==SQLITE_SHM_READ_FULL)
){
OSTRACE(("SHM-LOCK shmid-%d, pid-%d request %s and got %s\n",
@@ -5320,15 +5318,12 @@ static int unixShmLock(
p->lockState = SQLITE_SHM_READ;
}
}
}else if( p->lockState==SQLITE_SHM_WRITE ){
}else{
assert( p->lockState==SQLITE_SHM_WRITE
|| p->lockState==SQLITE_SHM_RECOVER );
rc = unixShmSharedLock(pFile, p, UNIX_SHM_A);
unixShmUnlock(pFile, p, UNIX_SHM_C|UNIX_SHM_D);
p->lockState = SQLITE_SHM_READ;
}else{
assert( p->lockState==SQLITE_SHM_RECOVER );
unixShmUnlock(pFile, p, UNIX_SHM_C);
p->lockState = SQLITE_SHM_READ;
rc = SQLITE_OK;
}
break;
}