void
StorageDBThread::SyncPreload(StorageCacheBridge* aCache, bool aForceSync)
{
PROFILER_LABEL_FUNC(js::ProfileEntry::Category::STORAGE);
if (!aForceSync && aCache->LoadedCount()) {
// Preload already started for this cache, just wait for it to finish.
// LoadWait will exit after LoadDone on the cache has been called.
SetHigherPriority();
aCache->LoadWait();
SetDefaultPriority();
return;
}
// Bypass sync load when an update is pending in the queue to write, we would
// get incosistent data in the cache. Also don't allow sync main-thread
// preload when DB open and init is still pending on the background thread.
if (mDBReady && mWALModeEnabled) {
bool pendingTasks;
{
MonitorAutoLock monitor(mThreadObserver->GetMonitor());
pendingTasks = mPendingTasks.IsOriginUpdatePending(aCache->OriginSuffix(), aCache->OriginNoSuffix()) ||
mPendingTasks.IsOriginClearPending(aCache->OriginSuffix(), aCache->OriginNoSuffix());
}
if (!pendingTasks) {
// WAL is enabled, thus do the load synchronously on the main thread.
DBOperation preload(DBOperation::opPreload, aCache);
preload.PerformAndFinalize(this);
return;
}
}
// Need to go asynchronously since WAL is not allowed or scheduled updates
// need to be flushed first.
// Schedule preload for this cache as the first operation.
nsresult rv = InsertDBOp(new DBOperation(DBOperation::opPreloadUrgent, aCache));
// LoadWait exits after LoadDone of the cache has been called.
if (NS_SUCCEEDED(rv)) {
aCache->LoadWait();
}
}
nsresult
DOMStorageDBThread::InsertDBOp(DOMStorageDBThread::DBOperation* aOperation)
{
MonitorAutoLock monitor(mThreadObserver->GetMonitor());
// Sentinel to don't forget to delete the operation when we exit early.
nsAutoPtr<DOMStorageDBThread::DBOperation> opScope(aOperation);
if (mStopIOThread) {
// Thread use after shutdown demanded.
MOZ_ASSERT(false);
return NS_ERROR_NOT_INITIALIZED;
}
if (NS_FAILED(mStatus)) {
MonitorAutoUnlock unlock(mThreadObserver->GetMonitor());
aOperation->Finalize(mStatus);
return mStatus;
}
switch (aOperation->Type()) {
case DBOperation::opPreload:
case DBOperation::opPreloadUrgent:
if (mPendingTasks.IsScopeUpdatePending(aOperation->Scope())) {
// If there is a pending update operation for the scope first do the flush
// before we preload the cache. This may happen in an extremely rare case
// when a child process throws away its cache before flush on the parent
// has finished. If we would preloaded the cache as a priority operation
// before the pending flush, we would have got an inconsistent cache content.
mFlushImmediately = true;
} else if (mPendingTasks.IsScopeClearPending(aOperation->Scope())) {
// The scope is scheduled to be cleared, so just quickly load as empty.
// We need to do this to prevent load of the DB data before the scope has
// actually been cleared from the database. Preloads are processed
// immediately before update and clear operations on the database that
// are flushed periodically in batches.
MonitorAutoUnlock unlock(mThreadObserver->GetMonitor());
aOperation->Finalize(NS_OK);
return NS_OK;
}
// NO BREAK
case DBOperation::opGetUsage:
if (aOperation->Type() == DBOperation::opPreloadUrgent) {
SetHigherPriority(); // Dropped back after urgent preload execution
mPreloads.InsertElementAt(0, aOperation);
} else {
mPreloads.AppendElement(aOperation);
}
// DB operation adopted, don't delete it.
opScope.forget();
// Immediately start executing this.
monitor.Notify();
break;
default:
// Update operations are first collected, coalesced and then flushed
// after a short time.
mPendingTasks.Add(aOperation);
// DB operation adopted, don't delete it.
opScope.forget();
ScheduleFlush();
break;
}
return NS_OK;
}