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authorwolfbeast <mcwerewolf@gmail.com>2018-02-08 11:43:07 +0100
committerwolfbeast <mcwerewolf@gmail.com>2018-02-08 11:43:07 +0100
commitbfa65f5d5f4fc1a1330acc91945d0587ddf65104 (patch)
tree37e97a62f8983a758a0ef96a56ec22f5ecb9005d /storage
parentb827a3a9cd60b10526e3bc99274a1465f1b6f2d1 (diff)
downloaduxp-bfa65f5d5f4fc1a1330acc91945d0587ddf65104.tar.gz
Cleanup async mozStorage callback management.
Also avoid raw pointers in mozStorageAsyncStatementExecution.cpp.
Diffstat (limited to 'storage')
-rw-r--r--storage/mozStorageAsyncStatementExecution.cpp215
-rw-r--r--storage/mozStorageAsyncStatementExecution.h13
2 files changed, 88 insertions, 140 deletions
diff --git a/storage/mozStorageAsyncStatementExecution.cpp b/storage/mozStorageAsyncStatementExecution.cpp
index add32131a3..e1d344aca6 100644
--- a/storage/mozStorageAsyncStatementExecution.cpp
+++ b/storage/mozStorageAsyncStatementExecution.cpp
@@ -40,122 +40,6 @@ namespace storage {
#define MAX_ROWS_PER_RESULT 15
////////////////////////////////////////////////////////////////////////////////
-//// Local Classes
-
-namespace {
-
-typedef AsyncExecuteStatements::ExecutionState ExecutionState;
-typedef AsyncExecuteStatements::StatementDataArray StatementDataArray;
-
-/**
- * Notifies a callback with a result set.
- */
-class CallbackResultNotifier : public Runnable
-{
-public:
- CallbackResultNotifier(mozIStorageStatementCallback *aCallback,
- mozIStorageResultSet *aResults,
- AsyncExecuteStatements *aEventStatus) :
- mCallback(aCallback)
- , mResults(aResults)
- , mEventStatus(aEventStatus)
- {
- }
-
- NS_IMETHOD Run() override
- {
- NS_ASSERTION(mCallback, "Trying to notify about results without a callback!");
-
- if (mEventStatus->shouldNotify()) {
- // Hold a strong reference to the callback while notifying it, so that if
- // it spins the event loop, the callback won't be released and freed out
- // from under us.
- nsCOMPtr<mozIStorageStatementCallback> callback = mCallback;
-
- (void)callback->HandleResult(mResults);
- }
-
- return NS_OK;
- }
-
-private:
- mozIStorageStatementCallback *mCallback;
- nsCOMPtr<mozIStorageResultSet> mResults;
- RefPtr<AsyncExecuteStatements> mEventStatus;
-};
-
-/**
- * Notifies the calling thread that an error has occurred.
- */
-class ErrorNotifier : public Runnable
-{
-public:
- ErrorNotifier(mozIStorageStatementCallback *aCallback,
- mozIStorageError *aErrorObj,
- AsyncExecuteStatements *aEventStatus) :
- mCallback(aCallback)
- , mErrorObj(aErrorObj)
- , mEventStatus(aEventStatus)
- {
- }
-
- NS_IMETHOD Run() override
- {
- if (mEventStatus->shouldNotify() && mCallback) {
- // Hold a strong reference to the callback while notifying it, so that if
- // it spins the event loop, the callback won't be released and freed out
- // from under us.
- nsCOMPtr<mozIStorageStatementCallback> callback = mCallback;
-
- (void)callback->HandleError(mErrorObj);
- }
-
- return NS_OK;
- }
-
-private:
- mozIStorageStatementCallback *mCallback;
- nsCOMPtr<mozIStorageError> mErrorObj;
- RefPtr<AsyncExecuteStatements> mEventStatus;
-};
-
-/**
- * Notifies the calling thread that the statement has finished executing. Takes
- * ownership of the StatementData so it is released on the proper thread.
- */
-class CompletionNotifier : public Runnable
-{
-public:
- /**
- * This takes ownership of the callback and the StatementData. They are
- * released on the thread this is dispatched to (which should always be the
- * calling thread).
- */
- CompletionNotifier(mozIStorageStatementCallback *aCallback,
- ExecutionState aReason)
- : mCallback(aCallback)
- , mReason(aReason)
- {
- }
-
- NS_IMETHOD Run() override
- {
- if (mCallback) {
- (void)mCallback->HandleCompletion(mReason);
- NS_RELEASE(mCallback);
- }
-
- return NS_OK;
- }
-
-private:
- mozIStorageStatementCallback *mCallback;
- ExecutionState mReason;
-};
-
-} // namespace
-
-////////////////////////////////////////////////////////////////////////////////
//// AsyncExecuteStatements
/* static */
@@ -208,16 +92,19 @@ AsyncExecuteStatements::AsyncExecuteStatements(StatementDataArray &aStatements,
, mCancelRequested(false)
, mMutex(aConnection->sharedAsyncExecutionMutex)
, mDBMutex(aConnection->sharedDBMutex)
- , mRequestStartDate(TimeStamp::Now())
+, mRequestStartDate(TimeStamp::Now())
{
(void)mStatements.SwapElements(aStatements);
NS_ASSERTION(mStatements.Length(), "We weren't given any statements!");
- NS_IF_ADDREF(mCallback);
}
AsyncExecuteStatements::~AsyncExecuteStatements()
{
+ MOZ_ASSERT(!mCallback, "Never called the Completion callback!");
MOZ_ASSERT(!mHasTransaction, "There should be no transaction at this point");
+ if (mCallback) {
+ NS_ProxyRelease(mCallingThread, mCallback.forget());
+ }
}
bool
@@ -255,7 +142,7 @@ AsyncExecuteStatements::bindExecuteAndProcessStatement(StatementData &aData,
BindingParamsArray::iterator end = paramsArray->end();
while (itr != end && continueProcessing) {
// Bind the data to our statement.
- nsCOMPtr<IStorageBindingParamsInternal> bindingInternal =
+ nsCOMPtr<IStorageBindingParamsInternal> bindingInternal =
do_QueryInterface(*itr);
nsCOMPtr<mozIStorageError> error = bindingInternal->bind(aStatement);
if (error) {
@@ -462,16 +349,30 @@ AsyncExecuteStatements::notifyComplete()
mHasTransaction = false;
}
- // Always generate a completion notification; it is what guarantees that our
- // destruction does not happen here on the async thread.
- RefPtr<CompletionNotifier> completionEvent =
- new CompletionNotifier(mCallback, mState);
-
- // We no longer own mCallback (the CompletionNotifier takes ownership).
- mCallback = nullptr;
+ // This will take ownership of mCallback and make sure its destruction will
+ // happen on the owner thread.
+ Unused << mCallingThread->Dispatch(
+ NewRunnableMethod(this, &AsyncExecuteStatements::notifyCompleteOnCallingThread),
+ NS_DISPATCH_NORMAL);
- (void)mCallingThread->Dispatch(completionEvent, NS_DISPATCH_NORMAL);
+ return NS_OK;
+}
+nsresult
+AsyncExecuteStatements::notifyCompleteOnCallingThread() {
+#ifdef DEBUG
+ bool onCallingThread = false;
+ (void)mCallingThread->IsOnCurrentThread(&onCallingThread);
+ MOZ_ASSERT(onCallingThread);
+#endif
+ // Take ownership of mCallback and responsibility for freeing it when we
+ // release it. Any notifyResultsOnCallingThread and notifyErrorOnCallingThread
+ // calls on the stack spinning the event loop have guaranteed their safety by
+ // creating their own strong reference before invoking the callback.
+ nsCOMPtr<mozIStorageStatementCallback> callback = mCallback.forget();
+ if (callback) {
+ Unused << callback->HandleCompletion(mState);
+ }
return NS_OK;
}
@@ -500,27 +401,63 @@ AsyncExecuteStatements::notifyError(mozIStorageError *aError)
if (!mCallback)
return NS_OK;
- RefPtr<ErrorNotifier> notifier =
- new ErrorNotifier(mCallback, aError, this);
- NS_ENSURE_TRUE(notifier, NS_ERROR_OUT_OF_MEMORY);
+ Unused << mCallingThread->Dispatch(
+ NewRunnableMethod<nsCOMPtr<mozIStorageError>>(this, &AsyncExecuteStatements::notifyErrorOnCallingThread, aError),
+ NS_DISPATCH_NORMAL);
- return mCallingThread->Dispatch(notifier, NS_DISPATCH_NORMAL);
+ return NS_OK;
+}
+
+nsresult
+AsyncExecuteStatements::notifyErrorOnCallingThread(mozIStorageError *aError) {
+#ifdef DEBUG
+ bool onCallingThread = false;
+ (void)mCallingThread->IsOnCurrentThread(&onCallingThread);
+ MOZ_ASSERT(onCallingThread);
+#endif
+ // Acquire our own strong reference so that if the callback spins a nested
+ // event loop and notifyCompleteOnCallingThread is executed, forgetting
+ // mCallback, we still have a valid/strong reference that won't be freed until
+ // we exit.
+ nsCOMPtr<mozIStorageStatementCallback> callback = mCallback;
+ if (shouldNotify() && callback) {
+ Unused << callback->HandleError(aError);
+ }
+ return NS_OK;
}
nsresult
AsyncExecuteStatements::notifyResults()
{
mMutex.AssertNotCurrentThreadOwns();
- NS_ASSERTION(mCallback, "notifyResults called without a callback!");
+ MOZ_ASSERT(mCallback, "notifyResults called without a callback!");
- RefPtr<CallbackResultNotifier> notifier =
- new CallbackResultNotifier(mCallback, mResultSet, this);
- NS_ENSURE_TRUE(notifier, NS_ERROR_OUT_OF_MEMORY);
+ // This takes ownership of mResultSet, a new one will be generated in
+ // buildAndNotifyResults() when further results will arrive.
+ Unused << mCallingThread->Dispatch(
+ NewRunnableMethod<RefPtr<ResultSet>>(this, &AsyncExecuteStatements::notifyResultsOnCallingThread, mResultSet.forget()),
+ NS_DISPATCH_NORMAL);
- nsresult rv = mCallingThread->Dispatch(notifier, NS_DISPATCH_NORMAL);
- if (NS_SUCCEEDED(rv))
- mResultSet = nullptr; // we no longer own it on success
- return rv;
+ return NS_OK;
+}
+
+nsresult
+AsyncExecuteStatements::notifyResultsOnCallingThread(ResultSet *aResultSet)
+{
+#ifdef DEBUG
+ bool onCallingThread = false;
+ (void)mCallingThread->IsOnCurrentThread(&onCallingThread);
+ MOZ_ASSERT(onCallingThread);
+#endif
+ // Acquire our own strong reference so that if the callback spins a nested
+ // event loop and notifyCompleteOnCallingThread is executed, forgetting
+ // mCallback, we still have a valid/strong reference that won't be freed until
+ // we exit.
+ nsCOMPtr<mozIStorageStatementCallback> callback = mCallback;
+ if (shouldNotify() && callback) {
+ Unused << callback->HandleResult(aResultSet);
+ }
+ return NS_OK;
}
NS_IMPL_ISUPPORTS(
diff --git a/storage/mozStorageAsyncStatementExecution.h b/storage/mozStorageAsyncStatementExecution.h
index c8493fd771..14ea49c2d9 100644
--- a/storage/mozStorageAsyncStatementExecution.h
+++ b/storage/mozStorageAsyncStatementExecution.h
@@ -82,6 +82,14 @@ public:
*/
bool shouldNotify();
+ /**
+ * Used by notifyComplete(), notifyError() and notifyResults() to notify on
+ * the calling thread.
+ */
+ nsresult notifyCompleteOnCallingThread();
+ nsresult notifyErrorOnCallingThread(mozIStorageError *aError);
+ nsresult notifyResultsOnCallingThread(ResultSet *aResultSet);
+
private:
AsyncExecuteStatements(StatementDataArray &aStatements,
Connection *aConnection,
@@ -186,7 +194,10 @@ private:
RefPtr<Connection> mConnection;
sqlite3 *mNativeConnection;
bool mHasTransaction;
- mozIStorageStatementCallback *mCallback;
+ // Note, this may not be a threadsafe object - never addref/release off
+ // the calling thread. We take a reference when this is created, and
+ // release it in the CompletionNotifier::Run() call back to this thread.
+ nsCOMPtr<mozIStorageStatementCallback> mCallback;
nsCOMPtr<nsIThread> mCallingThread;
RefPtr<ResultSet> mResultSet;