diff options
Diffstat (limited to 'storage/mozStorageAsyncStatementExecution.cpp')
| -rw-r--r-- | storage/mozStorageAsyncStatementExecution.cpp | 580 |
1 files changed, 580 insertions, 0 deletions
diff --git a/storage/mozStorageAsyncStatementExecution.cpp b/storage/mozStorageAsyncStatementExecution.cpp new file mode 100644 index 0000000000..5405555de5 --- /dev/null +++ b/storage/mozStorageAsyncStatementExecution.cpp @@ -0,0 +1,580 @@ +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- + * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ : + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#include "sqlite3.h" + +#include "mozIStorageStatementCallback.h" +#include "mozStorageBindingParams.h" +#include "mozStorageHelper.h" +#include "mozStorageResultSet.h" +#include "mozStorageRow.h" +#include "mozStorageConnection.h" +#include "mozStorageError.h" +#include "mozStoragePrivateHelpers.h" +#include "mozStorageStatementData.h" +#include "mozStorageAsyncStatementExecution.h" + +#include "mozilla/DebugOnly.h" +#include "mozilla/Telemetry.h" + +#ifndef MOZ_STORAGE_SORTWARNING_SQL_DUMP +# include "mozilla/Logging.h" +extern mozilla::LazyLogModule gStorageLog; +#endif + +namespace mozilla { +namespace storage { + +/** + * The following constants help batch rows into result sets. + * MAX_MILLISECONDS_BETWEEN_RESULTS was chosen because any user-based task that + * takes less than 200 milliseconds is considered to feel instantaneous to end + * users. MAX_ROWS_PER_RESULT was arbitrarily chosen to reduce the number of + * dispatches to calling thread, while also providing reasonably-sized sets of + * data for consumers. Both of these constants are used because we assume that + * consumers are trying to avoid blocking their execution thread for long + * periods of time, and dispatching many small events to the calling thread will + * end up blocking it. + */ +#define MAX_MILLISECONDS_BETWEEN_RESULTS 75 +#define MAX_ROWS_PER_RESULT 15 + +//////////////////////////////////////////////////////////////////////////////// +//// AsyncExecuteStatements + +/* static */ +nsresult AsyncExecuteStatements::execute( + StatementDataArray&& aStatements, Connection* aConnection, + sqlite3* aNativeConnection, mozIStorageStatementCallback* aCallback, + mozIStoragePendingStatement** _stmt) { + // Create our event to run in the background + RefPtr<AsyncExecuteStatements> event = new AsyncExecuteStatements( + std::move(aStatements), aConnection, aNativeConnection, aCallback); + NS_ENSURE_TRUE(event, NS_ERROR_OUT_OF_MEMORY); + + // Dispatch it to the background + nsIEventTarget* target = aConnection->getAsyncExecutionTarget(); + + // If we don't have a valid target, this is a bug somewhere else. In the past, + // this assert found cases where a Run method would schedule a new statement + // without checking if asyncClose had been called. The caller must prevent + // that from happening or, if the work is not critical, just avoid creating + // the new statement during shutdown. See bug 718449 for an example. + MOZ_ASSERT(target); + if (!target) { + return NS_ERROR_NOT_AVAILABLE; + } + + nsresult rv = target->Dispatch(event, NS_DISPATCH_NORMAL); + NS_ENSURE_SUCCESS(rv, rv); + + // Return it as the pending statement object and track it. + event.forget(_stmt); + return NS_OK; +} + +AsyncExecuteStatements::AsyncExecuteStatements( + StatementDataArray&& aStatements, Connection* aConnection, + sqlite3* aNativeConnection, mozIStorageStatementCallback* aCallback) + : Runnable("AsyncExecuteStatements"), + mStatements(std::move(aStatements)), + mConnection(aConnection), + mNativeConnection(aNativeConnection), + mHasTransaction(false), + mCallback(aCallback), + mCallingThread(::do_GetCurrentThread()), + mMaxWait( + TimeDuration::FromMilliseconds(MAX_MILLISECONDS_BETWEEN_RESULTS)), + mIntervalStart(TimeStamp::Now()), + mState(PENDING), + mCancelRequested(false), + mMutex(aConnection->sharedAsyncExecutionMutex), + mDBMutex(aConnection->sharedDBMutex) { + NS_ASSERTION(mStatements.Length(), "We weren't given any statements!"); +} + +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("AsyncExecuteStatements::mCallback", mCallingThread, + mCallback.forget()); + } +} + +bool AsyncExecuteStatements::shouldNotify() { +#ifdef DEBUG + mMutex.AssertNotCurrentThreadOwns(); + + bool onCallingThread = false; + (void)mCallingThread->IsOnCurrentThread(&onCallingThread); + NS_ASSERTION(onCallingThread, "runEvent not running on the calling thread!"); +#endif + + // We do not need to acquire mMutex here because it can only ever be written + // to on the calling thread, and the only thread that can call us is the + // calling thread, so we know that our access is serialized. + return !mCancelRequested; +} + +bool AsyncExecuteStatements::bindExecuteAndProcessStatement( + StatementData& aData, bool aLastStatement) { + mMutex.AssertNotCurrentThreadOwns(); + + sqlite3_stmt* aStatement = nullptr; + // This cannot fail; we are only called if it's available. + Unused << aData.getSqliteStatement(&aStatement); + MOZ_DIAGNOSTIC_ASSERT( + aStatement, + "bindExecuteAndProcessStatement called without an initialized statement"); + BindingParamsArray* paramsArray(aData); + + // Iterate through all of our parameters, bind them, and execute. + bool continueProcessing = true; + BindingParamsArray::iterator itr = paramsArray->begin(); + BindingParamsArray::iterator end = paramsArray->end(); + while (itr != end && continueProcessing) { + // Bind the data to our statement. + nsCOMPtr<IStorageBindingParamsInternal> bindingInternal = + do_QueryInterface(*itr); + nsCOMPtr<mozIStorageError> error = bindingInternal->bind(aStatement); + if (error) { + // Set our error state. + mState = ERROR; + + // And notify. + (void)notifyError(error); + return false; + } + + // Advance our iterator, execute, and then process the statement. + itr++; + bool lastStatement = aLastStatement && itr == end; + continueProcessing = executeAndProcessStatement(aData, lastStatement); + + // Always reset our statement. + (void)::sqlite3_reset(aStatement); + } + + return continueProcessing; +} + +bool AsyncExecuteStatements::executeAndProcessStatement(StatementData& aData, + bool aLastStatement) { + mMutex.AssertNotCurrentThreadOwns(); + + sqlite3_stmt* aStatement = nullptr; + // This cannot fail; we are only called if it's available. + Unused << aData.getSqliteStatement(&aStatement); + MOZ_DIAGNOSTIC_ASSERT( + aStatement, + "executeAndProcessStatement called without an initialized statement"); + + // Execute our statement + bool hasResults; + do { + hasResults = executeStatement(aData); + + // If we had an error, bail. + if (mState == ERROR || mState == CANCELED) return false; + + // If we have been canceled, there is no point in going on... + { + MutexAutoLock lockedScope(mMutex); + if (mCancelRequested) { + mState = CANCELED; + return false; + } + } + + // Build our result set and notify if we got anything back and have a + // callback to notify. + if (mCallback && hasResults && + NS_FAILED(buildAndNotifyResults(aStatement))) { + // We had an error notifying, so we notify on error and stop processing. + mState = ERROR; + + // Notify, and stop processing statements. + (void)notifyError(mozIStorageError::ERROR, + "An error occurred while notifying about results"); + + return false; + } + } while (hasResults); + +#ifndef MOZ_STORAGE_SORTWARNING_SQL_DUMP + if (MOZ_LOG_TEST(gStorageLog, LogLevel::Warning)) +#endif + { + // Check to make sure that this statement was smart about what it did. + checkAndLogStatementPerformance(aStatement); + } + + // If we are done, we need to set our state accordingly while we still hold + // our mutex. We would have already returned if we were canceled or had + // an error at this point. + if (aLastStatement) mState = COMPLETED; + + return true; +} + +bool AsyncExecuteStatements::executeStatement(StatementData& aData) { + mMutex.AssertNotCurrentThreadOwns(); + + sqlite3_stmt* aStatement = nullptr; + // This cannot fail; we are only called if it's available. + Unused << aData.getSqliteStatement(&aStatement); + MOZ_DIAGNOSTIC_ASSERT( + aStatement, "executeStatement called without an initialized statement"); + + bool busyRetry = false; + while (true) { + if (busyRetry) { + busyRetry = false; + + // Yield, and try again + Unused << PR_Sleep(PR_INTERVAL_NO_WAIT); + + // Check for cancellation before retrying + { + MutexAutoLock lockedScope(mMutex); + if (mCancelRequested) { + mState = CANCELED; + return false; + } + } + } + + // lock the sqlite mutex so sqlite3_errmsg cannot change + SQLiteMutexAutoLock lockedScope(mDBMutex); + + int rc = mConnection->stepStatement(mNativeConnection, aStatement); + + // Some errors are not fatal, and we can handle them and continue. + if (rc == SQLITE_BUSY) { + ::sqlite3_reset(aStatement); + busyRetry = true; + continue; + } + + aData.MaybeRecordQueryStatus(rc); + + // Stop if we have no more results. + if (rc == SQLITE_DONE) { + return false; + } + + // If we got results, we can return now. + if (rc == SQLITE_ROW) { + return true; + } + + if (rc == SQLITE_INTERRUPT) { + mState = CANCELED; + return false; + } + + // Set an error state. + mState = ERROR; + + // Construct the error message before giving up the mutex (which we cannot + // hold during the call to notifyError). + nsCOMPtr<mozIStorageError> errorObj( + new Error(rc, ::sqlite3_errmsg(mNativeConnection))); + // We cannot hold the DB mutex while calling notifyError. + SQLiteMutexAutoUnlock unlockedScope(mDBMutex); + (void)notifyError(errorObj); + + // Finally, indicate that we should stop processing. + return false; + } +} + +nsresult AsyncExecuteStatements::buildAndNotifyResults( + sqlite3_stmt* aStatement) { + NS_ASSERTION(mCallback, "Trying to dispatch results without a callback!"); + mMutex.AssertNotCurrentThreadOwns(); + + // Build result object if we need it. + if (!mResultSet) mResultSet = new ResultSet(); + NS_ENSURE_TRUE(mResultSet, NS_ERROR_OUT_OF_MEMORY); + + RefPtr<Row> row(new Row()); + NS_ENSURE_TRUE(row, NS_ERROR_OUT_OF_MEMORY); + + nsresult rv = row->initialize(aStatement); + NS_ENSURE_SUCCESS(rv, rv); + + rv = mResultSet->add(row); + NS_ENSURE_SUCCESS(rv, rv); + + // If we have hit our maximum number of allowed results, or if we have hit + // the maximum amount of time we want to wait for results, notify the + // calling thread about it. + TimeStamp now = TimeStamp::Now(); + TimeDuration delta = now - mIntervalStart; + if (mResultSet->rows() >= MAX_ROWS_PER_RESULT || delta > mMaxWait) { + // Notify the caller + rv = notifyResults(); + if (NS_FAILED(rv)) return NS_OK; // we'll try again with the next result + + // Reset our start time + mIntervalStart = now; + } + + return NS_OK; +} + +nsresult AsyncExecuteStatements::notifyComplete() { + mMutex.AssertNotCurrentThreadOwns(); + NS_ASSERTION(mState != PENDING, + "Still in a pending state when calling Complete!"); + + // Reset our statements before we try to commit or rollback. If we are + // canceling and have statements that think they have pending work, the + // rollback will fail. + for (uint32_t i = 0; i < mStatements.Length(); i++) mStatements[i].reset(); + + // Release references to the statement data as soon as possible. If this + // is the last reference, statements will be finalized immediately on the + // async thread, hence avoiding several bounces between threads and possible + // race conditions with AsyncClose(). + mStatements.Clear(); + + // Handle our transaction, if we have one + if (mHasTransaction) { + SQLiteMutexAutoLock lockedScope(mDBMutex); + if (mState == COMPLETED) { + nsresult rv = mConnection->commitTransactionInternal(lockedScope, + mNativeConnection); + if (NS_FAILED(rv)) { + mState = ERROR; + // We cannot hold the DB mutex while calling notifyError. + SQLiteMutexAutoUnlock unlockedScope(mDBMutex); + (void)notifyError(mozIStorageError::ERROR, + "Transaction failed to commit"); + } + } else { + DebugOnly<nsresult> rv = mConnection->rollbackTransactionInternal( + lockedScope, mNativeConnection); + NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), "Transaction failed to rollback"); + } + mHasTransaction = false; + } + + // This will take ownership of mCallback and make sure its destruction will + // happen on the owner thread. + Unused << mCallingThread->Dispatch( + NewRunnableMethod("AsyncExecuteStatements::notifyCompleteOnCallingThread", + this, + &AsyncExecuteStatements::notifyCompleteOnCallingThread), + NS_DISPATCH_NORMAL); + + return NS_OK; +} + +nsresult AsyncExecuteStatements::notifyCompleteOnCallingThread() { + MOZ_ASSERT(mCallingThread->IsOnCurrentThread()); + // 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 = std::move(mCallback); + if (callback) { + Unused << callback->HandleCompletion(mState); + } + return NS_OK; +} + +nsresult AsyncExecuteStatements::notifyError(int32_t aErrorCode, + const char* aMessage) { + mMutex.AssertNotCurrentThreadOwns(); + mDBMutex.assertNotCurrentThreadOwns(); + + if (!mCallback) return NS_OK; + + nsCOMPtr<mozIStorageError> errorObj(new Error(aErrorCode, aMessage)); + NS_ENSURE_TRUE(errorObj, NS_ERROR_OUT_OF_MEMORY); + + return notifyError(errorObj); +} + +nsresult AsyncExecuteStatements::notifyError(mozIStorageError* aError) { + mMutex.AssertNotCurrentThreadOwns(); + mDBMutex.assertNotCurrentThreadOwns(); + + if (!mCallback) return NS_OK; + + Unused << mCallingThread->Dispatch( + NewRunnableMethod<nsCOMPtr<mozIStorageError>>( + "AsyncExecuteStatements::notifyErrorOnCallingThread", this, + &AsyncExecuteStatements::notifyErrorOnCallingThread, aError), + NS_DISPATCH_NORMAL); + + return NS_OK; +} + +nsresult AsyncExecuteStatements::notifyErrorOnCallingThread( + mozIStorageError* aError) { + MOZ_ASSERT(mCallingThread->IsOnCurrentThread()); + // 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(); + MOZ_ASSERT(mCallback, "notifyResults called without a callback!"); + + // This takes ownership of mResultSet, a new one will be generated in + // buildAndNotifyResults() when further results will arrive. + Unused << mCallingThread->Dispatch( + NewRunnableMethod<RefPtr<ResultSet>>( + "AsyncExecuteStatements::notifyResultsOnCallingThread", this, + &AsyncExecuteStatements::notifyResultsOnCallingThread, + mResultSet.forget()), + NS_DISPATCH_NORMAL); + + return NS_OK; +} + +nsresult AsyncExecuteStatements::notifyResultsOnCallingThread( + ResultSet* aResultSet) { + MOZ_ASSERT(mCallingThread->IsOnCurrentThread()); + // 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_INHERITED(AsyncExecuteStatements, Runnable, + mozIStoragePendingStatement) + +bool AsyncExecuteStatements::statementsNeedTransaction() { + // If there is more than one write statement, run in a transaction. + // Additionally, if we have only one statement but it needs a transaction, due + // to multiple BindingParams, we will wrap it in one. + for (uint32_t i = 0, transactionsCount = 0; i < mStatements.Length(); ++i) { + transactionsCount += mStatements[i].needsTransaction(); + if (transactionsCount > 1) { + return true; + } + } + return false; +} + +//////////////////////////////////////////////////////////////////////////////// +//// mozIStoragePendingStatement + +NS_IMETHODIMP +AsyncExecuteStatements::Cancel() { +#ifdef DEBUG + bool onCallingThread = false; + (void)mCallingThread->IsOnCurrentThread(&onCallingThread); + NS_ASSERTION(onCallingThread, "Not canceling from the calling thread!"); +#endif + + // If we have already canceled, we have an error, but always indicate that + // we are trying to cancel. + NS_ENSURE_FALSE(mCancelRequested, NS_ERROR_UNEXPECTED); + + { + MutexAutoLock lockedScope(mMutex); + + // We need to indicate that we want to try and cancel now. + mCancelRequested = true; + } + + return NS_OK; +} + +//////////////////////////////////////////////////////////////////////////////// +//// nsIRunnable + +NS_IMETHODIMP +AsyncExecuteStatements::Run() { + MOZ_ASSERT(mConnection->isConnectionReadyOnThisThread()); + + // Do not run if we have been canceled. + { + MutexAutoLock lockedScope(mMutex); + if (mCancelRequested) mState = CANCELED; + } + if (mState == CANCELED) return notifyComplete(); + + if (statementsNeedTransaction()) { + SQLiteMutexAutoLock lockedScope(mDBMutex); + if (!mConnection->transactionInProgress(lockedScope)) { + if (NS_SUCCEEDED(mConnection->beginTransactionInternal( + lockedScope, mNativeConnection, + mozIStorageConnection::TRANSACTION_IMMEDIATE))) { + mHasTransaction = true; + } +#ifdef DEBUG + else { + NS_WARNING("Unable to create a transaction for async execution."); + } +#endif + } + } + + // Execute each statement, giving the callback results if it returns any. + for (uint32_t i = 0; i < mStatements.Length(); i++) { + bool finished = (i == (mStatements.Length() - 1)); + + sqlite3_stmt* stmt; + { // lock the sqlite mutex so sqlite3_errmsg cannot change + SQLiteMutexAutoLock lockedScope(mDBMutex); + + int rc = mStatements[i].getSqliteStatement(&stmt); + if (rc != SQLITE_OK) { + // Set our error state. + mState = ERROR; + + // Build the error object; can't call notifyError with the lock held + nsCOMPtr<mozIStorageError> errorObj( + new Error(rc, ::sqlite3_errmsg(mNativeConnection))); + { + // We cannot hold the DB mutex and call notifyError. + SQLiteMutexAutoUnlock unlockedScope(mDBMutex); + (void)notifyError(errorObj); + } + break; + } + } + + // If we have parameters to bind, bind them, execute, and process. + if (mStatements[i].hasParametersToBeBound()) { + if (!bindExecuteAndProcessStatement(mStatements[i], finished)) break; + } + // Otherwise, just execute and process the statement. + else if (!executeAndProcessStatement(mStatements[i], finished)) { + break; + } + } + + // If we still have results that we haven't notified about, take care of + // them now. + if (mResultSet) (void)notifyResults(); + + // Notify about completion + return notifyComplete(); +} + +} // namespace storage +} // namespace mozilla |