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/* -*- 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 "nsAutoPtr.h"
#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"
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
// It is not possible to use ESR52's nsProxyRelease.h without substantial and
// unacceptable modification, so we use part of it here to simulate it and
// fix bugs 1375217 and 1350752.
//
// XXX: If this is needed lots of places, we should move it to that header.
template<typename T>
class ProxyReleaseEvent : public nsRunnable
{
public:
explicit ProxyReleaseEvent(already_AddRefed<T> aDoomed)
: mDoomed(aDoomed.take()) {}
NS_IMETHOD Run() override
{
NS_IF_RELEASE(mDoomed);
return NS_OK;
}
private:
T* MOZ_OWNING_REF mDoomed;
};
////////////////////////////////////////////////////////////////////////////////
//// 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(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)
: 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)
, mRequestStartDate(TimeStamp::Now())
{
(void)mStatements.SwapElements(aStatements);
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(mCallingThread, mCallback.forget());
nsCOMPtr<nsIRunnable> ev =
new ProxyReleaseEvent<mozIStorageStatementCallback>(mCallback.forget());
if (NS_FAILED(mCallingThread->Dispatch(ev, NS_DISPATCH_NORMAL))) {
NS_WARNING("AsyncExecuteStatements dtor failed proxy release");
}
}
}
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.
(void)aData.getSqliteStatement(&aStatement);
NS_ASSERTION(aStatement, "You broke the code; do not call here like that!");
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(aStatement, lastStatement);
// Always reset our statement.
(void)::sqlite3_reset(aStatement);
}
return continueProcessing;
}
bool
AsyncExecuteStatements::executeAndProcessStatement(sqlite3_stmt *aStatement,
bool aLastStatement)
{
mMutex.AssertNotCurrentThreadOwns();
// Execute our statement
bool hasResults;
do {
hasResults = executeStatement(aStatement);
// If we had an error, bail.
if (mState == ERROR)
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(sqlite3_stmt *aStatement)
{
mMutex.AssertNotCurrentThreadOwns();
Telemetry::AutoTimer<Telemetry::MOZ_STORAGE_ASYNC_REQUESTS_MS> finallySendExecutionDuration(mRequestStartDate);
while (true) {
// lock the sqlite mutex so sqlite3_errmsg cannot change
SQLiteMutexAutoLock lockedScope(mDBMutex);
int rc = mConnection->stepStatement(mNativeConnection, aStatement);
// Stop if we have no more results.
if (rc == SQLITE_DONE)
{
Telemetry::Accumulate(Telemetry::MOZ_STORAGE_ASYNC_REQUESTS_SUCCESS, true);
return false;
}
// If we got results, we can return now.
if (rc == SQLITE_ROW)
{
Telemetry::Accumulate(Telemetry::MOZ_STORAGE_ASYNC_REQUESTS_SUCCESS, true);
return true;
}
// Some errors are not fatal, and we can handle them and continue.
if (rc == SQLITE_BUSY) {
// Don't hold the lock while we call outside our module.
SQLiteMutexAutoUnlock unlockedScope(mDBMutex);
// Yield, and try again
(void)::PR_Sleep(PR_INTERVAL_NO_WAIT);
continue;
}
// Set an error state.
mState = ERROR;
Telemetry::Accumulate(Telemetry::MOZ_STORAGE_ASYNC_REQUESTS_SUCCESS, false);
// 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) {
if (mState == COMPLETED) {
nsresult rv = mConnection->commitTransactionInternal(mNativeConnection);
if (NS_FAILED(rv)) {
mState = ERROR;
(void)notifyError(mozIStorageError::ERROR,
"Transaction failed to commit");
}
}
else {
DebugOnly<nsresult> rv =
mConnection->rollbackTransactionInternal(mNativeConnection);
NS_WARN_IF_FALSE(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.
(void)mCallingThread->Dispatch(
NS_NewRunnableMethod(this, &AsyncExecuteStatements::notifyCompleteOnCallingThread),
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) {
(void)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;
(void)mCallingThread->Dispatch(
NS_NewRunnableMethodWithArg<nsCOMPtr<mozIStorageError>>(this, &AsyncExecuteStatements::notifyErrorOnCallingThread, aError),
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) {
(void)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.
(void)mCallingThread->Dispatch(
NS_NewRunnableMethodWithArg<RefPtr<ResultSet>>(this, &AsyncExecuteStatements::notifyResultsOnCallingThread, mResultSet.forget()),
NS_DISPATCH_NORMAL);
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) {
(void)callback->HandleResult(aResultSet);
}
return NS_OK;
}
NS_IMPL_ISUPPORTS(
AsyncExecuteStatements,
nsIRunnable,
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->isClosed());
// Do not run if we have been canceled.
{
MutexAutoLock lockedScope(mMutex);
if (mCancelRequested)
mState = CANCELED;
}
if (mState == CANCELED)
return notifyComplete();
if (statementsNeedTransaction() && mConnection->getAutocommit()) {
if (NS_SUCCEEDED(mConnection->beginTransactionInternal(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(stmt, 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
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