The Tor Browser: comparison storage/src/StorageBaseStatementInternal.cpp

--1:000000000000
+:a02d6a4a3942
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+* vim: sw=2 ts=2 sts=2 expandtab
+* 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 "StorageBaseStatementInternal.h"
+#include "nsProxyRelease.h"
+#include "mozStorageBindingParamsArray.h"
+#include "mozStorageStatementData.h"
+#include "mozStorageAsyncStatementExecution.h"
+namespace mozilla {
+namespace storage {
+////////////////////////////////////////////////////////////////////////////////
+//// Local Classes
+/**
+* Used to finalize an asynchronous statement on the background thread.
+*/
+class AsyncStatementFinalizer : public nsRunnable
+{
+public:
+/**
+* Constructor for the event.
+*
+* @param aStatement
+*        We need the AsyncStatement to be able to get at the sqlite3_stmt;
+*        we only access/create it on the async thread.
+* @param aConnection
+*        We need the connection to know what thread to release the statement
+*        on.  We release the statement on that thread since releasing the
+*        statement might end up releasing the connection too.
+*/
+AsyncStatementFinalizer(StorageBaseStatementInternal *aStatement,
+Connection *aConnection)
+: mStatement(aStatement)
+, mConnection(aConnection)
+{
+}
+NS_IMETHOD Run()
+{
+if (mStatement->mAsyncStatement) {
+(void)::sqlite3_finalize(mStatement->mAsyncStatement);
+mStatement->mAsyncStatement = nullptr;
+}
+(void)::NS_ProxyRelease(mConnection->threadOpenedOn, mStatement);
+return NS_OK;
+}
+private:
+nsRefPtr<StorageBaseStatementInternal> mStatement;
+nsRefPtr<Connection> mConnection;
+};
+/**
+* Finalize a sqlite3_stmt on the background thread for a statement whose
+* destructor was invoked and the statement was non-null.
+*/
+class LastDitchSqliteStatementFinalizer : public nsRunnable
+{
+public:
+/**
+* Event constructor.
+*
+* @param aConnection
+*        Used to keep the connection alive.  If we failed to do this, it
+*        is possible that the statement going out of scope invoking us
+*        might have the last reference to the connection and so trigger
+*        an attempt to close the connection which is doomed to fail
+*        (because the asynchronous execution thread must exist which will
+*        trigger the failure case).
+* @param aStatement
+*        The sqlite3_stmt to finalize.  This object takes ownership /
+*        responsibility for the instance and all other references to it
+*        should be forgotten.
+*/
+LastDitchSqliteStatementFinalizer(nsRefPtr<Connection> &aConnection,
+sqlite3_stmt *aStatement)
+: mConnection(aConnection)
+, mAsyncStatement(aStatement)
+{
+NS_PRECONDITION(aConnection, "You must provide a Connection");
+}
+NS_IMETHOD Run()
+{
+(void)::sqlite3_finalize(mAsyncStatement);
+mAsyncStatement = nullptr;
+// Because of our ambiguous nsISupports we cannot use the NS_ProxyRelease
+// template helpers.
+Connection *rawConnection = nullptr;
+mConnection.swap(rawConnection);
+(void)::NS_ProxyRelease(
+rawConnection->threadOpenedOn,
+NS_ISUPPORTS_CAST(mozIStorageConnection *, rawConnection));
+return NS_OK;
+}
+private:
+nsRefPtr<Connection> mConnection;
+sqlite3_stmt *mAsyncStatement;
+};
+////////////////////////////////////////////////////////////////////////////////
+//// StorageBaseStatementInternal
+StorageBaseStatementInternal::StorageBaseStatementInternal()
+: mAsyncStatement(nullptr)
+{
+}
+void
+StorageBaseStatementInternal::asyncFinalize()
+{
+nsIEventTarget *target = mDBConnection->getAsyncExecutionTarget();
+if (target) {
+// Attempt to finalize asynchronously
+nsCOMPtr<nsIRunnable> event =
+new AsyncStatementFinalizer(this, mDBConnection);
+// Dispatch. Note that dispatching can fail, typically if
+// we have a race condition with asyncClose(). It's ok,
+// let asyncClose() win.
+(void)target->Dispatch(event, NS_DISPATCH_NORMAL);
+}
+// If we cannot get the background thread,
+// mozStorageConnection::AsyncClose() has already been called and
+// the statement either has been or will be cleaned up by
+// internalClose().
+}
+void
+StorageBaseStatementInternal::destructorAsyncFinalize()
+{
+if (!mAsyncStatement)
+return;
+// If we reach this point, our owner has not finalized this
+// statement, yet we are being destructed. If possible, we want to
+// auto-finalize it early, to release the resources early.
+nsIEventTarget *target = mDBConnection->getAsyncExecutionTarget();
+if (target) {
+// If we can get the async execution target, we can indeed finalize
+// the statement, as the connection is still open.
+bool isAsyncThread = false;
+(void)target->IsOnCurrentThread(&isAsyncThread);
+nsCOMPtr<nsIRunnable> event =
+new LastDitchSqliteStatementFinalizer(mDBConnection, mAsyncStatement);
+if (isAsyncThread) {
+(void)event->Run();
+} else {
+(void)target->Dispatch(event, NS_DISPATCH_NORMAL);
+}
+}
+// We might not be able to dispatch to the background thread,
+// presumably because it is being shutdown. Since said shutdown will
+// finalize the statement, we just need to clean-up around here.
+mAsyncStatement = nullptr;
+}
+NS_IMETHODIMP
+StorageBaseStatementInternal::NewBindingParamsArray(
+mozIStorageBindingParamsArray **_array
+)
+{
+nsCOMPtr<mozIStorageBindingParamsArray> array = new BindingParamsArray(this);
+NS_ENSURE_TRUE(array, NS_ERROR_OUT_OF_MEMORY);
+array.forget(_array);
+return NS_OK;
+}
+NS_IMETHODIMP
+StorageBaseStatementInternal::ExecuteAsync(
+mozIStorageStatementCallback *aCallback,
+mozIStoragePendingStatement **_stmt
+)
+{
+// We used to call Connection::ExecuteAsync but it takes a
+// mozIStorageBaseStatement signature because it is also a public API.  Since
+// our 'this' has no static concept of mozIStorageBaseStatement and Connection
+// would just QI it back across to a StorageBaseStatementInternal and the
+// actual logic is very simple, we now roll our own.
+nsTArray<StatementData> stmts(1);
+StatementData data;
+nsresult rv = getAsynchronousStatementData(data);
+NS_ENSURE_SUCCESS(rv, rv);
+NS_ENSURE_TRUE(stmts.AppendElement(data), NS_ERROR_OUT_OF_MEMORY);
+// Dispatch to the background
+return AsyncExecuteStatements::execute(stmts, mDBConnection,
+mNativeConnection, aCallback, _stmt);
+}
+NS_IMETHODIMP
+StorageBaseStatementInternal::EscapeStringForLIKE(
+const nsAString &aValue,
+const char16_t aEscapeChar,
+nsAString &_escapedString
+)
+{
+const char16_t MATCH_ALL('%');
+const char16_t MATCH_ONE('_');
+_escapedString.Truncate(0);
+for (uint32_t i = 0; i < aValue.Length(); i++) {
+if (aValue[i] == aEscapeChar || aValue[i] == MATCH_ALL ||
+aValue[i] == MATCH_ONE) {
+_escapedString += aEscapeChar;
+}
+_escapedString += aValue[i];
+}
+return NS_OK;
+}
+} // namespace storage
+} // namespace mozilla

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comparison: storage/src/StorageBaseStatementInternal.cpp

storage/src/StorageBaseStatementInternal.cpp