/* -*- 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/. */ #ifndef mozilla_storage_StatementCache_h #define mozilla_storage_StatementCache_h #include "mozIStorageConnection.h" #include "mozIStorageStatement.h" #include "mozIStorageAsyncStatement.h" #include "nsAutoPtr.h" #include "nsHashKeys.h" #include "nsInterfaceHashtable.h" namespace mozilla { namespace storage { /** * Class used to cache statements (mozIStorageStatement or * mozIStorageAsyncStatement). */ template<typename StatementType> class StatementCache { public: /** * Constructor for the cache. * * @note a connection can have more than one cache. * * @param aConnection * A reference to the nsCOMPtr for the connection this cache is to be * used for. This nsCOMPtr must at least live as long as this class, * otherwise crashes will happen. */ explicit StatementCache(nsCOMPtr<mozIStorageConnection>& aConnection) : mConnection(aConnection) { } /** * Obtains a cached statement. If this statement is not yet created, it will * be created and stored for later use. * * @param aQuery * The SQL string (either a const char [] or nsACString) to get a * cached query for. * @return the cached statement, or null upon error. */ inline already_AddRefed<StatementType> GetCachedStatement(const nsACString& aQuery) { nsCOMPtr<StatementType> stmt; if (!mCachedStatements.Get(aQuery, getter_AddRefs(stmt))) { stmt = CreateStatement(aQuery); NS_ENSURE_TRUE(stmt, nullptr); mCachedStatements.Put(aQuery, stmt); } return stmt.forget(); } template<int N> MOZ_ALWAYS_INLINE already_AddRefed<StatementType> GetCachedStatement(const char (&aQuery)[N]) { nsDependentCString query(aQuery, N - 1); return GetCachedStatement(query); } /** * Finalizes all cached statements so the database can be safely closed. The * behavior of this cache is unspecified after this method is called. */ inline void FinalizeStatements() { for (auto iter = mCachedStatements.Iter(); !iter.Done(); iter.Next()) { (void)iter.Data()->Finalize(); } // Clear the cache at this time too! (void)mCachedStatements.Clear(); } private: inline already_AddRefed<StatementType> CreateStatement(const nsACString& aQuery); nsInterfaceHashtable<nsCStringHashKey, StatementType> mCachedStatements; nsCOMPtr<mozIStorageConnection>& mConnection; }; template< > inline already_AddRefed<mozIStorageStatement> StatementCache<mozIStorageStatement>::CreateStatement(const nsACString& aQuery) { NS_ENSURE_TRUE(mConnection, nullptr); nsCOMPtr<mozIStorageStatement> stmt; nsresult rv = mConnection->CreateStatement(aQuery, getter_AddRefs(stmt)); if (NS_FAILED(rv)) { nsCString error; error.AppendLiteral("The statement '"); error.Append(aQuery); error.AppendLiteral("' failed to compile with the error message '"); nsCString msg; (void)mConnection->GetLastErrorString(msg); error.Append(msg); error.AppendLiteral("'."); NS_ERROR(error.get()); } NS_ENSURE_SUCCESS(rv, nullptr); return stmt.forget(); } template< > inline already_AddRefed<mozIStorageAsyncStatement> StatementCache<mozIStorageAsyncStatement>::CreateStatement(const nsACString& aQuery) { NS_ENSURE_TRUE(mConnection, nullptr); nsCOMPtr<mozIStorageAsyncStatement> stmt; nsresult rv = mConnection->CreateAsyncStatement(aQuery, getter_AddRefs(stmt)); NS_ENSURE_SUCCESS(rv, nullptr); return stmt.forget(); } } // namespace storage } // namespace mozilla #endif // mozilla_storage_StatementCache_h