• file
• revisions
• annotate
• diff
• comparison
• raw

storage/public/StatementCache.h@6474c204b198 (annotated)

storage/public/StatementCache.h

Wed, 31 Dec 2014 06:09:35 +0100

author

Michael Schloh von Bennewitz <michael@schloh.com>

date

Wed, 31 Dec 2014 06:09:35 +0100

changeset 0

6474c204b198

permissions

-rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

michael@0	1	/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
michael@0	2	* vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
michael@0	3	* This Source Code Form is subject to the terms of the Mozilla Public
michael@0	4	* License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0	5	* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0	6
michael@0	7	#ifndef mozilla_storage_StatementCache_h
michael@0	8	#define mozilla_storage_StatementCache_h
michael@0	9
michael@0	10	#include "mozIStorageConnection.h"
michael@0	11	#include "mozIStorageStatement.h"
michael@0	12	#include "mozIStorageAsyncStatement.h"
michael@0	13
michael@0	14	#include "nsAutoPtr.h"
michael@0	15	#include "nsHashKeys.h"
michael@0	16	#include "nsInterfaceHashtable.h"
michael@0	17
michael@0	18	namespace mozilla {
michael@0	19	namespace storage {
michael@0	20
michael@0	21	/**
michael@0	22	* Class used to cache statements (mozIStorageStatement or
michael@0	23	* mozIStorageAsyncStatement).
michael@0	24	*/
michael@0	25	template<typename StatementType>
michael@0	26	class StatementCache {
michael@0	27	public:
michael@0	28	/**
michael@0	29	* Constructor for the cache.
michael@0	30	*
michael@0	31	* @note a connection can have more than one cache.
michael@0	32	*
michael@0	33	* @param aConnection
michael@0	34	* A reference to the nsCOMPtr for the connection this cache is to be
michael@0	35	* used for. This nsCOMPtr must at least live as long as this class,
michael@0	36	* otherwise crashes will happen.
michael@0	37	*/
michael@0	38	StatementCache(nsCOMPtr<mozIStorageConnection>& aConnection)
michael@0	39	: mConnection(aConnection)
michael@0	40	{
michael@0	41	}
michael@0	42
michael@0	43	/**
michael@0	44	* Obtains a cached statement. If this statement is not yet created, it will
michael@0	45	* be created and stored for later use.
michael@0	46	*
michael@0	47	* @param aQuery
michael@0	48	* The SQL string (either a const char [] or nsACString) to get a
michael@0	49	* cached query for.
michael@0	50	* @return the cached statement, or null upon error.
michael@0	51	*/
michael@0	52	inline
michael@0	53	already_AddRefed<StatementType>
michael@0	54	GetCachedStatement(const nsACString& aQuery)
michael@0	55	{
michael@0	56	nsCOMPtr<StatementType> stmt;
michael@0	57	if (!mCachedStatements.Get(aQuery, getter_AddRefs(stmt))) {
michael@0	58	stmt = CreateStatement(aQuery);
michael@0	59	NS_ENSURE_TRUE(stmt, nullptr);
michael@0	60
michael@0	61	mCachedStatements.Put(aQuery, stmt);
michael@0	62	}
michael@0	63	return stmt.forget();
michael@0	64	}
michael@0	65
michael@0	66	template<int N>
michael@0	67	MOZ_ALWAYS_INLINE already_AddRefed<StatementType>
michael@0	68	GetCachedStatement(const char (&aQuery)[N])
michael@0	69	{
michael@0	70	nsDependentCString query(aQuery, N - 1);
michael@0	71	return GetCachedStatement(query);
michael@0	72	}
michael@0	73
michael@0	74	/**
michael@0	75	* Finalizes all cached statements so the database can be safely closed. The
michael@0	76	* behavior of this cache is unspecified after this method is called.
michael@0	77	*/
michael@0	78	inline
michael@0	79	void
michael@0	80	FinalizeStatements()
michael@0	81	{
michael@0	82	(void)mCachedStatements.Enumerate(FinalizeCachedStatements, nullptr);
michael@0	83
michael@0	84	// Clear the cache at this time too!
michael@0	85	(void)mCachedStatements.Clear();
michael@0	86	}
michael@0	87
michael@0	88	private:
michael@0	89	inline
michael@0	90	already_AddRefed<StatementType>
michael@0	91	CreateStatement(const nsACString& aQuery);
michael@0	92	static
michael@0	93	PLDHashOperator
michael@0	94	FinalizeCachedStatements(const nsACString& aKey,
michael@0	95	nsCOMPtr<StatementType>& aStatement,
michael@0	96	void*)
michael@0	97	{
michael@0	98	(void)aStatement->Finalize();
michael@0	99	return PL_DHASH_NEXT;
michael@0	100	}
michael@0	101
michael@0	102	nsInterfaceHashtable<nsCStringHashKey, StatementType> mCachedStatements;
michael@0	103	nsCOMPtr<mozIStorageConnection>& mConnection;
michael@0	104	};
michael@0	105
michael@0	106	template< >
michael@0	107	inline
michael@0	108	already_AddRefed<mozIStorageStatement>
michael@0	109	StatementCache<mozIStorageStatement>::CreateStatement(const nsACString& aQuery)
michael@0	110	{
michael@0	111	NS_ENSURE_TRUE(mConnection, nullptr);
michael@0	112
michael@0	113	nsCOMPtr<mozIStorageStatement> stmt;
michael@0	114	nsresult rv = mConnection->CreateStatement(aQuery, getter_AddRefs(stmt));
michael@0	115	if (NS_FAILED(rv)) {
michael@0	116	nsCString error;
michael@0	117	error.AppendLiteral("The statement '");
michael@0	118	error.Append(aQuery);
michael@0	119	error.AppendLiteral("' failed to compile with the error message '");
michael@0	120	nsCString msg;
michael@0	121	(void)mConnection->GetLastErrorString(msg);
michael@0	122	error.Append(msg);
michael@0	123	error.AppendLiteral("'.");
michael@0	124	NS_ERROR(error.get());
michael@0	125	}
michael@0	126	NS_ENSURE_SUCCESS(rv, nullptr);
michael@0	127
michael@0	128	return stmt.forget();
michael@0	129	}
michael@0	130
michael@0	131	template< >
michael@0	132	inline
michael@0	133	already_AddRefed<mozIStorageAsyncStatement>
michael@0	134	StatementCache<mozIStorageAsyncStatement>::CreateStatement(const nsACString& aQuery)
michael@0	135	{
michael@0	136	NS_ENSURE_TRUE(mConnection, nullptr);
michael@0	137
michael@0	138	nsCOMPtr<mozIStorageAsyncStatement> stmt;
michael@0	139	nsresult rv = mConnection->CreateAsyncStatement(aQuery, getter_AddRefs(stmt));
michael@0	140	NS_ENSURE_SUCCESS(rv, nullptr);
michael@0	141
michael@0	142	return stmt.forget();
michael@0	143	}
michael@0	144
michael@0	145	} // namespace storage
michael@0	146	} // namespace mozilla
michael@0	147
michael@0	148	#endif // mozilla_storage_StatementCache_h