The Tor Browser / file comparison
comparison: storage/public/StatementCache.h
storage/public/StatementCache.h
- branch
- TOR_BUG_9701
- changeset 15
- b8a032363ba2
equal
deleted
inserted
replaced
| -1:000000000000 | 0:63476cab6127 |
|---|---|
| 1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- | |
| 2 * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ : | |
| 3 * This Source Code Form is subject to the terms of the Mozilla Public | |
| 4 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
| 5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 6 | |
| 7 #ifndef mozilla_storage_StatementCache_h | |
| 8 #define mozilla_storage_StatementCache_h | |
| 9 | |
| 10 #include "mozIStorageConnection.h" | |
| 11 #include "mozIStorageStatement.h" | |
| 12 #include "mozIStorageAsyncStatement.h" | |
| 13 | |
| 14 #include "nsAutoPtr.h" | |
| 15 #include "nsHashKeys.h" | |
| 16 #include "nsInterfaceHashtable.h" | |
| 17 | |
| 18 namespace mozilla { | |
| 19 namespace storage { | |
| 20 | |
| 21 /** | |
| 22 * Class used to cache statements (mozIStorageStatement or | |
| 23 * mozIStorageAsyncStatement). | |
| 24 */ | |
| 25 template<typename StatementType> | |
| 26 class StatementCache { | |
| 27 public: | |
| 28 /** | |
| 29 * Constructor for the cache. | |
| 30 * | |
| 31 * @note a connection can have more than one cache. | |
| 32 * | |
| 33 * @param aConnection | |
| 34 * A reference to the nsCOMPtr for the connection this cache is to be | |
| 35 * used for. This nsCOMPtr must at least live as long as this class, | |
| 36 * otherwise crashes will happen. | |
| 37 */ | |
| 38 StatementCache(nsCOMPtr<mozIStorageConnection>& aConnection) | |
| 39 : mConnection(aConnection) | |
| 40 { | |
| 41 } | |
| 42 | |
| 43 /** | |
| 44 * Obtains a cached statement. If this statement is not yet created, it will | |
| 45 * be created and stored for later use. | |
| 46 * | |
| 47 * @param aQuery | |
| 48 * The SQL string (either a const char [] or nsACString) to get a | |
| 49 * cached query for. | |
| 50 * @return the cached statement, or null upon error. | |
| 51 */ | |
| 52 inline | |
| 53 already_AddRefed<StatementType> | |
| 54 GetCachedStatement(const nsACString& aQuery) | |
| 55 { | |
| 56 nsCOMPtr<StatementType> stmt; | |
| 57 if (!mCachedStatements.Get(aQuery, getter_AddRefs(stmt))) { | |
| 58 stmt = CreateStatement(aQuery); | |
| 59 NS_ENSURE_TRUE(stmt, nullptr); | |
| 60 | |
| 61 mCachedStatements.Put(aQuery, stmt); | |
| 62 } | |
| 63 return stmt.forget(); | |
| 64 } | |
| 65 | |
| 66 template<int N> | |
| 67 MOZ_ALWAYS_INLINE already_AddRefed<StatementType> | |
| 68 GetCachedStatement(const char (&aQuery)[N]) | |
| 69 { | |
| 70 nsDependentCString query(aQuery, N - 1); | |
| 71 return GetCachedStatement(query); | |
| 72 } | |
| 73 | |
| 74 /** | |
| 75 * Finalizes all cached statements so the database can be safely closed. The | |
| 76 * behavior of this cache is unspecified after this method is called. | |
| 77 */ | |
| 78 inline | |
| 79 void | |
| 80 FinalizeStatements() | |
| 81 { | |
| 82 (void)mCachedStatements.Enumerate(FinalizeCachedStatements, nullptr); | |
| 83 | |
| 84 // Clear the cache at this time too! | |
| 85 (void)mCachedStatements.Clear(); | |
| 86 } | |
| 87 | |
| 88 private: | |
| 89 inline | |
| 90 already_AddRefed<StatementType> | |
| 91 CreateStatement(const nsACString& aQuery); | |
| 92 static | |
| 93 PLDHashOperator | |
| 94 FinalizeCachedStatements(const nsACString& aKey, | |
| 95 nsCOMPtr<StatementType>& aStatement, | |
| 96 void*) | |
| 97 { | |
| 98 (void)aStatement->Finalize(); | |
| 99 return PL_DHASH_NEXT; | |
| 100 } | |
| 101 | |
| 102 nsInterfaceHashtable<nsCStringHashKey, StatementType> mCachedStatements; | |
| 103 nsCOMPtr<mozIStorageConnection>& mConnection; | |
| 104 }; | |
| 105 | |
| 106 template< > | |
| 107 inline | |
| 108 already_AddRefed<mozIStorageStatement> | |
| 109 StatementCache<mozIStorageStatement>::CreateStatement(const nsACString& aQuery) | |
| 110 { | |
| 111 NS_ENSURE_TRUE(mConnection, nullptr); | |
| 112 | |
| 113 nsCOMPtr<mozIStorageStatement> stmt; | |
| 114 nsresult rv = mConnection->CreateStatement(aQuery, getter_AddRefs(stmt)); | |
| 115 if (NS_FAILED(rv)) { | |
| 116 nsCString error; | |
| 117 error.AppendLiteral("The statement '"); | |
| 118 error.Append(aQuery); | |
| 119 error.AppendLiteral("' failed to compile with the error message '"); | |
| 120 nsCString msg; | |
| 121 (void)mConnection->GetLastErrorString(msg); | |
| 122 error.Append(msg); | |
| 123 error.AppendLiteral("'."); | |
| 124 NS_ERROR(error.get()); | |
| 125 } | |
| 126 NS_ENSURE_SUCCESS(rv, nullptr); | |
| 127 | |
| 128 return stmt.forget(); | |
| 129 } | |
| 130 | |
| 131 template< > | |
| 132 inline | |
| 133 already_AddRefed<mozIStorageAsyncStatement> | |
| 134 StatementCache<mozIStorageAsyncStatement>::CreateStatement(const nsACString& aQuery) | |
| 135 { | |
| 136 NS_ENSURE_TRUE(mConnection, nullptr); | |
| 137 | |
| 138 nsCOMPtr<mozIStorageAsyncStatement> stmt; | |
| 139 nsresult rv = mConnection->CreateAsyncStatement(aQuery, getter_AddRefs(stmt)); | |
| 140 NS_ENSURE_SUCCESS(rv, nullptr); | |
| 141 | |
| 142 return stmt.forget(); | |
| 143 } | |
| 144 | |
| 145 } // namespace storage | |
| 146 } // namespace mozilla | |
| 147 | |
| 148 #endif // mozilla_storage_StatementCache_h |
