storage/public/StatementCache.h@b8a032363ba2 (annotated)
storage/public/StatementCache.h
Thu, 22 Jan 2015 13:21:57 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Thu, 22 Jan 2015 13:21:57 +0100
- branch
- TOR_BUG_9701
- changeset 15
- b8a032363ba2
- permissions
- -rw-r--r--
Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6
| 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 |
