LCOV - app.info - objdir/dist/include/mozilla/storage/StatementCache.h

LCOV - code coverage report
| Current view: | directory - objdir/dist/include/mozilla/storage - StatementCache.h (source / functions) |  | Found | Hit | Coverage |
| Test: | app.info | Lines: | 45 | 34 | 75.6 %
| Date: | 2012-07-07 | Functions: | 18 | 18 | 100.0 %

           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                 :  * ***** BEGIN LICENSE BLOCK *****
           4                 :  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
           5                 :  *
           6                 :  * The contents of this file are subject to the Mozilla Public License Version
           7                 :  * 1.1 (the "License"); you may not use this file except in compliance with
           8                 :  * the License. You may obtain a copy of the License at
           9                 :  * http://www.mozilla.org/MPL/
          10                 :  *
          11                 :  * Software distributed under the License is distributed on an "AS IS" basis,
          12                 :  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
          13                 :  * for the specific language governing rights and limitations under the
          14                 :  * License.
          15                 :  *
          16                 :  * The Original Code is the mozStorage statement cache.
          17                 :  *
          18                 :  * The Initial Developer of the Original Code is
          19                 :  * the Mozilla Foundation.
          20                 :  * Portions created by the Initial Developer are Copyright (C) 2010
          21                 :  * the Initial Developer. All Rights Reserved.
          22                 :  *
          23                 :  * Contributor(s):
          24                 :  *   Shawn Wilsher <me@shawnwilsher.com>
          25                 :  *
          26                 :  * Alternatively, the contents of this file may be used under the terms of
          27                 :  * either the GNU General Public License Version 2 or later (the "GPL"), or
          28                 :  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
          29                 :  * in which case the provisions of the GPL or the LGPL are applicable instead
          30                 :  * of those above. If you wish to allow use of your version of this file only
          31                 :  * under the terms of either the GPL or the LGPL, and not to allow others to
          32                 :  * use your version of this file under the terms of the MPL, indicate your
          33                 :  * decision by deleting the provisions above and replace them with the notice
          34                 :  * and other provisions required by the GPL or the LGPL. If you do not delete
          35                 :  * the provisions above, a recipient may use your version of this file under
          36                 :  * the terms of any one of the MPL, the GPL or the LGPL.
          37                 :  *
          38                 :  * ***** END LICENSE BLOCK ***** */
          39                 :
          40                 : #ifndef mozilla_storage_StatementCache_h
          41                 : #define mozilla_storage_StatementCache_h
          42                 :
          43                 : #include "mozIStorageConnection.h"
          44                 : #include "mozIStorageStatement.h"
          45                 : #include "mozIStorageAsyncStatement.h"
          46                 :
          47                 : #include "nsAutoPtr.h"
          48                 : #include "nsHashKeys.h"
          49                 : #include "nsInterfaceHashtable.h"
          50                 :
          51                 : namespace mozilla {
          52                 : namespace storage {
          53                 :
          54                 : /**
          55                 :  * Class used to cache statements (mozIStorageStatement or
          56                 :  * mozIStorageAsyncStatement).
          57                 :  */
          58                 : template<typename StatementType>
          59             960 : class StatementCache {
          60                 : public:
          61                 :   /**
          62                 :    * Constructor for the cache.
          63                 :    *
          64                 :    * @note a connection can have more than one cache.
          65                 :    *
          66                 :    * @param aConnection
          67                 :    *        A reference to the nsCOMPtr for the connection this cache is to be
          68                 :    *        used for.  This nsCOMPtr must at least live as long as this class,
          69                 :    *        otherwise crashes will happen.
          70                 :    */
          71             960 :   StatementCache(nsCOMPtr<mozIStorageConnection>& aConnection)
          72             960 :   : mConnection(aConnection)
          73                 :   {
          74             960 :     if (!mCachedStatements.Init()) {
          75               0 :       NS_ERROR("Out of memory!?");
          76                 :     }
          77             960 :   }
          78                 :
          79                 :   /**
          80                 :    * Obtains a cached statement.  If this statement is not yet created, it will
          81                 :    * be created and stored for later use.
          82                 :    *
          83                 :    * @param aQuery
          84                 :    *        The SQL string (either a const char [] or nsACString) to get a
          85                 :    *        cached query for.
          86                 :    * @return the cached statement, or null upon error.
          87                 :    */
          88                 :   inline
          89                 :   already_AddRefed<StatementType>
          90           58918 :   GetCachedStatement(const nsACString& aQuery)
          91                 :   {
          92          117836 :     nsCOMPtr<StatementType> stmt;
          93           58918 :     if (!mCachedStatements.Get(aQuery, getter_AddRefs(stmt))) {
          94            4299 :       stmt = CreateStatement(aQuery);
          95            4299 :       NS_ENSURE_TRUE(stmt, nsnull);
          96                 :
          97            4299 :       if (!mCachedStatements.Put(aQuery, stmt)) {
          98               0 :         NS_ERROR("Out of memory!?");
          99                 :       }
         100                 :     }
         101           58918 :     return stmt.forget();
         102                 :   }
         103                 :
         104                 :   template<int N>
         105                 :   NS_ALWAYS_INLINE already_AddRefed<StatementType>
         106                 :   GetCachedStatement(const char (&aQuery)[N])
         107                 :   {
         108             422 :     nsDependentCString query(aQuery, N - 1);
         109             211 :     return GetCachedStatement(query);
         110                 :   }
         111                 :
         112                 :   /**
         113                 :    * Finalizes all cached statements so the database can be safely closed.  The
         114                 :    * behavior of this cache is unspecified after this method is called.
         115                 :    */
         116                 :   inline
         117                 :   void
         118             873 :   FinalizeStatements()
         119                 :   {
         120             873 :     (void)mCachedStatements.Enumerate(FinalizeCachedStatements, NULL);
         121                 :
         122                 :     // Clear the cache at this time too!
         123             873 :     (void)mCachedStatements.Clear();
         124             873 :   }
         125                 :
         126                 : private:
         127                 :   inline
         128                 :   already_AddRefed<StatementType>
         129                 :   CreateStatement(const nsACString& aQuery);
         130                 :   static
         131                 :   PLDHashOperator
         132            4295 :   FinalizeCachedStatements(const nsACString& aKey,
         133                 :                            nsCOMPtr<StatementType>& aStatement,
         134                 :                            void*)
         135                 :   {
         136            4295 :     (void)aStatement->Finalize();
         137            4295 :     return PL_DHASH_NEXT;
         138                 :   }
         139                 :
         140                 :   nsInterfaceHashtable<nsCStringHashKey, StatementType> mCachedStatements;
         141                 :   nsCOMPtr<mozIStorageConnection>& mConnection;
         142                 : };
         143                 :
         144                 : template< >
         145                 : inline
         146                 : already_AddRefed<mozIStorageStatement>
         147            3457 : StatementCache<mozIStorageStatement>::CreateStatement(const nsACString& aQuery)
         148                 : {
         149            3457 :   NS_ENSURE_TRUE(mConnection, nsnull);
         150                 :
         151            6914 :   nsCOMPtr<mozIStorageStatement> stmt;
         152            3457 :   nsresult rv = mConnection->CreateStatement(aQuery, getter_AddRefs(stmt));
         153            3457 :   if (NS_FAILED(rv)) {
         154               0 :     nsCString error;
         155               0 :     error.AppendLiteral("The statement '");
         156               0 :     error.Append(aQuery);
         157               0 :     error.AppendLiteral("' failed to compile with the error message '");
         158               0 :     nsCString msg;
         159               0 :     (void)mConnection->GetLastErrorString(msg);
         160               0 :     error.Append(msg);
         161               0 :     error.AppendLiteral("'.");
         162               0 :     NS_ERROR(error.get());
         163                 :   }
         164            3457 :   NS_ENSURE_SUCCESS(rv, nsnull);
         165                 :
         166            3457 :   return stmt.forget();
         167                 : }
         168                 :
         169                 : template< >
         170                 : inline
         171                 : already_AddRefed<mozIStorageAsyncStatement>
         172             842 : StatementCache<mozIStorageAsyncStatement>::CreateStatement(const nsACString& aQuery)
         173                 : {
         174             842 :   NS_ENSURE_TRUE(mConnection, nsnull);
         175                 :
         176            1684 :   nsCOMPtr<mozIStorageAsyncStatement> stmt;
         177             842 :   nsresult rv = mConnection->CreateAsyncStatement(aQuery, getter_AddRefs(stmt));
         178             842 :   NS_ENSURE_SUCCESS(rv, nsnull);
         179                 :
         180             842 :   return stmt.forget();
         181                 : }
         182                 :
         183                 : } // namespace storage
         184                 : } // namespace mozilla
         185                 :
         186                 : #endif // mozilla_storage_StatementCache_h

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