LCOV - code coverage report
Current view: directory - objdir/dist/include - mozStorageHelper.h (source / functions) Found Hit Coverage
Test: app.info Lines: 52 50 96.2 %
Date: 2012-06-02 Functions: 9 9 100.0 %

       1                 : /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
       2                 : /* ***** BEGIN LICENSE BLOCK *****
       3                 :  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
       4                 :  *
       5                 :  * The contents of this file are subject to the Mozilla Public License Version
       6                 :  * 1.1 (the "License"); you may not use this file except in compliance with
       7                 :  * the License. You may obtain a copy of the License at
       8                 :  * http://www.mozilla.org/MPL/
       9                 :  *
      10                 :  * Software distributed under the License is distributed on an "AS IS" basis,
      11                 :  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
      12                 :  * for the specific language governing rights and limitations under the
      13                 :  * License.
      14                 :  *
      15                 :  * The Original Code is Storage code
      16                 :  *
      17                 :  * The Initial Developer of the Original Code is
      18                 :  * Google Inc.
      19                 :  * Portions created by the Initial Developer are Copyright (C) 2005
      20                 :  * the Initial Developer. All Rights Reserved.
      21                 :  *
      22                 :  * Contributor(s):
      23                 :  *   Brett Wilson <brettw@gmail.com>
      24                 :  *
      25                 :  * Alternatively, the contents of this file may be used under the terms of
      26                 :  * either the GNU General Public License Version 2 or later (the "GPL"), or
      27                 :  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
      28                 :  * in which case the provisions of the GPL or the LGPL are applicable instead
      29                 :  * of those above. If you wish to allow use of your version of this file only
      30                 :  * under the terms of either the GPL or the LGPL, and not to allow others to
      31                 :  * use your version of this file under the terms of the MPL, indicate your
      32                 :  * decision by deleting the provisions above and replace them with the notice
      33                 :  * and other provisions required by the GPL or the LGPL. If you do not delete
      34                 :  * the provisions above, a recipient may use your version of this file under
      35                 :  * the terms of any one of the MPL, the GPL or the LGPL.
      36                 :  *
      37                 :  * ***** END LICENSE BLOCK ***** */
      38                 : 
      39                 : #ifndef MOZSTORAGEHELPER_H
      40                 : #define MOZSTORAGEHELPER_H
      41                 : 
      42                 : #include "nsAutoPtr.h"
      43                 : 
      44                 : #include "mozIStorageConnection.h"
      45                 : #include "mozIStorageStatement.h"
      46                 : #include "mozStorage.h"
      47                 : 
      48                 : 
      49                 : /**
      50                 :  * This class wraps a transaction inside a given C++ scope, guaranteeing that
      51                 :  * the transaction will be completed even if you have an exception or
      52                 :  * return early.
      53                 :  *
      54                 :  * aCommitOnComplete controls whether the transaction is committed or rolled
      55                 :  * back when it goes out of scope. A common use is to create an instance with
      56                 :  * commitOnComplete = FALSE (rollback), then call Commit on this object manually
      57                 :  * when your function completes successfully.
      58                 :  *
      59                 :  * Note that nested transactions are not supported by sqlite, so if a transaction
      60                 :  * is already in progress, this object does nothing. Note that in this case,
      61                 :  * you may not get the transaction type you ask for, and you won't be able
      62                 :  * to rollback.
      63                 :  */
      64                 : class mozStorageTransaction
      65                 : {
      66                 : public:
      67           12403 :   mozStorageTransaction(mozIStorageConnection* aConnection,
      68                 :                         bool aCommitOnComplete,
      69                 :                         PRInt32 aType = mozIStorageConnection::TRANSACTION_DEFERRED)
      70                 :     : mConnection(aConnection),
      71                 :       mHasTransaction(false),
      72                 :       mCommitOnComplete(aCommitOnComplete),
      73           12403 :       mCompleted(false)
      74                 :   {
      75                 :     // We won't try to get a transaction if one is already in progress.
      76           12403 :     if (mConnection)
      77           12402 :       mHasTransaction = NS_SUCCEEDED(mConnection->BeginTransactionAs(aType));
      78           12403 :   }
      79           12403 :   ~mozStorageTransaction()
      80           12403 :   {
      81           12403 :     if (mConnection && mHasTransaction && ! mCompleted) {
      82             131 :       if (mCommitOnComplete)
      83             109 :         mConnection->CommitTransaction();
      84                 :       else
      85              22 :         mConnection->RollbackTransaction();
      86                 :     }
      87           12403 :   }
      88                 : 
      89                 :   /**
      90                 :    * Commits the transaction if one is in progress. If one is not in progress,
      91                 :    * this is a NOP since the actual owner of the transaction outside of our
      92                 :    * scope is in charge of finally comitting or rolling back the transaction.
      93                 :    */
      94           12259 :   nsresult Commit()
      95                 :   {
      96           12259 :     if (!mConnection || mCompleted)
      97               1 :       return NS_OK; // no connection, or already done
      98           12258 :     mCompleted = true;
      99           12258 :     if (! mHasTransaction)
     100            5235 :       return NS_OK; // transaction not ours, ignore
     101            7023 :     nsresult rv = mConnection->CommitTransaction();
     102            7023 :     if (NS_SUCCEEDED(rv))
     103            7023 :       mHasTransaction = false;
     104                 : 
     105            7023 :     return rv;
     106                 :   }
     107                 : 
     108                 :   /**
     109                 :    * Rolls back the transaction in progress. You should only call this function
     110                 :    * if this object has a real transaction (HasTransaction() = true) because
     111                 :    * otherwise, there is no transaction to roll back.
     112                 :    */
     113               4 :   nsresult Rollback()
     114                 :   {
     115               4 :     if (!mConnection || mCompleted)
     116               1 :       return NS_OK; // no connection, or already done
     117               3 :     mCompleted = true;
     118               3 :     if (! mHasTransaction)
     119               0 :       return NS_ERROR_FAILURE;
     120                 : 
     121                 :     // It is possible that a rollback will return busy, so we busy wait...
     122               3 :     nsresult rv = NS_OK;
     123               3 :     do {
     124               3 :       rv = mConnection->RollbackTransaction();
     125               3 :       if (rv == NS_ERROR_STORAGE_BUSY)
     126               0 :         (void)PR_Sleep(PR_INTERVAL_NO_WAIT);
     127                 :     } while (rv == NS_ERROR_STORAGE_BUSY);
     128                 : 
     129               3 :     if (NS_SUCCEEDED(rv))
     130               3 :       mHasTransaction = false;
     131                 : 
     132               3 :     return rv;
     133                 :   }
     134                 : 
     135                 :   /**
     136                 :    * Returns whether this object wraps a real transaction. False means that
     137                 :    * this object doesn't do anything because there was already a transaction in
     138                 :    * progress when it was created.
     139                 :    */
     140               7 :   bool HasTransaction()
     141                 :   {
     142               7 :     return mHasTransaction;
     143                 :   }
     144                 : 
     145                 :   /**
     146                 :    * This sets the default action (commit or rollback) when this object goes
     147                 :    * out of scope.
     148                 :    */
     149               2 :   void SetDefaultAction(bool aCommitOnComplete)
     150                 :   {
     151               2 :     mCommitOnComplete = aCommitOnComplete;
     152               2 :   }
     153                 : 
     154                 : protected:
     155                 :   nsCOMPtr<mozIStorageConnection> mConnection;
     156                 :   bool mHasTransaction;
     157                 :   bool mCommitOnComplete;
     158                 :   bool mCompleted;
     159                 : };
     160                 : 
     161                 : 
     162                 : /**
     163                 :  * This class wraps a statement so that it is guaraneed to be reset when
     164                 :  * this object goes out of scope.
     165                 :  *
     166                 :  * Note that this always just resets the statement. If the statement doesn't
     167                 :  * need resetting, the reset operation is inexpensive.
     168                 :  */
     169                 : class NS_STACK_CLASS mozStorageStatementScoper
     170                 : {
     171                 : public:
     172           66363 :   mozStorageStatementScoper(mozIStorageStatement* aStatement)
     173           66363 :       : mStatement(aStatement)
     174                 :   {
     175           66363 :   }
     176           66363 :   ~mozStorageStatementScoper()
     177           66363 :   {
     178           66363 :     if (mStatement)
     179           62371 :       mStatement->Reset();
     180           66363 :   }
     181                 : 
     182                 :   /**
     183                 :    * Call this to make the statement not reset. You might do this if you know
     184                 :    * that the statement has been reset.
     185                 :    */
     186            3992 :   void Abandon()
     187                 :   {
     188            3992 :     mStatement = nsnull;
     189            3992 :   }
     190                 : 
     191                 : protected:
     192                 :   nsCOMPtr<mozIStorageStatement> mStatement;
     193                 : };
     194                 : 
     195                 : // Use this to make queries uniquely identifiable in telemetry
     196                 : // statistics, especially PRAGMAs.  We don't include __LINE__ so that
     197                 : // queries are stable in the face of source code changes.
     198                 : #define MOZ_STORAGE_UNIQUIFY_QUERY_STR "/* " __FILE__ " */ "
     199                 : 
     200                 : #endif /* MOZSTORAGEHELPER_H */

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