src/Utils/RWSection.h

   1 // TortoiseGit - a Windows shell extension for easy version control
   2
   3 // Copyright (C) 2003-2008 - TortoiseSVN
   4
   5 // This program is free software; you can redistribute it and/or
   6 // modify it under the terms of the GNU General Public License
   7 // as published by the Free Software Foundation; either version 2
   8 // of the License, or (at your option) any later version.
   9
  10 // This program is distributed in the hope that it will be useful,
  11 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 // GNU General Public License for more details.
  14
  15 // You should have received a copy of the GNU General Public License
  16 // along with this program; if not, write to the Free Software Foundation,
  17 // 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18 //
  19 #pragma once
  20
  21 /**
  22  * \ingroup Utils
  23  * Implements a reader-writer lock.
  24  */
  25 class CRWSection
  26 {
  27 public:
  28         CRWSection();
  29         ~CRWSection();
  30
  31         bool WaitToRead(DWORD waitTime = INFINITE);
  32         bool WaitToWrite(DWORD waitTime = INFINITE);
  33         void Done();
  34         bool IsWriter() {return ((m_nWaitingWriters > 0) || (m_nActive < 0));}
  35 #if defined (DEBUG) || defined (_DEBUG)
  36         void AssertLock() {ATLASSERT(m_nActive);}
  37         void AssertWriting() {ATLASSERT((m_nWaitingWriters || (m_nActive < 0)));}
  38 #else
  39         void AssertLock() {;}
  40         void AssertWriting() {;}
  41 #endif
  42 private:
  43         int                                     m_nWaitingReaders;      // Number of readers waiting for access
  44         int                                     m_nWaitingWriters;      // Number of writers waiting for access
  45         int                                     m_nActive;                      // Number of threads accessing the section
  46         CRITICAL_SECTION        m_cs;
  47         HANDLE                          m_hReaders;
  48         HANDLE                          m_hWriters;
  49 };