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      1 // Copyright (c) 2008, Google Inc.
      2 // All rights reserved.
      3 //
      4 // Redistribution and use in source and binary forms, with or without
      5 // modification, are permitted provided that the following conditions are
      6 // met:
      7 //
      8 //     * Redistributions of source code must retain the above copyright
      9 // notice, this list of conditions and the following disclaimer.
     10 //     * Redistributions in binary form must reproduce the above
     11 // copyright notice, this list of conditions and the following disclaimer
     12 // in the documentation and/or other materials provided with the
     13 // distribution.
     14 //     * Neither the name of Google Inc. nor the names of its
     15 // contributors may be used to endorse or promote products derived from
     16 // this software without specific prior written permission.
     17 //
     18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29 
     30 #ifndef CLIENT_WINDOWS_COMMON_AUTO_CRITICAL_SECTION_H__
     31 #define CLIENT_WINDOWS_COMMON_AUTO_CRITICAL_SECTION_H__
     32 
     33 #include <windows.h>
     34 
     35 namespace google_breakpad {
     36 
     37 // Automatically enters the critical section in the constructor and leaves
     38 // the critical section in the destructor.
     39 class AutoCriticalSection {
     40  public:
     41   // Creates a new instance with the given critical section object
     42   // and enters the critical section immediately.
     43   explicit AutoCriticalSection(CRITICAL_SECTION* cs) : cs_(cs), taken_(false) {
     44     assert(cs_);
     45     Acquire();
     46   }
     47 
     48   // Destructor: leaves the critical section.
     49   ~AutoCriticalSection() {
     50     if (taken_) {
     51       Release();
     52     }
     53   }
     54 
     55   // Enters the critical section. Recursive Acquire() calls are not allowed.
     56   void Acquire() {
     57     assert(!taken_);
     58     EnterCriticalSection(cs_);
     59     taken_ = true;
     60   }
     61 
     62   // Leaves the critical section. The caller should not call Release() unless
     63   // the critical seciton has been entered already.
     64   void Release() {
     65     assert(taken_);
     66     taken_ = false;
     67     LeaveCriticalSection(cs_);
     68   }
     69 
     70  private:
     71   // Disable copy ctor and operator=.
     72   AutoCriticalSection(const AutoCriticalSection&);
     73   AutoCriticalSection& operator=(const AutoCriticalSection&);
     74 
     75   CRITICAL_SECTION* cs_;
     76   bool taken_;
     77 };
     78 
     79 }  // namespace google_breakpad
     80 
     81 #endif  // CLIENT_WINDOWS_COMMON_AUTO_CRITICAL_SECTION_H__
     82