chrome/common/multi_process_lock_win.cc

   1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "chrome/common/multi_process_lock.h"
   6
   7 #include "base/logging.h"
   8 #include "base/strings/utf_string_conversions.h"
   9 #include "base/win/scoped_handle.h"
  10
  11 class MultiProcessLockWin : public MultiProcessLock {
  12  public:
  13   explicit MultiProcessLockWin(const std::string& name) : name_(name) { }
  14
  15   virtual ~MultiProcessLockWin() {
  16     if (event_.Get() != NULL) {
  17       Unlock();
  18     }
  19   }
  20
  21   virtual bool TryLock() {
  22     if (event_.Get() != NULL) {
  23       DLOG(ERROR) << "MultiProcessLock is already locked - " << name_;
  24       return true;
  25     }
  26
  27     if (name_.length() >= MAX_PATH) {
  28       LOG(ERROR) << "Socket name too long (" << name_.length()
  29                  << " >= " << MAX_PATH << ") - " << name_;
  30       return false;
  31     }
  32
  33     base::string16 wname = UTF8ToUTF16(name_);
  34     event_.Set(CreateEvent(NULL, FALSE, FALSE, wname.c_str()));
  35     if (event_.Get() && GetLastError() != ERROR_ALREADY_EXISTS) {
  36       return true;
  37     } else {
  38       event_.Set(NULL);
  39       return false;
  40     }
  41   }
  42
  43   virtual void Unlock() {
  44     if (event_.Get() == NULL) {
  45       DLOG(ERROR) << "Over-unlocked MultiProcessLock - " << name_;
  46       return;
  47     }
  48     event_.Set(NULL);
  49   }
  50
  51  private:
  52   std::string name_;
  53   base::win::ScopedHandle event_;
  54   DISALLOW_COPY_AND_ASSIGN(MultiProcessLockWin);
  55 };
  56
  57 MultiProcessLock* MultiProcessLock::Create(const std::string &name) {
  58   return new MultiProcessLockWin(name);
  59 }