text: // Copyright (c) 2011 The Chromium Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  #include "chrome/common/multi_process_lock.h"
  
  #include "base/logging.h"
  #include "base/macros.h"
  #include "base/strings/utf_string_conversions.h"
  #include "base/win/scoped_handle.h"
  
  #include <windows.h>
  
  class MultiProcessLockWin : public MultiProcessLock {
   public:
    explicit MultiProcessLockWin(const std::string& name) : name_(name) { }
  
    ~MultiProcessLockWin() override {
      if (event_.Get() != NULL) {
        Unlock();
      }
    }
  
    bool TryLock() override {
      if (event_.Get() != NULL) {
        DLOG(ERROR) << "MultiProcessLock is already locked - " << name_;
        return true;
      }
  
      if (name_.length() >= MAX_PATH) {
        LOG(ERROR) << "Socket name too long (" << name_.length()
                   << " >= " << MAX_PATH << ") - " << name_;
        return false;
      }
  
      std::wstring wname = base::UTF8ToWide(name_);
      event_.Set(CreateEvent(NULL, FALSE, FALSE, wname.c_str()));
      if (event_.Get() && GetLastError() != ERROR_ALREADY_EXISTS) {
        return true;
      } else {
        event_.Set(NULL);
        return false;
      }
    }
  
    void Unlock() override {
      if (event_.Get() == NULL) {
        DLOG(ERROR) << "Over-unlocked MultiProcessLock - " << name_;
        return;
      }
      event_.Set(NULL);
    }
  
   private:
    std::string name_;
    base::win::ScopedHandle event_;
    DISALLOW_COPY_AND_ASSIGN(MultiProcessLockWin);
  };
  
  std::unique_ptr<MultiProcessLock> MultiProcessLock::Create(
      const std::string& name) {
    return std::make_unique<MultiProcessLockWin>(name);
  }
  