components/browser_watcher/watcher_client_win.h

   1 // Copyright (c) 2014 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 #ifndef COMPONENTS_BROWSER_WATCHER_WATCHER_CLIENT_WIN_H_
   6 #define COMPONENTS_BROWSER_WATCHER_WATCHER_CLIENT_WIN_H_
   7
   8 #include "base/command_line.h"
   9 #include "base/macros.h"
  10 #include "base/process/process_handle.h"
  11 #include "base/win/scoped_handle.h"
  12
  13 namespace browser_watcher {
  14
  15 // An interface class to take care of the details in launching a browser
  16 // watch process.
  17 class WatcherClient {
  18  public:
  19   // Constructs a watcher client with a |base_command_line|, which should be
  20   // a command line sufficient to invoke the watcher process. This command
  21   // line will be augmented with the value of the inherited handle.
  22   explicit WatcherClient(const base::CommandLine& base_command_line);
  23
  24   // Launches the watcher process.
  25   void LaunchWatcher();
  26
  27   // Accessors, exposed only for testing.
  28   bool use_legacy_launch() const { return use_legacy_launch_; }
  29   void set_use_legacy_launch(bool use_legacy_launch) {
  30       use_legacy_launch_ = use_legacy_launch;
  31   }
  32   base::ProcessHandle process() const { return process_.Get(); }
  33
  34  private:
  35   // Launches |cmd_line| such that the child process is able to inherit
  36   // |handle|. If |use_legacy_launch_| is true, this uses a non-threadsafe
  37   // legacy launch mode that's compatible with Windows XP.
  38   // Returns a handle to the child process.
  39   base::win::ScopedHandle LaunchWatcherProcess(
  40         const base::CommandLine& cmd_line, base::ProcessHandle self_handle);
  41
  42   // If true, the watcher process will be launched with XP legacy handle
  43   // inheritance. This is not thread safe and can leak random handles into the
  44   // child process, but it's the best we can do on XP.
  45   bool use_legacy_launch_;
  46
  47   // The base command line passed to the constructor.
  48   base::CommandLine base_command_line_;
  49
  50   // A handle to the launched watcher process. Valid after a successful
  51   // LaunchWatcher() call.
  52   base::win::ScopedHandle process_;
  53
  54   DISALLOW_COPY_AND_ASSIGN(WatcherClient);
  55 };
  56
  57 }  // namespace browser_watcher
  58
  59 #endif  // COMPONENTS_BROWSER_WATCHER_WATCHER_CLIENT_WIN_H_