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/callback.h"
   9 #include "base/macros.h"
  10 #include "base/process/process.h"
  11
  12 namespace base {
  13 class CommandLine;
  14 }  // namespace base
  15
  16 namespace browser_watcher {
  17
  18 // An interface class to take care of the details in launching a browser
  19 // watch process.
  20 class WatcherClient {
  21  public:
  22   // A CommandLineGenerator generates command lines that will launch a separate
  23   // process and pass the supplied HANDLE to ExitCodeWatcher in that process.
  24   typedef base::Callback<base::CommandLine(HANDLE)> CommandLineGenerator;
  25
  26   // Constructs a watcher client that launches its watcher process using the
  27   // command line generated by |command_line_generator|.
  28   explicit WatcherClient(const CommandLineGenerator& command_line_generator);
  29
  30   ~WatcherClient();
  31
  32   // Launches the watcher process such that the child process is able to inherit
  33   // a handle to the current process. If use_legacy_launch() is true, this uses
  34   // a non-threadsafe legacy launch mode that's compatible with Windows XP.
  35   void LaunchWatcher();
  36
  37   // Ensures that |handle| may be inherited by the watcher process. |handle|
  38   // must still be inheritable, and it's the client's responsibility to
  39   // communicate the value of |handle| to the launched process.
  40   void AddInheritedHandle(HANDLE handle);
  41
  42   // Returns the launched process.
  43   const base::Process& process() const { return process_; }
  44
  45   // Accessors, exposed only for testing.
  46   bool use_legacy_launch() const { return use_legacy_launch_; }
  47   void set_use_legacy_launch(bool use_legacy_launch) {
  48       use_legacy_launch_ = use_legacy_launch;
  49   }
  50
  51  private:
  52   // If true, the watcher process will be launched with XP legacy handle
  53   // inheritance. This is not thread safe and can leak random handles into the
  54   // child process, but it's the best we can do on XP.
  55   bool use_legacy_launch_;
  56
  57   // The CommandLineGenerator passed to the constructor.
  58   CommandLineGenerator command_line_generator_;
  59
  60   // A handle to the launched watcher process. Valid after a successful
  61   // LaunchWatcher() call.
  62   base::Process process_;
  63
  64   std::vector<HANDLE> inherited_handles_;
  65
  66   DISALLOW_COPY_AND_ASSIGN(WatcherClient);
  67 };
  68
  69 }  // namespace browser_watcher
  70
  71 #endif  // COMPONENTS_BROWSER_WATCHER_WATCHER_CLIENT_WIN_H_