content/browser/child_process_launcher.h

   1 // Copyright (c) 2012 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 CONTENT_BROWSER_CHILD_PROCESS_LAUNCHER_H_
   6 #define CONTENT_BROWSER_CHILD_PROCESS_LAUNCHER_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/memory/ref_counted.h"
  10 #include "base/process/kill.h"
  11 #include "base/process/launch.h"
  12 #include "base/process/process.h"
  13 #include "content/common/content_export.h"
  14
  15 namespace base {
  16 class CommandLine;
  17 }
  18
  19 namespace content {
  20 class SandboxedProcessLauncherDelegate;
  21
  22 // Launches a process asynchronously and notifies the client of the process
  23 // handle when it's available.  It's used to avoid blocking the calling thread
  24 // on the OS since often it can take > 100 ms to create the process.
  25 class CONTENT_EXPORT ChildProcessLauncher {
  26  public:
  27   class CONTENT_EXPORT Client {
  28    public:
  29     // Will be called on the thread that the ChildProcessLauncher was
  30     // constructed on.
  31     virtual void OnProcessLaunched() = 0;
  32
  33     virtual void OnProcessLaunchFailed() {};
  34
  35    protected:
  36     virtual ~Client() {}
  37   };
  38
  39   // Launches the process asynchronously, calling the client when the result is
  40   // ready.  Deleting this object before the process is created is safe, since
  41   // the callback won't be called.  If the process is still running by the time
  42   // this object destructs, it will be terminated.
  43   // Takes ownership of cmd_line.
  44   ChildProcessLauncher(
  45       SandboxedProcessLauncherDelegate* delegate,
  46       base::CommandLine* cmd_line,
  47       int child_process_id,
  48       Client* client);
  49   ~ChildProcessLauncher();
  50
  51   // True if the process is being launched and so the handle isn't available.
  52   bool IsStarting();
  53
  54   // Getter for the process.  Only call after the process has started.
  55   const base::Process& GetProcess() const;
  56
  57   // Call this when the child process exits to know what happened to it.
  58   // |known_dead| can be true if we already know the process is dead as it can
  59   // help the implemention figure the proper TerminationStatus.
  60   // On Linux, the use of |known_dead| is subtle and can be crucial if an
  61   // accurate status is important. With |known_dead| set to false, a dead
  62   // process could be seen as running. With |known_dead| set to true, the
  63   // process will be killed if it was still running. See ZygoteHostImpl for
  64   // more discussion of Linux implementation details.
  65   // |exit_code| is the exit code of the process if it exited (e.g. status from
  66   // waitpid if on posix, from GetExitCodeProcess on Windows). |exit_code| may
  67   // be NULL.
  68   base::TerminationStatus GetChildTerminationStatus(bool known_dead,
  69                                                     int* exit_code);
  70
  71   // Changes whether the process runs in the background or not.  Only call
  72   // this after the process has started.
  73   void SetProcessBackgrounded(bool background);
  74
  75   // Controls whether the child process should be terminated on browser
  76   // shutdown.
  77   void SetTerminateChildOnShutdown(bool terminate_on_shutdown);
  78
  79  private:
  80   class Context;
  81
  82   scoped_refptr<Context> context_;
  83
  84   DISALLOW_COPY_AND_ASSIGN(ChildProcessLauncher);
  85 };
  86
  87 }  // namespace content
  88
  89 #endif  // CONTENT_BROWSER_CHILD_PROCESS_LAUNCHER_H_