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