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