mojo/shell/child_process_host.h

   1 // Copyright 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 SHELL_CHILD_PROCESS_HOST_H_
   6 #define SHELL_CHILD_PROCESS_HOST_H_
   7
   8 #include "base/macros.h"
   9 #include "base/process/process.h"
  10 #include "mojo/edk/embedder/channel_info_forward.h"
  11 #include "mojo/edk/embedder/platform_channel_pair.h"
  12 #include "mojo/edk/embedder/scoped_platform_handle.h"
  13 #include "mojo/shell/child_process.mojom.h"
  14 #include "mojo/shell/child_process_host.h"
  15
  16 namespace mojo {
  17 namespace shell {
  18
  19 class Context;
  20
  21 // This class represents a "child process host". Handles launching and
  22 // connecting a platform-specific "pipe" to the child, and supports joining the
  23 // child process. Currently runs a single app (loaded from the file system).
  24 //
  25 // This class is not thread-safe. It should be created/used/destroyed on a
  26 // single thread.
  27 //
  28 // Note: Does not currently work on Windows before Vista.
  29 // Note: After |Start()|, |StartApp| must be called and this object must
  30 // remained alive until the |on_app_complete| callback is called.
  31 class ChildProcessHost {
  32  public:
  33   explicit ChildProcessHost(Context* context);
  34   virtual ~ChildProcessHost();
  35
  36   // |Start()|s the child process; calls |DidStart()| (on the thread on which
  37   // |Start()| was called) when the child has been started (or failed to start).
  38   // After calling |Start()|, this object must not be destroyed until
  39   // |DidStart()| has been called.
  40   // TODO(vtl): Consider using weak pointers and removing this requirement.
  41   void Start();
  42
  43   // Waits for the child process to terminate, and returns its exit code.
  44   // Note: If |Start()| has been called, this must not be called until the
  45   // callback has been called.
  46   int Join();
  47
  48   // See |ChildController|:
  49   void StartApp(const String& app_path,
  50                 bool clean_app_path,
  51                 InterfaceRequest<Application> application_request,
  52                 const ChildController::StartAppCallback& on_app_complete);
  53   void ExitNow(int32_t exit_code);
  54
  55  protected:
  56   // virtual for testing.
  57   virtual void DidStart(bool success);
  58
  59  private:
  60   bool DoLaunch();
  61
  62   void AppCompleted(int32_t result);
  63
  64   // Callback for |embedder::CreateChannel()|.
  65   void DidCreateChannel(embedder::ChannelInfo* channel_info);
  66
  67   Context* const context_;
  68   base::Process child_process_;
  69   embedder::PlatformChannelPair platform_channel_pair_;
  70   ChildControllerPtr controller_;
  71   embedder::ChannelInfo* channel_info_;
  72   ChildController::StartAppCallback on_app_complete_;
  73
  74   // Platform-specific "pipe" to the child process. Valid immediately after
  75   // creation.
  76   embedder::ScopedPlatformHandle platform_channel_;
  77
  78   DISALLOW_COPY_AND_ASSIGN(ChildProcessHost);
  79 };
  80
  81 }  // namespace shell
  82 }  // namespace mojo
  83
  84 #endif  // SHELL_CHILD_PROCESS_HOST_H_