ppapi/shared_impl/ppb_message_loop_shared.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 PPAPI_SHARED_IMPL_PPB_MESSAGE_LOOP_SHARED_H_
   6 #define PPAPI_SHARED_IMPL_PPB_MESSAGE_LOOP_SHARED_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/callback_forward.h"
  10 #include "base/location.h"
  11 #include "ppapi/c/pp_instance.h"
  12 #include "ppapi/shared_impl/ppapi_shared_export.h"
  13 #include "ppapi/shared_impl/resource.h"
  14 #include "ppapi/thunk/ppb_message_loop_api.h"
  15
  16 namespace base {
  17 class SingleThreadTaskRunner;
  18 }
  19
  20 namespace tracked_objects {
  21 class Location;
  22 }
  23
  24 namespace ppapi {
  25
  26 // MessageLoopShared doesn't really do anything interesting. It exists so that
  27 // shared code (in particular, TrackedCallback) can keep a pointer to a
  28 // MessageLoop resource. In the host side, there is not a concrete class that
  29 // implements this. So pointers to MessageLoopShared can only really be valid
  30 // on the plugin side.
  31 class PPAPI_SHARED_EXPORT MessageLoopShared
  32     : public Resource,
  33       public thunk::PPB_MessageLoop_API {
  34  public:
  35   explicit MessageLoopShared(PP_Instance instance);
  36   // Construct the one MessageLoopShared for the main thread. This must be
  37   // invoked on the main thread.
  38   struct ForMainThread {};
  39   explicit MessageLoopShared(ForMainThread);
  40   virtual ~MessageLoopShared();
  41
  42   // Handles posting to the message loop if there is one, or the pending queue
  43   // if there isn't.
  44   // NOTE: The given closure will be run *WITHOUT* acquiring the Proxy lock.
  45   //       This only makes sense for user code and completely thread-safe
  46   //       proxy operations (e.g., MessageLoop::QuitClosure).
  47   virtual void PostClosure(const tracked_objects::Location& from_here,
  48                            const base::Closure& closure,
  49                            int64 delay_ms) = 0;
  50
  51   virtual base::SingleThreadTaskRunner* GetTaskRunner() = 0;
  52
  53   // Returns whether this MessageLoop is currently handling a blocking message
  54   // from JavaScript. This is used to make it illegal to use blocking callbacks
  55   // while the thread is handling a blocking message.
  56   virtual bool CurrentlyHandlingBlockingMessage() = 0;
  57
  58   DISALLOW_COPY_AND_ASSIGN(MessageLoopShared);
  59 };
  60
  61 }  // namespace ppapi
  62
  63 #endif  // PPAPI_SHARED_IMPL_PPB_MESSAGE_LOOP_SHARED_H_