ipc/mojo/async_handle_waiter.h

   1 // Copyright 2015 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 IPC_MOJO_ASYNC_HANDLE_WAITER_H_
   6 #define IPC_MOJO_ASYNC_HANDLE_WAITER_H_
   7
   8 #include "base/callback.h"
   9 #include "base/memory/ref_counted.h"
  10 #include "base/memory/weak_ptr.h"
  11 #include "ipc/ipc_export.h"
  12 #include "mojo/public/c/system/types.h"
  13
  14 namespace IPC {
  15 namespace internal {
  16
  17 // |AsyncHandleWaiter| waits on a mojo handle asynchronously and
  18 // invokes the given |callback| through |runner| when it is signaled.
  19 //  * To start waiting, the client must call |AsyncHandleWaiter::Wait()|.
  20 //    The client can call |Wait()| again once it is signaled and
  21 //    the |callback| is invoked.
  22 //  * To cancel waiting, delete the instance.
  23 //
  24 // |AsyncHandleWaiter| must be created, used and deleted only from the IO
  25 // |thread.
  26 class IPC_MOJO_EXPORT AsyncHandleWaiter {
  27  public:
  28   class Context;
  29
  30   explicit AsyncHandleWaiter(base::Callback<void(MojoResult)> callback);
  31   ~AsyncHandleWaiter();
  32
  33   MojoResult Wait(MojoHandle handle, MojoHandleSignals signals);
  34
  35  private:
  36   void InvokeCallback(MojoResult result);
  37
  38   scoped_refptr<Context> context_;
  39   base::Callback<void(MojoResult)> callback_;
  40   base::WeakPtrFactory<AsyncHandleWaiter> weak_factory_;
  41
  42   DISALLOW_COPY_AND_ASSIGN(AsyncHandleWaiter);
  43 };
  44
  45 }  // namespace internal
  46 }  // namespace IPC
  47
  48 #endif  // IPC_MOJO_ASYNC_HANDLE_WAITER_H_