Home | History | Annotate | Download | only in base 
      1 $$ This is a pump file for generating file templates.  Pump is a python
      2 $$ script that is part of the Google Test suite of utilities.  Description
      3 $$ can be found here:
      4 $$
      5 $$ http://code.google.com/p/googletest/wiki/PumpManual
      6 $$
      7 
      8 $$ See comment for MAX_ARITY in base/bind.h.pump.
      9 $var MAX_ARITY = 7
     10 
     11 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
     12 // Use of this source code is governed by a BSD-style license that can be
     13 // found in the LICENSE file.
     14 
     15 #ifndef MEDIA_BASE_BIND_TO_CURRENT_LOOP_H_
     16 #define MEDIA_BASE_BIND_TO_CURRENT_LOOP_H_
     17 
     18 #include "base/bind.h"
     19 #include "base/location.h"
     20 #include "base/message_loop/message_loop_proxy.h"
     21 #include "base/single_thread_task_runner.h"
     22 
     23 // This is a helper utility for base::Bind()ing callbacks to the current
     24 // MessageLoop. The typical use is when |a| (of class |A|) wants to hand a
     25 // callback such as base::Bind(&A::AMethod, a) to |b|, but needs to ensure that
     26 // when |b| executes the callback, it does so on |a|'s current MessageLoop.
     27 //
     28 // Typical usage: request to be called back on the current thread:
     29 // other->StartAsyncProcessAndCallMeBack(
     30 //    media::BindToCurrentLoop(base::Bind(&MyClass::MyMethod, this)));
     31 //
     32 // Note that like base::Bind(), BindToCurrentLoop() can't bind non-constant
     33 // references, and that *unlike* base::Bind(), BindToCurrentLoop() makes copies
     34 // of its arguments, and thus can't be used with arrays.
     35 
     36 namespace media {
     37 
     38 // Mimic base::internal::CallbackForward, replacing p.Pass() with
     39 // base::Passed(&p) to account for the extra layer of indirection.
     40 namespace internal {
     41 template <typename T>
     42 T& TrampolineForward(T& t) { return t; }
     43 
     44 template <typename T, typename R>
     45 base::internal::PassedWrapper<scoped_ptr<T, R> > TrampolineForward(
     46     scoped_ptr<T, R>& p) { return base::Passed(&p); }
     47 
     48 template <typename T>
     49 base::internal::PassedWrapper<ScopedVector<T> > TrampolineForward(
     50     ScopedVector<T>& p) { return base::Passed(&p); }
     51 
     52 template <typename T> struct TrampolineHelper;
     53 
     54 $range ARITY 0..MAX_ARITY
     55 $for ARITY [[
     56 $range ARG 1..ARITY
     57 
     58 template <$for ARG , [[typename A$(ARG)]]>
     59 struct TrampolineHelper<void($for ARG , [[A$(ARG)]])> {
     60   static void Run(
     61       const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
     62       const base::Callback<void($for ARG , [[A$(ARG)]])>& cb
     63 $if ARITY != 0 [[, ]]
     64 $for ARG , [[A$(ARG) a$(ARG)]]
     65 ) {
     66     task_runner->PostTask(FROM_HERE, base::Bind(cb
     67 $if ARITY != 0 [[, ]]
     68 $for ARG , [[internal::TrampolineForward(a$(ARG))]]));
     69   }
     70 };
     71 
     72 
     73 ]]  $$ for ARITY
     74 
     75 }  // namespace internal
     76 
     77 template<typename T>
     78 static base::Callback<T> BindToCurrentLoop(
     79     const base::Callback<T>& cb) {
     80   return base::Bind(&internal::TrampolineHelper<T>::Run,
     81                     base::MessageLoopProxy::current(), cb);
     82 }
     83 
     84 }  // namespace media
     85 
     86 #endif  // MEDIA_BASE_BIND_TO_CURRENT_LOOP_H_
     87