google_apis/drive/task_util.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 GOOGLE_APIS_DRIVE_TASK_UTIL_H_
   6 #define GOOGLE_APIS_DRIVE_TASK_UTIL_H_
   7
   8 #include "base/bind.h"
   9 #include "base/thread_task_runner_handle.h"
  10
  11 namespace google_apis {
  12
  13 // Runs the task with the task runner.
  14 void RunTaskWithTaskRunner(scoped_refptr<base::TaskRunner> task_runner,
  15                            const base::Closure& task);
  16
  17 namespace internal {
  18
  19 // Implementation of the composed callback, whose signature is |Sig|.
  20 template<typename Sig> struct ComposedCallback;
  21
  22 // ComposedCallback with no argument.
  23 template<>
  24 struct ComposedCallback<void()> {
  25   static void Run(
  26       const base::Callback<void(const base::Closure&)>& runner,
  27       const base::Closure& callback) {
  28     runner.Run(callback);
  29   }
  30 };
  31
  32 // ComposedCallback with one argument.
  33 template<typename T1>
  34 struct ComposedCallback<void(T1)> {
  35   static void Run(
  36       const base::Callback<void(const base::Closure&)>& runner,
  37       const base::Callback<void(T1)>& callback,
  38       T1 arg1) {
  39     runner.Run(base::Bind(callback, arg1));
  40   }
  41 };
  42
  43 // ComposedCallback with two arguments.
  44 template<typename T1, typename T2>
  45 struct ComposedCallback<void(T1, T2)> {
  46   static void Run(
  47       const base::Callback<void(const base::Closure&)>& runner,
  48       const base::Callback<void(T1, T2)>& callback,
  49       T1 arg1, T2 arg2) {
  50     runner.Run(base::Bind(callback, arg1, arg2));
  51   }
  52 };
  53
  54 // ComposedCallback with two arguments, and the last one is scoped_ptr.
  55 template<typename T1, typename T2, typename D2>
  56 struct ComposedCallback<void(T1, scoped_ptr<T2, D2>)> {
  57   static void Run(
  58       const base::Callback<void(const base::Closure&)>& runner,
  59       const base::Callback<void(T1, scoped_ptr<T2, D2>)>& callback,
  60       T1 arg1, scoped_ptr<T2, D2> arg2) {
  61     runner.Run(base::Bind(callback, arg1, base::Passed(&arg2)));
  62   }
  63 };
  64
  65 // ComposedCallback with three arguments.
  66 template<typename T1, typename T2, typename T3>
  67 struct ComposedCallback<void(T1, T2, T3)> {
  68   static void Run(
  69       const base::Callback<void(const base::Closure&)>& runner,
  70       const base::Callback<void(T1, T2, T3)>& callback,
  71       T1 arg1, T2 arg2, T3 arg3) {
  72     runner.Run(base::Bind(callback, arg1, arg2, arg3));
  73   }
  74 };
  75
  76 // ComposedCallback with three arguments, and the last one is scoped_ptr.
  77 template<typename T1, typename T2, typename T3, typename D3>
  78 struct ComposedCallback<void(T1, T2, scoped_ptr<T3, D3>)> {
  79   static void Run(
  80       const base::Callback<void(const base::Closure&)>& runner,
  81       const base::Callback<void(T1, T2, scoped_ptr<T3, D3>)>& callback,
  82       T1 arg1, T2 arg2, scoped_ptr<T3, D3> arg3) {
  83     runner.Run(base::Bind(callback, arg1, arg2, base::Passed(&arg3)));
  84   }
  85 };
  86
  87 // ComposedCallback with four arguments.
  88 template<typename T1, typename T2, typename T3, typename T4>
  89 struct ComposedCallback<void(T1, T2, T3, T4)> {
  90   static void Run(
  91       const base::Callback<void(const base::Closure&)>& runner,
  92       const base::Callback<void(T1, T2, T3, T4)>& callback,
  93       T1 arg1, T2 arg2, T3 arg3, T4 arg4) {
  94     runner.Run(base::Bind(callback, arg1, arg2, arg3, arg4));
  95   }
  96 };
  97
  98 }  // namespace internal
  99
 100 // Returns callback that takes arguments (arg1, arg2, ...), create a closure
 101 // by binding them to |callback|, and runs |runner| with the closure.
 102 // I.e. the returned callback works as follows:
 103 //   runner.Run(Bind(callback, arg1, arg2, ...))
 104 template<typename CallbackType>
 105 CallbackType CreateComposedCallback(
 106     const base::Callback<void(const base::Closure&)>& runner,
 107     const CallbackType& callback) {
 108   DCHECK(!runner.is_null());
 109   DCHECK(!callback.is_null());
 110   return base::Bind(
 111       &internal::ComposedCallback<typename CallbackType::RunType>::Run,
 112       runner, callback);
 113 }
 114
 115 // Returns callback which runs the given |callback| on the current thread.
 116 template<typename CallbackType>
 117 CallbackType CreateRelayCallback(const CallbackType& callback) {
 118   return CreateComposedCallback(
 119       base::Bind(&RunTaskWithTaskRunner, base::ThreadTaskRunnerHandle::Get()),
 120       callback);
 121 }
 122
 123 }  // namespace google_apis
 124
 125 #endif  // GOOGLE_APIS_DRIVE_TASK_UTIL_H_