[SyncFS] Refine callback helpers

chrome/browser/sync_file_system/drive_backend/callback_helper.h

+// This file was GENERATED by command:
+//     pump.py callback_helper.h.pump
+// DO NOT EDIT BY HAND!!!
+
+
 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_CALLBACK_HELPER_H_
 #define CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_CALLBACK_HELPER_H_
 
 #include "base/bind.h"
 #include "base/location.h"
-#include "base/message_loop/message_loop_proxy.h"
+#include "base/logging.h"
+#include "base/thread_task_runner_handle.h"
+
+// TODO(tzik): Merge this file to media/base/bind_to_current_loop.h.
 
 namespace sync_file_system {
 namespace drive_backend {
 
 namespace internal {
 
 template <typename T>
 typename base::enable_if<
     base::internal::IsMoveOnlyType<T>::value,
     base::internal::PassedWrapper<T> >::type
 RebindForward(T& t) {
   return base::Passed(&t);
 }
 
 template <typename T>
 typename base::enable_if<
     !base::internal::IsMoveOnlyType<T>::value,
     T&>::type
 RebindForward(T& t) {
   return t;
 }
 
-template <typename T>
-void RelayToTaskRunner1(base::SequencedTaskRunner* task_runner,
-                        const tracked_objects::Location& from_here,
-                        const base::Callback<void(T)>& callback,
-                        T arg) {
-  task_runner->PostTask(
-      from_here, base::Bind(callback, RebindForward(arg)));
-}
+template <typename>
+struct RelayToTaskRunnerHelper;
 
-template <typename T1, typename T2>
-void RelayToTaskRunner2(base::SequencedTaskRunner* task_runner,
-                        const tracked_objects::Location& from_here,
-                        const base::Callback<void(T1, T2)>& callback,
-                        T1 arg1,
-                        T2 arg2) {
-  task_runner->PostTask(
-      from_here, base::Bind(callback,
-                            RebindForward(arg1),
-                            RebindForward(arg2)));
-}
+template <>
+struct RelayToTaskRunnerHelper<void()> {
+  static void Run(base::TaskRunner* task_runner,
+                  const tracked_objects::Location& from_here,
+                  const base::Callback<void()>& callback) {
+    task_runner->PostTask(from_here, base::Bind(callback));
+  }
+};
+
+template <typename A1>
+struct RelayToTaskRunnerHelper<void(A1)> {
+  static void Run(base::TaskRunner* task_runner,
+                  const tracked_objects::Location& from_here,
+                  const base::Callback<void(A1)>& callback, A1 a1) {
+    task_runner->PostTask(from_here, base::Bind(callback, RebindForward(a1)));
+  }
+};
+
+template <typename A1, typename A2>
+struct RelayToTaskRunnerHelper<void(A1, A2)> {
+  static void Run(base::TaskRunner* task_runner,
+                  const tracked_objects::Location& from_here,
+                  const base::Callback<void(A1, A2)>& callback, A1 a1, A2 a2) {
+    task_runner->PostTask(from_here, base::Bind(callback, RebindForward(a1),
+        RebindForward(a2)));
+  }
+};
+
+template <typename A1, typename A2, typename A3>
+struct RelayToTaskRunnerHelper<void(A1, A2, A3)> {
+  static void Run(base::TaskRunner* task_runner,
+                  const tracked_objects::Location& from_here,
+                  const base::Callback<void(A1, A2, A3)>& callback, A1 a1,
+                      A2 a2, A3 a3) {
+    task_runner->PostTask(from_here, base::Bind(callback, RebindForward(a1),
+        RebindForward(a2), RebindForward(a3)));
+  }
+};
+
+template <typename A1, typename A2, typename A3, typename A4>
+struct RelayToTaskRunnerHelper<void(A1, A2, A3, A4)> {
+  static void Run(base::TaskRunner* task_runner,
+                  const tracked_objects::Location& from_here,
+                  const base::Callback<void(A1, A2, A3, A4)>& callback, A1 a1,
+                      A2 a2, A3 a3, A4 a4) {
+    task_runner->PostTask(from_here, base::Bind(callback, RebindForward(a1),
+        RebindForward(a2), RebindForward(a3), RebindForward(a4)));
+  }
+};
+
+template <typename A1, typename A2, typename A3, typename A4, typename A5>
+struct RelayToTaskRunnerHelper<void(A1, A2, A3, A4, A5)> {
+  static void Run(base::TaskRunner* task_runner,
+                  const tracked_objects::Location& from_here,
+                  const base::Callback<void(A1, A2, A3, A4, A5)>& callback,
+                      A1 a1, A2 a2, A3 a3, A4 a4, A5 a5) {
+    task_runner->PostTask(from_here, base::Bind(callback, RebindForward(a1),
+        RebindForward(a2), RebindForward(a3), RebindForward(a4),
+        RebindForward(a5)));
+  }
+};
+
+template <typename A1, typename A2, typename A3, typename A4, typename A5,
+    typename A6>
+struct RelayToTaskRunnerHelper<void(A1, A2, A3, A4, A5, A6)> {
+  static void Run(base::TaskRunner* task_runner,
+                  const tracked_objects::Location& from_here,
+                  const base::Callback<void(A1, A2, A3, A4, A5, A6)>& callback,
+                      A1 a1, A2 a2, A3 a3, A4 a4, A5 a5, A6 a6) {
+    task_runner->PostTask(from_here, base::Bind(callback, RebindForward(a1),
+        RebindForward(a2), RebindForward(a3), RebindForward(a4),
+        RebindForward(a5), RebindForward(a6)));
+  }
+};
+
+template <typename A1, typename A2, typename A3, typename A4, typename A5,
+    typename A6, typename A7>
+struct RelayToTaskRunnerHelper<void(A1, A2, A3, A4, A5, A6, A7)> {
+  static void Run(base::TaskRunner* task_runner,
+                  const tracked_objects::Location& from_here,
+                  const base::Callback<void(A1, A2, A3, A4, A5, A6,
+                      A7)>& callback, A1 a1, A2 a2, A3 a3, A4 a4, A5 a5, A6 a6,
+                      A7 a7) {
+    task_runner->PostTask(from_here, base::Bind(callback, RebindForward(a1),
+        RebindForward(a2), RebindForward(a3), RebindForward(a4),
+        RebindForward(a5), RebindForward(a6), RebindForward(a7)));
+  }
+};
 
 }  // namespace internal
 
 template <typename T>
-base::Callback<void(T)> CreateRelayedCallback(
-    const base::Callback<void(T)>& callback) {
-  return base::Bind(&internal::RelayToTaskRunner1<T>,
-                    base::MessageLoopProxy::current(),
-                    FROM_HERE,
+base::Callback<T> RelayCallbackToTaskRunner(
+    base::TaskRunner* task_runner,
+    const tracked_objects::Location& from_here,
+    const base::Callback<T>& callback) {
+  DCHECK(task_runner->RunsTasksOnCurrentThread());
+  return base::Bind(&internal::RelayToTaskRunnerHelper<T>::Run,
+                    make_scoped_refptr(task_runner), from_here,
                     callback);
 }
 
-template <typename T1, typename T2>
-base::Callback<void(T1, T2)> CreateRelayedCallback(
-    const base::Callback<void(T1, T2)>& callback) {
-  return base::Bind(&internal::RelayToTaskRunner2<T1, T2>,
-                    base::MessageLoopProxy::current(),
-                    FROM_HERE,
-                    callback);
+template <typename T>
+base::Callback<T> RelayCallbackToCurrentThread(
+    const tracked_objects::Location& from_here,
+    const base::Callback<T>& callback) {
+  return RelayCallbackToTaskRunner(
+      base::ThreadTaskRunnerHandle::Get(),
+      from_here, callback);
 }
 
 }  // namespace drive_backend
 }  // namespace sync_file_system
 
 #endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_CALLBACK_HELPER_H_