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// Copyright 2014 The Chromium Authors
// 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 <functional>
#include <memory>
#include <type_traits>
#include "base/check.h"
#include "base/functional/bind.h"
#include "base/location.h"
#include "base/task/sequenced_task_runner.h"
#include "base/task/single_thread_task_runner.h"
// TODO(tzik): Merge this file to base/task/bind_post_task.h.
namespace sync_file_system {
namespace drive_backend {
namespace internal {
template <typename Signature, typename... Args>
base::OnceClosure MakeClosure(base::RepeatingCallback<Signature>* callback,
Args&&... args) {
return base::BindOnce(*callback, std::forward<Args>(args)...);
}
template <typename Signature, typename... Args>
base::OnceClosure MakeClosure(base::OnceCallback<Signature>* callback,
Args&&... args) {
return base::BindOnce(std::move(*callback), std::forward<Args>(args)...);
}
template <typename CallbackType>
class CallbackHolder {
public:
CallbackHolder(const scoped_refptr<base::SequencedTaskRunner>& task_runner,
const base::Location& from_here,
CallbackType callback)
: task_runner_(task_runner),
from_here_(from_here),
callback_(std::move(callback)) {
DCHECK(task_runner_.get());
}
CallbackHolder(const CallbackHolder&) = delete;
CallbackHolder& operator=(const CallbackHolder&) = delete;
~CallbackHolder() {
if (callback_) {
task_runner_->PostTask(from_here_,
base::BindOnce(&CallbackHolder::DeleteCallback,
std::move(callback_)));
}
}
template <typename... Args>
void Run(Args... args) {
task_runner_->PostTask(
from_here_, MakeClosure(&callback_, std::forward<Args>(args)...));
}
private:
static void DeleteCallback(CallbackType callback) {}
scoped_refptr<base::SequencedTaskRunner> task_runner_;
const base::Location from_here_;
CallbackType callback_;
};
} // namespace internal
template <typename... Args>
base::OnceCallback<void(Args...)> RelayCallbackToTaskRunner(
const scoped_refptr<base::SequencedTaskRunner>& task_runner,
const base::Location& from_here,
base::OnceCallback<void(Args...)> callback) {
DCHECK(task_runner->RunsTasksInCurrentSequence());
if (callback.is_null())
return {};
using CallbackType = base::OnceCallback<void(Args...)>;
using HelperType = internal::CallbackHolder<CallbackType>;
using RunnerType = void (HelperType::*)(Args...);
RunnerType run = &HelperType::Run;
return base::BindOnce(run, std::make_unique<HelperType>(
task_runner, from_here, std::move(callback)));
}
template <typename... Args>
base::RepeatingCallback<void(Args...)> RelayCallbackToTaskRunner(
const scoped_refptr<base::SequencedTaskRunner>& task_runner,
const base::Location& from_here,
base::RepeatingCallback<void(Args...)> callback) {
DCHECK(task_runner->RunsTasksInCurrentSequence());
if (callback.is_null())
return {};
using CallbackType = base::RepeatingCallback<void(Args...)>;
using HelperType = internal::CallbackHolder<CallbackType>;
using RunnerType = void (HelperType::*)(Args...);
RunnerType run = &HelperType::Run;
return base::BindRepeating(
run, std::make_unique<HelperType>(task_runner, from_here,
std::move(callback)));
}
template <typename CallbackType>
CallbackType RelayCallbackToCurrentThread(const base::Location& from_here,
CallbackType callback) {
return RelayCallbackToTaskRunner(
base::SingleThreadTaskRunner::GetCurrentDefault(), from_here,
std::move(callback));
}
} // namespace drive_backend
} // namespace sync_file_system
#endif // CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_CALLBACK_HELPER_H_
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