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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_TRACKER_H_
#define CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_CALLBACK_TRACKER_H_
#include <map>
#include "base/functional/bind.h"
#include "base/functional/callback_forward.h"
#include "base/memory/weak_ptr.h"
#include "chrome/browser/sync_file_system/drive_backend/callback_tracker_internal.h"
namespace sync_file_system {
namespace drive_backend {
// A helper class to ensure one-shot callback to be called exactly once.
//
// Usage:
// class Foo {
// private:
// CallbackTracker callback_tracker_;
// };
//
// void DoSomethingAsync(const SomeCallbackType& callback) {
// base::OnceClosure abort_case_handler =
// base::BindOnce(callback, ABORT_ERROR);
//
// SomeCallbackType wrapped_callback =
// callback_tracker_.Register(
// abort_case_handler, callback);
//
// // The body of the operation goes here.
// }
class CallbackTracker {
public:
using AbortClosureByHelper =
std::map<internal::AbortHelper*, base::OnceClosure>;
CallbackTracker();
CallbackTracker(const CallbackTracker&) = delete;
CallbackTracker& operator=(const CallbackTracker&) = delete;
~CallbackTracker();
// Returns a wrapped callback.
// Upon AbortAll() call, CallbackTracker invokes |abort_closure| and voids all
// wrapped callbacks returned by Register().
// Invocation of the wrapped callback unregisters |callback| from
// CallbackTracker.
template <typename T>
base::OnceCallback<T> Register(base::OnceClosure abort_closure,
base::OnceCallback<T> callback) {
internal::AbortHelper* helper = new internal::AbortHelper(this);
helpers_[helper] = std::move(abort_closure);
return base::BindOnce(&internal::InvokeAndInvalidateHelper<T>::Run,
helper->AsWeakPtr(), std::move(callback));
}
void AbortAll();
private:
friend class internal::AbortHelper;
std::unique_ptr<internal::AbortHelper> PassAbortHelper(
internal::AbortHelper* helper);
AbortClosureByHelper helpers_; // Owns AbortHelpers.
};
} // namespace drive_backend
} // namespace sync_file_system
#endif // CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_CALLBACK_TRACKER_H_
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