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// Copyright (c) 2011 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.
#include <string>
#include "base/callback.h"
#include "base/memory/ref_counted.h"
#include "base/single_thread_task_runner.h"
#include "extensions/common/extension_resource.h"
// This file defines an interface for reading a file asynchronously on a
// background thread.
// Consider abstracting out a FilePathProvider (ExtensionResource) and moving
// back to chrome/browser/net if other subsystems want to use it.
class FileReader : public base::RefCountedThreadSafe<FileReader> {
// Reports success or failure and the data of the file upon success.
using DoneCallback = base::Callback<void(bool, std::unique_ptr<std::string>)>;
// Lets the caller accomplish tasks on the file data, after the file content
// has been read.
// If the file reading doesn't succeed, this will be ignored.
using OptionalFileThreadTaskCallback = base::Callback<void(std::string*)>;
FileReader(const extensions::ExtensionResource& resource,
const OptionalFileThreadTaskCallback& file_thread_task_callback,
const DoneCallback& done_callback);
// Called to start reading the file on a background thread. Upon completion,
// the callback will be notified of the results.
void Start();
friend class base::RefCountedThreadSafe<FileReader>;
virtual ~FileReader();
void ReadFileOnBackgroundThread();
extensions::ExtensionResource resource_;
OptionalFileThreadTaskCallback optional_file_thread_task_callback_;
DoneCallback done_callback_;
const scoped_refptr<base::SingleThreadTaskRunner> origin_task_runner_;