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// Copyright 2017 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_ASH_ARC_FILEAPI_FILE_STREAM_FORWARDER_H_
#define CHROME_BROWSER_ASH_ARC_FILEAPI_FILE_STREAM_FORWARDER_H_
#include <memory>
#include "base/files/scoped_file.h"
#include "base/functional/callback.h"
#include "base/memory/weak_ptr.h"
#include "base/task/sequenced_task_runner.h"
#include "net/base/io_buffer.h"
#include "storage/browser/file_system/file_stream_reader.h"
#include "storage/browser/file_system/file_system_context.h"
namespace arc {
// FileStreamForwarder reads data of the given FileSystemURL, and writes it to
// the given FD. While all internal actions happen on the IO thread, all public
// methods should be called on the UI thread. If this object is destroyed before
// the completion, the in-flight operation may abort before finishing, and the
// callback will be called with false when aborted.
class FileStreamForwarder {
public:
struct DestroyHelper {
void operator()(FileStreamForwarder* object) const { object->Destroy(); }
};
// |result| is true when the specified amount of data was successfully
// forwarded.
using ResultCallback = base::OnceCallback<void(bool result)>;
// Starts reading the part of the file specified by |offset| and |size|, and
// writes the data to |fd_dest|, and runs |callback| with true iff |size|
// bytes of data were successfully read and written.
FileStreamForwarder(scoped_refptr<storage::FileSystemContext> context,
const storage::FileSystemURL& url,
int64_t offset,
int64_t size,
base::ScopedFD fd_dest,
ResultCallback callback);
FileStreamForwarder(const FileStreamForwarder&) = delete;
FileStreamForwarder& operator=(const FileStreamForwarder&) = delete;
// Posts a task to destruct this object on the IO thread.
// Must not be called multiple times for the same object.
void Destroy();
private:
// Use Destroy() to destruct this object.
~FileStreamForwarder();
// Destructs this object.
void DestroyOnIOThread();
// Starts reading the data.
void Start();
// Does the actual reading.
void DoRead();
// Called when read is completed. |result| is the number of bytes read, or an
// error code if it's negative.
void OnReadCompleted(int result);
// Called when write is completed.
void OnWriteCompleted(bool result);
// Runs the result callback on the UI thread.
void NotifyCompleted(bool result);
scoped_refptr<storage::FileSystemContext> context_;
const storage::FileSystemURL url_;
const int64_t offset_;
int64_t remaining_size_;
base::ScopedFD fd_dest_;
ResultCallback callback_;
scoped_refptr<base::SequencedTaskRunner> task_runner_; // For blocking IO.
scoped_refptr<net::IOBufferWithSize> buf_;
std::unique_ptr<storage::FileStreamReader> stream_reader_;
base::WeakPtrFactory<FileStreamForwarder> weak_ptr_factory_{this};
};
// FileStreamForwarderPtr is unique_ptr with a custom deleter. Use this to
// safely handle the ownership of FileStreamForwarder.
using FileStreamForwarderPtr =
std::unique_ptr<FileStreamForwarder, FileStreamForwarder::DestroyHelper>;
} // namespace arc
#endif // CHROME_BROWSER_ASH_ARC_FILEAPI_FILE_STREAM_FORWARDER_H_
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