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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_ASH_FILE_SYSTEM_PROVIDER_FILEAPI_FILE_STREAM_READER_H_
#define CHROME_BROWSER_ASH_FILE_SYSTEM_PROVIDER_FILEAPI_FILE_STREAM_READER_H_
#include <stdint.h>
#include <memory>
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "base/time/time.h"
#include "net/base/completion_once_callback.h"
#include "net/base/completion_repeating_callback.h"
#include "storage/browser/file_system/file_stream_reader.h"
#include "storage/browser/file_system/file_system_url.h"
namespace storage {
class FileSystemContext;
} // namespace storage
namespace ash::file_system_provider {
struct EntryMetadata;
// Implements a streamed file reader. It is lazily initialized by the first call
// to Read().
class FileStreamReader : public storage::FileStreamReader {
public:
FileStreamReader(storage::FileSystemContext* context,
const storage::FileSystemURL& url,
int64_t initial_offset,
const base::Time& expected_modification_time);
FileStreamReader(const FileStreamReader&) = delete;
FileStreamReader& operator=(const FileStreamReader&) = delete;
~FileStreamReader() override;
// storage::FileStreamReader overrides.
int Read(net::IOBuffer* buf,
int buf_len,
net::CompletionOnceCallback callback) override;
int64_t GetLength(net::Int64CompletionOnceCallback callback) override;
private:
// Helper class for executing operations on the provided file system. All
// of its methods must be called on UI thread. Callbacks are called on IO
// thread.
class OperationRunner;
// State of the file stream reader.
enum State { NOT_INITIALIZED, INITIALIZING, INITIALIZED, FAILED };
// Called when Read() operation is completed with either a success or an
// error.
void OnReadCompleted(int result);
// Called when GetLength() operation is completed with either a success of an
// error.
void OnGetLengthCompleted(int64_t result);
// Initializes the reader by opening the file. When completed with success,
// runs the |pending_closure|. Otherwise, calls the |error_callback|.
void Initialize(base::OnceClosure pending_closure,
net::Int64CompletionOnceCallback error_callback);
// Called when opening a file is completed with either a success or an error.
void OnOpenFileCompleted(base::OnceClosure pending_closure,
net::Int64CompletionOnceCallback error_callback,
base::File::Error result);
// Called when initialization is completed with either a success or an error.
void OnInitializeCompleted(base::OnceClosure pending_closure,
net::Int64CompletionOnceCallback error_callback,
std::unique_ptr<EntryMetadata> metadata,
base::File::Error result);
// Called when a file system provider returns chunk of read data. Note, that
// this may be called multiple times per single Read() call, as long as
// |has_more| is set to true. |result| is set to success only if reading is
// successful, and the file has not changed while reading.
void OnReadChunkReceived(const net::CompletionRepeatingCallback& callback,
int chunk_length,
bool has_more,
base::File::Error result);
// Called when fetching length of the file is completed with either a success
// or an error.
void OnGetMetadataForGetLengthReceived(
std::unique_ptr<EntryMetadata> metadata,
base::File::Error result);
// Same as Read(), but called after initializing is completed.
void ReadAfterInitialized(scoped_refptr<net::IOBuffer> buffer,
int buffer_length,
const net::CompletionRepeatingCallback& callback);
// Same as GetLength(), but called after initializing is completed.
void GetLengthAfterInitialized();
net::CompletionOnceCallback read_callback_;
net::Int64CompletionOnceCallback get_length_callback_;
storage::FileSystemURL url_;
int64_t current_offset_;
int64_t current_length_;
base::Time expected_modification_time_;
scoped_refptr<OperationRunner> runner_;
State state_;
base::WeakPtrFactory<FileStreamReader> weak_ptr_factory_{this};
};
} // namespace ash::file_system_provider
#endif // CHROME_BROWSER_ASH_FILE_SYSTEM_PROVIDER_FILEAPI_FILE_STREAM_READER_H_
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