| // Copyright (c) 2012 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. |
| |
| #ifndef STORAGE_BROWSER_FILEAPI_FILE_STREAM_WRITER_H_ |
| #define STORAGE_BROWSER_FILEAPI_FILE_STREAM_WRITER_H_ |
| |
| #include <stdint.h> |
| |
| #include <memory> |
| |
| #include "base/component_export.h" |
| #include "base/memory/weak_ptr.h" |
| #include "net/base/completion_once_callback.h" |
| |
| namespace base { |
| class FilePath; |
| class TaskRunner; |
| } |
| |
| namespace net { |
| class IOBuffer; |
| } |
| |
| namespace storage { |
| class ObfuscatedFileUtilMemoryDelegate; |
| } |
| |
| namespace storage { |
| |
| // A generic interface for writing to a file-like object. |
| class FileStreamWriter { |
| public: |
| enum OpenOrCreate { OPEN_EXISTING_FILE, CREATE_NEW_FILE }; |
| |
| // Creates a writer for the existing file in the path |file_path| starting |
| // from |initial_offset|. Uses |task_runner| for async file operations. |
| COMPONENT_EXPORT(STORAGE_BROWSER) |
| static std::unique_ptr<FileStreamWriter> CreateForLocalFile( |
| base::TaskRunner* task_runner, |
| const base::FilePath& file_path, |
| int64_t initial_offset, |
| OpenOrCreate open_or_create); |
| |
| // Creates a writer for the existing memory file in the path |file_path| |
| // starting from |initial_offset|. |
| COMPONENT_EXPORT(STORAGE_BROWSER) |
| static std::unique_ptr<FileStreamWriter> CreateForMemoryFile( |
| base::WeakPtr<ObfuscatedFileUtilMemoryDelegate> memory_file_util, |
| const base::FilePath& file_path, |
| int64_t initial_offset, |
| OpenOrCreate open_or_create); |
| |
| // Closes the file. If there's an in-flight operation, it is canceled (i.e., |
| // the callback function associated with the operation is not called). |
| virtual ~FileStreamWriter() {} |
| |
| // Writes to the current cursor position asynchronously. |
| // |
| // Up to buf_len bytes will be written. (In other words, partial |
| // writes are allowed.) If the write completed synchronously, it returns |
| // the number of bytes written. If the operation could not be performed, it |
| // returns an error code. Otherwise, net::ERR_IO_PENDING is returned, and the |
| // callback will be run on the thread where Write() was called when the write |
| // has completed. |
| // |
| // After the last write, Flush() must be called if the file system written to |
| // was registered with the FlushPolicy::FLUSH_ON_COMPLETION policy in mount |
| // options. |
| // |
| // This errors out (either synchronously or via callback) with: |
| // net::ERR_FILE_NOT_FOUND: When the target file is not found. |
| // net::ERR_ACCESS_DENIED: When the target file is a directory or |
| // the writer has no permission on the file. |
| // net::ERR_FILE_NO_SPACE: When the write will result in out of quota |
| // or there is not enough room left on the disk. |
| // |
| // It is invalid to call Write while there is an in-flight async operation. |
| virtual int Write(net::IOBuffer* buf, |
| int buf_len, |
| net::CompletionOnceCallback callback) = 0; |
| |
| // Cancels an in-flight async operation. |
| // |
| // If the cancel is finished synchronously, it returns net::OK. If the |
| // cancel could not be performed, it returns an error code. Especially when |
| // there is no in-flight operation, net::ERR_UNEXPECTED is returned. |
| // Otherwise, net::ERR_IO_PENDING is returned, and the callback will be run on |
| // the thread where Cancel() was called when the cancel has completed. It is |
| // invalid to call Cancel() more than once on the same async operation. |
| // |
| // In either case, the callback function passed to the in-flight async |
| // operation is dismissed immediately when Cancel() is called, and thus |
| // will never be called. |
| virtual int Cancel(net::CompletionOnceCallback callback) = 0; |
| |
| // Flushes the data written so far. |
| // |
| // If the flush finished synchronously, it return net::OK. If the flush could |
| // not be performed, it returns an error code. Otherwise, net::ERR_IO_PENDING |
| // is returned, and the callback will be run on the thread where Flush() was |
| // called when the flush has completed. |
| // |
| // It is invalid to call Flush while there is an in-flight async operation. |
| virtual int Flush(net::CompletionOnceCallback callback) = 0; |
| }; |
| |
| } // namespace storage |
| |
| #endif // STORAGE_BROWSER_FILEAPI_FILE_STREAM_WRITER_H_ |