1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 #ifndef WEBKIT_BROWSER_FILEAPI_FILE_STREAM_WRITER_H_
6 #define WEBKIT_BROWSER_FILEAPI_FILE_STREAM_WRITER_H_
8 #include "base/basictypes.h"
9 #include "net/base/completion_callback.h"
10 #include "webkit/browser/webkit_storage_browser_export.h"
23 // A generic interface for writing to a file-like object.
24 class FileStreamWriter {
26 // Creates a writer for the existing file in the path |file_path| starting
27 // from |initial_offset|. Uses |task_runner| for async file operations.
28 WEBKIT_STORAGE_BROWSER_EXPORT static FileStreamWriter* CreateForLocalFile(
29 base::TaskRunner* task_runner,
30 const base::FilePath& file_path,
31 int64 initial_offset);
33 // Closes the file. If there's an in-flight operation, it is canceled (i.e.,
34 // the callback function associated with the operation is not called).
35 virtual ~FileStreamWriter() {}
37 // Writes to the current cursor position asynchronously.
39 // Up to buf_len bytes will be written. (In other words, partial
40 // writes are allowed.) If the write completed synchronously, it returns
41 // the number of bytes written. If the operation could not be performed, it
42 // returns an error code. Otherwise, net::ERR_IO_PENDING is returned, and the
43 // callback will be run on the thread where Write() was called when the write
46 // This errors out (either synchronously or via callback) with:
47 // net::ERR_FILE_NOT_FOUND: When the target file is not found.
48 // net::ERR_ACCESS_DENIED: When the target file is a directory or
49 // the writer has no permission on the file.
50 // net::ERR_FILE_NO_SPACE: When the write will result in out of quota
51 // or there is not enough room left on the disk.
53 // It is invalid to call Write while there is an in-flight async operation.
54 virtual int Write(net::IOBuffer* buf, int buf_len,
55 const net::CompletionCallback& callback) = 0;
57 // Cancels an in-flight async operation.
59 // If the cancel is finished synchronously, it returns net::OK. If the
60 // cancel could not be performed, it returns an error code. Especially when
61 // there is no in-flight operation, net::ERR_UNEXPECTED is returned.
62 // Otherwise, net::ERR_IO_PENDING is returned, and the callback will be run on
63 // the thread where Cancel() was called when the cancel has completed. It is
64 // invalid to call Cancel() more than once on the same async operation.
66 // In either case, the callback function passed to the in-flight async
67 // operation is dismissed immediately when Cancel() is called, and thus
68 // will never be called.
69 virtual int Cancel(const net::CompletionCallback& callback) = 0;
71 // Flushes the data written so far.
73 // If the flush finished synchronously, it return net::OK. If the flush could
74 // not be performed, it returns an error code. Otherwise, net::ERR_IO_PENDING
75 // is returned, and the callback will be run on the thread where Flush() was
76 // called when the flush has completed.
78 // It is invalid to call Flush while there is an in-flight async operation.
79 virtual int Flush(const net::CompletionCallback& callback) = 0;
82 } // namespace fileapi
84 #endif // WEBKIT_BROWSER_FILEAPI_FILE_STREAM_WRITER_H_