Index: chrome/browser/chromeos/file_system_provider/fileapi/buffering_file_stream_reader.h |
diff --git a/chrome/browser/chromeos/file_system_provider/fileapi/buffering_file_stream_reader.h b/chrome/browser/chromeos/file_system_provider/fileapi/buffering_file_stream_reader.h |
new file mode 100644 |
index 0000000000000000000000000000000000000000..5a7ac2faa5ecee54ff2c52b7c703ccfb00bc190e |
--- /dev/null |
+++ b/chrome/browser/chromeos/file_system_provider/fileapi/buffering_file_stream_reader.h |
@@ -0,0 +1,72 @@ |
+// Copyright 2014 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 CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_FILEAPI_BUFFERING_FILE_STREAM_READER_H_ |
+#define CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_FILEAPI_BUFFERING_FILE_STREAM_READER_H_ |
+ |
+#include "base/basictypes.h" |
+#include "base/memory/ref_counted.h" |
+#include "base/memory/scoped_ptr.h" |
+#include "base/memory/weak_ptr.h" |
+#include "webkit/browser/blob/file_stream_reader.h" |
+ |
+namespace net { |
+class IOBuffer; |
+} // namespace net |
+ |
+namespace chromeos { |
+namespace file_system_provider { |
+ |
+// Wraps the file stream reader implementation with a prefetching buffer. |
+// Reads data from the internal file stream reader in chunks of size at least |
+// |buffer_size| bytes (or less for the last chunk, because of EOF). |
+// |
+// The underlying inner file stream reader *must not* return any values |
+// synchronously. Instead, results must be returned by a callback, including |
+// errors. |
+class BufferingFileStreamReader : public webkit_blob::FileStreamReader { |
+ public: |
+ BufferingFileStreamReader( |
+ scoped_ptr<webkit_blob::FileStreamReader> file_stream_reader, |
+ int buffer_size); |
+ |
+ virtual ~BufferingFileStreamReader(); |
+ |
+ // webkit_blob::FileStreamReader overrides. |
+ virtual int Read(net::IOBuffer* buf, |
+ int buf_len, |
+ const net::CompletionCallback& callback) OVERRIDE; |
+ virtual int64 GetLength( |
+ const net::Int64CompletionCallback& callback) OVERRIDE; |
+ |
+ private: |
+ // Copies data from the preloading buffer and updates the internal iterator. |
+ // Returns number of bytes successfully copied. |
+ int CopyFromPreloadingBuffer(scoped_refptr<net::IOBuffer> buffer, |
+ int buffer_length); |
+ |
+ // Preloads data from the internal stream reader and calls the |callback|. |
+ void Preload(const net::CompletionCallback& callback); |
+ |
+ // Called when preloading of a buffer chunk is finished. Updates state of the |
+ // preloading buffer and copied requested data to the |buffer|. |
+ void OnPreloadCompleted(scoped_refptr<net::IOBuffer> buffer, |
+ int buffer_length, |
+ const net::CompletionCallback& callback, |
+ int result); |
+ |
+ scoped_ptr<webkit_blob::FileStreamReader> file_stream_reader_; |
+ int buffer_size_; |
+ scoped_refptr<net::IOBuffer> preloading_buffer_; |
+ int preloading_buffer_offset_; |
+ int buffered_bytes_; |
+ |
+ base::WeakPtrFactory<BufferingFileStreamReader> weak_ptr_factory_; |
+ DISALLOW_COPY_AND_ASSIGN(BufferingFileStreamReader); |
+}; |
+ |
+} // namespace file_system_provider |
+} // namespace chromeos |
+ |
+#endif // CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_FILEAPI_BUFFERING_FILE_STREAM_READER_H_ |