Index: chrome/browser/chromeos/file_system_provider/fileapi/buffering_file_stream_reader.cc |
diff --git a/chrome/browser/chromeos/file_system_provider/fileapi/buffering_file_stream_reader.cc b/chrome/browser/chromeos/file_system_provider/fileapi/buffering_file_stream_reader.cc |
new file mode 100644 |
index 0000000000000000000000000000000000000000..4b64051dd1970ab6342f385b98660ef9d714c515 |
--- /dev/null |
+++ b/chrome/browser/chromeos/file_system_provider/fileapi/buffering_file_stream_reader.cc |
@@ -0,0 +1,97 @@ |
+// 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. |
+ |
+#include "chrome/browser/chromeos/file_system_provider/fileapi/buffering_file_stream_reader.h" |
+ |
+#include "net/base/net_errors.h" |
+ |
+namespace chromeos { |
+namespace file_system_provider { |
+ |
+BufferingFileStreamReader::BufferingFileStreamReader( |
+ scoped_ptr<webkit_blob::FileStreamReader> file_stream_reader, |
+ int buffer_size) |
+ : file_stream_reader_(file_stream_reader.Pass()), |
+ buffer_size_(buffer_size), |
+ preloading_buffer_(new net::IOBuffer(buffer_size_)), |
+ preloading_buffer_offset_(0), |
+ buffered_bytes_(0), |
+ weak_ptr_factory_(this) { |
+} |
+ |
+BufferingFileStreamReader::~BufferingFileStreamReader() { |
+} |
+ |
+int BufferingFileStreamReader::Read(net::IOBuffer* buffer, |
+ int buffer_length, |
+ const net::CompletionCallback& callback) { |
+ // Return as much as available in the internal buffer. It may be less than |
+ // |buffer_length|, what is valid. |
+ const int bytes_read = |
+ CopyFromBuffer(make_scoped_refptr(buffer), buffer_length); |
+ if (bytes_read) |
+ return bytes_read; |
+ |
+ // Nothing copied, so contents have to be preloaded. |
+ Preload(base::Bind(&BufferingFileStreamReader::OnPreloadCompleted, |
+ weak_ptr_factory_.GetWeakPtr(), |
+ make_scoped_refptr(buffer), |
+ buffer_length, |
+ callback)); |
+ |
+ return net::ERR_IO_PENDING; |
+} |
+ |
+int64 BufferingFileStreamReader::GetLength( |
+ const net::Int64CompletionCallback& callback) { |
+ return file_stream_reader_->GetLength(callback); |
+} |
+ |
+int BufferingFileStreamReader::CopyFromBuffer( |
+ scoped_refptr<net::IOBuffer> buffer, |
+ int buffer_length) { |
+ const int read_bytes = |
+ buffer_length <= buffered_bytes_ ? buffer_length : buffered_bytes_; |
hashimoto
2014/06/05 03:18:36
nit: std::min(buffer_length, buffered_bytes_)?
mtomasz
2014/06/05 09:22:27
Done.
|
+ |
+ memcpy(buffer->data(), |
+ preloading_buffer_->data() + preloading_buffer_offset_, |
+ read_bytes); |
+ preloading_buffer_offset_ += read_bytes; |
+ buffered_bytes_ -= read_bytes; |
+ |
+ return read_bytes; |
+} |
+ |
+void BufferingFileStreamReader::Preload( |
+ const net::CompletionCallback& callback) { |
+ // TODO(mtomasz): Dynamically calculate the chunk size. Start from a small |
+ // one, then increase for consecutive requests. That would improve performance |
+ // when reading just small chunks, instead of the entire file. |
+ const int preload_bytes = buffer_size_; |
+ |
+ const int result = |
+ file_stream_reader_->Read(preloading_buffer_, preload_bytes, callback); |
+ |
+ if (result != net::ERR_IO_PENDING) |
+ callback.Run(result); |
hashimoto
2014/06/05 03:18:36
Return the result as a return value, or post a tas
mtomasz
2014/06/05 09:22:27
Done.
|
+} |
+ |
+void BufferingFileStreamReader::OnPreloadCompleted( |
+ scoped_refptr<net::IOBuffer> buffer, |
+ int buffer_length, |
+ const net::CompletionCallback& callback, |
+ int result) { |
+ if (result < 0) { |
+ callback.Run(result); |
+ return; |
+ } |
+ |
+ preloading_buffer_offset_ = 0; |
+ buffered_bytes_ = result; |
+ |
+ callback.Run(CopyFromBuffer(buffer, buffer_length)); |
+} |
+ |
+} // namespace file_system_provider |
+} // namespace chromeos |