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1 // Copyright 2014 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. | |
4 | |
5 #include "chrome/browser/chromeos/file_system_provider/fileapi/buffering_file_st ream_reader.h" | |
6 | |
7 #include "net/base/net_errors.h" | |
8 | |
9 namespace chromeos { | |
10 namespace file_system_provider { | |
11 | |
12 BufferingFileStreamReader::BufferingFileStreamReader( | |
13 scoped_ptr<webkit_blob::FileStreamReader> file_stream_reader, | |
14 int buffer_size) | |
15 : file_stream_reader_(file_stream_reader.Pass()), | |
16 buffer_size_(buffer_size), | |
17 preloading_buffer_(new net::IOBuffer(buffer_size_)), | |
18 preloading_buffer_offset_(0), | |
19 buffered_bytes_(0), | |
20 weak_ptr_factory_(this) { | |
21 } | |
22 | |
23 BufferingFileStreamReader::~BufferingFileStreamReader() { | |
24 } | |
25 | |
26 int BufferingFileStreamReader::Read(net::IOBuffer* buffer, | |
27 int buffer_length, | |
28 const net::CompletionCallback& callback) { | |
29 // Return as much as available in the internal buffer. It may be less than | |
30 // |buffer_length|, what is valid. | |
31 const int bytes_read = | |
32 CopyFromBuffer(make_scoped_refptr(buffer), buffer_length); | |
33 if (bytes_read) | |
34 return bytes_read; | |
35 | |
36 // Nothing copied, so contents have to be preloaded. | |
37 Preload(base::Bind(&BufferingFileStreamReader::OnPreloadCompleted, | |
38 weak_ptr_factory_.GetWeakPtr(), | |
39 make_scoped_refptr(buffer), | |
40 buffer_length, | |
41 callback)); | |
42 | |
43 return net::ERR_IO_PENDING; | |
44 } | |
45 | |
46 int64 BufferingFileStreamReader::GetLength( | |
47 const net::Int64CompletionCallback& callback) { | |
48 return file_stream_reader_->GetLength(callback); | |
49 } | |
50 | |
51 int BufferingFileStreamReader::CopyFromBuffer( | |
52 scoped_refptr<net::IOBuffer> buffer, | |
53 int buffer_length) { | |
54 const int read_bytes = | |
55 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.
| |
56 | |
57 memcpy(buffer->data(), | |
58 preloading_buffer_->data() + preloading_buffer_offset_, | |
59 read_bytes); | |
60 preloading_buffer_offset_ += read_bytes; | |
61 buffered_bytes_ -= read_bytes; | |
62 | |
63 return read_bytes; | |
64 } | |
65 | |
66 void BufferingFileStreamReader::Preload( | |
67 const net::CompletionCallback& callback) { | |
68 // TODO(mtomasz): Dynamically calculate the chunk size. Start from a small | |
69 // one, then increase for consecutive requests. That would improve performance | |
70 // when reading just small chunks, instead of the entire file. | |
71 const int preload_bytes = buffer_size_; | |
72 | |
73 const int result = | |
74 file_stream_reader_->Read(preloading_buffer_, preload_bytes, callback); | |
75 | |
76 if (result != net::ERR_IO_PENDING) | |
77 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.
| |
78 } | |
79 | |
80 void BufferingFileStreamReader::OnPreloadCompleted( | |
81 scoped_refptr<net::IOBuffer> buffer, | |
82 int buffer_length, | |
83 const net::CompletionCallback& callback, | |
84 int result) { | |
85 if (result < 0) { | |
86 callback.Run(result); | |
87 return; | |
88 } | |
89 | |
90 preloading_buffer_offset_ = 0; | |
91 buffered_bytes_ = result; | |
92 | |
93 callback.Run(CopyFromBuffer(buffer, buffer_length)); | |
94 } | |
95 | |
96 } // namespace file_system_provider | |
97 } // namespace chromeos | |
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