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// 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_writer.h"
#include <algorithm>
#include "net/base/io_buffer.h"
#include "net/base/net_errors.h"
namespace chromeos {
namespace file_system_provider {
BufferingFileStreamWriter::BufferingFileStreamWriter(
scoped_ptr<storage::FileStreamWriter> file_stream_writer,
int intermediate_buffer_length)
: file_stream_writer_(file_stream_writer.Pass()),
intermediate_buffer_length_(intermediate_buffer_length),
intermediate_buffer_(new net::IOBuffer(intermediate_buffer_length_)),
buffered_bytes_(0),
weak_ptr_factory_(this) {
}
BufferingFileStreamWriter::~BufferingFileStreamWriter() {
if (buffered_bytes_)
LOG(ERROR) << "File stream writer not flushed. Data will be lost.";
}
int BufferingFileStreamWriter::Write(net::IOBuffer* buffer,
int buffer_length,
const net::CompletionCallback& callback) {
// If |buffer_length| is larger than the intermediate buffer, then call the
// inner file stream writer directly. Note, that the intermediate buffer
// (used for buffering) must be flushed first.
if (buffer_length > intermediate_buffer_length_) {
if (buffered_bytes_) {
FlushIntermediateBuffer(
base::Bind(&BufferingFileStreamWriter::
OnFlushIntermediateBufferForDirectWriteCompleted,
weak_ptr_factory_.GetWeakPtr(),
make_scoped_refptr(buffer),
buffer_length,
callback));
} else {
// Nothing to flush, so skip it.
OnFlushIntermediateBufferForDirectWriteCompleted(
make_scoped_refptr(buffer), buffer_length, callback, net::OK);
}
return net::ERR_IO_PENDING;
}
// Buffer consecutive writes to larger chunks.
const int buffer_bytes =
std::min(intermediate_buffer_length_ - buffered_bytes_, buffer_length);
CopyToIntermediateBuffer(
make_scoped_refptr(buffer), 0 /* buffer_offset */, buffer_bytes);
const int bytes_left = buffer_length - buffer_bytes;
if (buffered_bytes_ == intermediate_buffer_length_) {
FlushIntermediateBuffer(
base::Bind(&BufferingFileStreamWriter::
OnFlushIntermediateBufferForBufferedWriteCompleted,
weak_ptr_factory_.GetWeakPtr(),
make_scoped_refptr(buffer),
buffer_bytes,
bytes_left,
callback));
return net::ERR_IO_PENDING;
}
// Optimistically return a success.
return buffer_length;
}
int BufferingFileStreamWriter::Cancel(const net::CompletionCallback& callback) {
// Since there is no any asynchronous call in this class other than on
// |file_stream_writer_|, then there must be an in-flight operation going on.
return file_stream_writer_->Cancel(callback);
}
int BufferingFileStreamWriter::Flush(const net::CompletionCallback& callback) {
// Flush all the buffered bytes first, then invoke Flush() on the inner file
// stream writer.
FlushIntermediateBuffer(base::Bind(
&BufferingFileStreamWriter::OnFlushIntermediateBufferForFlushCompleted,
weak_ptr_factory_.GetWeakPtr(),
callback));
return net::ERR_IO_PENDING;
}
void BufferingFileStreamWriter::CopyToIntermediateBuffer(
scoped_refptr<net::IOBuffer> buffer,
int buffer_offset,
int buffer_length) {
DCHECK_GE(intermediate_buffer_length_, buffer_length + buffered_bytes_);
memcpy(intermediate_buffer_->data() + buffered_bytes_,
buffer->data() + buffer_offset,
buffer_length);
buffered_bytes_ += buffer_length;
}
void BufferingFileStreamWriter::FlushIntermediateBuffer(
const net::CompletionCallback& callback) {
const int result = file_stream_writer_->Write(
intermediate_buffer_.get(),
buffered_bytes_,
base::Bind(&BufferingFileStreamWriter::OnFlushIntermediateBufferCompleted,
weak_ptr_factory_.GetWeakPtr(),
buffered_bytes_,
callback));
DCHECK_EQ(net::ERR_IO_PENDING, result);
}
void BufferingFileStreamWriter::OnFlushIntermediateBufferCompleted(
int length,
const net::CompletionCallback& callback,
int result) {
if (result < 0) {
callback.Run(result);
return;
}
DCHECK_EQ(length, result) << "Partial writes are not supported.";
buffered_bytes_ = 0;
callback.Run(net::OK);
}
void
BufferingFileStreamWriter::OnFlushIntermediateBufferForDirectWriteCompleted(
scoped_refptr<net::IOBuffer> buffer,
int length,
const net::CompletionCallback& callback,
int result) {
if (result < 0) {
callback.Run(result);
return;
}
// The following logic is only valid if the intermediate buffer is empty.
DCHECK_EQ(0, buffered_bytes_);
const int write_result =
file_stream_writer_->Write(buffer.get(), length, callback);
DCHECK_EQ(net::ERR_IO_PENDING, write_result);
}
void
BufferingFileStreamWriter::OnFlushIntermediateBufferForBufferedWriteCompleted(
scoped_refptr<net::IOBuffer> buffer,
int buffered_bytes,
int bytes_left,
const net::CompletionCallback& callback,
int result) {
if (result < 0) {
callback.Run(result);
return;
}
// Copy the rest of bytes to the buffer.
DCHECK_EQ(net::OK, result);
DCHECK_EQ(0, buffered_bytes_);
DCHECK_GE(intermediate_buffer_length_, bytes_left);
CopyToIntermediateBuffer(buffer, buffered_bytes, bytes_left);
callback.Run(buffered_bytes + bytes_left);
}
void BufferingFileStreamWriter::OnFlushIntermediateBufferForFlushCompleted(
const net::CompletionCallback& callback,
int result) {
if (result < 0) {
callback.Run(result);
return;
}
const int flush_result = file_stream_writer_->Flush(callback);
DCHECK_EQ(net::ERR_IO_PENDING, flush_result);
}
} // namespace file_system_provider
} // namespace chromeos
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