chromeos/dbus/pipe_reader.cc

   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 "chromeos/dbus/pipe_reader.h"
   6
   7 #include "base/bind.h"
   8 #include "base/posix/eintr_wrapper.h"
   9 #include "base/task_runner.h"
  10 #include "net/base/file_stream.h"
  11 #include "net/base/io_buffer.h"
  12 #include "net/base/net_errors.h"
  13
  14 namespace chromeos {
  15
  16 PipeReader::PipeReader(const scoped_refptr<base::TaskRunner>& task_runner,
  17                        const IOCompleteCallback& callback)
  18     : io_buffer_(new net::IOBufferWithSize(4096)),
  19       task_runner_(task_runner),
  20       callback_(callback),
  21       weak_ptr_factory_(this) {}
  22
  23 PipeReader::~PipeReader() {
  24 }
  25
  26 base::File PipeReader::StartIO() {
  27   // Use a pipe to collect data
  28   int pipe_fds[2];
  29   const int status = HANDLE_EINTR(pipe(pipe_fds));
  30   if (status < 0) {
  31     PLOG(ERROR) << "pipe";
  32     return base::File();
  33   }
  34   base::File pipe_write_end(pipe_fds[1]);
  35   // Pass ownership of pipe_fds[0] to data_stream_, which will close it.
  36   data_stream_.reset(new net::FileStream(
  37       base::File(pipe_fds[0]), task_runner_));
  38
  39   // Post an initial async read to setup data collection
  40   int rv = data_stream_->Read(
  41       io_buffer_.get(), io_buffer_->size(),
  42       base::Bind(&PipeReader::OnDataReady, weak_ptr_factory_.GetWeakPtr()));
  43   if (rv != net::ERR_IO_PENDING) {
  44     LOG(ERROR) << "Unable to post initial read";
  45     return base::File();
  46   }
  47   return pipe_write_end.Pass();
  48 }
  49
  50 void PipeReader::OnDataReady(int byte_count) {
  51   DVLOG(1) << "OnDataReady byte_count " << byte_count;
  52   if (byte_count <= 0) {
  53     callback_.Run();  // signal creator to take data and delete us
  54     return;
  55   }
  56
  57   AcceptData(io_buffer_->data(), byte_count);
  58
  59   // Post another read
  60   int rv = data_stream_->Read(
  61       io_buffer_.get(), io_buffer_->size(),
  62       base::Bind(&PipeReader::OnDataReady, weak_ptr_factory_.GetWeakPtr()));
  63   if (rv != net::ERR_IO_PENDING) {
  64     LOG(ERROR) << "Unable to post another read";
  65     // TODO(sleffler) do something more intelligent?
  66   }
  67 }
  68
  69 PipeReaderForString::PipeReaderForString(
  70     const scoped_refptr<base::TaskRunner>& task_runner,
  71     const IOCompleteCallback& callback)
  72     : PipeReader(task_runner, callback) {
  73 }
  74
  75 void PipeReaderForString::AcceptData(const char *data, int byte_count) {
  76   data_.append(data, byte_count);
  77 }
  78
  79 void PipeReaderForString::GetData(std::string* data) {
  80   data_.swap(*data);
  81 }
  82
  83 }  // namespace chromeos