Refactor FFmpegURLProtocol code from FFmpegDemuxer into BlockingUrlProtocol.

media/filters/blocking_url_protocol.cc

+// Copyright (c) 2012 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 "media/filters/blocking_url_protocol.h"
+
+#include "base/bind.h"
+#include "media/base/data_source.h"
+#include "media/ffmpeg/ffmpeg_common.h"
+
+namespace media {
+
+BlockingUrlProtocol::BlockingUrlProtocol(
+    const scoped_refptr<DataSource>& data_source,
+    const base::Closure& error_cb)
+    : data_source_(data_source),
+      error_cb_(error_cb),
+      read_event_(false, false),
+      read_has_failed_(false),
+      last_read_bytes_(0),
+      read_position_(0) {
+}
+
+BlockingUrlProtocol::~BlockingUrlProtocol() {}
+
+void BlockingUrlProtocol::Abort() {
+  SignalReadCompleted(DataSource::kReadError);
+}
+
+int BlockingUrlProtocol::Read(int size, uint8* data) {
+  // Read errors are unrecoverable.
+  if (read_has_failed_)
+    return AVERROR(EIO);
+
+  // Even though FFmpeg defines AVERROR_EOF, it's not to be used with I/O

[DaleCurtis, 2012/11/13 03:42:28]

+rbultje; I wonder if this is still true, Ronald?

+  // routines. Instead return 0 for any read at or past EOF.
+  int64 file_size;
+  if (data_source_->GetSize(&file_size) && read_position_ >= file_size)
+    return 0;
+
+  // Blocking read from data source until |last_read_bytes_| is set and event is
+  // signalled.
+  data_source_->Read(read_position_, size, data, base::Bind(
+      &BlockingUrlProtocol::SignalReadCompleted, base::Unretained(this)));
+  read_event_.Wait();
+
+  if (last_read_bytes_ == DataSource::kReadError) {
+    // TODO(scherkus): We shouldn't fire |error_cb_| if it was due to Abort().
+    error_cb_.Run();
+    read_has_failed_ = true;
+    return AVERROR(EIO);
+  }
+
+  read_position_ += last_read_bytes_;
+  return last_read_bytes_;
+}
+
+bool BlockingUrlProtocol::GetPosition(int64* position_out) {
+  *position_out = read_position_;
+  return true;
+}
+
+bool BlockingUrlProtocol::SetPosition(int64 position) {
+  int64 file_size;
+  if ((data_source_->GetSize(&file_size) && position >= file_size) ||
+      position < 0) {
+    return false;
+  }
+
+  read_position_ = position;
+  return true;
+}
+
+bool BlockingUrlProtocol::GetSize(int64* size_out) {
+  return data_source_->GetSize(size_out);
+}
+
+bool BlockingUrlProtocol::IsStreaming() {
+  return data_source_->IsStreaming();
+}
+
+void BlockingUrlProtocol::SignalReadCompleted(int size) {
+  last_read_bytes_ = size;
+  read_event_.Signal();
+}
+
+}  // namespace media