Motown in-proc streaming framework used to implement media services.

services/media/framework/parts/reader.h

+// Copyright 2016 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.
+
+#ifndef SERVICES_MEDIA_FRAMEWORK_PARTS_READER_H_
+#define SERVICES_MEDIA_FRAMEWORK_PARTS_READER_H_
+
+#include <memory>
+
+#include "services/media/framework/result.h"
+#include "url/gurl.h"
+
+namespace mojo {
+namespace media {
+
+class Reader;
+
+typedef std::shared_ptr<Reader> ReaderPtr;
+
+// Abstract base class for objects that read raw data on behalf of demuxes.
+// This model is synchronous, because that's how ffmpeg works.
+class Reader {
+ public:
+  // Creates a Reader object for a given url.
+  static Result Create(const GURL& gurl, ReaderPtr* reader_out);
+
+  virtual ~Reader() {}
+
+  // Initializes the reader.
+  virtual Result Init(const GURL& gurl) = 0;
+
+  // Reads the given number of bytes into the buffer and returns the number of
+  // bytes read. Returns -1 if the operation fails.
+  virtual size_t Read(uint8* buffer, int bytes_to_read) = 0;
+
+  // Gets the current position or -1 if the operation fails.
+  virtual int64_t GetPosition() const = 0;
+
+  // Seeks to the given position and returns it. Returns -1 if the operation
+  // fails.
+  virtual int64_t SetPosition(int64 position) = 0;
+
+  // Returns the file size. Returns -1 if the operation fails or the size isn't
+  // known.
+  virtual size_t GetSize() const = 0;
+
+  // Returns true if this object supports seeking, false otherwise.
+  virtual bool CanSeek() const = 0;
+};
+
+}  // namespace media
+}  // namespace mojo
+
+#endif // MOJO_SERVICES_MEDIA_READER_H_