Implement the Stream registry in content

content/browser/streams/stream.h

+// Copyright (c) 2013 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 CONTENT_BROWSER_STREAMS_STREAM_H_
+#define CONTENT_BROWSER_STREAMS_STREAM_H_
+
+#include <deque>
+
+#include "base/basictypes.h"
+#include "base/memory/ref_counted.h"
+#include "base/observer_list.h"
+#include "content/browser/download/byte_stream.h"
+#include "googleurl/src/gurl.h"
+
+namespace net {
+class IOBuffer;
+}
+
+namespace content {
+
+class StreamReadObserver;
+class StreamRegistry;
+class StreamWriteObserver;
+
+// A stream that sends data from an existing ResourceHandler to an internal URL

[darin (slow to review), 2013/02/27 06:18:59]

nit: probably best not to mention ResourceHandler here.  this system is
independent of the details of ResourceHandler.

[Zachary Kuznia, 2013/02/27 07:36:56]

Changed to arbitrary source.

+// that can be read by an internal consumer.  It will continue to pull from the
+// original URL as long as there is data available.  It can be read from from

[darin (slow to review), 2013/02/27 06:18:59]

nit: "from from"

[Zachary Kuznia, 2013/02/27 07:36:56]

Done.

+// multiple clients, but results are undefined if more than one client reads at
+// the same time.  This allows a reader to consume part of the stream, then pass
+// it along to another client to continue processing the stream.
+class Stream : public base::RefCountedThreadSafe<Stream> {
+ public:
+  // Creates a stream useable from the |security_origin|.
+  Stream(StreamRegistry* registry,
+         const GURL& security_origin,
+         const GURL& url);
+
+  void AddReadObserver(StreamReadObserver* observer);
+  void RemoveReadObserver(StreamReadObserver* observer);
+
+  void AddWriteObserver(StreamWriteObserver* observer);
+  void RemoveWriteObserver(StreamWriteObserver* observer);
+
+  // Adds the data in |buffer| to the stream.  Takes ownership of |buffer|.
+  void AddData(scoped_refptr<net::IOBuffer> buffer, size_t size);
+
+  // Notifies this stream that it will not be receiving any more data.
+  void Finalize();
+
+  // Reads a maximum of |buf_size| from the stream into |buf|.  Sets
+  // |*bytes_read| to the number of bytes actually read.
+  // returns false if there is no data available, but the stream is not
+  // finalized, and true otherwise.
+  bool ReadRawData(net::IOBuffer* buf, int buf_size, int* bytes_read);
+
+  // Indicates whether there is space in the buffer to add more data.
+  bool can_add_data() const { return can_add_data_; }
+
+  void SetStreamUrl(const GURL& url) { stream_url_ = url; }

[darin (slow to review), 2013/02/27 06:18:59]

nit: set_stream_url

actually, since the class name is Stream, perhaps the property doesn't have to
repeat the substring "Stream"?  can this just be set_url() and url() methods?

[Zachary Kuznia, 2013/02/27 07:36:56]

Done.

+  const GURL& stream_url() { return stream_url_; }

[darin (slow to review), 2013/02/27 06:18:59]

nit: getters probably should be 'const' methods

[Zachary Kuznia, 2013/02/27 07:36:56]

Done.

+
+  const GURL& security_origin() { return security_origin_; }
+
+ private:
+  friend class base::RefCountedThreadSafe<Stream>;
+
+  ~Stream();
+
+  void OnSpaceAvailable();
+  void OnDataAvailable();
+
+  size_t bytes_read_;
+  bool can_add_data_;
+
+  GURL security_origin_;
+  GURL stream_url_;
+
+  scoped_refptr<net::IOBuffer> data_;
+  size_t data_length_;
+
+  scoped_ptr<ByteStreamWriter> writer_;
+  scoped_ptr<ByteStreamReader> reader_;
+
+  StreamRegistry* registry_;
+  ObserverList<StreamReadObserver> read_observers_;
+  ObserverList<StreamWriteObserver> write_observers_;
+
+  DISALLOW_COPY_AND_ASSIGN(Stream);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_STREAMS_STREAM_H_