Define Stable API for WebRTC/Quartc

net/quic/quartc/quartc_stream.cc

+// Copyright (c) 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.
+
+#include "net/quic/quartc/quartc_stream.h"
+
+namespace net {
+
+QuartcStream::QuartcStream(QuicStreamId id, QuicSession* session)
+    : ReliableQuicStream(id, session) {}
+QuartcStream::~QuartcStream() {}
+
+void QuartcStream::OnDataAvailable() {
+  struct iovec iov;
+  while (sequencer()->GetReadableRegions(&iov, 1) == 1) {
+    DCHECK(delegate_);
+    delegate_->OnReceived(this, reinterpret_cast<const char*>(iov.iov_base),
+                          iov.iov_len);
+    sequencer()->MarkConsumed(iov.iov_len);
+  }
+}
+
+void QuartcStream::OnClose() {
+  ReliableQuicStream::OnClose();
+  DCHECK(delegate_);
+  delegate_->OnClose(this, connection_error());
+}
+
+void QuartcStream::OnCanWrite() {
+  ReliableQuicStream::OnCanWrite();
+  DCHECK(delegate_);
+  delegate_->OnBufferedAmountChanged(this);
+}
+
+uint32_t QuartcStream::stream_id() {
+  return id();
+}
+
+uint64_t QuartcStream::buffered_amount() {
+  return queued_data_bytes();
+}
+
+void QuartcStream::Write(const char* data,
+                         size_t size,
+                         const WriteParameters& param) {
+  WriteOrBufferData(base::StringPiece(data, size), param.fin, nullptr);
+}
+
+void QuartcStream::Close() {
+  ReliableQuicStream::session()->CloseStream(id());
+}
+
+void QuartcStream::SetDelegate(QuartcStreamInterface::Delegate* delegate) {
+  if (delegate_) {
+    DVLOG(1) << "The delegate for Stream " << id() << " has already been set.";
+    return;
+  }

[pthatcher2, 2016/10/05 22:12:07]

Why not just set it to something different?

[zhihuang1, 2016/10/13 06:22:40]

Same as before.

I feel that the delegate implies a kind of 1:1 relationship. 

Beside, it seems that other delegates in QUIC are only be set once. For example.
https://cs.chromium.org/chromium/src/net/quic/chromium/quic_chromium_client_s...

But I'm not sure if there are other consideration (delegate context switch?)
about this.

In our case, I think it will also be fine to replace the delegate.

+  delegate_ = delegate;
+  DCHECK(delegate_);
+}
+
+}  // namespace net