Do not crash on null stream in writing to bidirectional streams

net/quic/bidirectional_stream_quic_impl.cc

 // 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.
 
 #include "net/quic/bidirectional_stream_quic_impl.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/timer/timer.h"
@@ skipping 101 matching lines @@
   // Read will complete asynchronously and Delegate::OnReadCompleted will be
   // called upon completion.
   read_buffer_ = buffer;
   read_buffer_len_ = buffer_len;
   return ERR_IO_PENDING;
 }
 
 void BidirectionalStreamQuicImpl::SendData(const scoped_refptr<IOBuffer>& data,
                                            int length,
                                            bool end_stream) {
-  DCHECK(stream_);
   DCHECK(length > 0 || (length == 0 && end_stream));
 
+  if (!stream_) {
+    LOG(ERROR) << "Trying to send data when stream has been destroyed.";

[mef, 2016/06/01 21:53:15]

when -> after

[xunjieli, 2016/06/01 23:08:22]

Done.

+    base::ThreadTaskRunnerHandle::Get()->PostTask(
+        FROM_HERE, base::Bind(&BidirectionalStreamQuicImpl::NotifyError,
+                              weak_factory_.GetWeakPtr(), ERR_UNEXPECTED));

[mef, 2016/06/01 21:53:15]

nit: Should say ERR_UNEXPECTED in CL description.

[xunjieli, 2016/06/01 23:08:22]

Done.

+    return;
+  }
+
   std::unique_ptr<QuicConnection::ScopedPacketBundler> bundler;
   if (!has_sent_headers_) {
     DCHECK(!send_request_headers_automatically_);
     // Creates a bundler only if there are headers to be sent along with the
     // single data buffer.
     bundler.reset(new QuicConnection::ScopedPacketBundler(
         session_->connection(), QuicConnection::SEND_ACK_IF_PENDING));
     SendRequestHeaders();
   }
 
   base::StringPiece string_data(data->data(), length);
   int rv = stream_->WriteStreamData(
       string_data, end_stream,
       base::Bind(&BidirectionalStreamQuicImpl::OnSendDataComplete,
                  weak_factory_.GetWeakPtr()));
   DCHECK(rv == OK || rv == ERR_IO_PENDING);
   if (rv == OK) {
     base::ThreadTaskRunnerHandle::Get()->PostTask(
         FROM_HERE, base::Bind(&BidirectionalStreamQuicImpl::OnSendDataComplete,
                               weak_factory_.GetWeakPtr(), OK));
   }
 }
 
 void BidirectionalStreamQuicImpl::SendvData(
     const std::vector<scoped_refptr<IOBuffer>>& buffers,
     const std::vector<int>& lengths,
     bool end_stream) {
-  DCHECK(stream_);
   DCHECK_EQ(buffers.size(), lengths.size());
 
+  if (!stream_) {
+    LOG(ERROR) << "Trying to send data when stream has been destroyed.";

[mef, 2016/06/01 21:53:15]

when -> after

[xunjieli, 2016/06/01 23:08:22]

Done.

+    base::ThreadTaskRunnerHandle::Get()->PostTask(
+        FROM_HERE, base::Bind(&BidirectionalStreamQuicImpl::NotifyError,
+                              weak_factory_.GetWeakPtr(), ERR_UNEXPECTED));
+    return;
+  }
+
   QuicConnection::ScopedPacketBundler bundler(
       session_->connection(), QuicConnection::SEND_ACK_IF_PENDING);
   if (!has_sent_headers_) {
     DCHECK(!send_request_headers_automatically_);
     SendRequestHeaders();
   }
 
   int rv = stream_->WritevStreamData(
       buffers, lengths, end_stream,
       base::Bind(&BidirectionalStreamQuicImpl::OnSendDataComplete,
@@ skipping 61 matching lines @@
     // Spurrious notification. Wait for the next one.
     return;
   }
   read_buffer_ = nullptr;
   read_buffer_len_ = 0;
   delegate_->OnDataRead(rv);
 }
 
 void BidirectionalStreamQuicImpl::OnClose(QuicErrorCode error) {
   DCHECK(stream_);
+
   if (error == QUIC_NO_ERROR &&
       stream_->stream_error() == QUIC_STREAM_NO_ERROR) {
     ResetStream();
     return;
   }
-  ResetStream();

[mef, 2016/06/01 21:53:15]

Why no longer ResetStream() here?

[xunjieli, 2016/06/01 23:08:22]

It is redundant. NotifyError will call ResetStream().

   NotifyError(was_handshake_confirmed_ ? ERR_QUIC_PROTOCOL_ERROR
                                        : ERR_QUIC_HANDSHAKE_FAILED);
 }
 
 void BidirectionalStreamQuicImpl::OnError(int error) {
   NotifyError(error);
 }
 
 bool BidirectionalStreamQuicImpl::HasSendHeadersComplete() {
   return has_sent_headers_;
@@ skipping 46 matching lines @@
 void BidirectionalStreamQuicImpl::ResetStream() {
   if (!stream_)
     return;
   closed_stream_received_bytes_ = stream_->stream_bytes_read();
   closed_stream_sent_bytes_ = stream_->stream_bytes_written();
   stream_->SetDelegate(nullptr);
   stream_ = nullptr;
 }
 
 }  // namespace net