Add an async ReadTrailers method to QuicChromiumClientStream::Handle

net/quic/chromium/bidirectional_stream_quic_impl.cc

Index: net/quic/chromium/bidirectional_stream_quic_impl.cc
diff --git a/net/quic/chromium/bidirectional_stream_quic_impl.cc b/net/quic/chromium/bidirectional_stream_quic_impl.cc
index a21f4251bd9e390a4291fadb8b98f6a4c93aacc6..607bd3be095ca892b57b747c49c147d4303fab79 100644
--- a/net/quic/chromium/bidirectional_stream_quic_impl.cc
+++ b/net/quic/chromium/bidirectional_stream_quic_impl.cc
@@ -232,15 +232,6 @@ bool BidirectionalStreamQuicImpl::GetLoadTimingInfo(
   return true;
 }
 
-void BidirectionalStreamQuicImpl::OnTrailingHeadersAvailable(
-    const SpdyHeaderBlock& headers,
-    size_t frame_len) {
-  headers_bytes_received_ += frame_len;
-  if (delegate_)
-    delegate_->OnTrailersReceived(headers);
-  // |this| can be destroyed after this point.
-}
-
 void BidirectionalStreamQuicImpl::OnClose() {
   DCHECK(stream_);
 
@@ -310,6 +301,32 @@ void BidirectionalStreamQuicImpl::OnReadInitialHeadersComplete(int rv) {
   connect_timing_ = session_->GetConnectTiming();
   if (delegate_)
     delegate_->OnHeadersReceived(initial_headers_);
+  base::ThreadTaskRunnerHandle::Get()->PostTask(
+      FROM_HERE, base::Bind(&BidirectionalStreamQuicImpl::ReadTrailingHeaders,
+                            weak_factory_.GetWeakPtr()));

[xunjieli, 2017/05/26 15:53:05]

Should we post this task before calling into the |delegate_| ?
If |delegate_| destroys |this| during the callback, then we will have a
segmentation fault when dereferencing |weak_factory_|, right?

[Ryan Hamilton, 2017/05/26 22:35:50]

Indeed! I noticed this in a followup, but forgot to upload the new patch set. :(

+}
+
+void BidirectionalStreamQuicImpl::ReadTrailingHeaders() {
+  int rv = stream_->ReadTrailingHeaders(
+      &trailing_headers_,
+      base::Bind(&BidirectionalStreamQuicImpl::OnReadTrailingHeadersComplete,
+                 weak_factory_.GetWeakPtr()));
+
+  if (rv != ERR_IO_PENDING)
+    OnReadTrailingHeadersComplete(rv);
+}
+
+void BidirectionalStreamQuicImpl::OnReadTrailingHeadersComplete(int rv) {
+  DCHECK_NE(ERR_IO_PENDING, rv);
+  if (rv < 0) {
+    NotifyError(rv);
+    return;
+  }
+
+  headers_bytes_received_ += rv;
+
+  if (delegate_)
+    delegate_->OnTrailersReceived(trailing_headers_);
 }
 
 void BidirectionalStreamQuicImpl::OnReadDataComplete(int rv) {