Factor out the code to write control frame headers into a new constructor of SpdyFrameBuilder.

net/spdy/spdy_frame_builder.cc

 // Copyright (c) 2012 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 <limits>
 
 #include "net/spdy/spdy_frame_builder.h"
 #include "net/spdy/spdy_protocol.h"
 
 namespace net {
 
-SpdyFrameBuilder::SpdyFrameBuilder(size_t size)
+namespace {
+
+// Creates a FlagsAndLength.
+FlagsAndLength CreateFlagsAndLength(SpdyControlFlags flags, size_t length) {
+  DCHECK_EQ(0u, length & ~static_cast<size_t>(kLengthMask));
+  FlagsAndLength flags_length;
+  flags_length.length_ = htonl(static_cast<uint32>(length));
+  DCHECK_EQ(0, flags & ~kControlFlagsMask);
+  flags_length.flags_[0] = flags;
+  return flags_length;
+}
+
+}  // namespace
+
+SpdyFrameBuilder::SpdyFrameBuilder(SpdyControlType type,
+                                   SpdyControlFlags flags,
+                                   int spdy_version,
+                                   size_t size)
     : buffer_(new char[size]),
       capacity_(size),
       length_(0) {
+  FlagsAndLength flags_length = CreateFlagsAndLength(
+      flags, size - SpdyFrame::kHeaderSize);
+  WriteUInt16(kControlFlagMask | spdy_version);
+  WriteUInt16(type);
+  WriteBytes(&flags_length, sizeof(flags_length));
+}
+
+SpdyFrameBuilder::SpdyFrameBuilder(SpdyStreamId stream_id,
+                                   SpdyDataFlags flags,
+                                   size_t size)
+    : buffer_(new char[size]),
+      capacity_(size),
+      length_(0) {
+  DCHECK_EQ(0u, stream_id & ~kStreamIdMask);
+  WriteUInt32(stream_id);
+  size_t length = size - SpdyFrame::kHeaderSize;
+  DCHECK_EQ(0u, length & ~static_cast<size_t>(kLengthMask));
+  FlagsAndLength flags_length;
+  flags_length.length_ = htonl(length);
+  DCHECK_EQ(0, flags & ~kDataFlagsMask);
+  flags_length.flags_[0] = flags;
+  WriteBytes(&flags_length, sizeof(flags_length));
 }
 
 SpdyFrameBuilder::~SpdyFrameBuilder() {
   if (buffer_)
     delete[] buffer_;
 }
 
 char* SpdyFrameBuilder::BeginWrite(size_t length) {
   size_t offset = length_;
   size_t needed_size = length_ + length;
@@ skipping 38 matching lines @@
 
 bool SpdyFrameBuilder::WriteStringPiece32(const base::StringPiece& value) {
   if (!WriteUInt32(value.size())) {
     return false;
   }
 
   return WriteBytes(value.data(), value.size());
 }
 
 }  // namespace net