SPDY: Headers & Push-Promise now use Continuations

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 "net/spdy/spdy_frame_builder.h"
 
 #include <limits>
 
 #include "base/logging.h"
 #include "net/spdy/spdy_framer.h"
@@ skipping 14 matching lines @@
   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(size_t size)
+  SpdyFrameBuilder::SpdyFrameBuilder(size_t size, SpdyMajorVersion version)
     : buffer_(new char[size]),
       capacity_(size),
-      length_(0) {
+      length_(0),
+      offset_(0),
+      version_(version) {
 }
 
 SpdyFrameBuilder::~SpdyFrameBuilder() {
 }
 
 char* SpdyFrameBuilder::GetWritableBuffer(size_t length) {
   if (!CanWrite(length)) {
     return NULL;
   }
-  return buffer_.get() + length_;
+  return buffer_.get() + offset_ + length_;
 }
 
 bool SpdyFrameBuilder::Seek(size_t length) {
   if (!CanWrite(length)) {
     return false;
   }
 
   length_ += length;
   return true;
 }
@@ skipping 12 matching lines @@
       SpdyConstants::SerializeFrameType(framer.protocol_version(), type));
   success &= WriteBytes(&flags_length, sizeof(flags_length));
   DCHECK_EQ(framer.GetControlFrameHeaderSize(), length());
   return success;
 }
 
 bool SpdyFrameBuilder::WriteDataFrameHeader(const SpdyFramer& framer,
                                             SpdyStreamId stream_id,
                                             uint8 flags) {
   if (framer.protocol_version() >= 4) {
-    return WriteFramePrefix(framer, DATA, flags, stream_id);
+    return BeginNewFrame(framer, DATA, flags, stream_id);
   }
   DCHECK_EQ(0u, stream_id & ~kStreamIdMask);
   bool success = true;
   success &= WriteUInt32(stream_id);
   size_t length_field = capacity_ - framer.GetDataFrameMinimumSize();
   DCHECK_EQ(0u, length_field & ~static_cast<size_t>(kLengthMask));
   FlagsAndLength flags_length;
   flags_length.length_ = htonl(length_field);
   DCHECK_EQ(0, flags & ~kDataFlagsMask);
   flags_length.flags_[0] = flags;
   success &= WriteBytes(&flags_length, sizeof(flags_length));
   DCHECK_EQ(framer.GetDataFrameMinimumSize(), length());
   return success;
 }
 
-bool SpdyFrameBuilder::WriteFramePrefix(const SpdyFramer& framer,
-                                        SpdyFrameType type,
-                                        uint8 flags,
-                                        SpdyStreamId stream_id) {
-  DCHECK_NE(-1,
-            SpdyConstants::SerializeFrameType(framer.protocol_version(), type));
+bool SpdyFrameBuilder::BeginNewFrame(const SpdyFramer& framer,
+                                     SpdyFrameType type,
+                                     uint8 flags,
+                                     SpdyStreamId stream_id) {
+  DCHECK(SpdyConstants::IsValidFrameType(version_,
+      SpdyConstants::SerializeFrameType(version_, type)));
   DCHECK_EQ(0u, stream_id & ~kStreamIdMask);
-  DCHECK_LE(4, framer.protocol_version());
+  DCHECK_LE(4, version_);
+
   bool success = true;
-  // Upstream DCHECK's that capacity_ is under the maximum frame size at this
-  // point. Chromium does not, because of the large additional zlib inflation
-  // factor we use. (Frame size is is still checked by OverwriteLength() below).
-  if (type != DATA) {
-    success &= WriteUInt16(capacity_ - framer.GetControlFrameHeaderSize());
-  } else {
-    success &= WriteUInt16(capacity_ - framer.GetDataFrameMinimumSize());
+  if (length_ > 0) {
+    // Update length field for previous frame.
+    OverwriteLength(framer, length_ - framer.GetPrefixLength(type));
+    DLOG_IF(DFATAL, SpdyConstants::GetFrameMaximumSize(version_) < length_)
+        << "Frame length  " << length_
+        << " is longer than the maximum allowed length.";
   }
+
+  offset_ += length_;
+  length_ = 0;
+
+  // Assume all remaining capacity will be used for this frame. If not,
+  // the length will get overwritten when we begin the next frame.
+  // Don't check for length limits here because this may be larger than the
+  // actual frame length.
+  success &= WriteUInt16(capacity_ - offset_ - framer.GetPrefixLength(type));
   success &= WriteUInt8(
-      SpdyConstants::SerializeFrameType(framer.protocol_version(), type));
+      SpdyConstants::SerializeFrameType(version_, type));
   success &= WriteUInt8(flags);
   success &= WriteUInt32(stream_id);
-  DCHECK_EQ(framer.GetDataFrameMinimumSize(), length());
+  DCHECK_EQ(framer.GetDataFrameMinimumSize(), length_);
   return success;
 }
 
 bool SpdyFrameBuilder::WriteString(const std::string& value) {
   if (value.size() > 0xffff) {
     DCHECK(false) << "Tried to write string with length > 16bit.";
     return false;
   }
 
   if (!WriteUInt16(static_cast<int>(value.size())))
@@ skipping 21 matching lines @@
   return true;
 }
 
 bool SpdyFrameBuilder::RewriteLength(const SpdyFramer& framer) {
   return OverwriteLength(framer,
                          length_ - framer.GetControlFrameHeaderSize());
 }
 
 bool SpdyFrameBuilder::OverwriteLength(const SpdyFramer& framer,
                                        size_t length) {
-  if (framer.protocol_version() < 4) {
-    DCHECK_GE(framer.GetFrameMaximumSize() - framer.GetFrameMinimumSize(),
+  if (version_ < 4) {
+    DCHECK_GE(SpdyConstants::GetFrameMaximumSize(version_) -
+              framer.GetFrameMinimumSize(),
               length);
   } else {
-    DCHECK_GE(framer.GetFrameMaximumSize(), length);
+    DCHECK_GE(SpdyConstants::GetFrameMaximumSize(version_), length);
   }
   bool success = false;
   const size_t old_length = length_;
 
-  if (framer.protocol_version() < 4) {
+  if (version_ < 4) {
     FlagsAndLength flags_length = CreateFlagsAndLength(
         0,  // We're not writing over the flags value anyway.
         length);
 
     // Write into the correct location by temporarily faking the offset.
     length_ = 5;  // Offset at which the length field occurs.
     success = WriteBytes(reinterpret_cast<char*>(&flags_length) + 1,
                          sizeof(flags_length) - 1);
   } else {
     length_ = 0;
@@ skipping 15 matching lines @@
   length_ = old_length;
   return success;
 }
 
 bool SpdyFrameBuilder::CanWrite(size_t length) const {
   if (length > kLengthMask) {
     DCHECK(false);
     return false;
   }
 
-  if (length_ + length > capacity_) {
+  if (offset_ + length_ + length > capacity_) {
     DCHECK(false);
     return false;
   }
 
   return true;
 }
 
 }  // namespace net