1 files changed, 191 insertions, 0 deletions
diff --git a/chromium/net/spdy/spdy_frame_builder.cc b/chromium/net/spdy/spdy_frame_builder.cc
new file mode 100644
index 00000000000..9e779ff4594
--- /dev/null
+++ b/chromium/net/spdy/spdy_frame_builder.cc
@@ -0,0 +1,191 @@
+// 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"
+#include "net/spdy/spdy_protocol.h"
+
+namespace net {
+
+namespace {
+
+// A special structure for the 8 bit flags and 24 bit length fields.
+union FlagsAndLength {
+  uint8 flags_[4];  // 8 bits
+  uint32 length_;   // 24 bits
+};
+
+// Creates a FlagsAndLength.
+FlagsAndLength CreateFlagsAndLength(uint8 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(size_t size)
+    : buffer_(new char[size]),
+      capacity_(size),
+      length_(0) {
+}
+
+SpdyFrameBuilder::~SpdyFrameBuilder() {
+}
+
+char* SpdyFrameBuilder::GetWritableBuffer(size_t length) {
+  if (!CanWrite(length)) {
+    return NULL;
+  }
+  return buffer_.get() + length_;
+}
+
+bool SpdyFrameBuilder::Seek(size_t length) {
+  if (!CanWrite(length)) {
+    return false;
+  }
+
+  length_ += length;
+  return true;
+}
+
+bool SpdyFrameBuilder::WriteControlFrameHeader(const SpdyFramer& framer,
+                                               SpdyFrameType type,
+                                               uint8 flags) {
+  DCHECK_GE(type, FIRST_CONTROL_TYPE);
+  DCHECK_LE(type, LAST_CONTROL_TYPE);
+  DCHECK_GT(4, framer.protocol_version());
+  bool success = true;
+  FlagsAndLength flags_length = CreateFlagsAndLength(
+      flags, capacity_ - framer.GetControlFrameHeaderSize());
+  success &= WriteUInt16(kControlFlagMask | framer.protocol_version());
+  success &= WriteUInt16(type);
+  success &= WriteBytes(&flags_length, sizeof(flags_length));
+  DCHECK_EQ(framer.GetControlFrameHeaderSize(), length());
+  return success;
+}
+
+bool SpdyFrameBuilder::WriteDataFrameHeader(const SpdyFramer& framer,
+                                            SpdyStreamId stream_id,
+                                            SpdyDataFlags flags) {
+  if (framer.protocol_version() >= 4) {
+    return WriteFramePrefix(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_LE(DATA, type);
+  DCHECK_GE(LAST_CONTROL_TYPE, type);
+  DCHECK_EQ(0u, stream_id & ~kStreamIdMask);
+  DCHECK_LE(4, framer.protocol_version());
+  bool success = true;
+  DCHECK_GT(1u<<16, capacity_);  // Make sure length fits in 2B.
+  success &= WriteUInt16(capacity_);
+  success &= WriteUInt8(type);
+  success &= WriteUInt8(flags);
+  success &= WriteUInt32(stream_id);
+  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())))
+    return false;
+
+  return WriteBytes(value.data(), static_cast<uint16>(value.size()));
+}
+
+bool SpdyFrameBuilder::WriteStringPiece32(const base::StringPiece& value) {
+  if (!WriteUInt32(value.size())) {
+    return false;
+  }
+
+  return WriteBytes(value.data(), value.size());
+}
+
+bool SpdyFrameBuilder::WriteBytes(const void* data, uint32 data_len) {
+  if (!CanWrite(data_len)) {
+    return false;
+  }
+
+  char* dest = GetWritableBuffer(data_len);
+  memcpy(dest, data, data_len);
+  Seek(data_len);
+  return true;
+}
+
+bool SpdyFrameBuilder::RewriteLength(const SpdyFramer& framer) {
+  if (framer.protocol_version() < 4) {
+    return OverwriteLength(framer,
+                           length_ - framer.GetControlFrameHeaderSize());
+  } else {
+    return OverwriteLength(framer, length_);
+  }
+}
+
+bool SpdyFrameBuilder::OverwriteLength(const SpdyFramer& framer,
+                                       size_t length) {
+  bool success = false;
+  const size_t old_length = length_;
+
+  if (framer.protocol_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;
+    success = WriteUInt16(length);
+  }
+
+  length_ = old_length;
+  return success;
+}
+
+bool SpdyFrameBuilder::CanWrite(size_t length) const {
+  if (length > kLengthMask) {
+    DCHECK(false);
+    return false;
+  }
+
+  if (length_ + length > capacity_) {
+    DCHECK(false);
+    return false;
+  }
+
+  return true;
+}
+
+}  // namespace net