HPACK: Refactor and simplify HpackOutputStream

net/spdy/hpack_output_stream.cc

 // Copyright 2014 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/hpack_output_stream.h"
 
 #include "base/logging.h"
 
-using base::StringPiece;
 
 namespace net {
 
+using base::StringPiece;
 using std::string;
 
-HpackOutputStream::HpackOutputStream(uint32 max_string_literal_size)
-    : max_string_literal_size_(max_string_literal_size),
-      bit_offset_(0) {}
+HpackOutputStream::HpackOutputStream()
+    : bit_offset_(0) {}
 
 HpackOutputStream::~HpackOutputStream() {}
 
-void HpackOutputStream::AppendIndexedHeader(uint32 index_or_zero) {
-  AppendPrefix(kIndexedOpcode);
-  AppendUint32(index_or_zero);
-}
-
-bool HpackOutputStream::AppendLiteralHeaderNoIndexingWithName(
-    StringPiece name, StringPiece value) {
-  AppendPrefix(kLiteralNoIndexOpcode);
-  AppendBits(0x0, 8 - kLiteralNoIndexOpcode.bit_size);
-  if (!AppendStringLiteral(name))
-    return false;
-  if (!AppendStringLiteral(value))
-    return false;
-  return true;
-}
-
-void HpackOutputStream::TakeString(string* output) {
-  // This must hold, since all public functions cause the buffer to
-  // end on a byte boundary.
-  DCHECK_EQ(bit_offset_, 0u);
-  buffer_.swap(*output);
-  buffer_.clear();
-  bit_offset_ = 0;
-}
-
 void HpackOutputStream::AppendBits(uint8 bits, size_t bit_size) {
   DCHECK_GT(bit_size, 0u);
   DCHECK_LE(bit_size, 8u);
   DCHECK_EQ(bits >> bit_size, 0);
   size_t new_bit_offset = bit_offset_ + bit_size;
   if (bit_offset_ == 0) {
     // Buffer ends on a byte boundary.
     DCHECK_LE(bit_size, 8u);
     buffer_.append(1, bits << (8 - bit_size));
   } else if (new_bit_offset <= 8) {
     // Buffer does not end on a byte boundary but the given bits fit
     // in the remainder of the last byte.
     *buffer_.rbegin() |= bits << (8 - new_bit_offset);
   } else {
     // Buffer does not end on a byte boundary and the given bits do
     // not fit in the remainder of the last byte.
     *buffer_.rbegin() |= bits >> (new_bit_offset - 8);
     buffer_.append(1, bits << (16 - new_bit_offset));
   }
   bit_offset_ = new_bit_offset % 8;
 }
 
 void HpackOutputStream::AppendPrefix(HpackPrefix prefix) {
   AppendBits(prefix.bits, prefix.bit_size);
 }
 
+void HpackOutputStream::AppendBytes(StringPiece buffer) {
+  DCHECK_EQ(bit_offset_, 0u);
+  buffer_.append(buffer.data(), buffer.size());
+}
+
 void HpackOutputStream::AppendUint32(uint32 I) {
   // The algorithm below is adapted from the pseudocode in 4.1.1.
   size_t N = 8 - bit_offset_;
   uint8 max_first_byte = static_cast<uint8>((1 << N) - 1);
   if (I < max_first_byte) {
     AppendBits(static_cast<uint8>(I), N);
   } else {
     AppendBits(max_first_byte, N);
     I -= max_first_byte;
     while ((I & ~0x7f) != 0) {
       buffer_.append(1, (I & 0x7f) | 0x80);
       I >>= 7;
     }
     AppendBits(static_cast<uint8>(I), 8);
   }
 }
 
-bool HpackOutputStream::AppendStringLiteral(base::StringPiece str) {
+void HpackOutputStream::TakeString(string* output) {
+  // This must hold, since all public functions cause the buffer to
+  // end on a byte boundary.
   DCHECK_EQ(bit_offset_, 0u);
-  // TODO(akalin): Implement Huffman encoding.
-  AppendPrefix(kStringLiteralIdentityEncoded);
-  if (str.size() > max_string_literal_size_)
-    return false;
-  AppendUint32(static_cast<uint32>(str.size()));
-  buffer_.append(str.data(), str.size());
-  return true;
+  buffer_.swap(*output);
+  buffer_.clear();
+  bit_offset_ = 0;
 }
 
 }  // namespace net