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| 1 // Copyright 2016 The Chromium Authors. All rights reserved. |
| 2 // Use of this source code is governed by a BSD-style license that can be |
| 3 // found in the LICENSE file. |
| 4 |
| 5 #include "net/http2/hpack/decoder/hpack_decoder_string_buffer.h" |
| 6 |
| 7 #include "base/logging.h" |
| 8 |
| 9 using base::StringPiece; |
| 10 |
| 11 namespace net { |
| 12 |
| 13 std::ostream& operator<<(std::ostream& out, |
| 14 const HpackDecoderStringBuffer::State v) { |
| 15 switch (v) { |
| 16 case HpackDecoderStringBuffer::State::RESET: |
| 17 return out << "RESET"; |
| 18 case HpackDecoderStringBuffer::State::COLLECTING: |
| 19 return out << "COLLECTING"; |
| 20 case HpackDecoderStringBuffer::State::COMPLETE: |
| 21 return out << "COMPLETE"; |
| 22 default: |
| 23 return out << "Unknown HpackDecoderStringBuffer::State!"; |
| 24 } |
| 25 } |
| 26 |
| 27 std::ostream& operator<<(std::ostream& out, |
| 28 const HpackDecoderStringBuffer::Backing v) { |
| 29 switch (v) { |
| 30 case HpackDecoderStringBuffer::Backing::RESET: |
| 31 return out << "RESET"; |
| 32 case HpackDecoderStringBuffer::Backing::UNBUFFERED: |
| 33 return out << "UNBUFFERED"; |
| 34 case HpackDecoderStringBuffer::Backing::BUFFERED: |
| 35 return out << "BUFFERED"; |
| 36 case HpackDecoderStringBuffer::Backing::STATIC: |
| 37 return out << "STATIC"; |
| 38 default: |
| 39 return out << "Unknown HpackDecoderStringBuffer::Backing!"; |
| 40 } |
| 41 } |
| 42 |
| 43 HpackDecoderStringBuffer::HpackDecoderStringBuffer() { |
| 44 Reset(); |
| 45 } |
| 46 HpackDecoderStringBuffer::~HpackDecoderStringBuffer() {} |
| 47 |
| 48 // TODO(jamessynge): Consider eliminating most of Reset (i.e. do less); in |
| 49 // particular, if a variable won't be read again until after it is next set |
| 50 // (e.g. is_huffman_encoded_ or remaining_len_), then it doesn't need to be |
| 51 // cleared here. This will be easier when not supporting both HpackDecoder2 |
| 52 // (in net/spdy/hpack) and HpackWholeEntryDecoder, so we can eliminate |
| 53 // the Set() and str() methods. |
| 54 void HpackDecoderStringBuffer::Reset() { |
| 55 DVLOG(3) << "HpackDecoderStringBuffer::Reset"; |
| 56 buffer_.clear(); |
| 57 value_.clear(); |
| 58 remaining_len_ = 0; |
| 59 is_huffman_encoded_ = false; |
| 60 state_ = State::RESET; |
| 61 backing_ = Backing::RESET; |
| 62 } |
| 63 |
| 64 void HpackDecoderStringBuffer::Set(StringPiece value, bool is_static) { |
| 65 DVLOG(2) << "HpackDecoderStringBuffer::Set"; |
| 66 DCHECK_EQ(state_, State::RESET); |
| 67 DCHECK_EQ(backing_, Backing::RESET); |
| 68 value_ = value; |
| 69 state_ = State::COMPLETE; |
| 70 backing_ = is_static ? Backing::STATIC : Backing::UNBUFFERED; |
| 71 } |
| 72 |
| 73 void HpackDecoderStringBuffer::OnStart(bool huffman_encoded, size_t len) { |
| 74 DVLOG(2) << "HpackDecoderStringBuffer::OnStart"; |
| 75 DCHECK_EQ(state_, State::RESET); |
| 76 DCHECK_EQ(backing_, Backing::RESET); |
| 77 buffer_.clear(); |
| 78 value_.clear(); |
| 79 |
| 80 remaining_len_ = len; |
| 81 is_huffman_encoded_ = huffman_encoded; |
| 82 |
| 83 state_ = State::COLLECTING; |
| 84 |
| 85 if (huffman_encoded) { |
| 86 decoder_.Reset(); |
| 87 backing_ = Backing::BUFFERED; |
| 88 |
| 89 // Reserve space in buffer_ for the uncompressed string, assuming the |
| 90 // maximum expansion. The shortest Huffman codes in the RFC are 5 bits long, |
| 91 // which then expand to 8 bits during decoding (i.e. each code is for one |
| 92 // plain text octet, aka byte), so the maximum size is 60% longer than the |
| 93 // encoded size. |
| 94 len = len * 8 / 5; |
| 95 if (buffer_.capacity() < len) { |
| 96 buffer_.reserve(len); |
| 97 } |
| 98 } else { |
| 99 // Assume for now that we won't need to use buffer_, so don't reserve space |
| 100 // in it. |
| 101 backing_ = Backing::RESET; |
| 102 } |
| 103 } |
| 104 |
| 105 bool HpackDecoderStringBuffer::OnData(const char* data, size_t len) { |
| 106 DVLOG(2) << "HpackDecoderStringBuffer::OnData state=" << state_ |
| 107 << ", backing=" << backing_; |
| 108 DCHECK_EQ(state_, State::COLLECTING); |
| 109 DCHECK_LE(len, remaining_len_); |
| 110 remaining_len_ -= len; |
| 111 |
| 112 if (is_huffman_encoded_) { |
| 113 DCHECK_EQ(backing_, Backing::BUFFERED); |
| 114 // We don't set value_ for buffered strings until OnEnd, |
| 115 // so it should be empty. |
| 116 DCHECK_EQ(0u, value_.size()); |
| 117 return decoder_.Decode(StringPiece(data, len), &buffer_); |
| 118 } |
| 119 |
| 120 if (backing_ == Backing::RESET) { |
| 121 // This is the first call to OnData. |
| 122 DCHECK_EQ(0u, buffer_.size()); |
| 123 DCHECK_EQ(0u, value_.size()); |
| 124 // If data contains the entire string, don't copy the string. If we later |
| 125 // find that the HPACK entry is split across input buffers, then we'll |
| 126 // copy the string into buffer_. |
| 127 if (remaining_len_ == 0) { |
| 128 value_ = StringPiece(data, len); |
| 129 backing_ = Backing::UNBUFFERED; |
| 130 return true; |
| 131 } |
| 132 |
| 133 // We need to buffer the string because it is split across input buffers. |
| 134 backing_ = Backing::BUFFERED; |
| 135 buffer_.assign(data, len); |
| 136 return true; |
| 137 } |
| 138 |
| 139 // This is not the first call to OnData for this string, so it should be |
| 140 // buffered. |
| 141 DCHECK_EQ(backing_, Backing::BUFFERED); |
| 142 // We don't set value_ for buffered strings until OnEnd, so it should be |
| 143 // empty. |
| 144 DCHECK_EQ(0u, value_.size()); |
| 145 |
| 146 // Append to the current contents of the buffer. |
| 147 buffer_.append(data, len); |
| 148 return true; |
| 149 } |
| 150 |
| 151 bool HpackDecoderStringBuffer::OnEnd() { |
| 152 DVLOG(2) << "HpackDecoderStringBuffer::OnEnd"; |
| 153 DCHECK_EQ(state_, State::COLLECTING); |
| 154 DCHECK_EQ(0u, remaining_len_); |
| 155 |
| 156 if (is_huffman_encoded_) { |
| 157 DCHECK_EQ(backing_, Backing::BUFFERED); |
| 158 // Did the Huffman encoding of the string end properly? |
| 159 if (!decoder_.InputProperlyTerminated()) { |
| 160 return false; // No, it didn't. |
| 161 } |
| 162 } |
| 163 state_ = State::COMPLETE; |
| 164 if (backing_ == Backing::BUFFERED) { |
| 165 value_ = buffer_; |
| 166 } |
| 167 return true; |
| 168 } |
| 169 |
| 170 void HpackDecoderStringBuffer::BufferStringIfUnbuffered() { |
| 171 DVLOG(3) << "HpackDecoderStringBuffer::BufferStringIfUnbuffered state=" |
| 172 << state_ << ", backing=" << backing_; |
| 173 if (state_ != State::RESET && backing_ == Backing::UNBUFFERED) { |
| 174 DVLOG(2) << "HpackDecoderStringBuffer buffering string of length " |
| 175 << value_.size(); |
| 176 value_.CopyToString(&buffer_); |
| 177 if (state_ == State::COMPLETE) { |
| 178 value_ = buffer_; |
| 179 } |
| 180 backing_ = Backing::BUFFERED; |
| 181 } |
| 182 } |
| 183 |
| 184 size_t HpackDecoderStringBuffer::BufferedLength() const { |
| 185 DVLOG(3) << "HpackDecoderStringBuffer::BufferedLength"; |
| 186 return backing_ == Backing::BUFFERED ? buffer_.size() : 0; |
| 187 } |
| 188 |
| 189 StringPiece HpackDecoderStringBuffer::str() const { |
| 190 DVLOG(3) << "HpackDecoderStringBuffer::str"; |
| 191 DCHECK_EQ(state_, State::COMPLETE); |
| 192 return value_; |
| 193 } |
| 194 |
| 195 void HpackDecoderStringBuffer::OutputDebugStringTo(std::ostream& out) const { |
| 196 out << "{state=" << state_; |
| 197 if (state_ != State::RESET) { |
| 198 out << ", backing=" << backing_; |
| 199 out << ", remaining_len=" << remaining_len_; |
| 200 out << ", is_huffman_encoded=" << is_huffman_encoded_; |
| 201 if (backing_ == Backing::BUFFERED) { |
| 202 out << ", buffer: " << buffer_; |
| 203 } else { |
| 204 out << ", value: " << value_; |
| 205 } |
| 206 } |
| 207 out << "}"; |
| 208 } |
| 209 |
| 210 std::ostream& operator<<(std::ostream& out, const HpackDecoderStringBuffer& v) { |
| 211 v.OutputDebugStringTo(out); |
| 212 return out; |
| 213 } |
| 214 |
| 215 } // namespace net |
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