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// Copyright 2016 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/third_party/quiche/src/http2/hpack/decoder/hpack_decoder_string_buffer.h"
#include <utility>
#include "net/third_party/quiche/src/http2/platform/api/http2_bug_tracker.h"
#include "net/third_party/quiche/src/http2/platform/api/http2_estimate_memory_usage.h"
#include "net/third_party/quiche/src/http2/platform/api/http2_logging.h"
namespace http2 {
std::ostream& operator<<(std::ostream& out,
const HpackDecoderStringBuffer::State v) {
switch (v) {
case HpackDecoderStringBuffer::State::RESET:
return out << "RESET";
case HpackDecoderStringBuffer::State::COLLECTING:
return out << "COLLECTING";
case HpackDecoderStringBuffer::State::COMPLETE:
return out << "COMPLETE";
}
// Since the value doesn't come over the wire, only a programming bug should
// result in reaching this point.
int unknown = static_cast<int>(v);
HTTP2_BUG << "Invalid HpackDecoderStringBuffer::State: " << unknown;
return out << "HpackDecoderStringBuffer::State(" << unknown << ")";
}
std::ostream& operator<<(std::ostream& out,
const HpackDecoderStringBuffer::Backing v) {
switch (v) {
case HpackDecoderStringBuffer::Backing::RESET:
return out << "RESET";
case HpackDecoderStringBuffer::Backing::UNBUFFERED:
return out << "UNBUFFERED";
case HpackDecoderStringBuffer::Backing::BUFFERED:
return out << "BUFFERED";
case HpackDecoderStringBuffer::Backing::STATIC:
return out << "STATIC";
}
// Since the value doesn't come over the wire, only a programming bug should
// result in reaching this point.
auto v2 = static_cast<int>(v);
HTTP2_BUG << "Invalid HpackDecoderStringBuffer::Backing: " << v2;
return out << "HpackDecoderStringBuffer::Backing(" << v2 << ")";
}
HpackDecoderStringBuffer::HpackDecoderStringBuffer()
: remaining_len_(0),
is_huffman_encoded_(false),
state_(State::RESET),
backing_(Backing::RESET) {}
HpackDecoderStringBuffer::~HpackDecoderStringBuffer() = default;
void HpackDecoderStringBuffer::Reset() {
HTTP2_DVLOG(3) << "HpackDecoderStringBuffer::Reset";
state_ = State::RESET;
}
void HpackDecoderStringBuffer::Set(quiche::QuicheStringPiece value,
bool is_static) {
HTTP2_DVLOG(2) << "HpackDecoderStringBuffer::Set";
DCHECK_EQ(state_, State::RESET);
value_ = value;
state_ = State::COMPLETE;
backing_ = is_static ? Backing::STATIC : Backing::UNBUFFERED;
// TODO(jamessynge): Determine which of these two fields must be set.
remaining_len_ = 0;
is_huffman_encoded_ = false;
}
void HpackDecoderStringBuffer::OnStart(bool huffman_encoded, size_t len) {
HTTP2_DVLOG(2) << "HpackDecoderStringBuffer::OnStart";
DCHECK_EQ(state_, State::RESET);
remaining_len_ = len;
is_huffman_encoded_ = huffman_encoded;
state_ = State::COLLECTING;
if (huffman_encoded) {
// We don't set, clear or use value_ for buffered strings until OnEnd.
decoder_.Reset();
buffer_.clear();
backing_ = Backing::BUFFERED;
// Reserve space in buffer_ for the uncompressed string, assuming the
// maximum expansion. The shortest Huffman codes in the RFC are 5 bits long,
// which then expand to 8 bits during decoding (i.e. each code is for one
// plain text octet, aka byte), so the maximum size is 60% longer than the
// encoded size.
len = len * 8 / 5;
if (buffer_.capacity() < len) {
buffer_.reserve(len);
}
} else {
// Assume for now that we won't need to use buffer_, so don't reserve space
// in it.
backing_ = Backing::RESET;
// OnData is not called for empty (zero length) strings, so make sure that
// value_ is cleared.
value_ = quiche::QuicheStringPiece();
}
}
bool HpackDecoderStringBuffer::OnData(const char* data, size_t len) {
HTTP2_DVLOG(2) << "HpackDecoderStringBuffer::OnData state=" << state_
<< ", backing=" << backing_;
DCHECK_EQ(state_, State::COLLECTING);
DCHECK_LE(len, remaining_len_);
remaining_len_ -= len;
if (is_huffman_encoded_) {
DCHECK_EQ(backing_, Backing::BUFFERED);
return decoder_.Decode(quiche::QuicheStringPiece(data, len), &buffer_);
}
if (backing_ == Backing::RESET) {
// This is the first call to OnData. If data contains the entire string,
// don't copy the string. If we later find that the HPACK entry is split
// across input buffers, then we'll copy the string into buffer_.
if (remaining_len_ == 0) {
value_ = quiche::QuicheStringPiece(data, len);
backing_ = Backing::UNBUFFERED;
return true;
}
// We need to buffer the string because it is split across input buffers.
// Reserve space in buffer_ for the entire string.
backing_ = Backing::BUFFERED;
buffer_.reserve(remaining_len_ + len);
buffer_.assign(data, len);
return true;
}
// This is not the first call to OnData for this string, so it should be
// buffered.
DCHECK_EQ(backing_, Backing::BUFFERED);
// Append to the current contents of the buffer.
buffer_.append(data, len);
return true;
}
bool HpackDecoderStringBuffer::OnEnd() {
HTTP2_DVLOG(2) << "HpackDecoderStringBuffer::OnEnd";
DCHECK_EQ(state_, State::COLLECTING);
DCHECK_EQ(0u, remaining_len_);
if (is_huffman_encoded_) {
DCHECK_EQ(backing_, Backing::BUFFERED);
// Did the Huffman encoding of the string end properly?
if (!decoder_.InputProperlyTerminated()) {
return false; // No, it didn't.
}
value_ = buffer_;
} else if (backing_ == Backing::BUFFERED) {
value_ = buffer_;
}
state_ = State::COMPLETE;
return true;
}
void HpackDecoderStringBuffer::BufferStringIfUnbuffered() {
HTTP2_DVLOG(3) << "HpackDecoderStringBuffer::BufferStringIfUnbuffered state="
<< state_ << ", backing=" << backing_;
if (state_ != State::RESET && backing_ == Backing::UNBUFFERED) {
HTTP2_DVLOG(2)
<< "HpackDecoderStringBuffer buffering std::string of length "
<< value_.size();
buffer_.assign(value_.data(), value_.size());
if (state_ == State::COMPLETE) {
value_ = buffer_;
}
backing_ = Backing::BUFFERED;
}
}
bool HpackDecoderStringBuffer::IsBuffered() const {
HTTP2_DVLOG(3) << "HpackDecoderStringBuffer::IsBuffered";
return state_ != State::RESET && backing_ == Backing::BUFFERED;
}
size_t HpackDecoderStringBuffer::BufferedLength() const {
HTTP2_DVLOG(3) << "HpackDecoderStringBuffer::BufferedLength";
return IsBuffered() ? buffer_.size() : 0;
}
quiche::QuicheStringPiece HpackDecoderStringBuffer::str() const {
HTTP2_DVLOG(3) << "HpackDecoderStringBuffer::str";
DCHECK_EQ(state_, State::COMPLETE);
return value_;
}
quiche::QuicheStringPiece HpackDecoderStringBuffer::GetStringIfComplete()
const {
if (state_ != State::COMPLETE) {
return {};
}
return str();
}
std::string HpackDecoderStringBuffer::ReleaseString() {
HTTP2_DVLOG(3) << "HpackDecoderStringBuffer::ReleaseString";
DCHECK_EQ(state_, State::COMPLETE);
DCHECK_EQ(backing_, Backing::BUFFERED);
if (state_ == State::COMPLETE) {
state_ = State::RESET;
if (backing_ == Backing::BUFFERED) {
return std::move(buffer_);
} else {
return std::string(value_);
}
}
return "";
}
void HpackDecoderStringBuffer::OutputDebugStringTo(std::ostream& out) const {
out << "{state=" << state_;
if (state_ != State::RESET) {
out << ", backing=" << backing_;
out << ", remaining_len=" << remaining_len_;
out << ", is_huffman_encoded=" << is_huffman_encoded_;
if (backing_ == Backing::BUFFERED) {
out << ", buffer: " << buffer_;
} else {
out << ", value: " << value_;
}
}
out << "}";
}
size_t HpackDecoderStringBuffer::EstimateMemoryUsage() const {
return Http2EstimateMemoryUsage(buffer_);
}
std::ostream& operator<<(std::ostream& out, const HpackDecoderStringBuffer& v) {
v.OutputDebugStringTo(out);
return out;
}
} // namespace http2
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