http2/hpack/decoder/hpack_entry_decoder.cc - quiche - Git at Google

 // 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 "http2/hpack/decoder/hpack_entry_decoder.h"

 #include <stddef.h>

 #include <cstdint>

 #include "http2/platform/api/http2_bug_tracker.h"
 #include "http2/platform/api/http2_flag_utils.h"
 #include "http2/platform/api/http2_flags.h"
 #include "http2/platform/api/http2_logging.h"
 #include "http2/platform/api/http2_macros.h"

 namespace http2 {
 namespace {
 // Converts calls from HpackStringDecoder when decoding a header name into the
 // appropriate HpackEntryDecoderListener::OnName* calls.
 class NameDecoderListener {
  public:
   explicit NameDecoderListener(HpackEntryDecoderListener* listener)
       : listener_(listener) {}
   bool OnStringStart(bool huffman_encoded, size_t len) {
     listener_->OnNameStart(huffman_encoded, len);
     return true;
   }
   void OnStringData(const char* data, size_t len) {
     listener_->OnNameData(data, len);
   }
   void OnStringEnd() { listener_->OnNameEnd(); }

  private:
   HpackEntryDecoderListener* listener_;
 };

 // Converts calls from HpackStringDecoder when decoding a header value into
 // the appropriate HpackEntryDecoderListener::OnValue* calls.
 class ValueDecoderListener {
  public:
   explicit ValueDecoderListener(HpackEntryDecoderListener* listener)
       : listener_(listener) {}
   bool OnStringStart(bool huffman_encoded, size_t len) {
     listener_->OnValueStart(huffman_encoded, len);
     return true;
   }
   void OnStringData(const char* data, size_t len) {
     listener_->OnValueData(data, len);
   }
   void OnStringEnd() { listener_->OnValueEnd(); }

  private:
   HpackEntryDecoderListener* listener_;
 };
 }  // namespace

 DecodeStatus HpackEntryDecoder::Start(DecodeBuffer* db,
                                       HpackEntryDecoderListener* listener) {
   DCHECK(db != nullptr);
   DCHECK(listener != nullptr);
   DCHECK(db->HasData());
   DecodeStatus status = entry_type_decoder_.Start(db);
   switch (status) {
     case DecodeStatus::kDecodeDone:
       // The type of the entry and its varint fit into the current decode
       // buffer.
       if (entry_type_decoder_.entry_type() == HpackEntryType::kIndexedHeader) {
         // The entry consists solely of the entry type and varint.
         // This is by far the most common case in practice.
         listener->OnIndexedHeader(entry_type_decoder_.varint());
         return DecodeStatus::kDecodeDone;
       }
       state_ = EntryDecoderState::kDecodedType;
       return Resume(db, listener);
     case DecodeStatus::kDecodeInProgress:
       // Hit the end of the decode buffer before fully decoding
       // the entry type and varint.
       DCHECK_EQ(0u, db->Remaining());
       state_ = EntryDecoderState::kResumeDecodingType;
       return status;
     case DecodeStatus::kDecodeError:
       HTTP2_CODE_COUNT_N(decompress_failure_3, 11, 23);
       error_ = HpackDecodingError::kIndexVarintError;
       // The varint must have been invalid (too long).
       return status;
   }

   HTTP2_BUG << "Unreachable";
   return DecodeStatus::kDecodeError;
 }

 DecodeStatus HpackEntryDecoder::Resume(DecodeBuffer* db,
                                        HpackEntryDecoderListener* listener) {
   DCHECK(db != nullptr);
   DCHECK(listener != nullptr);

   DecodeStatus status;

   do {
     switch (state_) {
       case EntryDecoderState::kResumeDecodingType:
         // entry_type_decoder_ returned kDecodeInProgress when last called.
         HTTP2_DVLOG(1) << "kResumeDecodingType: db->Remaining="
                        << db->Remaining();
         status = entry_type_decoder_.Resume(db);
         if (status == DecodeStatus::kDecodeError) {
           HTTP2_CODE_COUNT_N(decompress_failure_3, 12, 23);
           error_ = HpackDecodingError::kIndexVarintError;
         }
         if (status != DecodeStatus::kDecodeDone) {
           return status;
         }
         state_ = EntryDecoderState::kDecodedType;
         HTTP2_FALLTHROUGH;

       case EntryDecoderState::kDecodedType:
         // entry_type_decoder_ returned kDecodeDone, now need to decide how
         // to proceed.
         HTTP2_DVLOG(1) << "kDecodedType: db->Remaining=" << db->Remaining();
         if (DispatchOnType(listener)) {
           // All done.
           return DecodeStatus::kDecodeDone;
         }
         continue;

       case EntryDecoderState::kStartDecodingName:
         HTTP2_DVLOG(1) << "kStartDecodingName: db->Remaining="
                        << db->Remaining();
         {
           NameDecoderListener ncb(listener);
           status = string_decoder_.Start(db, &ncb);
         }
         if (status != DecodeStatus::kDecodeDone) {
           // On the assumption that the status is kDecodeInProgress, set
           // state_ accordingly; unnecessary if status is kDecodeError, but
           // that will only happen if the varint encoding the name's length
           // is too long.
           state_ = EntryDecoderState::kResumeDecodingName;
           if (status == DecodeStatus::kDecodeError) {
             HTTP2_CODE_COUNT_N(decompress_failure_3, 13, 23);
             error_ = HpackDecodingError::kNameLengthVarintError;
           }
           return status;
         }
         state_ = EntryDecoderState::kStartDecodingValue;
         HTTP2_FALLTHROUGH;

       case EntryDecoderState::kStartDecodingValue:
         HTTP2_DVLOG(1) << "kStartDecodingValue: db->Remaining="
                        << db->Remaining();
         {
           ValueDecoderListener vcb(listener);
           status = string_decoder_.Start(db, &vcb);
         }
         if (status == DecodeStatus::kDecodeError) {
           HTTP2_CODE_COUNT_N(decompress_failure_3, 14, 23);
           error_ = HpackDecodingError::kValueLengthVarintError;
         }
         if (status == DecodeStatus::kDecodeDone) {
           // Done with decoding the literal value, so we've reached the
           // end of the header entry.
           return status;
         }
         // On the assumption that the status is kDecodeInProgress, set
         // state_ accordingly; unnecessary if status is kDecodeError, but
         // that will only happen if the varint encoding the value's length
         // is too long.
         state_ = EntryDecoderState::kResumeDecodingValue;
         return status;

       case EntryDecoderState::kResumeDecodingName:
         // The literal name was split across decode buffers.
         HTTP2_DVLOG(1) << "kResumeDecodingName: db->Remaining="
                        << db->Remaining();
         {
           NameDecoderListener ncb(listener);
           status = string_decoder_.Resume(db, &ncb);
         }
         if (status != DecodeStatus::kDecodeDone) {
           // On the assumption that the status is kDecodeInProgress, set
           // state_ accordingly; unnecessary if status is kDecodeError, but
           // that will only happen if the varint encoding the name's length
           // is too long.
           state_ = EntryDecoderState::kResumeDecodingName;
           if (status == DecodeStatus::kDecodeError) {
             HTTP2_CODE_COUNT_N(decompress_failure_3, 15, 23);
             error_ = HpackDecodingError::kNameLengthVarintError;
           }
           return status;
         }
         state_ = EntryDecoderState::kStartDecodingValue;
         break;

       case EntryDecoderState::kResumeDecodingValue:
         // The literal value was split across decode buffers.
         HTTP2_DVLOG(1) << "kResumeDecodingValue: db->Remaining="
                        << db->Remaining();
         {
           ValueDecoderListener vcb(listener);
           status = string_decoder_.Resume(db, &vcb);
         }
         if (status == DecodeStatus::kDecodeError) {
           HTTP2_CODE_COUNT_N(decompress_failure_3, 16, 23);
           error_ = HpackDecodingError::kValueLengthVarintError;
         }
         if (status == DecodeStatus::kDecodeDone) {
           // Done with decoding the value, therefore the entry as a whole.
           return status;
         }
         // On the assumption that the status is kDecodeInProgress, set
         // state_ accordingly; unnecessary if status is kDecodeError, but
         // that will only happen if the varint encoding the value's length
         // is too long.
         state_ = EntryDecoderState::kResumeDecodingValue;
         return status;
     }
   } while (true);
 }

 bool HpackEntryDecoder::DispatchOnType(HpackEntryDecoderListener* listener) {
   const HpackEntryType entry_type = entry_type_decoder_.entry_type();
   const uint32_t varint = static_cast<uint32_t>(entry_type_decoder_.varint());
   switch (entry_type) {
     case HpackEntryType::kIndexedHeader:
       // The entry consists solely of the entry type and varint. See:
       // http://httpwg.org/specs/rfc7541.html#indexed.header.representation
       listener->OnIndexedHeader(varint);
       return true;

     case HpackEntryType::kIndexedLiteralHeader:
     case HpackEntryType::kUnindexedLiteralHeader:
     case HpackEntryType::kNeverIndexedLiteralHeader:
       // The entry has a literal value, and if the varint is zero also has a
       // literal name preceding the value. See:
       // http://httpwg.org/specs/rfc7541.html#literal.header.representation
       listener->OnStartLiteralHeader(entry_type, varint);
       if (varint == 0) {
         state_ = EntryDecoderState::kStartDecodingName;
       } else {
         state_ = EntryDecoderState::kStartDecodingValue;
       }
       return false;

     case HpackEntryType::kDynamicTableSizeUpdate:
       // The entry consists solely of the entry type and varint. FWIW, I've
       // never seen this type of entry in production (primarily browser
       // traffic) so if you're designing an HPACK successor someday, consider
       // dropping it or giving it a much longer prefix. See:
       // http://httpwg.org/specs/rfc7541.html#encoding.context.update
       listener->OnDynamicTableSizeUpdate(varint);
       return true;
   }

   HTTP2_BUG << "Unreachable, entry_type=" << entry_type;
   return true;
 }

 void HpackEntryDecoder::OutputDebugString(std::ostream& out) const {
   out << "HpackEntryDecoder(state=" << state_ << ", " << entry_type_decoder_
       << ", " << string_decoder_ << ")";
 }

 std::string HpackEntryDecoder::DebugString() const {
   std::stringstream s;
   s << *this;
   return s.str();
 }

 std::ostream& operator<<(std::ostream& out, const HpackEntryDecoder& v) {
   v.OutputDebugString(out);
   return out;
 }

 std::ostream& operator<<(std::ostream& out,
                          HpackEntryDecoder::EntryDecoderState state) {
   typedef HpackEntryDecoder::EntryDecoderState EntryDecoderState;
   switch (state) {
     case EntryDecoderState::kResumeDecodingType:
       return out << "kResumeDecodingType";
     case EntryDecoderState::kDecodedType:
       return out << "kDecodedType";
     case EntryDecoderState::kStartDecodingName:
       return out << "kStartDecodingName";
     case EntryDecoderState::kResumeDecodingName:
       return out << "kResumeDecodingName";
     case EntryDecoderState::kStartDecodingValue:
       return out << "kStartDecodingValue";
     case EntryDecoderState::kResumeDecodingValue:
       return out << "kResumeDecodingValue";
   }
   return out << static_cast<int>(state);
 }

 }  // namespace http2
	// 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 "http2/hpack/decoder/hpack_entry_decoder.h"

	#include <stddef.h>

	#include <cstdint>

	#include "http2/platform/api/http2_bug_tracker.h"
	#include "http2/platform/api/http2_flag_utils.h"
	#include "http2/platform/api/http2_flags.h"
	#include "http2/platform/api/http2_logging.h"
	#include "http2/platform/api/http2_macros.h"

	namespace http2 {
	namespace {
	// Converts calls from HpackStringDecoder when decoding a header name into the
	// appropriate HpackEntryDecoderListener::OnName* calls.
	class NameDecoderListener {
	public:
	explicit NameDecoderListener(HpackEntryDecoderListener* listener)
	: listener_(listener) {}
	bool OnStringStart(bool huffman_encoded, size_t len) {
	listener_->OnNameStart(huffman_encoded, len);
	return true;
	}
	void OnStringData(const char* data, size_t len) {
	listener_->OnNameData(data, len);
	}
	void OnStringEnd() { listener_->OnNameEnd(); }

	private:
	HpackEntryDecoderListener* listener_;
	};

	// Converts calls from HpackStringDecoder when decoding a header value into
	// the appropriate HpackEntryDecoderListener::OnValue* calls.
	class ValueDecoderListener {
	public:
	explicit ValueDecoderListener(HpackEntryDecoderListener* listener)
	: listener_(listener) {}
	bool OnStringStart(bool huffman_encoded, size_t len) {
	listener_->OnValueStart(huffman_encoded, len);
	return true;
	}
	void OnStringData(const char* data, size_t len) {
	listener_->OnValueData(data, len);
	}
	void OnStringEnd() { listener_->OnValueEnd(); }

	private:
	HpackEntryDecoderListener* listener_;
	};
	} // namespace

	DecodeStatus HpackEntryDecoder::Start(DecodeBuffer* db,
	HpackEntryDecoderListener* listener) {
	DCHECK(db != nullptr);
	DCHECK(listener != nullptr);
	DCHECK(db->HasData());
	DecodeStatus status = entry_type_decoder_.Start(db);
	switch (status) {
	case DecodeStatus::kDecodeDone:
	// The type of the entry and its varint fit into the current decode
	// buffer.
	if (entry_type_decoder_.entry_type() == HpackEntryType::kIndexedHeader) {
	// The entry consists solely of the entry type and varint.
	// This is by far the most common case in practice.
	listener->OnIndexedHeader(entry_type_decoder_.varint());
	return DecodeStatus::kDecodeDone;
	}
	state_ = EntryDecoderState::kDecodedType;
	return Resume(db, listener);
	case DecodeStatus::kDecodeInProgress:
	// Hit the end of the decode buffer before fully decoding
	// the entry type and varint.
	DCHECK_EQ(0u, db->Remaining());
	state_ = EntryDecoderState::kResumeDecodingType;
	return status;
	case DecodeStatus::kDecodeError:
	HTTP2_CODE_COUNT_N(decompress_failure_3, 11, 23);
	error_ = HpackDecodingError::kIndexVarintError;
	// The varint must have been invalid (too long).
	return status;
	}

	HTTP2_BUG << "Unreachable";
	return DecodeStatus::kDecodeError;
	}

	DecodeStatus HpackEntryDecoder::Resume(DecodeBuffer* db,
	HpackEntryDecoderListener* listener) {
	DCHECK(db != nullptr);
	DCHECK(listener != nullptr);

	DecodeStatus status;

	do {
	switch (state_) {
	case EntryDecoderState::kResumeDecodingType:
	// entry_type_decoder_ returned kDecodeInProgress when last called.
	HTTP2_DVLOG(1) << "kResumeDecodingType: db->Remaining="
	<< db->Remaining();
	status = entry_type_decoder_.Resume(db);
	if (status == DecodeStatus::kDecodeError) {
	HTTP2_CODE_COUNT_N(decompress_failure_3, 12, 23);
	error_ = HpackDecodingError::kIndexVarintError;
	}
	if (status != DecodeStatus::kDecodeDone) {
	return status;
	}
	state_ = EntryDecoderState::kDecodedType;
	HTTP2_FALLTHROUGH;

	case EntryDecoderState::kDecodedType:
	// entry_type_decoder_ returned kDecodeDone, now need to decide how
	// to proceed.
	HTTP2_DVLOG(1) << "kDecodedType: db->Remaining=" << db->Remaining();
	if (DispatchOnType(listener)) {
	// All done.
	return DecodeStatus::kDecodeDone;
	}
	continue;

	case EntryDecoderState::kStartDecodingName:
	HTTP2_DVLOG(1) << "kStartDecodingName: db->Remaining="
	<< db->Remaining();
	{
	NameDecoderListener ncb(listener);
	status = string_decoder_.Start(db, &ncb);
	}
	if (status != DecodeStatus::kDecodeDone) {
	// On the assumption that the status is kDecodeInProgress, set
	// state_ accordingly; unnecessary if status is kDecodeError, but
	// that will only happen if the varint encoding the name's length
	// is too long.
	state_ = EntryDecoderState::kResumeDecodingName;
	if (status == DecodeStatus::kDecodeError) {
	HTTP2_CODE_COUNT_N(decompress_failure_3, 13, 23);
	error_ = HpackDecodingError::kNameLengthVarintError;
	}
	return status;
	}
	state_ = EntryDecoderState::kStartDecodingValue;
	HTTP2_FALLTHROUGH;

	case EntryDecoderState::kStartDecodingValue:
	HTTP2_DVLOG(1) << "kStartDecodingValue: db->Remaining="
	<< db->Remaining();
	{
	ValueDecoderListener vcb(listener);
	status = string_decoder_.Start(db, &vcb);
	}
	if (status == DecodeStatus::kDecodeError) {
	HTTP2_CODE_COUNT_N(decompress_failure_3, 14, 23);
	error_ = HpackDecodingError::kValueLengthVarintError;
	}
	if (status == DecodeStatus::kDecodeDone) {
	// Done with decoding the literal value, so we've reached the
	// end of the header entry.
	return status;
	}
	// On the assumption that the status is kDecodeInProgress, set
	// state_ accordingly; unnecessary if status is kDecodeError, but
	// that will only happen if the varint encoding the value's length
	// is too long.
	state_ = EntryDecoderState::kResumeDecodingValue;
	return status;

	case EntryDecoderState::kResumeDecodingName:
	// The literal name was split across decode buffers.
	HTTP2_DVLOG(1) << "kResumeDecodingName: db->Remaining="
	<< db->Remaining();
	{
	NameDecoderListener ncb(listener);
	status = string_decoder_.Resume(db, &ncb);
	}
	if (status != DecodeStatus::kDecodeDone) {
	// On the assumption that the status is kDecodeInProgress, set
	// state_ accordingly; unnecessary if status is kDecodeError, but
	// that will only happen if the varint encoding the name's length
	// is too long.
	state_ = EntryDecoderState::kResumeDecodingName;
	if (status == DecodeStatus::kDecodeError) {
	HTTP2_CODE_COUNT_N(decompress_failure_3, 15, 23);
	error_ = HpackDecodingError::kNameLengthVarintError;
	}
	return status;
	}
	state_ = EntryDecoderState::kStartDecodingValue;
	break;

	case EntryDecoderState::kResumeDecodingValue:
	// The literal value was split across decode buffers.
	HTTP2_DVLOG(1) << "kResumeDecodingValue: db->Remaining="
	<< db->Remaining();
	{
	ValueDecoderListener vcb(listener);
	status = string_decoder_.Resume(db, &vcb);
	}
	if (status == DecodeStatus::kDecodeError) {
	HTTP2_CODE_COUNT_N(decompress_failure_3, 16, 23);
	error_ = HpackDecodingError::kValueLengthVarintError;
	}
	if (status == DecodeStatus::kDecodeDone) {
	// Done with decoding the value, therefore the entry as a whole.
	return status;
	}
	// On the assumption that the status is kDecodeInProgress, set
	// state_ accordingly; unnecessary if status is kDecodeError, but
	// that will only happen if the varint encoding the value's length
	// is too long.
	state_ = EntryDecoderState::kResumeDecodingValue;
	return status;
	}
	} while (true);
	}

	bool HpackEntryDecoder::DispatchOnType(HpackEntryDecoderListener* listener) {
	const HpackEntryType entry_type = entry_type_decoder_.entry_type();
	const uint32_t varint = static_cast<uint32_t>(entry_type_decoder_.varint());
	switch (entry_type) {
	case HpackEntryType::kIndexedHeader:
	// The entry consists solely of the entry type and varint. See:
	// http://httpwg.org/specs/rfc7541.html#indexed.header.representation
	listener->OnIndexedHeader(varint);
	return true;

	case HpackEntryType::kIndexedLiteralHeader:
	case HpackEntryType::kUnindexedLiteralHeader:
	case HpackEntryType::kNeverIndexedLiteralHeader:
	// The entry has a literal value, and if the varint is zero also has a
	// literal name preceding the value. See:
	// http://httpwg.org/specs/rfc7541.html#literal.header.representation
	listener->OnStartLiteralHeader(entry_type, varint);
	if (varint == 0) {
	state_ = EntryDecoderState::kStartDecodingName;
	} else {
	state_ = EntryDecoderState::kStartDecodingValue;
	}
	return false;

	case HpackEntryType::kDynamicTableSizeUpdate:
	// The entry consists solely of the entry type and varint. FWIW, I've
	// never seen this type of entry in production (primarily browser
	// traffic) so if you're designing an HPACK successor someday, consider
	// dropping it or giving it a much longer prefix. See:
	// http://httpwg.org/specs/rfc7541.html#encoding.context.update
	listener->OnDynamicTableSizeUpdate(varint);
	return true;
	}

	HTTP2_BUG << "Unreachable, entry_type=" << entry_type;
	return true;
	}

	void HpackEntryDecoder::OutputDebugString(std::ostream& out) const {
	out << "HpackEntryDecoder(state=" << state_ << ", " << entry_type_decoder_
	<< ", " << string_decoder_ << ")";
	}

	std::string HpackEntryDecoder::DebugString() const {
	std::stringstream s;
	s << *this;
	return s.str();
	}

	std::ostream& operator<<(std::ostream& out, const HpackEntryDecoder& v) {
	v.OutputDebugString(out);
	return out;
	}

	std::ostream& operator<<(std::ostream& out,
	HpackEntryDecoder::EntryDecoderState state) {
	typedef HpackEntryDecoder::EntryDecoderState EntryDecoderState;
	switch (state) {
	case EntryDecoderState::kResumeDecodingType:
	return out << "kResumeDecodingType";
	case EntryDecoderState::kDecodedType:
	return out << "kDecodedType";
	case EntryDecoderState::kStartDecodingName:
	return out << "kStartDecodingName";
	case EntryDecoderState::kResumeDecodingName:
	return out << "kResumeDecodingName";
	case EntryDecoderState::kStartDecodingValue:
	return out << "kStartDecodingValue";
	case EntryDecoderState::kResumeDecodingValue:
	return out << "kResumeDecodingValue";
	}
	return out << static_cast<int>(state);
	}

	} // namespace http2