1 // Copyright 2017 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 #ifndef QUICHE_SPDY_CORE_HPACK_HPACK_DECODER_ADAPTER_H_ 6 #define QUICHE_SPDY_CORE_HPACK_HPACK_DECODER_ADAPTER_H_ 7 8 // HpackDecoderAdapter uses http2::HpackDecoder to decode HPACK blocks into 9 // HTTP/2 header lists as outlined in http://tools.ietf.org/html/rfc7541. 10 11 #include <stddef.h> 12 13 #include <string> 14 15 #include "absl/strings/string_view.h" 16 #include "quiche/http2/hpack/decoder/hpack_decoder.h" 17 #include "quiche/http2/hpack/decoder/hpack_decoder_listener.h" 18 #include "quiche/http2/hpack/decoder/hpack_decoding_error.h" 19 #include "quiche/common/platform/api/quiche_export.h" 20 #include "quiche/spdy/core/http2_header_block.h" 21 #include "quiche/spdy/core/spdy_headers_handler_interface.h" 22 23 namespace spdy { 24 namespace test { 25 class HpackDecoderAdapterPeer; 26 } // namespace test 27 28 class QUICHE_EXPORT HpackDecoderAdapter { 29 public: 30 friend test::HpackDecoderAdapterPeer; 31 HpackDecoderAdapter(); 32 HpackDecoderAdapter(const HpackDecoderAdapter&) = delete; 33 HpackDecoderAdapter& operator=(const HpackDecoderAdapter&) = delete; 34 ~HpackDecoderAdapter(); 35 36 // Called upon acknowledgement of SETTINGS_HEADER_TABLE_SIZE. 37 void ApplyHeaderTableSizeSetting(size_t size_setting); 38 39 // Returns the most recently applied value of SETTINGS_HEADER_TABLE_SIZE. 40 size_t GetCurrentHeaderTableSizeSetting() const; 41 42 // If a SpdyHeadersHandlerInterface is provided, the decoder will emit 43 // headers to it rather than accumulating them in a Http2HeaderBlock. 44 // Does not take ownership of the handler, but does use the pointer until 45 // the current HPACK block is completely decoded. 46 void HandleControlFrameHeadersStart(SpdyHeadersHandlerInterface* handler); 47 48 // Called as HPACK block fragments arrive. Returns false if an error occurred 49 // while decoding the block. Does not take ownership of headers_data. 50 bool HandleControlFrameHeadersData(const char* headers_data, 51 size_t headers_data_length); 52 53 // Called after a HPACK block has been completely delivered via 54 // HandleControlFrameHeadersData(). Returns false if an error occurred. 55 // |compressed_len| if non-null will be set to the size of the encoded 56 // buffered block that was accumulated in HandleControlFrameHeadersData(), 57 // to support subsequent calculation of compression percentage. 58 // Discards the handler supplied at the start of decoding the block. 59 bool HandleControlFrameHeadersComplete(); 60 61 // Accessor for the most recently decoded headers block. Valid until the next 62 // call to HandleControlFrameHeadersData(). 63 // TODO(birenroy): Remove this method when all users of HpackDecoder specify 64 // a SpdyHeadersHandlerInterface. 65 const Http2HeaderBlock& decoded_block() const; 66 67 // Returns the current dynamic table size, including the 32 bytes per entry 68 // overhead mentioned in RFC 7541 section 4.1. GetDynamicTableSize()69 size_t GetDynamicTableSize() const { 70 return hpack_decoder_.GetDynamicTableSize(); 71 } 72 73 // Set how much encoded data this decoder is willing to buffer. 74 // TODO(jamessynge): Resolve definition of this value, as it is currently 75 // too tied to a single implementation. We probably want to limit one or more 76 // of these: individual name or value strings, header entries, the entire 77 // header list, or the HPACK block; we probably shouldn't care about the size 78 // of individual transport buffers. 79 void set_max_decode_buffer_size_bytes(size_t max_decode_buffer_size_bytes); 80 81 // Specifies the maximum size of an on-the-wire header block that will be 82 // accepted. 83 void set_max_header_block_bytes(size_t max_header_block_bytes); 84 85 // Error code if an error has occurred, Error::kOk otherwise. error()86 http2::HpackDecodingError error() const { return error_; } 87 detailed_error()88 std::string detailed_error() const { return detailed_error_; } 89 90 private: 91 class QUICHE_EXPORT ListenerAdapter : public http2::HpackDecoderListener { 92 public: 93 ListenerAdapter(); 94 ~ListenerAdapter() override; 95 96 // If a SpdyHeadersHandlerInterface is provided, the decoder will emit 97 // headers to it rather than accumulating them in a Http2HeaderBlock. 98 // Does not take ownership of the handler, but does use the pointer until 99 // the current HPACK block is completely decoded. 100 void set_handler(SpdyHeadersHandlerInterface* handler); decoded_block()101 const Http2HeaderBlock& decoded_block() const { return decoded_block_; } 102 103 // Override the HpackDecoderListener methods: 104 void OnHeaderListStart() override; 105 void OnHeader(const std::string& name, const std::string& value) override; 106 void OnHeaderListEnd() override; 107 void OnHeaderErrorDetected(absl::string_view error_message) override; 108 AddToTotalHpackBytes(size_t delta)109 void AddToTotalHpackBytes(size_t delta) { total_hpack_bytes_ += delta; } total_hpack_bytes()110 size_t total_hpack_bytes() const { return total_hpack_bytes_; } 111 112 private: 113 // If the caller doesn't provide a handler, the header list is stored in 114 // this Http2HeaderBlock. 115 Http2HeaderBlock decoded_block_; 116 117 // If non-NULL, handles decoded headers. Not owned. 118 SpdyHeadersHandlerInterface* handler_; 119 120 // Total bytes that have been received as input (i.e. HPACK encoded) 121 // in the current HPACK block. 122 size_t total_hpack_bytes_; 123 124 // Total bytes of the name and value strings in the current HPACK block. 125 size_t total_uncompressed_bytes_; 126 }; 127 128 // Converts calls to HpackDecoderListener into calls to 129 // SpdyHeadersHandlerInterface. 130 ListenerAdapter listener_adapter_; 131 132 // The actual decoder. 133 http2::HpackDecoder hpack_decoder_; 134 135 // How much encoded data this decoder is willing to buffer. 136 size_t max_decode_buffer_size_bytes_; 137 138 // How much encoded data this decoder is willing to process. 139 size_t max_header_block_bytes_; 140 141 // Flag to keep track of having seen the header block start. Needed at the 142 // moment because HandleControlFrameHeadersStart won't be called if a handler 143 // is not being provided by the caller. 144 bool header_block_started_; 145 146 // Error code if an error has occurred, Error::kOk otherwise. 147 http2::HpackDecodingError error_; 148 std::string detailed_error_; 149 }; 150 151 } // namespace spdy 152 153 #endif // QUICHE_SPDY_CORE_HPACK_HPACK_DECODER_ADAPTER_H_ 154