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-rw-r--r--src/HTTP/TransferEncodingParser.cpp393
1 files changed, 393 insertions, 0 deletions
diff --git a/src/HTTP/TransferEncodingParser.cpp b/src/HTTP/TransferEncodingParser.cpp
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+
+// TransferEncodingParser.cpp
+
+// Implements the cTransferEncodingParser class and its descendants representing the parser for the various transfer encodings (chunked etc.)
+
+#include "Globals.h"
+#include "TransferEncodingParser.h"
+#include "EnvelopeParser.h"
+
+
+
+
+
+////////////////////////////////////////////////////////////////////////////////
+// cChunkedTEParser:
+
+class cChunkedTEParser:
+ public cTransferEncodingParser,
+ public cEnvelopeParser::cCallbacks
+{
+ typedef cTransferEncodingParser Super;
+
+public:
+ cChunkedTEParser(Super::cCallbacks & a_Callbacks):
+ Super(a_Callbacks),
+ m_State(psChunkLength),
+ m_ChunkDataLengthLeft(0),
+ m_TrailerParser(*this)
+ {
+ }
+
+
+protected:
+ enum eState
+ {
+ psChunkLength, ///< Parsing the chunk length hex number
+ psChunkLengthTrailer, ///< Any trailer (chunk extension) specified after the chunk length
+ psChunkLengthLF, ///< The LF character after the CR character terminating the chunk length
+ psChunkData, ///< Relaying chunk data
+ psChunkDataCR, ///< Skipping the extra CR character after chunk data
+ psChunkDataLF, ///< Skipping the extra LF character after chunk data
+ psTrailer, ///< Received an empty chunk, parsing the trailer (through the envelope parser)
+ psFinished, ///< The parser has finished parsing, either successfully or with an error
+ };
+
+ /** The current state of the parser (parsing chunk length / chunk data). */
+ eState m_State;
+
+ /** Number of bytes that still belong to the chunk currently being parsed.
+ When in psChunkLength, the value is the currently parsed length digits. */
+ size_t m_ChunkDataLengthLeft;
+
+ cEnvelopeParser m_TrailerParser;
+
+
+ /** Calls the OnError callback and sets parser state to finished. */
+ void Error(const AString & a_ErrorMsg)
+ {
+ m_State = psFinished;
+ m_Callbacks.OnError(a_ErrorMsg);
+ }
+
+
+ /** Parses the incoming data, the current state is psChunkLength.
+ Stops parsing when either the chunk length has been read, or there is no more data in the input.
+ Returns the number of bytes consumed from the input, or AString::npos on error (calls the Error handler). */
+ size_t ParseChunkLength(const char * a_Data, size_t a_Size)
+ {
+ // Expected input: <hexnumber>[;<trailer>]<CR><LF>
+ // Only the hexnumber is parsed into m_ChunkDataLengthLeft, the rest is postponed into psChunkLengthTrailer or psChunkLengthLF
+ for (size_t i = 0; i < a_Size; i++)
+ {
+ switch (a_Data[i])
+ {
+ case '0':
+ case '1':
+ case '2':
+ case '3':
+ case '4':
+ case '5':
+ case '6':
+ case '7':
+ case '8':
+ case '9':
+ {
+ m_ChunkDataLengthLeft = m_ChunkDataLengthLeft * 16 + static_cast<decltype(m_ChunkDataLengthLeft)>(a_Data[i] - '0');
+ break;
+ }
+ case 'a':
+ case 'b':
+ case 'c':
+ case 'd':
+ case 'e':
+ case 'f':
+ {
+ m_ChunkDataLengthLeft = m_ChunkDataLengthLeft * 16 + static_cast<decltype(m_ChunkDataLengthLeft)>(a_Data[i] - 'a' + 10);
+ break;
+ }
+ case 'A':
+ case 'B':
+ case 'C':
+ case 'D':
+ case 'E':
+ case 'F':
+ {
+ m_ChunkDataLengthLeft = m_ChunkDataLengthLeft * 16 + static_cast<decltype(m_ChunkDataLengthLeft)>(a_Data[i] - 'A' + 10);
+ break;
+ }
+ case '\r':
+ {
+ m_State = psChunkLengthLF;
+ return i + 1;
+ }
+ case ';':
+ {
+ m_State = psChunkLengthTrailer;
+ return i + 1;
+ }
+ default:
+ {
+ Error(Printf("Invalid character in chunk length line: 0x%x", a_Data[i]));
+ return AString::npos;
+ }
+ } // switch (a_Data[i])
+ } // for i - a_Data[]
+ return a_Size;
+ }
+
+
+ /** Parses the incoming data, the current state is psChunkLengthTrailer.
+ Stops parsing when either the chunk length trailer has been read, or there is no more data in the input.
+ Returns the number of bytes consumed from the input, or AString::npos on error (calls the Error handler). */
+ size_t ParseChunkLengthTrailer(const char * a_Data, size_t a_Size)
+ {
+ // Expected input: <trailer><CR><LF>
+ // The LF itself is not parsed, it is instead postponed into psChunkLengthLF
+ for (size_t i = 0; i < a_Size; i++)
+ {
+ switch (a_Data[i])
+ {
+ case '\r':
+ {
+ m_State = psChunkLengthLF;
+ return i;
+ }
+ default:
+ {
+ if (a_Data[i] < 32)
+ {
+ // Only printable characters are allowed in the trailer
+ Error(Printf("Invalid character in chunk length line: 0x%x", a_Data[i]));
+ return AString::npos;
+ }
+ }
+ } // switch (a_Data[i])
+ } // for i - a_Data[]
+ return a_Size;
+ }
+
+
+ /** Parses the incoming data, the current state is psChunkLengthLF.
+ Only the LF character is expected, if found, moves to psChunkData, otherwise issues an error.
+ If the chunk length that just finished reading is equal to 0, signals the end of stream (via psTrailer).
+ Returns the number of bytes consumed from the input, or AString::npos on error (calls the Error handler). */
+ size_t ParseChunkLengthLF(const char * a_Data, size_t a_Size)
+ {
+ // Expected input: <LF>
+ if (a_Size == 0)
+ {
+ return 0;
+ }
+ if (a_Data[0] == '\n')
+ {
+ if (m_ChunkDataLengthLeft == 0)
+ {
+ m_State = psTrailer;
+ }
+ else
+ {
+ m_State = psChunkData;
+ }
+ return 1;
+ }
+ Error(Printf("Invalid character past chunk length's CR: 0x%x", a_Data[0]));
+ return AString::npos;
+ }
+
+
+ /** Consumes as much chunk data from the input as possible.
+ Returns the number of bytes consumed from the input, or AString::npos on error (calls the Error() handler). */
+ size_t ParseChunkData(const char * a_Data, size_t a_Size)
+ {
+ ASSERT(m_ChunkDataLengthLeft > 0);
+ auto bytes = std::min(a_Size, m_ChunkDataLengthLeft);
+ m_ChunkDataLengthLeft -= bytes;
+ m_Callbacks.OnBodyData(a_Data, bytes);
+ if (m_ChunkDataLengthLeft == 0)
+ {
+ m_State = psChunkDataCR;
+ }
+ return bytes;
+ }
+
+
+ /** Parses the incoming data, the current state is psChunkDataCR.
+ Only the CR character is expected, if found, moves to psChunkDataLF, otherwise issues an error.
+ Returns the number of bytes consumed from the input, or AString::npos on error (calls the Error handler). */
+ size_t ParseChunkDataCR(const char * a_Data, size_t a_Size)
+ {
+ // Expected input: <CR>
+ if (a_Size == 0)
+ {
+ return 0;
+ }
+ if (a_Data[0] == '\r')
+ {
+ m_State = psChunkDataLF;
+ return 1;
+ }
+ Error(Printf("Invalid character past chunk data: 0x%x", a_Data[0]));
+ return AString::npos;
+ }
+
+
+
+
+ /** Parses the incoming data, the current state is psChunkDataCR.
+ Only the CR character is expected, if found, moves to psChunkDataLF, otherwise issues an error.
+ Returns the number of bytes consumed from the input, or AString::npos on error (calls the Error handler). */
+ size_t ParseChunkDataLF(const char * a_Data, size_t a_Size)
+ {
+ // Expected input: <LF>
+ if (a_Size == 0)
+ {
+ return 0;
+ }
+ if (a_Data[0] == '\n')
+ {
+ m_State = psChunkLength;
+ return 1;
+ }
+ Error(Printf("Invalid character past chunk data's CR: 0x%x", a_Data[0]));
+ return AString::npos;
+ }
+
+
+ /** Parses the incoming data, the current state is psChunkDataCR.
+ The trailer is normally a set of "Header: Value" lines, terminated by an empty line. Use the m_TrailerParser for that.
+ Returns the number of bytes consumed from the input, or AString::npos on error (calls the Error handler). */
+ size_t ParseTrailer(const char * a_Data, size_t a_Size)
+ {
+ auto res = m_TrailerParser.Parse(a_Data, a_Size);
+ if (res == AString::npos)
+ {
+ Error("Error while parsing the trailer");
+ }
+ if ((res < a_Size) || !m_TrailerParser.IsInHeaders())
+ {
+ m_Callbacks.OnBodyFinished();
+ m_State = psFinished;
+ }
+ return res;
+ }
+
+
+ // cTransferEncodingParser overrides:
+ virtual size_t Parse(const char * a_Data, size_t a_Size) override
+ {
+ while ((a_Size > 0) && (m_State != psFinished))
+ {
+ size_t consumed = 0;
+ switch (m_State)
+ {
+ case psChunkLength: consumed = ParseChunkLength (a_Data, a_Size); break;
+ case psChunkLengthTrailer: consumed = ParseChunkLengthTrailer(a_Data, a_Size); break;
+ case psChunkLengthLF: consumed = ParseChunkLengthLF (a_Data, a_Size); break;
+ case psChunkData: consumed = ParseChunkData (a_Data, a_Size); break;
+ case psChunkDataCR: consumed = ParseChunkDataCR (a_Data, a_Size); break;
+ case psChunkDataLF: consumed = ParseChunkDataLF (a_Data, a_Size); break;
+ case psTrailer: consumed = ParseTrailer (a_Data, a_Size); break;
+ case psFinished: consumed = 0; break; // Not supposed to happen, but Clang complains without it
+ }
+ if (consumed == AString::npos)
+ {
+ return AString::npos;
+ }
+ a_Data += consumed;
+ a_Size -= consumed;
+ }
+ return a_Size;
+ }
+
+ virtual void Finish(void) override
+ {
+ if (m_State != psFinished)
+ {
+ Error(Printf("ChunkedTransferEncoding: Finish signal received before the data stream ended (state: %d)", m_State));
+ }
+ m_State = psFinished;
+ }
+
+
+ // cEnvelopeParser::cCallbacks overrides:
+ virtual void OnHeaderLine(const AString & a_Key, const AString & a_Value) override
+ {
+ // Ignored
+ }
+};
+
+
+
+
+
+////////////////////////////////////////////////////////////////////////////////
+// cIdentityTEParser:
+
+class cIdentityTEParser:
+ public cTransferEncodingParser
+{
+ typedef cTransferEncodingParser Super;
+
+public:
+ cIdentityTEParser(cCallbacks & a_Callbacks, size_t a_ContentLength):
+ Super(a_Callbacks),
+ m_BytesLeft(a_ContentLength)
+ {
+ }
+
+
+protected:
+ /** How many bytes of content are left before the message ends. */
+ size_t m_BytesLeft;
+
+ // cTransferEncodingParser overrides:
+ virtual size_t Parse(const char * a_Data, size_t a_Size) override
+ {
+ auto size = std::min(a_Size, m_BytesLeft);
+ if (size > 0)
+ {
+ m_Callbacks.OnBodyData(a_Data, size);
+ }
+ m_BytesLeft -= size;
+ if (m_BytesLeft == 0)
+ {
+ m_Callbacks.OnBodyFinished();
+ }
+ return a_Size - size;
+ }
+
+ virtual void Finish(void) override
+ {
+ if (m_BytesLeft > 0)
+ {
+ m_Callbacks.OnError("IdentityTransferEncoding: body was truncated");
+ }
+ else
+ {
+ // BodyFinished has already been called, just bail out
+ }
+ }
+};
+
+
+
+
+
+////////////////////////////////////////////////////////////////////////////////
+// cTransferEncodingParser:
+
+cTransferEncodingParserPtr cTransferEncodingParser::Create(
+ cCallbacks & a_Callbacks,
+ const AString & a_TransferEncoding,
+ size_t a_ContentLength
+)
+{
+ if (a_TransferEncoding == "chunked")
+ {
+ return std::make_shared<cChunkedTEParser>(a_Callbacks);
+ }
+ if (a_TransferEncoding == "identity")
+ {
+ return std::make_shared<cIdentityTEParser>(a_Callbacks, a_ContentLength);
+ }
+ if (a_TransferEncoding.empty())
+ {
+ return std::make_shared<cIdentityTEParser>(a_Callbacks, a_ContentLength);
+ }
+ return nullptr;
+}
+
+
+
+