Transaction script and witness data parsing

.gitignore

@@ -1,8 +1,10 @@
 bestchain
 parser
+transaction
 *.dat
 *.d
 *.o
+*.dSYM
 include/hexxer.hpp
 include/ranger.hpp
 include/serial.hpp

Makefile

@@ -9,20 +9,24 @@ SOURCES=$(shell find src -name '*.c' -o -name '*.cpp')
 OBJECTS=$(addsuffix .o, $(basename $(SOURCES)))
 DEPENDENCIES=$(OBJECTS:.o=.d)
 INCLUDES=include/hexxer.hpp include/ranger.hpp include/serial.hpp include/threadpool.hpp
+PROGRAMS=bestchain parser transaction
 
 # TARGETS
 .PHONY: all clean includes
 
-all: $(INCLUDES) bestchain parser
+all: $(INCLUDES) bestchain parser transaction
 
 clean:
 	$(RM) $(INCLUDES) $(DEPENDENCIES) $(OBJECTS) bestchain parser
 
-bestchain: $(filter-out src/parser.o, $(OBJECTS))
-	$(CXX) $(filter-out src/parser.o, $(OBJECTS)) $(LFLAGS) $(OFLAGS) -o $@
+bestchain: $(filter-out src/parser.o src/transaction.o, $(OBJECTS))
+	$(CXX) $(filter-out src/parser.o src/transaction.o, $(OBJECTS)) $(LFLAGS) $(OFLAGS) -o $@
 
-parser: $(filter-out src/bestchain.o, $(OBJECTS))
-	$(CXX) $(filter-out src/bestchain.o, $(OBJECTS)) $(LFLAGS) $(OFLAGS) -pthread -o $@
+parser: $(filter-out src/bestchain.o src/transaction.o, $(OBJECTS))
+	$(CXX) $(filter-out src/bestchain.o src/transaction.o, $(OBJECTS)) $(LFLAGS) $(OFLAGS) -pthread -o $@
+
+transaction: $(filter-out src/bestchain.o src/parser.o, $(OBJECTS))
+	$(CXX) $(filter-out src/bestchain.o src/parser.o, $(OBJECTS)) $(LFLAGS) $(OFLAGS) -o $@
 
 # INFERENCES
 %.o: %.cpp

include/bitcoin-ops.hpp

@@ -137,6 +137,13 @@ enum OP {
     OP_NOP9 = 0xb8,
     OP_NOP10 = 0xb9,
 
+    // magic operators
+    OP_NOWITNESS = 0xe0,
+    OP_P2WPKH = 0xe2,
+    OP_P2WSH = 0xe3,
+
+    OP_ERROR = 0xf0,
+
     // template matching params
     OP_SMALLINTEGER = 0xfa,
     OP_PUBKEYS = 0xfb,
@@ -262,6 +269,13 @@ auto getOpString (const uint8_t opcode) {
     case OP_CHECKMULTISIG          : return "OP_CHECKMULTISIG";
     case OP_CHECKMULTISIGVERIFY    : return "OP_CHECKMULTISIGVERIFY";
 
+    // magic operators
+    case OP_NOWITNESS              : return "OP_NOWITNESS";
+    case OP_P2WPKH                 : return "OP_P2WPKH";
+    case OP_P2WSH                  : return "OP_P2WSH";
+
+    case OP_ERROR                   : return "OP_ERROR";
+
     // expansion
     case OP_NOP1                   : return "OP_NOP1";
     case OP_CHECKLOCKTIMEVERIFY    : return "OP_CHECKLOCKTIMEVERIFY";

include/bitcoin.hpp

@@ -19,7 +19,9 @@ struct TransactionBase {
 		R hash;
 		uint32_t vout;
 		R script;
+		std::vector<R> scriptStack;
 		uint32_t sequence;
+		uint8_t witnessFlag; // OP_NOWITNESS means not a witness program
 	};
 
 	struct Output {
@@ -111,11 +113,60 @@ namespace {
 			const auto vout = serial::read<uint32_t>(data);
 
 			const auto scriptLen = readVI(data);
+
+			__ranger::Range scriptRanger(data.begin(), data.begin() + scriptLen);
+
+			std::vector<R> scriptStack;
+
+			while(scriptRanger.size()) {
+
+				auto opcode = serial::read<uint8_t>(scriptRanger);
+
+				if(!opcode || opcode > OP_PUSHDATA4)
+					continue;
+
+				auto size = readPD(opcode, scriptRanger);
+
+				assert(size <= scriptRanger.size());
+
+				if(size > scriptRanger.size())
+					size = (uint32_t)scriptRanger.size();
+
+				scriptStack.push_back(readRange(scriptRanger, size));
+			}
+
 			const auto script = readRange(data, scriptLen);
 			const auto sequence = serial::read<uint32_t>(data);
 			isave.popBackN(data.size());
 
-			inputs.emplace_back(typename Transaction::Input{isave, hash, vout, script, sequence});
+			uint8_t witnessFlag = OP_NOWITNESS;
+
+			if(hasWitnesses) {
+
+				if(script.size() == 0) {
+
+					// In this case we must analyze witness data to determine the witness type.
+					// We'll check for OP_ERROR during witness data processing and set the type there.
+
+					witnessFlag = OP_ERROR;
+				}
+				else if(script.size() >= 3) {
+
+					// As per https://github.com/bitcoin/bips/blob/master/bip-0141.mediawiki#witness-program
+
+					if(script[0] > 2 && script[0] < 40 && script[1] == 0) {
+
+						if(script[2] == 0x14)
+							witnessFlag |= OP_P2WPKH;
+						else if(script[2] == 0x20)
+							witnessFlag |= OP_P2WSH;
+						else
+							witnessFlag = OP_ERROR;
+					}
+				}
+			}
+
+			inputs.emplace_back(typename Transaction::Input{isave, hash, vout, script, scriptStack, sequence, witnessFlag});
 		}
 
 		const auto nOutputs = readVI(data);
@@ -139,6 +190,22 @@ namespace {
 				wsave.popBackN(data.size());
 
 				witnesses.emplace_back(typename Transaction::Witness{wsave, std::move(stack)});
+
+				if(inputs[i].witnessFlag == OP_ERROR && !inputs[i].script.size()) {
+
+					// As stated in https://github.com/bitcoin/bips/blob/master/bip-0141.mediawiki#witness-program
+					//
+					// If the version byte is 0, and the witness program is 20 bytes:
+					// It is interpreted as a pay-to-witness-public-key-hash (P2WPKH) program.
+					// The witness must consist of exactly 2 items (≤ 520 bytes each). The first one a signature, and the second one a public key.
+
+					// We will check for exactly 2 items in witness stack to conform to above
+
+					if(witnesses.back().stack.size() == 2)
+						inputs[i].witnessFlag = OP_P2WPKH;
+					else if(witnesses.back().stack.size() > 2)
+						inputs[i].witnessFlag = OP_P2WSH;
+				}
 			}
 		}