1 files changed, 86 insertions, 0 deletions
diff --git a/eth/tracers/internal/tracers/4byte_tracer.js b/eth/tracers/internal/tracers/4byte_tracer.js
new file mode 100644
index 0000000..462b4ad
--- /dev/null
+++ b/eth/tracers/internal/tracers/4byte_tracer.js
@@ -0,0 +1,86 @@
+// Copyright 2017 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// 4byteTracer searches for 4byte-identifiers, and collects them for post-processing.
+// It collects the methods identifiers along with the size of the supplied data, so
+// a reversed signature can be matched against the size of the data.
+//
+// Example:
+//   > debug.traceTransaction( "0x214e597e35da083692f5386141e69f47e973b2c56e7a8073b1ea08fd7571e9de", {tracer: "4byteTracer"})
+//   {
+//     0x27dc297e-128: 1,
+//     0x38cc4831-0: 2,
+//     0x524f3889-96: 1,
+//     0xadf59f99-288: 1,
+//     0xc281d19e-0: 1
+//   }
+{
+	// ids aggregates the 4byte ids found.
+	ids : {},
+
+	// callType returns 'false' for non-calls, or the peek-index for the first param
+	// after 'value', i.e. meminstart.
+	callType: function(opstr){
+		switch(opstr){
+		case "CALL": case "CALLCODE":
+			// gas, addr, val, memin, meminsz, memout, memoutsz
+			return 3; // stack ptr to memin
+
+		case "DELEGATECALL": case "STATICCALL":
+			// gas, addr, memin, meminsz, memout, memoutsz
+			return 2; // stack ptr to memin
+		}
+		return false;
+	},
+
+	// store save the given indentifier and datasize.
+	store: function(id, size){
+		var key = "" + toHex(id) + "-" + size;
+		this.ids[key] = this.ids[key] + 1 || 1;
+	},
+
+	// step is invoked for every opcode that the VM executes.
+	step: function(log, db) {
+		// Skip any opcodes that are not internal calls
+		var ct = this.callType(log.op.toString());
+		if (!ct) {
+			return;
+		}
+		// Skip any pre-compile invocations, those are just fancy opcodes
+		if (isPrecompiled(toAddress(log.stack.peek(1).toString(16)))) {
+			return;
+		}
+		// Gather internal call details
+		var inSz = log.stack.peek(ct + 1).valueOf();
+		if (inSz >= 4) {
+			var inOff = log.stack.peek(ct).valueOf();
+			this.store(log.memory.slice(inOff, inOff + 4), inSz-4);
+		}
+	},
+
+	// fault is invoked when the actual execution of an opcode fails.
+	fault: function(log, db) { },
+
+	// result is invoked when all the opcodes have been iterated over and returns
+	// the final result of the tracing.
+	result: function(ctx) {
+		// Save the outer calldata also
+		if (ctx.input.length >= 4) {
+			this.store(slice(ctx.input, 0, 4), ctx.input.length-4)
+		}
+		return this.ids;
+	},
+}