account/abi: implements event parsing

Implementation of basic event parsing and its input types. This
separates methods and events and fixes an issue with go type parsing and
validation.

accounts/abi/event.go

@@ -0,0 +1,44 @@
+// Copyright 2016 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/>.
+
+package abi
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/crypto"
+)
+
+// Event is an event potentially triggered by the EVM's LOG mechanism. The Event
+// holds type information (inputs) about the yielded output
+type Event struct {
+	Name   string
+	Inputs []Argument
+}
+
+// Id returns the canonical representation of the event's signature used by the
+// abi definition to identify event names and types.
+func (e Event) Id() common.Hash {
+	types := make([]string, len(e.Inputs))
+	i := 0
+	for _, input := range e.Inputs {
+		types[i] = input.Type.String()
+		i++
+	}
+	return common.BytesToHash(crypto.Sha3([]byte(fmt.Sprintf("%v(%v)", e.Name, strings.Join(types, ",")))))
+}