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_test.go

@@ -0,0 +1,40 @@
+package abi
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/crypto"
+)
+
+func TestEventId(t *testing.T) {
+	var table = []struct {
+		definition   string
+		expectations map[string]common.Hash
+	}{
+		{
+			definition: `[
+			{ "type" : "event", "name" : "balance", "inputs": [{ "name" : "in", "type": "uint" }] },
+			{ "type" : "event", "name" : "check", "inputs": [{ "name" : "t", "type": "address" }, { "name": "b", "type": "uint256" }] }
+			]`,
+			expectations: map[string]common.Hash{
+				"balance": crypto.Sha3Hash([]byte("balance(uint256)")),
+				"check":   crypto.Sha3Hash([]byte("check(address,uint256)")),
+			},
+		},
+	}
+
+	for _, test := range table {
+		abi, err := JSON(strings.NewReader(test.definition))
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		for name, event := range abi.Events {
+			if event.Id() != test.expectations[name] {
+				t.Errorf("expected id to be %x, got %x", test.expectations[name], event.Id())
+			}
+		}
+	}
+}