Merge pull request #932 from seanyoung/vent-abi-changes

Allow reading abi from abi file or bin file and merging of abis

execution/evm/abi/abi.go

@@ -846,6 +846,9 @@ func readArgSpec(argsJ []ArgumentJSON) ([]Argument, error) {
 			args[i].EVM = EVMBytes{M: 0}
 		case "string":
 			args[i].EVM = EVMString{}
+		default:
+			// Assume it is a type of Contract
+			args[i].EVM = EVMAddress{}
 		}
 	}
 
@@ -856,7 +859,15 @@ func ReadAbiSpec(specBytes []byte) (*AbiSpec, error) {
 	var specJ []AbiSpecJSON
 	err := json.Unmarshal(specBytes, &specJ)
 	if err != nil {
-		return nil, err
+		// The abi spec file might a bin file, with the Abi under the Abi field in json
+		var binFile struct {
+			Abi []AbiSpecJSON
+		}
+		err = json.Unmarshal(specBytes, &binFile)
+		if err != nil {
+			return nil, err
+		}
+		specJ = binFile.Abi
 	}
 
 	abiSpec := AbiSpec{
@@ -919,6 +930,32 @@ func ReadAbiSpecFile(filename string) (*AbiSpec, error) {
 	return ReadAbiSpec(specBytes)
 }
 
+// MergeAbiSpec takes multiple AbiSpecs and merges them into once structure. Note that
+// the same function name or event name can occur in different abis, so there might be
+// some information loss.
+func MergeAbiSpec(abiSpec []*AbiSpec) *AbiSpec {
+	newSpec := AbiSpec{
+		Events:     make(map[string]EventSpec),
+		EventsById: make(map[EventID]EventSpec),
+		Functions:  make(map[string]FunctionSpec),
+	}
+
+	for _, s := range abiSpec {
+		for n, f := range s.Functions {
+			newSpec.Functions[n] = f
+		}
+
+		// Different Abis can have the Event name, but with a different signature
+		// Loop over the signatures, as these are less likely to have collisions
+		for _, e := range s.EventsById {
+			newSpec.Events[e.Name] = e
+			newSpec.EventsById[e.EventID] = e
+		}
+	}
+
+	return &newSpec
+}
+
 func EVMTypeFromReflect(v reflect.Type) Argument {
 	arg := Argument{Name: v.Name()}