intents: use ethcoder abi parser for more robust abi string parsing (#…

…155)

* intents: use ethcoder abi parser for more robust abi string parsing

* comment

intents/intent_data_transaction_delayed_abi.go

@@ -106,6 +106,28 @@ func EncodeDelayedABI(data *delayedEncodeType) (string, error) {
 // - transferFrom(address,address,uint256)
 // making sure that the method matches the returned one
 func getMethodFromAbi(abi string, method string) (string, []string, error) {
+	//
+	// First attempt to parse `abi` string as a plain method abi
+	// ie. transferFrom(address,address,uint256)
+	//
+
+	// Handle the case for already encoded method abi
+	if strings.Contains(abi, "(") && strings.Contains(abi, ")") && strings.HasPrefix(abi, method) {
+		// NOTE: even though the ethcoder function is `ParseEventDef`, designed for event type parsing
+		// the abi format for a single function structure is the same, so it works. Perhaps we will rename
+		// `ParseEventDef` in the future, or just add another method with a different name.
+		eventDef, err := ethcoder.ParseEventDef(abi)
+		if err != nil {
+			return "", nil, err
+		}
+		return eventDef.Sig, eventDef.ArgNames, nil
+	}
+
+	//
+	// If above didn't work, attempt to parse `abi` string as
+	// a JSON object of the full abi definition
+	//
+
 	type FunctionAbi struct {
 		Name   string `json:"name"`
 		Type   string `json:"type"`
@@ -116,55 +138,6 @@ func getMethodFromAbi(abi string, method string) (string, []string, error) {
 		} `json:"inputs"`
 	}
 
-	// Handle the case for already encoded method abi
-	if strings.Contains(abi, "(") && strings.Contains(abi, ")") && strings.HasPrefix(abi, method) {
-		// We may or may not have name information
-		// transferFrom(address,address,uint256)
-		// vs
-		// transferFrom(address from,address to,uint256 val)
-
-		// Start by obtaning only the args
-		args := strings.Split(abi, "(")[1]
-		args = strings.Split(args, ")")[0]
-
-		// Split the args by comma, to get the individual types
-		argTypes := strings.Split(args, ",")
-
-		order := make([]string, len(argTypes))
-		types := make([]string, len(argTypes))
-
-		incompleteNaming := false
-
-		for i, arg := range argTypes {
-			// If starts with space, trim it
-			arg = strings.TrimLeft(arg, " ")
-
-			if strings.Contains(arg, " ") {
-				// We have name information, so we need to extract it
-				spl := strings.Split(arg, " ")
-
-				order[i] = spl[1]
-				types[i] = spl[0]
-
-			} else {
-				// We don't have name information, so we must
-				// mark this case as incomplete
-				incompleteNaming = true
-
-				// Assume that arg is the type
-				types[i] = arg
-			}
-		}
-
-		if incompleteNaming {
-			order = nil
-		}
-
-		// Re encode abi, now without name information
-		fnc := method + "(" + strings.Join(types, ",") + ")"
-		return fnc, order, nil
-	}
-
 	// Handle array of function abis and single function abi
 	var abis []FunctionAbi
 	if strings.HasPrefix(abi, "[") {

intents/intent_data_transaction_delayed_abi_test.go

@@ -46,7 +46,7 @@ func TestGetMethodFromABI(t *testing.T) {
 	assert.Nil(t, err)
 
 	assert.Equal(t, "transfer(address,uint256)", res)
-	assert.Nil(t, order)
+	assert.Equal(t, []string{"arg1", "arg2"}, order)
 
 	// From plain method, with named args
 	res, order, err = getMethodFromAbi(`transfer(address _to,uint256 _value, bytes _mas)`, "transfer")
@@ -60,7 +60,7 @@ func TestGetMethodFromABI(t *testing.T) {
 
 	assert.Nil(t, err)
 	assert.Equal(t, "transfer(address,uint256,bytes)", res)
-	assert.Nil(t, order)
+	assert.Equal(t, []string{"_to", "arg2", "_mas"}, order)
 }
 
 func TestEncodeDelayedABI(t *testing.T) {