From ad18014854eb225a590f183a2b3d7fd77909e1ae Mon Sep 17 00:00:00 2001
From: Marius van der Wijden <m.vanderwijden@live.de>
Date: Wed, 1 Apr 2020 14:06:08 +0200
Subject: [PATCH] accounts/abi/bind: use store function to remove code
 duplication

---
 accounts/abi/bind/topics.go | 79 +++++++++++++++++--------------------
 1 file changed, 36 insertions(+), 43 deletions(-)

diff --git a/accounts/abi/bind/topics.go b/accounts/abi/bind/topics.go
index 7ebf510ee1..39c8084b1e 100644
--- a/accounts/abi/bind/topics.go
+++ b/accounts/abi/bind/topics.go
@@ -111,31 +111,28 @@ var (
 )
 
 // parseTopics converts the indexed topic fields into actual log field values.
-//
-// Note, dynamic types cannot be reconstructed since they get mapped to Keccak256
-// hashes as the topic value!
 func parseTopics(out interface{}, fields abi.Arguments, topics []common.Hash) error {
-	// Sanity check that the fields and topics match up
-	if len(fields) != len(topics) {
-		return errors.New("topic/field count mismatch")
-	}
-	// Iterate over all the fields and reconstruct them from topics
-	for i, arg := range fields {
-		if !arg.Indexed {
-			return errors.New("non-indexed field in topic reconstruction")
-		}
+	store := func(arg abi.Argument, reconstr interface{}) {
 		field := reflect.ValueOf(out).Elem().FieldByName(capitalise(arg.Name))
-		reconstr, err := parseField(arg, topics[i])
-		if err != nil {
-			return err
-		}
 		field.Set(reflect.ValueOf(reconstr))
 	}
-	return nil
+	return parseTopicIntoFunc(fields, topics, store)
 }
 
 // parseTopicsIntoMap converts the indexed topic field-value pairs into map key-value pairs
 func parseTopicsIntoMap(out map[string]interface{}, fields abi.Arguments, topics []common.Hash) error {
+	store := func(arg abi.Argument, reconstr interface{}) {
+		out[arg.Name] = reconstr
+	}
+	return parseTopicIntoFunc(fields, topics, store)
+}
+
+// parseTopicIntoFunc converts the indexed topic field-value pairs and stores them using the
+// provided store function.
+//
+// Note, dynamic types cannot be reconstructed since they get mapped to Keccak256
+// hashes as the topic value!
+func parseTopicIntoFunc(fields abi.Arguments, topics []common.Hash, store func(abi.Argument, interface{})) error {
 	// Sanity check that the fields and topics match up
 	if len(fields) != len(topics) {
 		return errors.New("topic/field count mismatch")
@@ -145,34 +142,30 @@ func parseTopicsIntoMap(out map[string]interface{}, fields abi.Arguments, topics
 		if !arg.Indexed {
 			return errors.New("non-indexed field in topic reconstruction")
 		}
-		reconstr, err := parseField(arg, topics[i])
-		if err != nil {
-			return err
+		//reconstr, err := parseField(arg, topics[i])
+		var reconstr interface{}
+		switch arg.Type.T {
+		case abi.StringTy, abi.BytesTy, abi.SliceTy, abi.ArrayTy:
+			// Array types (including strings and bytes) have their keccak256 hashes stored in the topic- not a hash
+			// whose bytes can be decoded to the actual value- so the best we can do is retrieve that hash
+			reconstr = topics[i]
+		case abi.FunctionTy:
+			if garbage := binary.BigEndian.Uint64(topics[i][0:8]); garbage != 0 {
+				return fmt.Errorf("bind: got improperly encoded function type, got %v", topics[i].Bytes())
+			}
+			var tmp [24]byte
+			copy(tmp[:], topics[i][8:32])
+			reconstr = tmp
+		default:
+			var err error
+			reconstr, err = abi.ToGoType(0, arg.Type, topics[i].Bytes())
+			if err != nil {
+				return err
+			}
 		}
-		out[arg.Name] = reconstr
+		// Use the store function to store the value
+		store(arg, reconstr)
 	}
 
 	return nil
 }
-
-func parseField(arg abi.Argument, topic common.Hash) (interface{}, error) {
-	if !arg.Indexed {
-		return nil, errors.New("non-indexed field in topic reconstruction")
-	}
-
-	switch arg.Type.T {
-	case abi.StringTy, abi.BytesTy, abi.SliceTy, abi.ArrayTy:
-		// Array types (including strings and bytes) have their keccak256 hashes stored in the topic- not a hash
-		// whose bytes can be decoded to the actual value- so the best we can do is retrieve that hash
-		return topic, nil
-	case abi.FunctionTy:
-		if garbage := binary.BigEndian.Uint64(topic[0:8]); garbage != 0 {
-			return nil, fmt.Errorf("bind: got improperly encoded function type, got %v", topic.Bytes())
-		}
-		var tmp [24]byte
-		copy(tmp[:], topic[8:32])
-		return tmp, nil
-	default:
-		return abi.ToGoType(0, arg.Type, topic.Bytes())
-	}
-}