From afe7ae8daa78c036948a6172da12788fa9efa7c9 Mon Sep 17 00:00:00 2001
From: Supun Setunga <supun.setunga@gmail.com>
Date: Wed, 30 Jun 2021 08:24:53 +0530
Subject: [PATCH] Re-arrange encoding format to move types to the start

---
 runtime/interpreter/decode.go | 21 +++++++++++----------
 runtime/interpreter/encode.go | 26 +++++++++++++-------------
 2 files changed, 24 insertions(+), 23 deletions(-)

diff --git a/runtime/interpreter/decode.go b/runtime/interpreter/decode.go
index 00474f0640..c05fdaf951 100644
--- a/runtime/interpreter/decode.go
+++ b/runtime/interpreter/decode.go
@@ -1897,6 +1897,15 @@ func decodeDictionaryMetaInfo(v *DictionaryValue, content []byte) error {
 		)
 	}
 
+	// Decode type
+	// TODO: store dictionary type
+	//   Option 1: convert to sema type. - Don't have the interpreter
+	//   Option 2: Store static type in dictionary
+	_, err = d.decodeStaticType()
+	if err != nil {
+		return err
+	}
+
 	// Lazily decode keys
 
 	var keysContent []byte
@@ -1939,17 +1948,9 @@ func decodeDictionaryMetaInfo(v *DictionaryValue, content []byte) error {
 		return err
 	}
 
-	// Decode type
-	// TODO: store dictionary type
-	//   Option 1: convert to sema type. - Don't have the interpreter
-	//   Option 2: Store static type in array
-	_, err = d.decodeStaticType()
-	if err != nil {
-		return err
-	}
+	keysContent = append(keysContent, valuesContent...)
 
-	//nolint:gocritic
-	v.entriesContent = append(keysContent, valuesContent...)
+	v.entriesContent = keysContent
 	v.Type = nil
 
 	return nil
diff --git a/runtime/interpreter/encode.go b/runtime/interpreter/encode.go
index 2ee13f00b6..a32051849a 100644
--- a/runtime/interpreter/encode.go
+++ b/runtime/interpreter/encode.go
@@ -853,9 +853,9 @@ func (e *EncoderV5) encodeArray(
 
 // NOTE: NEVER change, only add/increment; ensure uint64
 const (
-	encodedDictionaryValueKeysFieldKey    uint64 = 0
-	encodedDictionaryValueEntriesFieldKey uint64 = 1
-	encodedDictionaryValueTypeFieldKey    uint64 = 2
+	encodedDictionaryValueTypeFieldKey    uint64 = 0
+	encodedDictionaryValueKeysFieldKey    uint64 = 1
+	encodedDictionaryValueEntriesFieldKey uint64 = 2
 
 	// !!! *WARNING* !!!
 	//
@@ -871,9 +871,9 @@ const dictionaryValuePathPrefix = "v"
 // cbor.Tag{
 //			Number: cborTagDictionaryValue,
 //			Content: cborArray{
+// 				encodedDictionaryValueTypeFieldKey:    []interface{}(type),
 //				encodedDictionaryValueKeysFieldKey:    []interface{}(keys),
 //				encodedDictionaryValueEntriesFieldKey: []interface{}(entries),
-// 				encodedDictionaryValueTypeFieldKey:    []interface{}(type),
 //			},
 // }
 func (e *EncoderV5) encodeDictionaryValue(
@@ -902,7 +902,7 @@ func (e *EncoderV5) encodeDictionaryValue(
 
 	// Encode array head
 	err = e.enc.EncodeRawBytes([]byte{
-		// array, 2 items follow
+		// array, 3 items follow
 		0x83,
 	})
 	if err != nil {
@@ -912,7 +912,13 @@ func (e *EncoderV5) encodeDictionaryValue(
 	//nolint:gocritic
 	keysPath := append(path, dictionaryKeyPathPrefix)
 
-	// Encode keys (as array) at array index encodedDictionaryValueKeysFieldKey
+	// (1) Encode dictionary static type at array index encodedDictionaryValueTypeFieldKey
+	err = e.encodeStaticType(v.StaticType())
+	if err != nil {
+		return err
+	}
+
+	// (2) Encode keys (as array) at array index encodedDictionaryValueKeysFieldKey
 	err = e.encodeArray(v.Keys(), keysPath, deferrals)
 	if err != nil {
 		return err
@@ -944,7 +950,7 @@ func (e *EncoderV5) encodeDictionaryValue(
 		entriesLength = 0
 	}
 
-	// Encode values (as array) at array index encodedDictionaryValueEntriesFieldKey
+	// (3) Encode values (as array) at array index encodedDictionaryValueEntriesFieldKey
 	err = e.enc.EncodeArrayHead(uint64(entriesLength))
 	if err != nil {
 		return err
@@ -1011,12 +1017,6 @@ func (e *EncoderV5) encodeDictionaryValue(
 		}
 	}
 
-	// Encode dictionary static type at array index encodedDictionaryValueTypeFieldKey
-	err = e.encodeStaticType(v.StaticType())
-	if err != nil {
-		return err
-	}
-
 	return nil
 }