From 46281945f08385e43d9633ad5b6057a9ca2d2369 Mon Sep 17 00:00:00 2001
From: Arijit Das <arijit@chainsafe.io>
Date: Wed, 27 Oct 2021 19:19:37 +0530
Subject: [PATCH] Address comments

---
 lib/common/optional/types.go  | 17 +++++++++--------
 lib/runtime/constants.go      |  2 +-
 lib/runtime/interface.go      |  2 +-
 lib/runtime/storage/trie.go   | 13 +++----------
 lib/runtime/wasmer/imports.go | 15 ++++++---------
 5 files changed, 20 insertions(+), 29 deletions(-)

diff --git a/lib/common/optional/types.go b/lib/common/optional/types.go
index 1b58fab701..9247453a99 100644
--- a/lib/common/optional/types.go
+++ b/lib/common/optional/types.go
@@ -25,7 +25,7 @@ import (
 	"math/big"
 
 	"github.com/ChainSafe/gossamer/lib/common"
-	"github.com/ChainSafe/gossamer/lib/scale"
+	"github.com/ChainSafe/gossamer/pkg/scale"
 )
 
 const none = "None"
@@ -134,7 +134,7 @@ func (x *Bytes) Encode() ([]byte, error) {
 		return []byte{0}, nil
 	}
 
-	value, err := scale.Encode(x.value)
+	value, err := scale.Marshal(x.value)
 	if err != nil {
 		return nil, err
 	}
@@ -153,15 +153,15 @@ func (x *Bytes) Decode(r io.Reader) (*Bytes, error) {
 		return nil, ErrInvalidOptional
 	}
 
-	x.exists = (exists != 0)
+	x.exists = exists != 0
 
 	if x.exists {
-		sd := scale.Decoder{Reader: r}
-		value, err := sd.DecodeByteArray()
+		sd := scale.NewDecoder(r)
+		err := sd.Decode(&x.value)
+
 		if err != nil {
 			return nil, err
 		}
-		x.value = value
 	}
 
 	return x, nil
@@ -176,11 +176,12 @@ func (x *Bytes) DecodeBytes(data []byte) (*Bytes, error) {
 	x.exists = data[0] != 0
 
 	if x.exists {
-		decData, err := scale.Decode(data[1:], []byte{})
+		var decData []byte
+		err := scale.Unmarshal(data[1:], &decData)
 		if err != nil {
 			return nil, err
 		}
-		x.value = decData.([]byte)
+		x.value = decData
 	} else {
 		x.value = nil
 	}
diff --git a/lib/runtime/constants.go b/lib/runtime/constants.go
index 0dc5f8fa78..97da61485d 100644
--- a/lib/runtime/constants.go
+++ b/lib/runtime/constants.go
@@ -44,7 +44,7 @@ const (
 	POLKADOT_RUNTIME_FP  = "polkadot_runtime.compact.wasm"
 	POLKADOT_RUNTIME_URL = "https://github.com/noot/polkadot/blob/noot/v0.8.25/polkadot_runtime.wasm?raw=true"
 
-	// v0.8 test API wasm
+	// v0.9 test API wasm
 	HOST_API_TEST_RUNTIME     = "hostapi_runtime"
 	HOST_API_TEST_RUNTIME_FP  = "hostapi_runtime.compact.wasm"
 	HOST_API_TEST_RUNTIME_URL = "https://github.com/ChainSafe/polkadot-spec/blob/update-hostapi-wasm/test/runtimes/hostapi/hostapi_runtime.compact.wasm?raw=true"
diff --git a/lib/runtime/interface.go b/lib/runtime/interface.go
index 1a6df6951d..e540151f01 100644
--- a/lib/runtime/interface.go
+++ b/lib/runtime/interface.go
@@ -76,7 +76,7 @@ type Storage interface {
 	GetChildNextKey(keyToChild, key []byte) ([]byte, error)
 	GetChild(keyToChild []byte) (*trie.Trie, error)
 	ClearPrefix(prefix []byte) error
-	ClearPrefixLimit(prefix []byte, limit *optional.Bytes) (uint32, bool, error)
+	ClearPrefixLimit(prefix []byte, limit uint32) (uint32, bool)
 	BeginStorageTransaction()
 	CommitStorageTransaction()
 	RollbackStorageTransaction()
diff --git a/lib/runtime/storage/trie.go b/lib/runtime/storage/trie.go
index 8789fbdcda..101f65ae54 100644
--- a/lib/runtime/storage/trie.go
+++ b/lib/runtime/storage/trie.go
@@ -18,7 +18,6 @@ package storage
 
 import (
 	"encoding/binary"
-	"errors"
 	"sort"
 	"sync"
 
@@ -140,18 +139,12 @@ func (s *TrieState) ClearPrefix(prefix []byte) error {
 }
 
 // ClearPrefixLimit deletes key-value pairs from the trie where the key starts with the given prefix till limit reached
-func (s *TrieState) ClearPrefixLimit(prefix []byte, limit *optional.Bytes) (uint32, bool, error) {
+func (s *TrieState) ClearPrefixLimit(prefix []byte, limit uint32) (uint32, bool) {
 	s.lock.Lock()
 	defer s.lock.Unlock()
 
-	if limit == nil || !limit.Exists() {
-		return 0, false, errors.New("limit not exists")
-	}
-
-	limitUint := binary.LittleEndian.Uint32(limit.Value())
-
-	num, del := s.t.ClearPrefixLimit(prefix, limitUint)
-	return num, del, nil
+	num, del := s.t.ClearPrefixLimit(prefix, limit)
+	return num, del
 }
 
 // TrieEntries returns every key-value pair in the trie
diff --git a/lib/runtime/wasmer/imports.go b/lib/runtime/wasmer/imports.go
index 93d59e19f7..48703b1353 100644
--- a/lib/runtime/wasmer/imports.go
+++ b/lib/runtime/wasmer/imports.go
@@ -1803,20 +1803,17 @@ func ext_storage_clear_prefix_version_2(context unsafe.Pointer, prefixSpan, lim
 	logger.Debug("[ext_storage_clear_prefix_version_2]", "prefix", fmt.Sprintf("0x%x", prefix))
 
 	limitBytes := asMemorySlice(instanceContext, lim)
-	buf := &bytes.Buffer{}
-	buf.Write(limitBytes)
 
-	limit, err := optional.NewBytes(true, nil).Decode(buf)
+	var limit []byte
+	err := scale.Unmarshal(limitBytes, &limit)
 	if err != nil {
 		logger.Warn("[ext_storage_clear_prefix_version_2] cannot generate limit", "error", err)
-		return 0
-	}
-
-	numRemoved, all, err := storage.ClearPrefixLimit(prefix, limit)
-	if err != nil {
-		logger.Error("[ext_storage_clear_prefix_version_2]", "error", err)
+		ret, _ := toWasmMemory(instanceContext, nil)
+		return C.int64_t(ret)
 	}
 
+	limitUint := binary.LittleEndian.Uint32(limit)
+	numRemoved, all := storage.ClearPrefixLimit(prefix, limitUint)
 	encBytes, err := toKillStorageResultEnum(all, numRemoved)
 
 	if err != nil {