feat: implement ext_default_child_storage_storage_kill_version_2 (ChainSafe#1799)

* add code to parse limit param

* add optional encoding for limit

* implement functionity for ext function

* lint

* implement trie.DeleteChildLimit function

* address PR comments

* update HOST_API_TEST_RUNTIME_URL to use master branch

* lint

* combine parameters

* add unit test for DeleteChildLimit

Co-authored-by: noot <[email protected]>

Author: edwardmack

lib/runtime/interface.go

@@ -19,6 +19,7 @@ package runtime
 import (
 	"github.com/ChainSafe/gossamer/dot/types"
 	"github.com/ChainSafe/gossamer/lib/common"
+	"github.com/ChainSafe/gossamer/lib/common/optional"
 	"github.com/ChainSafe/gossamer/lib/keystore"
 	"github.com/ChainSafe/gossamer/lib/transaction"
 	"github.com/ChainSafe/gossamer/lib/trie"
@@ -66,6 +67,7 @@ type Storage interface {
 	GetChildStorage(keyToChild, key []byte) ([]byte, error)
 	Delete(key []byte)
 	DeleteChild(keyToChild []byte)
+	DeleteChildLimit(keyToChild []byte, limit *optional.Bytes) (uint32, bool, error)
 	ClearChildStorage(keyToChild, key []byte) error
 	NextKey([]byte) []byte
 	ClearPrefixInChild(keyToChild, prefix []byte) error

lib/runtime/storage/trie.go

@@ -18,9 +18,11 @@ package storage
 
 import (
 	"encoding/binary"
+	"sort"
 	"sync"
 
 	"github.com/ChainSafe/gossamer/lib/common"
+	"github.com/ChainSafe/gossamer/lib/common/optional"
 	"github.com/ChainSafe/gossamer/lib/trie"
 )
 
@@ -178,6 +180,43 @@ func (s *TrieState) DeleteChild(key []byte) {
 	s.t.DeleteChild(key)
 }
 
+// DeleteChildLimit deletes up to limit of database entries by lexicographic order, return number
+//  deleted, true if all delete otherwise false
+func (s *TrieState) DeleteChildLimit(key []byte, limit *optional.Bytes) (uint32, bool, error) {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+	tr, err := s.t.GetChild(key)
+	if err != nil {
+		return 0, false, err
+	}
+	qtyEntries := uint32(len(tr.Entries()))
+	if limit == nil || !limit.Exists() {
+		s.t.DeleteChild(key)
+		return qtyEntries, true, nil
+	}
+	limitUint := binary.LittleEndian.Uint32(limit.Value())
+
+	keys := make([]string, 0, len(tr.Entries()))
+	for k := range tr.Entries() {
+		keys = append(keys, k)
+	}
+	sort.Strings(keys)
+	deleted := uint32(0)
+	for _, k := range keys {
+		tr.Delete([]byte(k))
+		deleted++
+		if deleted == limitUint {
+			break
+		}
+	}
+
+	if deleted == qtyEntries {
+		return deleted, true, nil
+	}
+
+	return deleted, false, nil
+}
+
 // ClearChildStorage removes the child storage entry from the trie
 func (s *TrieState) ClearChildStorage(keyToChild, key []byte) error {
 	s.lock.Lock()

lib/runtime/storage/trie_test.go

@@ -18,10 +18,12 @@ package storage
 
 import (
 	"bytes"
+	"encoding/binary"
 	"sort"
 	"testing"
 
 	"github.com/ChainSafe/gossamer/lib/common"
+	"github.com/ChainSafe/gossamer/lib/common/optional"
 	"github.com/ChainSafe/gossamer/lib/trie"
 	"github.com/stretchr/testify/require"
 )
@@ -197,3 +199,50 @@ func TestTrieState_RollbackStorageTransaction(t *testing.T) {
 	val := ts.Get([]byte(testCases[0]))
 	require.Equal(t, []byte(testCases[0]), val)
 }
+
+func TestTrieState_DeleteChildLimit(t *testing.T) {
+	ts := newTestTrieState(t)
+	child := trie.NewEmptyTrie()
+
+	keys := []string{
+		"key3",
+		"key1",
+		"key2",
+	}
+
+	for i, key := range keys {
+		child.Put([]byte(key), []byte{byte(i)})
+	}
+
+	keyToChild := []byte("keytochild")
+
+	err := ts.SetChild(keyToChild, child)
+	require.NoError(t, err)
+
+	testLimitBytes := make([]byte, 4)
+	binary.LittleEndian.PutUint32(testLimitBytes, uint32(2))
+	optLimit2 := optional.NewBytes(true, testLimitBytes)
+
+	testCases := []struct {
+		key             []byte
+		limit           *optional.Bytes
+		expectedDeleted uint32
+		expectedDelAll  bool
+		errMsg          string
+	}{
+		{key: []byte("fakekey"), limit: optLimit2, expectedDeleted: 0, expectedDelAll: false, errMsg: "child trie does not exist at key :child_storage:default:fakekey"},
+		{key: []byte("keytochild"), limit: optLimit2, expectedDeleted: 2, expectedDelAll: false},
+		{key: []byte("keytochild"), limit: nil, expectedDeleted: 1, expectedDelAll: true},
+	}
+	for _, test := range testCases {
+		deleted, all, err := ts.DeleteChildLimit(test.key, test.limit)
+		if test.errMsg != "" {
+			require.Error(t, err)
+			require.EqualError(t, err, test.errMsg)
+			continue
+		}
+		require.NoError(t, err)
+		require.Equal(t, test.expectedDeleted, deleted)
+		require.Equal(t, test.expectedDelAll, all)
+	}
+}

lib/runtime/wasmer/imports.go

@@ -1118,19 +1118,33 @@ func ext_default_child_storage_storage_kill_version_1(context unsafe.Pointer, ch
 }
 
 //export ext_default_child_storage_storage_kill_version_2
-func ext_default_child_storage_storage_kill_version_2(context unsafe.Pointer, childStorageKeySpan, _ C.int64_t) C.int32_t {
+func ext_default_child_storage_storage_kill_version_2(context unsafe.Pointer, childStorageKeySpan, lim C.int64_t) C.int32_t {
 	logger.Debug("[ext_default_child_storage_storage_kill_version_2] executing...")
-	logger.Warn("[ext_default_child_storage_storage_kill_version_2] somewhat unimplemented")
-	// TODO: need to use `limit` parameter
 
 	instanceContext := wasm.IntoInstanceContext(context)
 	ctx := instanceContext.Data().(*runtime.Context)
 	storage := ctx.Storage
-
 	childStorageKey := asMemorySlice(instanceContext, childStorageKeySpan)
-	storage.DeleteChild(childStorageKey)
 
-	// note: this function always returns `KillStorageResult::AllRemoved`, which is 0
+	limitBytes := asMemorySlice(instanceContext, lim)
+	buf := &bytes.Buffer{}
+	buf.Write(limitBytes)
+
+	limit, err := optional.NewBytes(true, nil).Decode(buf)
+	if err != nil {
+		logger.Warn("[ext_default_child_storage_storage_kill_version_2] cannot generate limit", "error", err)
+		return 0
+	}
+
+	_, all, err := storage.DeleteChildLimit(childStorageKey, limit)
+	if err != nil {
+		logger.Warn("[ext_default_child_storage_storage_kill_version_2] cannot get child storage", "error", err)
+	}
+
+	if all {
+		return 1
+	}
+
 	return 0
 }
 

lib/runtime/wasmer/imports_test.go

@@ -18,6 +18,7 @@ package wasmer
 
 import (
 	"bytes"
+	"encoding/binary"
 	"os"
 	"sort"
 	"testing"
@@ -1071,6 +1072,101 @@ func Test_ext_default_child_storage_storage_kill_version_1(t *testing.T) {
 	require.Nil(t, child)
 }
 
+func Test_ext_default_child_storage_storage_kill_version_2_limit_all(t *testing.T) {
+	inst := NewTestInstance(t, runtime.HOST_API_TEST_RUNTIME)
+
+	tr := trie.NewEmptyTrie()
+	tr.Put([]byte(`key2`), []byte(`value2`))
+	tr.Put([]byte(`key1`), []byte(`value1`))
+	err := inst.ctx.Storage.SetChild(testChildKey, tr)
+	require.NoError(t, err)
+
+	// Confirm if value is set
+	child, err := inst.ctx.Storage.GetChild(testChildKey)
+	require.NoError(t, err)
+	require.NotNil(t, child)
+
+	encChildKey, err := scale.Encode(testChildKey)
+	require.NoError(t, err)
+
+	testLimit := uint32(2)
+	testLimitBytes := make([]byte, 4)
+	binary.LittleEndian.PutUint32(testLimitBytes, testLimit)
+
+	optLimit, err := optional.NewBytes(true, testLimitBytes).Encode()
+	require.NoError(t, err)
+
+	res, err := inst.Exec("rtm_ext_default_child_storage_storage_kill_version_2", append(encChildKey, optLimit...))
+	require.NoError(t, err)
+	require.Equal(t, []byte{1, 0, 0, 0}, res)
+
+	child, err = inst.ctx.Storage.GetChild(testChildKey)
+	require.NoError(t, err)
+	require.Equal(t, 0, len(child.Entries()))
+}
+
+func Test_ext_default_child_storage_storage_kill_version_2_limit_1(t *testing.T) {
+	inst := NewTestInstance(t, runtime.HOST_API_TEST_RUNTIME)
+
+	tr := trie.NewEmptyTrie()
+	tr.Put([]byte(`key2`), []byte(`value2`))
+	tr.Put([]byte(`key1`), []byte(`value1`))
+	err := inst.ctx.Storage.SetChild(testChildKey, tr)
+	require.NoError(t, err)
+
+	// Confirm if value is set
+	child, err := inst.ctx.Storage.GetChild(testChildKey)
+	require.NoError(t, err)
+	require.NotNil(t, child)
+
+	encChildKey, err := scale.Encode(testChildKey)
+	require.NoError(t, err)
+
+	testLimit := uint32(1)
+	testLimitBytes := make([]byte, 4)
+	binary.LittleEndian.PutUint32(testLimitBytes, testLimit)
+
+	optLimit, err := optional.NewBytes(true, testLimitBytes).Encode()
+	require.NoError(t, err)
+
+	res, err := inst.Exec("rtm_ext_default_child_storage_storage_kill_version_2", append(encChildKey, optLimit...))
+	require.NoError(t, err)
+	require.Equal(t, []byte{0, 0, 0, 0}, res)
+
+	child, err = inst.ctx.Storage.GetChild(testChildKey)
+	require.NoError(t, err)
+	require.Equal(t, 1, len(child.Entries()))
+}
+
+func Test_ext_default_child_storage_storage_kill_version_2_limit_none(t *testing.T) {
+	inst := NewTestInstance(t, runtime.HOST_API_TEST_RUNTIME)
+
+	tr := trie.NewEmptyTrie()
+	tr.Put([]byte(`key2`), []byte(`value2`))
+	tr.Put([]byte(`key1`), []byte(`value1`))
+	err := inst.ctx.Storage.SetChild(testChildKey, tr)
+	require.NoError(t, err)
+
+	// Confirm if value is set
+	child, err := inst.ctx.Storage.GetChild(testChildKey)
+	require.NoError(t, err)
+	require.NotNil(t, child)
+
+	encChildKey, err := scale.Encode(testChildKey)
+	require.NoError(t, err)
+
+	optLimit, err := optional.NewBytes(false, nil).Encode()
+	require.NoError(t, err)
+
+	res, err := inst.Exec("rtm_ext_default_child_storage_storage_kill_version_2", append(encChildKey, optLimit...))
+	require.NoError(t, err)
+	require.Equal(t, []byte{1, 0, 0, 0}, res)
+
+	child, err = inst.ctx.Storage.GetChild(testChildKey)
+	require.Error(t, err)
+	require.Nil(t, child)
+}
+
 func Test_ext_storage_append_version_1(t *testing.T) {
 	inst := NewTestInstance(t, runtime.HOST_API_TEST_RUNTIME)