lib/runtime: implement ext_kill_child_storage and ext_get_allocated_c…

…hild_storage (#1110)

* implement DeleteChildStorage interface

* implement ext_kill_child_storage and tests

* implement ext_get_allocated_child_storage

dot/state/trie.go

@@ -137,3 +137,10 @@ func (s *TrieState) GetBalance(key [32]byte) (uint64, error) {
 
 	return binary.LittleEndian.Uint64(bal), nil
 }
+
+// DeleteChildStorage deletes child storage from the trie
+func (s *TrieState) DeleteChildStorage(key []byte) error {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+	return s.t.DeleteFromChild(key)
+}

lib/runtime/imports.go

@@ -82,9 +82,20 @@ import (
 )
 
 //export ext_kill_child_storage
-func ext_kill_child_storage(context unsafe.Pointer, a, b C.int32_t) {
+func ext_kill_child_storage(context unsafe.Pointer, storageKeyData, storageKeyLen C.int32_t) {
 	logger.Trace("[ext_kill_child_storage] executing...")
-	logger.Warn("[ext_kill_child_storage] not yet implemented")
+	instanceContext := wasm.IntoInstanceContext(context)
+	memory := instanceContext.Memory().Data()
+
+	runtimeCtx := instanceContext.Data().(*Ctx)
+	s := runtimeCtx.storage
+
+	keyToChild := memory[storageKeyData : storageKeyData+storageKeyLen]
+
+	err := s.DeleteChildStorage(keyToChild)
+	if err != nil {
+		logger.Error("[ext_kill_child_storage]", "error", err)
+	}
 }
 
 //export ext_sandbox_memory_new
@@ -121,10 +132,40 @@ func ext_sandbox_instance_teardown(context unsafe.Pointer, a C.int32_t) {
 }
 
 //export ext_get_allocated_child_storage
-func ext_get_allocated_child_storage(context unsafe.Pointer, a, b, c, d, e C.int32_t) C.int32_t {
+func ext_get_allocated_child_storage(context unsafe.Pointer, storageKeyData, storageKeyLen, keyData, keyLen, writtenOut C.int32_t) int32 {
 	logger.Trace("[ext_get_allocated_child_storage] executing...")
-	logger.Warn("[ext_get_allocated_child_storage] not yet implemented")
-	return 0
+	instanceContext := wasm.IntoInstanceContext(context)
+	memory := instanceContext.Memory().Data()
+
+	runtimeCtx := instanceContext.Data().(*Ctx)
+	s := runtimeCtx.storage
+
+	keyToChild := memory[storageKeyData : storageKeyData+storageKeyLen]
+	key := memory[keyData : keyData+keyLen]
+
+	value, err := s.GetChildStorage(keyToChild, key)
+	if err != nil {
+		logger.Error("[ext_get_allocated_child_storage]", "error", err)
+		return 0
+	}
+	valueLen := uint32(len(value))
+	if valueLen == 0 {
+		copy(memory[writtenOut:writtenOut+4], []byte{0xff, 0xff, 0xff, 0xff})
+		return 0
+	}
+
+	// copy length to memory
+	byteLen := make([]byte, 4)
+	binary.LittleEndian.PutUint32(byteLen, valueLen)
+	copy(memory[writtenOut:writtenOut+4], byteLen)
+
+	resPtr, err := runtimeCtx.allocator.Allocate(valueLen)
+	if err != nil {
+		logger.Error("[ext_get_allocated_child_storage]", "error", err)
+		return 0
+	}
+	copy(memory[resPtr:resPtr+valueLen], value)
+	return int32(resPtr)
 }
 
 //export ext_child_storage_root

lib/runtime/imports_test.go

@@ -5,7 +5,7 @@ import (
 	"testing"
 
 	"github.com/ChainSafe/gossamer/lib/common"
-
+	"github.com/ChainSafe/gossamer/lib/trie"
 	"github.com/stretchr/testify/require"
 )
 
@@ -36,3 +36,115 @@ func Test_ext_twox_256(t *testing.T) {
 		t.Fatalf("fail: got %x expected %x", mem[out:out+32], expected[:])
 	}
 }
+
+func Test_ext_kill_child_storage(t *testing.T) {
+	runtime := NewTestRuntime(t, TEST_RUNTIME)
+	mem := runtime.vm.Memory.Data()
+	// set child storage
+	storageKey := []byte("childstore1")
+	childKey := []byte("key1")
+	value := []byte("value")
+	err := runtime.ctx.storage.SetChild(storageKey, trie.NewEmptyTrie())
+	require.Nil(t, err)
+
+	storageKeyLen := uint32(len(storageKey))
+	storageKeyPtr, err := runtime.malloc(storageKeyLen)
+	require.NoError(t, err)
+
+	childKeyLen := uint32(len(childKey))
+	childKeyPtr, err := runtime.malloc(childKeyLen)
+	require.NoError(t, err)
+
+	valueLen := uint32(len(value))
+	valuePtr, err := runtime.malloc(valueLen)
+	require.NoError(t, err)
+
+	copy(mem[storageKeyPtr:storageKeyPtr+storageKeyLen], storageKey)
+	copy(mem[childKeyPtr:childKeyPtr+childKeyLen], childKey)
+	copy(mem[valuePtr:valuePtr+valueLen], value)
+
+	// call wasm function to set child storage
+	testFunc, ok := runtime.vm.Exports["test_ext_set_child_storage"]
+	if !ok {
+		t.Fatal("could not find exported function")
+	}
+
+	_, err = testFunc(int32(storageKeyPtr), int32(storageKeyLen), int32(childKeyPtr), int32(childKeyLen), int32(valuePtr), int32(valueLen))
+	require.Nil(t, err)
+
+	// confirm set
+	checkValue, err := runtime.ctx.storage.GetChildStorage(storageKey, childKey)
+	require.NoError(t, err)
+	require.Equal(t, value, checkValue)
+
+	// call wasm function to kill child storage
+	testDelete, ok := runtime.vm.Exports["test_ext_kill_child_storage"]
+	if !ok {
+		t.Fatal("could not find exported function")
+	}
+
+	_, err = testDelete(int32(storageKeyPtr), int32(storageKeyLen))
+	require.NoError(t, err)
+
+	// confirm value is deleted
+	checkDelete, err := runtime.ctx.storage.GetChildStorage(storageKey, childKey)
+	require.EqualError(t, err, "child trie does not exist at key :child_storage:default:"+string(storageKey))
+	require.Equal(t, []byte(nil), checkDelete)
+}
+
+func Test_ext_get_allocated_child_storage(t *testing.T) {
+	runtime := NewTestRuntime(t, TEST_RUNTIME)
+	mem := runtime.vm.Memory.Data()
+
+	// set child storage
+	storageKey := []byte("childstore1")
+	childKey := []byte("key1")
+	err := runtime.ctx.storage.SetChild(storageKey, trie.NewEmptyTrie())
+	require.Nil(t, err)
+
+	storageKeyLen := uint32(len(storageKey))
+	storageKeyPtr, err := runtime.malloc(storageKeyLen)
+	require.NoError(t, err)
+
+	childKeyLen := uint32(len(childKey))
+	childKeyPtr, err := runtime.malloc(childKeyLen)
+	require.NoError(t, err)
+
+	copy(mem[storageKeyPtr:storageKeyPtr+storageKeyLen], storageKey)
+	copy(mem[childKeyPtr:childKeyPtr+childKeyLen], childKey)
+
+	// call wasm function to get child value (should be not found since we haven't set it yet)
+	getValueFunc, ok := runtime.vm.Exports["test_ext_get_allocated_child_storage"]
+	if !ok {
+		t.Fatal("could not find exported function")
+	}
+
+	writtenOut, err := runtime.malloc(4)
+	require.NoError(t, err)
+	res, err := getValueFunc(int32(storageKeyPtr), int32(storageKeyLen), int32(childKeyPtr), int32(childKeyLen), int32(writtenOut))
+	require.NoError(t, err)
+	require.Equal(t, []byte{0xff, 0xff, 0xff, 0xff}, mem[writtenOut:writtenOut+4])
+	require.Equal(t, int32(0), res.ToI32())
+
+	// store the child value
+	value := []byte("value")
+	valueLen := uint32(len(value))
+	valuePtr, err := runtime.malloc(valueLen)
+	require.NoError(t, err)
+	copy(mem[valuePtr:valuePtr+valueLen], value)
+
+	// call wasm function to set child storage
+	setValueFunc, ok := runtime.vm.Exports["test_ext_set_child_storage"]
+	if !ok {
+		t.Fatal("could not find exported function")
+	}
+
+	_, err = setValueFunc(int32(storageKeyPtr), int32(storageKeyLen), int32(childKeyPtr), int32(childKeyLen), int32(valuePtr), int32(valueLen))
+	require.Nil(t, err)
+
+	// call wasm function to check for value, this should be set now
+	res, err = getValueFunc(int32(storageKeyPtr), int32(storageKeyLen), int32(childKeyPtr), int32(childKeyLen), int32(writtenOut))
+	require.NoError(t, err)
+	require.Equal(t, []byte{0x5, 0x0, 0x0, 0x0}, mem[writtenOut:writtenOut+4])
+	require.Equal(t, value, mem[res.ToI32():res.ToI32()+5])
+}

lib/runtime/interface.go

@@ -33,6 +33,7 @@ type Storage interface {
 	Entries() map[string][]byte
 	SetBalance(key [32]byte, balance uint64) error
 	GetBalance(key [32]byte) (uint64, error)
+	DeleteChildStorage(key []byte) error
 }
 
 // BasicNetwork interface for functions used by runtime network state function

lib/runtime/test_helpers.go

@@ -283,6 +283,10 @@ func (trs testRuntimeStorage) GetBalance(key [32]byte) (uint64, error) {
 	return binary.LittleEndian.Uint64(bal), nil
 }
 
+func (trs testRuntimeStorage) DeleteChildStorage(key []byte) error {
+	return trs.trie.DeleteFromChild(key)
+}
+
 type testRuntimeNetwork struct {
 }
 

lib/trie/child_storage.go

@@ -23,7 +23,7 @@ import (
 )
 
 // ChildStorageKeyPrefix is the prefix for all child storage keys
-var ChildStorageKeyPrefix = []byte(":child_storage:")
+var ChildStorageKeyPrefix = []byte(":child_storage:default:")
 
 // PutChild inserts a child trie into the main trie at key :child_storage:[keyToChild]
 func (t *Trie) PutChild(keyToChild []byte, child *Trie) error {
@@ -98,3 +98,9 @@ func (t *Trie) GetFromChild(keyToChild, key []byte) ([]byte, error) {
 
 	return child.Get(key)
 }
+
+// DeleteFromChild deletes from child storage
+func (t *Trie) DeleteFromChild(keyToChild []byte) error {
+	key := append(ChildStorageKeyPrefix, keyToChild...)
+	return t.Delete(key)
+}