Entitlements Migration

migrations/entitlements/migration.go

@@ -0,0 +1,245 @@
+/*
+ * Cadence - The resource-oriented smart contract programming language
+ *
+ * Copyright Dapper Labs, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package entitlements
+
+import (
+	"github.com/onflow/cadence/migrations"
+	"github.com/onflow/cadence/runtime/interpreter"
+	"github.com/onflow/cadence/runtime/sema"
+)
+
+type EntitlementsMigration struct {
+	Interpreter *interpreter.Interpreter
+}
+
+var _ migrations.Migration = EntitlementsMigration{}
+
+func NewEntitlementsMigration(inter *interpreter.Interpreter) EntitlementsMigration {
+	return EntitlementsMigration{Interpreter: inter}
+}
+
+func (EntitlementsMigration) Name() string {
+	return "EntitlementsMigration"
+}
+
+// Converts its input to an entitled type according to the following rules:
+// * `ConvertToEntitledType(&T) ---> auth(Entitlements(T)) &T`
+// * `ConvertToEntitledType(Capability<T>) ---> Capability<ConvertToEntitledType(T)>`
+// * `ConvertToEntitledType(T?) ---> ConvertToEntitledType(T)?
+// * `ConvertToEntitledType(T) ---> T`
+// where Entitlements(I) is defined as the result of T.SupportedEntitlements()
+func ConvertToEntitledType(t sema.Type) sema.Type {
+	switch t := t.(type) {
+	case *sema.ReferenceType:
+		switch t.Authorization {
+		case sema.UnauthorizedAccess:
+			innerType := ConvertToEntitledType(t.Type)
+			auth := sema.UnauthorizedAccess
+			if entitlementSupportingType, ok := innerType.(sema.EntitlementSupportingType); ok {
+				supportedEntitlements := entitlementSupportingType.SupportedEntitlements()
+				if supportedEntitlements.Len() > 0 {
+					auth = sema.EntitlementSetAccess{
+						SetKind:      sema.Conjunction,
+						Entitlements: supportedEntitlements,
+					}
+				}
+			}
+			return sema.NewReferenceType(
+				nil,
+				auth,
+				innerType,
+			)
+		// type is already entitled
+		default:
+			return t
+		}
+	case *sema.OptionalType:
+		return sema.NewOptionalType(nil, ConvertToEntitledType(t.Type))
+	case *sema.CapabilityType:
+		return sema.NewCapabilityType(nil, ConvertToEntitledType(t.BorrowType))
+	case *sema.VariableSizedType:
+		return sema.NewVariableSizedType(nil, ConvertToEntitledType(t.Type))
+	case *sema.ConstantSizedType:
+		return sema.NewConstantSizedType(nil, ConvertToEntitledType(t.Type), t.Size)
+	case *sema.DictionaryType:
+		return sema.NewDictionaryType(nil, ConvertToEntitledType(t.KeyType), ConvertToEntitledType(t.ValueType))
+	default:
+		return t
+	}
+}
+
+// Converts the input value into a version compatible with the new entitlements feature,
+// with the same members/operations accessible on any references as would have been accessible in the past.
+func ConvertValueToEntitlements(
+	inter *interpreter.Interpreter,
+	v interpreter.Value,
+) interpreter.Value {
+
+	var staticType interpreter.StaticType
+	// for reference types, we want to use the borrow type, rather than the type of the referenced value
+	switch referenceValue := v.(type) {
+	case *interpreter.EphemeralReferenceValue:
+		staticType = interpreter.NewReferenceStaticType(
+			inter,
+			referenceValue.Authorization,
+			interpreter.ConvertSemaToStaticType(inter, referenceValue.BorrowedType),
+		)
+	case *interpreter.StorageReferenceValue:
+		staticType = interpreter.NewReferenceStaticType(
+			inter,
+			referenceValue.Authorization,
+			interpreter.ConvertSemaToStaticType(inter, referenceValue.BorrowedType),
+		)
+	default:
+		staticType = v.StaticType(inter)
+	}
+
+	// if the static type contains a legacy restricted type, convert it to a new type according to some rules:
+	// &T{I} -> auth(SupportedEntitlements(I)) &T
+	// Capability<&T{I}> -> Capability<auth(SupportedEntitlements(I)) &T>
+	var convertLegacyStaticType func(interpreter.StaticType)
+	convertLegacyStaticType = func(staticType interpreter.StaticType) {
+		switch t := staticType.(type) {
+		case *interpreter.ReferenceStaticType:
+			switch referencedType := t.ReferencedType.(type) {
+			case *interpreter.IntersectionStaticType:
+				if referencedType.LegacyType != nil {
+					t.ReferencedType = referencedType.LegacyType
+					intersectionSemaType := inter.MustConvertStaticToSemaType(referencedType).(*sema.IntersectionType)
+					auth := sema.UnauthorizedAccess
+					supportedEntitlements := intersectionSemaType.SupportedEntitlements()
+					if supportedEntitlements.Len() > 0 {
+						auth = sema.EntitlementSetAccess{
+							SetKind:      sema.Conjunction,
+							Entitlements: supportedEntitlements,
+						}
+					}
+					t.Authorization = interpreter.ConvertSemaAccessToStaticAuthorization(inter, auth)
+				}
+			}
+		case *interpreter.CapabilityStaticType:
+			convertLegacyStaticType(t.BorrowType)
+		case *interpreter.VariableSizedStaticType:
+			convertLegacyStaticType(t.Type)
+		case *interpreter.ConstantSizedStaticType:
+			convertLegacyStaticType(t.Type)
+		case *interpreter.DictionaryStaticType:
+			convertLegacyStaticType(t.KeyType)
+			convertLegacyStaticType(t.ValueType)
+		case *interpreter.OptionalStaticType:
+			convertLegacyStaticType(t.Type)
+		}
+	}
+
+	convertLegacyStaticType(staticType)
+	semaType := inter.MustConvertStaticToSemaType(staticType)
+	entitledType := ConvertToEntitledType(semaType)
+
+	// if the types of the values are equal and the value is not a runtime type, there's nothing to migrate
+	if entitledType.Equal(semaType) && !entitledType.Equal(sema.MetaType) {
+		return nil
+	}
+
+	switch v := v.(type) {
+	case *interpreter.EphemeralReferenceValue:
+		entitledReferenceType := entitledType.(*sema.ReferenceType)
+		staticAuthorization := interpreter.ConvertSemaAccessToStaticAuthorization(inter, entitledReferenceType.Authorization)
+		convertedValue := ConvertValueToEntitlements(inter, v.Value)
+		// if the underlying value did not change, we still want to use the old value in the newly created reference
+		if convertedValue == nil {
+			convertedValue = v.Value
+		}
+		return interpreter.NewEphemeralReferenceValue(
+			inter,
+			staticAuthorization,
+			convertedValue,
+			entitledReferenceType.Type,
+			interpreter.EmptyLocationRange,
+		)
+
+	case *interpreter.StorageReferenceValue:
+		// a stored value will in itself be migrated at another point, so no need to do anything here other than change the type
+		entitledReferenceType := entitledType.(*sema.ReferenceType)
+		staticAuthorization := interpreter.ConvertSemaAccessToStaticAuthorization(inter, entitledReferenceType.Authorization)
+		return interpreter.NewStorageReferenceValue(
+			inter,
+			staticAuthorization,
+			v.TargetStorageAddress,
+			v.TargetPath,
+			entitledReferenceType.Type,
+		)
+
+	case *interpreter.ArrayValue:
+		entitledArrayType := entitledType.(sema.ArrayType)
+		arrayStaticType := interpreter.ConvertSemaArrayTypeToStaticArrayType(inter, entitledArrayType)
+
+		iterator := v.Iterator(inter)
+
+		newArray := interpreter.NewArrayValueWithIterator(inter, arrayStaticType, v.GetOwner(), uint64(v.Count()), func() interpreter.Value {
+			return iterator.Next(inter)
+		})
+		return newArray
+
+	case *interpreter.DictionaryValue:
+		entitledDictionaryType := entitledType.(*sema.DictionaryType)
+		dictionaryStaticType := interpreter.ConvertSemaDictionaryTypeToStaticDictionaryType(inter, entitledDictionaryType)
+
+		var values []interpreter.Value
+
+		v.Iterate(inter, func(key, value interpreter.Value) (resume bool) {
+			values = append(values, key)
+			values = append(values, value)
+			return true
+		})
+
+		newDict := interpreter.NewDictionaryValue(
+			inter,
+			interpreter.EmptyLocationRange,
+			dictionaryStaticType,
+			values...,
+		)
+		return newDict
+
+	case *interpreter.CapabilityValue:
+		// capabilities should just have their borrow type updated, as the pointed-to value will also be visited
+		// by the migration on its own
+		entitledCapabilityValue := entitledType.(*sema.CapabilityType)
+		capabilityStaticType := interpreter.ConvertSemaToStaticType(inter, entitledCapabilityValue.BorrowType)
+		return interpreter.NewCapabilityValue(inter, v.ID, v.Address, capabilityStaticType)
+
+	case interpreter.TypeValue:
+		if v.Type == nil {
+			return nil
+		}
+		// convert the static type of the value
+		entitledStaticType := interpreter.ConvertSemaToStaticType(
+			inter,
+			ConvertToEntitledType(
+				inter.MustConvertStaticToSemaType(v.Type),
+			),
+		)
+		return interpreter.NewTypeValue(inter, entitledStaticType)
+	}
+
+	return nil
+}
+
+func (mig EntitlementsMigration) Migrate(value interpreter.Value) (newValue interpreter.Value) {
+	return ConvertValueToEntitlements(mig.Interpreter, value)
+}