| // Copyright 2022 The Bazel Authors. All rights reserved. |
| // |
| // 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 net.starlark.java.eval; |
| |
| import javax.annotation.Nullable; |
| |
| /** |
| * Wrapper interface on a value in the predeclared lexical block, that controls its accessibility to |
| * Starlark based on the value of a semantic flag and/or the Module's client data. |
| * |
| * <p>For example, this could control whether symbol "Foo" exists in the Starlark global frame: such |
| * a symbol might only be accessible if --experimental_foo is set to true. In order to create this |
| * control, an instance of this class should be added to the global frame under name "Foo". This |
| * guard will throw a descriptive {@link EvalException} when "Foo" would be accessed without the |
| * proper flag. |
| */ |
| public interface GuardedValue { |
| |
| /** |
| * Returns an error describing an attempt to access this guard's protected object when it should |
| * be inaccessible under the (contextually implied) semantics and client data. |
| */ |
| String getErrorFromAttemptingAccess(String name); |
| |
| /** |
| * Returns this guard's underlying object. This should be called when appropriate validation has |
| * occurred to ensure that the object is accessible with the (implied) semantics. |
| */ |
| Object getObject(); |
| |
| /** |
| * Returns true if this guard's underlying object is accessible under the given semantics and |
| * client data. |
| */ |
| boolean isObjectAccessibleUsingSemantics( |
| StarlarkSemantics semantics, @Nullable Object clientData); |
| } |