| // 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 com.google.devtools.build.lib.starlarkbuildapi.core; |
| |
| import com.google.common.collect.ImmutableSet; |
| import com.google.devtools.build.lib.cmdline.BazelCompileContext; |
| import com.google.devtools.build.lib.cmdline.Label; |
| import com.google.devtools.build.lib.cmdline.PackageIdentifier; |
| import java.util.stream.Collectors; |
| import javax.annotation.Nullable; |
| import net.starlark.java.eval.FlagGuardedValue; |
| import net.starlark.java.eval.GuardedValue; |
| import net.starlark.java.eval.StarlarkSemantics; |
| |
| /** |
| * Wrapper on a value in the predeclared lexical block that controls its accessibility to Starlark |
| * based on the value of a semantic flag and context, in particular the package path the requesting |
| * .bzl file falls under. |
| */ |
| public final class ContextAndFlagGuardedValue { |
| /** |
| * Creates a flag guard which only permits access of the given object when the given boolean flag |
| * is false or the requesting .bzl file is in a specific patckage path. If the given flag is true |
| * and the object would be accessed, an error is thrown describing the feature as deprecated, and |
| * describing that the flag may be set to false to re-enable it. |
| * |
| * <p>The flag identifier must have a + or - prefix; see StarlarkSemantics. |
| */ |
| public static GuardedValue onlyInAllowedReposOrWhenIncompatibleFlagIsFalse( |
| String flag, Object obj, ImmutableSet<PackageIdentifier> allowedPrefixes) { |
| GuardedValue flagGuard = FlagGuardedValue.onlyWhenIncompatibleFlagIsFalse(flag, obj); |
| return new GuardedValue() { |
| @Override |
| public boolean isObjectAccessibleUsingSemantics( |
| StarlarkSemantics semantics, @Nullable Object clientData) { |
| boolean accessible = flagGuard.isObjectAccessibleUsingSemantics(semantics, clientData); |
| // Filtering of predeclareds is only done at compile time, when the client data is |
| // BazelCompileContext and not BazelModuleContext. |
| if (!accessible && clientData != null && clientData instanceof BazelCompileContext) { |
| BazelCompileContext context = (BazelCompileContext) clientData; |
| Label label = context.label(); |
| |
| for (PackageIdentifier prefix : allowedPrefixes) { |
| if (label.getRepository().equals(prefix.getRepository()) |
| && label.getPackageFragment().startsWith(prefix.getPackageFragment())) { |
| return true; |
| } |
| } |
| } |
| return accessible; |
| } |
| |
| @Override |
| public String getErrorFromAttemptingAccess(String name) { |
| return name |
| + " may only be used from one of the following repositories or prefixes: " |
| + allowedPrefixes.stream() |
| .map(PackageIdentifier::toString) |
| .collect(Collectors.joining(", ")) |
| + ". It may be temporarily re-enabled for general use by setting --" |
| + flag.substring(1) |
| + "=false"; |
| } |
| |
| @Override |
| public Object getObject() { |
| return obj; |
| } |
| }; |
| } |
| |
| private ContextAndFlagGuardedValue() {} |
| } |