| // 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.regex.Pattern; |
| import java.util.stream.Collectors; |
| import javax.annotation.Nullable; |
| 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 context, in particular the package path the requesting .bzl file falls under. |
| */ |
| public final class ContextGuardedValue { |
| |
| private ContextGuardedValue() {} |
| |
| /** |
| * Creates a guard which only permits access of the given object when the requesting .bzl file's |
| * repo name matches one of the (repoNameSubstr, pathPrefix) entries (note: under bzlmod, repos |
| * are prefixed with the bzlmod module name). An error is thrown if accessing it is done outside |
| * the allowed package paths. |
| */ |
| public static GuardedValue onlyInAllowedRepos( |
| Object obj, ImmutableSet<PackageIdentifier> allowedEntries) { |
| return new GuardedValue() { |
| @Override |
| public boolean isObjectAccessibleUsingSemantics( |
| StarlarkSemantics semantics, @Nullable Object clientData) { |
| // Filtering of predeclareds is only done at compile time, when the client data is |
| // BazelCompileContext and not BazelModuleContext. |
| if (clientData != null && clientData instanceof BazelCompileContext) { |
| BazelCompileContext context = (BazelCompileContext) clientData; |
| Label label = context.label(); |
| |
| for (PackageIdentifier entry : allowedEntries) { |
| String pattern; |
| if (entry.getRepository().getName().isEmpty()) { |
| // String.matches has ^$ implicilty, so an empty pattern matches exactly the empty |
| // string. |
| pattern = ""; |
| } else { |
| // Surrounding .* because String.matches has implicit "^$" anchor. |
| // Surrounding \b so it doesn't match a substring of the intended repo name. |
| // Quote the name so dots in the repo name don't get treated as part of the pattern |
| pattern = ".*\\b" + Pattern.quote(entry.getRepository().getName()) + "\\b.*"; |
| } |
| if (label.getRepository().getName().matches(pattern) |
| && label.getPackageFragment().startsWith(entry.getPackageFragment())) { |
| return true; |
| } |
| } |
| } |
| return false; |
| } |
| |
| @Override |
| public String getErrorFromAttemptingAccess(String name) { |
| return name |
| + " may only be used from one of the following repositories or prefixes: " |
| + allowedEntries.stream() |
| .map(PackageIdentifier::toString) |
| .collect(Collectors.joining(", ")); |
| } |
| |
| @Override |
| public Object getObject() { |
| return obj; |
| } |
| }; |
| } |
| } |