| // Copyright 2015 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.analysis.constraints; |
| |
| import static com.google.devtools.build.lib.packages.Attribute.attr; |
| |
| import com.google.common.collect.ImmutableList; |
| import com.google.devtools.build.lib.analysis.BaseRuleClasses; |
| import com.google.devtools.build.lib.analysis.RuleDefinition; |
| import com.google.devtools.build.lib.analysis.RuleDefinitionEnvironment; |
| import com.google.devtools.build.lib.analysis.config.HostTransition; |
| import com.google.devtools.build.lib.packages.BuildType; |
| import com.google.devtools.build.lib.packages.RuleClass; |
| import com.google.devtools.build.lib.syntax.Type; |
| import com.google.devtools.build.lib.util.FileTypeSet; |
| |
| /** |
| * Rule definition for environment rules (for Bazel's constraint enforcement system). |
| */ |
| public class EnvironmentRule implements RuleDefinition { |
| public static final String RULE_NAME = "environment"; |
| |
| public static final String FULFILLS_ATTRIBUTE = "fulfills"; |
| |
| @Override |
| public RuleClass build(RuleClass.Builder builder, RuleDefinitionEnvironment env) { |
| return builder |
| .cfg(HostTransition.createFactory()) |
| .override( |
| attr("tags", Type.STRING_LIST) |
| // No need to show up in ":all", etc. target patterns. |
| .value(ImmutableList.of("manual")) |
| .nonconfigurable("low-level attribute, used in TargetUtils without configurations")) |
| /* <!-- #BLAZE_RULE(environment).ATTRIBUTE(fulfills) --> |
| The set of environments this one is considered a valid "standin" for. |
| <p> |
| If rule A depends on rule B, A declares compatibility with environment <code>:foo</code>, |
| and B declares compatibility with environment <code>:bar</code>, this is normally not |
| considered a valid dependency. But if <code>:bar</code> fulfills <code>:foo</code>, the |
| dependency is considered valid. B's own dependencies are subsequently expected to support |
| <code>:bar</code> (the original expectation for <code>:foo</code> is dropped). |
| </p> |
| <p> |
| Environments may only fulfill other environments in the same environment group. |
| </p> |
| <!-- #END_BLAZE_RULE.ATTRIBUTE --> */ |
| .add( |
| attr(FULFILLS_ATTRIBUTE, BuildType.LABEL_LIST) |
| .allowedRuleClasses(EnvironmentRule.RULE_NAME) |
| .allowedFileTypes(FileTypeSet.NO_FILE) |
| .nonconfigurable( |
| "used for defining constraint models - this shouldn't be configured")) |
| .exemptFromConstraintChecking("this rule *defines* a constraint") |
| .setUndocumented() |
| .build(); |
| } |
| |
| @Override |
| public Metadata getMetadata() { |
| return RuleDefinition.Metadata.builder() |
| .name(EnvironmentRule.RULE_NAME) |
| .ancestors(BaseRuleClasses.BaseRule.class) |
| .factoryClass(Environment.class) |
| .build(); |
| } |
| } |