Add CommonAliasRule.

We need to have base class with logic related to alias rule. Based on this class other rule classes should be created, to avoid total code duplication.

RELNOTES:none
PiperOrigin-RevId: 195066568

1 files changed, 110 insertions, 0 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/rules/LateBoundAlias.java b/src/main/java/com/google/devtools/build/lib/rules/LateBoundAlias.java
new file mode 100644
index 0000000000..3e309c338b
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/rules/LateBoundAlias.java
@@ -0,0 +1,110 @@
+// Copyright 2018 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.rules;
+
+import static com.google.devtools.build.lib.packages.Attribute.attr;
+import static com.google.devtools.build.lib.packages.BuildType.LABEL;
+
+import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableMap;
+import com.google.devtools.build.lib.analysis.AliasProvider;
+import com.google.devtools.build.lib.analysis.BaseRuleClasses;
+import com.google.devtools.build.lib.analysis.ConfiguredTarget;
+import com.google.devtools.build.lib.analysis.RuleConfiguredTargetFactory;
+import com.google.devtools.build.lib.analysis.RuleContext;
+import com.google.devtools.build.lib.analysis.RuleDefinition;
+import com.google.devtools.build.lib.analysis.RuleDefinitionEnvironment;
+import com.google.devtools.build.lib.analysis.VisibilityProvider;
+import com.google.devtools.build.lib.analysis.VisibilityProviderImpl;
+import com.google.devtools.build.lib.analysis.config.BuildConfiguration;
+import com.google.devtools.build.lib.analysis.configuredtargets.RuleConfiguredTarget.Mode;
+import com.google.devtools.build.lib.cmdline.Label;
+import com.google.devtools.build.lib.packages.Attribute;
+import com.google.devtools.build.lib.packages.Attribute.LateBoundDefault;
+import com.google.devtools.build.lib.packages.RuleClass;
+import java.util.function.Function;
+
+/** Implements template for creating custom alias rules. */
+public class LateBoundAlias implements RuleConfiguredTargetFactory {
+
+  private static final String ATTRIBUTE_NAME = ":alias";
+
+  @Override
+  public ConfiguredTarget create(RuleContext ruleContext) {
+    ConfiguredTarget actual =
+        (ConfiguredTarget) ruleContext.getPrerequisite(ATTRIBUTE_NAME, Mode.TARGET);
+    return new AliasConfiguredTarget(
+        ruleContext,
+        actual,
+        ImmutableMap.of(
+            AliasProvider.class,
+            AliasProvider.fromAliasRule(ruleContext.getLabel(), actual),
+            VisibilityProvider.class,
+            new VisibilityProviderImpl(ruleContext.getVisibility())));
+  }
+
+  /**
+   *  Rule definition for custom alias rules"
+   */
+  public static class CommonAliasRule implements RuleDefinition {
+
+    private static final String ATTRIBUTE_NAME = ":alias";
+
+    private final String ruleName;
+    private final Function<
+            RuleDefinitionEnvironment,
+            LateBoundDefault<? extends BuildConfiguration.Fragment, Label>>
+        labelResolver;
+    private final Class<? extends BuildConfiguration.Fragment> fragmentClass;
+
+    public CommonAliasRule(
+        String ruleName,
+        Function<
+                RuleDefinitionEnvironment,
+                LateBoundDefault<? extends BuildConfiguration.Fragment, Label>>
+            labelResolver,
+        Class<? extends BuildConfiguration.Fragment> fragmentClass) {
+      this.ruleName = Preconditions.checkNotNull(ruleName);
+      this.labelResolver = Preconditions.checkNotNull(labelResolver);
+      this.fragmentClass = Preconditions.checkNotNull(fragmentClass);
+    }
+
+    protected Attribute.Builder<Label> makeAttribute(RuleDefinitionEnvironment environment) {
+      return attr(ATTRIBUTE_NAME, LABEL).value(labelResolver.apply(environment));
+    }
+
+    @Override
+    public RuleClass build(RuleClass.Builder builder, RuleDefinitionEnvironment environment) {
+      Attribute attribute = makeAttribute(environment).build();
+      Preconditions.checkArgument(attribute.getName().equals(ATTRIBUTE_NAME));
+      Preconditions.checkArgument(attribute.getType().equals(LABEL));
+
+      return builder
+          .requiresConfigurationFragments(fragmentClass)
+          .removeAttribute("licenses")
+          .removeAttribute("distribs")
+          .addAttribute(attribute)
+          .build();
+    }
+
+    @Override
+    public Metadata getMetadata() {
+      return Metadata.builder()
+          .name(ruleName)
+          .ancestors(BaseRuleClasses.BaseRule.class)
+          .factoryClass(LateBoundAlias.class)
+          .build();
+    }
+  }
+}