Add flag_values attribute to config_setting.

This gives the ability to select on config_feature_flags. They still
have not been publicly documented, because there's no way to set them.
But, progress.

config_setting still needs to have either values or flag_values; it cannot
have both be empty. However, values is no longer mandatory, nor must it be
nonempty (as long as flag_values is set nonempty).

RELNOTES: None.
PiperOrigin-RevId: 152515036

1 files changed, 101 insertions, 0 deletions

diff --git a/src/test/java/com/google/devtools/build/lib/rules/config/FeatureFlagSetterRule.java b/src/test/java/com/google/devtools/build/lib/rules/config/FeatureFlagSetterRule.java
new file mode 100644
index 0000000000..0f40a0d8b0
--- /dev/null
+++ b/src/test/java/com/google/devtools/build/lib/rules/config/FeatureFlagSetterRule.java
@@ -0,0 +1,101 @@
+// Copyright 2017 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.config;
+
+import static com.google.devtools.build.lib.collect.nestedset.Order.STABLE_ORDER;
+import static com.google.devtools.build.lib.packages.Attribute.attr;
+import static com.google.devtools.build.lib.packages.BuildType.LABEL;
+import static com.google.devtools.build.lib.packages.BuildType.LABEL_KEYED_STRING_DICT;
+import static com.google.devtools.build.lib.packages.BuildType.LABEL_LIST;
+
+import com.google.common.collect.ImmutableMap;
+import com.google.devtools.build.lib.actions.Artifact;
+import com.google.devtools.build.lib.analysis.BaseRuleClasses;
+import com.google.devtools.build.lib.analysis.ConfiguredTarget;
+import com.google.devtools.build.lib.analysis.RuleConfiguredTarget.Mode;
+import com.google.devtools.build.lib.analysis.RuleConfiguredTargetBuilder;
+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.RunfilesProvider;
+import com.google.devtools.build.lib.analysis.TransitiveInfoCollection;
+import com.google.devtools.build.lib.analysis.config.ConfigMatchingProvider;
+import com.google.devtools.build.lib.cmdline.Label;
+import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
+import com.google.devtools.build.lib.packages.RuleClass;
+import com.google.devtools.build.lib.packages.RuleClass.Builder;
+import com.google.devtools.build.lib.rules.RuleConfiguredTargetFactory;
+
+/** Rule introducing a transition to set feature flags for dependencies. */
+public final class FeatureFlagSetterRule implements RuleDefinition, RuleConfiguredTargetFactory {
+
+  @Override
+  public RuleClass build(Builder builder, RuleDefinitionEnvironment env) {
+    return builder
+        .requiresConfigurationFragments(ConfigFeatureFlagConfiguration.class)
+        .cfg(new ConfigFeatureFlagTransitionFactory("flag_values"))
+        .add(attr("deps", LABEL_LIST).allowedFileTypes())
+        .add(
+            attr("exports_setting", LABEL)
+                .allowedRuleClasses("config_setting")
+                .allowedFileTypes())
+        .add(
+            attr("exports_flag", LABEL)
+                .allowedRuleClasses("config_feature_flag")
+                .allowedFileTypes())
+        .add(
+            attr("flag_values", LABEL_KEYED_STRING_DICT)
+                .allowedRuleClasses("config_feature_flag")
+                .allowedFileTypes()
+                .nonconfigurable("used in RuleTransitionFactory")
+                .value(ImmutableMap.<Label, String>of()))
+        .build();
+  }
+
+  @Override
+  public Metadata getMetadata() {
+    return RuleDefinition.Metadata.builder()
+        .name("feature_flag_setter")
+        .ancestors(BaseRuleClasses.BaseRule.class)
+        .factoryClass(FeatureFlagSetterRule.class)
+        .build();
+  }
+
+  @Override
+  public ConfiguredTarget create(RuleContext ruleContext)
+      throws InterruptedException, RuleErrorException {
+    TransitiveInfoCollection exportedFlag =
+        ruleContext.getPrerequisite("exports_flag", Mode.TARGET);
+    ConfigFeatureFlagProvider exportedFlagProvider =
+        exportedFlag != null ? ConfigFeatureFlagProvider.fromTarget(exportedFlag) : null;
+
+    TransitiveInfoCollection exportedSetting =
+        ruleContext.getPrerequisite("exports_setting", Mode.TARGET);
+    ConfigMatchingProvider exportedSettingProvider =
+        exportedSetting != null ? exportedSetting.getProvider(ConfigMatchingProvider.class) : null;
+
+    RuleConfiguredTargetBuilder builder =
+        new RuleConfiguredTargetBuilder(ruleContext)
+            .setFilesToBuild(NestedSetBuilder.<Artifact>emptySet(STABLE_ORDER))
+            .addProvider(RunfilesProvider.class, RunfilesProvider.EMPTY);
+    if (exportedFlagProvider != null) {
+      builder.addNativeDeclaredProvider(exportedFlagProvider);
+    }
+    if (exportedSettingProvider != null) {
+      builder.addProvider(ConfigMatchingProvider.class, exportedSettingProvider);
+    }
+    return builder.build();
+  }
+}