1 files changed, 28 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/rules/platform/ConstraintSetting.java b/src/main/java/com/google/devtools/build/lib/rules/platform/ConstraintSetting.java
index 653ea2fe4f..6c903fd04a 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/platform/ConstraintSetting.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/platform/ConstraintSetting.java
@@ -14,13 +14,18 @@
 
 package com.google.devtools.build.lib.rules.platform;
 
+import com.google.common.base.Function;
+import com.google.common.collect.Iterables;
 import com.google.devtools.build.lib.analysis.ConfiguredTarget;
 import com.google.devtools.build.lib.analysis.FileProvider;
 import com.google.devtools.build.lib.analysis.FilesToRunProvider;
 import com.google.devtools.build.lib.analysis.RuleConfiguredTargetBuilder;
 import com.google.devtools.build.lib.analysis.RuleContext;
 import com.google.devtools.build.lib.analysis.RunfilesProvider;
+import com.google.devtools.build.lib.analysis.TransitiveInfoCollection;
+import com.google.devtools.build.lib.analysis.platform.ConstraintSettingInfo;
 import com.google.devtools.build.lib.rules.RuleConfiguredTargetFactory;
+import com.google.devtools.build.lib.util.Preconditions;
 
 /**
  * Defines a category of constraint that can be fulfilled by a constraint_value rule in a platform
@@ -39,4 +44,27 @@ public class ConstraintSetting implements RuleConfiguredTargetFactory {
         .addNativeDeclaredProvider(ConstraintSettingInfo.create(ruleContext.getLabel()))
         .build();
   }
+
+  /** Retrieves and casts the provider from the given target. */
+  public static ConstraintSettingInfo constraintSetting(TransitiveInfoCollection target) {
+    Object provider = target.get(ConstraintSettingInfo.SKYLARK_IDENTIFIER);
+    if (provider == null) {
+      return null;
+    }
+    Preconditions.checkState(provider instanceof ConstraintSettingInfo);
+    return (ConstraintSettingInfo) provider;
+  }
+
+  /** Retrieves and casts the providers from the given targets. */
+  public static Iterable<ConstraintSettingInfo> constraintSettings(
+      Iterable<? extends TransitiveInfoCollection> targets) {
+    return Iterables.transform(
+        targets,
+        new Function<TransitiveInfoCollection, ConstraintSettingInfo>() {
+          @Override
+          public ConstraintSettingInfo apply(TransitiveInfoCollection target) {
+            return constraintSetting(target);
+          }
+        });
+  }
 }