Skylark: Package environment extensions can register functions with t…

…he native module.

--
MOS_MIGRATED_REVID=89309511

src/main/java/com/google/devtools/build/lib/packages/PackageFactory.java

@@ -142,6 +142,11 @@ public interface EnvironmentExtension {
     void update(Environment environment, MakeEnvironment.Builder pkgMakeEnv,
         Label buildFileLabel);
 
+    /**
+     * Returns the extra functions needed to be added to the Skylark native module.
+     */
+    ImmutableList<Function> nativeModuleFunctions();
+
     Iterable<PackageArgument<?>> getPackageArguments();
   }
 
@@ -821,7 +826,7 @@ private static RuleClass getBuiltInRuleClass(String ruleClassName, RuleFactory r
   /**
    * Get the PackageContext by looking up in the environment.
    */
-  private static PackageContext getContext(Environment env, FuncallExpression ast)
+  public static PackageContext getContext(Environment env, FuncallExpression ast)
       throws EvalException {
     try {
       return (PackageContext) env.lookup(PKG_CONTEXT);
@@ -1069,6 +1074,13 @@ public PackageContext(Package.LegacyBuilder pkgBuilder, Globber globber,
       this.eventHandler = eventHandler;
       this.globber = globber;
     }
+
+    /**
+     * Returns the Label of this Package.
+     */
+    public Label getLabel() {
+      return pkgBuilder.getBuildFileLabel();
+    }
   }
 
   /**
@@ -1081,6 +1093,9 @@ public ImmutableList<Function> collectNativeRuleFunctions() {
       builder.add(newRuleFunction(ruleFactory, ruleClass));
     }
     builder.add(newPackageFunction(packageArguments));
+    for (EnvironmentExtension extension : environmentExtensions) {
+      builder.addAll(extension.nativeModuleFunctions());
+    }
     return builder.build();
   }
 

src/main/java/com/google/devtools/build/lib/runtime/BlazeModule.java

@@ -40,6 +40,7 @@
 import com.google.devtools.build.lib.skyframe.SkyframeExecutor;
 import com.google.devtools.build.lib.skyframe.SkyframeExecutorFactory;
 import com.google.devtools.build.lib.syntax.Environment;
+import com.google.devtools.build.lib.syntax.Function;
 import com.google.devtools.build.lib.syntax.Label;
 import com.google.devtools.build.lib.util.AbruptExitException;
 import com.google.devtools.build.lib.util.Clock;
@@ -359,6 +360,11 @@ public void update(
       public Iterable<PackageArgument<?>> getPackageArguments() {
         return ImmutableList.of();
       }
+
+      @Override
+      public ImmutableList<Function> nativeModuleFunctions() {
+        return ImmutableList.<Function>of();
+      }
     };
   }