1 files changed, 65 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/ExternalPackageFunction.java b/src/main/java/com/google/devtools/build/lib/skyframe/ExternalPackageFunction.java
new file mode 100644
index 0000000000..283e1a64ba
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/ExternalPackageFunction.java
@@ -0,0 +1,65 @@
+// Copyright 2016 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.skyframe;
+
+import com.google.devtools.build.lib.vfs.RootedPath;
+import com.google.devtools.build.skyframe.SkyFunction;
+import com.google.devtools.build.skyframe.SkyFunctionException;
+import com.google.devtools.build.skyframe.SkyKey;
+import com.google.devtools.build.skyframe.SkyValue;
+
+import javax.annotation.Nullable;
+
+/**
+ * A SkyFunction for resolving //external:* bindings.
+ *
+ * <p>This function iterates through the WorkspaceFileValue-s to get the last WorkspaceFileValue
+ * that will contains all the bind statements from the workspace file.
+ */
+public class ExternalPackageFunction implements SkyFunction {
+
+  @Nullable
+  @Override
+  public SkyValue compute(SkyKey skyKey, Environment env)
+      throws SkyFunctionException, InterruptedException {
+    RootedPath workspacePath = (RootedPath) skyKey.argument();
+    SkyKey key = WorkspaceFileValue.key(workspacePath);
+    WorkspaceFileValue value = (WorkspaceFileValue) env.getValue(key);
+    if (value == null) {
+      return null;
+    }
+    // Walk to the last WorkspaceFileValue that accumulate all the bindings of the WORKSPACE
+    // file.
+    while (value.next() != null) {
+      value = (WorkspaceFileValue) env.getValue(value.next());
+      if (value == null) {
+        return null;
+      }
+    }
+    return new PackageValue(value.getPackage());
+  }
+
+  @Override
+  public String extractTag(SkyKey skyKey) {
+    return null;
+  }
+
+  /**
+   * Returns a SkyKey to find the WORKSPACE file at the given path.
+   */
+  public static SkyKey key(RootedPath workspacePath) {
+    return new SkyKey(SkyFunctions.EXTERNAL_PACKAGE, workspacePath);
+  }
+}