Pull PrerequisitePackageFunction out from TransitiveDependencyState.
This will be used later as a serialization dependency.
PiperOrigin-RevId: 566617390
Change-Id: If88b0f629580575b2a73f0af162b6a7e6ea7ca3d
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/PrerequisitePackageFunction.java b/src/main/java/com/google/devtools/build/lib/skyframe/PrerequisitePackageFunction.java
new file mode 100644
index 0000000..857042f
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/PrerequisitePackageFunction.java
@@ -0,0 +1,30 @@
+// Copyright 2023 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.cmdline.PackageIdentifier;
+import com.google.devtools.build.lib.packages.Package;
+import javax.annotation.Nullable;
+
+/**
+ * Looks up previously loaded packages.
+ *
+ * <p>Used by {@link ConfiguredTargetFunction} to lookup packages of dependencies.
+ */
+public interface PrerequisitePackageFunction {
+
+ /** Directly retrieves packages of dependencies from Skyframe without adding a dependency edge. */
+ @Nullable // Null if the package not available.
+ Package getExistingPackage(PackageIdentifier id) throws InterruptedException;
+}
