1 files changed, 78 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/MakeVariableSupplier.java b/src/main/java/com/google/devtools/build/lib/analysis/MakeVariableSupplier.java
new file mode 100644
index 0000000000..911456965b
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/analysis/MakeVariableSupplier.java
@@ -0,0 +1,78 @@
+// Copyright 2014 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.analysis;
+
+import com.google.common.collect.ImmutableMap;
+import com.google.devtools.build.lib.packages.Package;
+import com.google.devtools.build.lib.util.Preconditions;
+import javax.annotation.Nullable;
+
+/**
+ * Instances of {@link MakeVariableSupplier} passed to {@link ConfigurationMakeVariableContext} will
+ * be called before getting value from {@link ConfigurationMakeVariableContext} itself.
+ */
+public interface MakeVariableSupplier {
+
+  /** Returns Make variable value or null if value is not supplied. */
+  @Nullable
+  String getMakeVariable(String variableName);
+
+  /** Returns all Make variables that it supplies */
+  ImmutableMap<String, String> getAllMakeVariables();
+
+  /** {@link MakeVariableSupplier} that reads variables it supplies from a map. */
+  class MapBackedMakeVariableSupplier implements MakeVariableSupplier {
+
+    private final ImmutableMap<String, String> makeVariables;
+
+    public MapBackedMakeVariableSupplier(ImmutableMap<String, String> makeVariables) {
+      this.makeVariables = Preconditions.checkNotNull(makeVariables);
+    }
+
+    @Nullable
+    @Override
+    public String getMakeVariable(String variableName) {
+      return makeVariables.get(variableName);
+    }
+
+    @Override
+    public ImmutableMap<String, String> getAllMakeVariables() {
+      return makeVariables;
+    }
+  }
+
+  /** {@link MakeVariableSupplier} that reads variables it supplies from a {@link Package} */
+  class PackageBackedMakeVariableSupplier implements MakeVariableSupplier {
+
+    private final String platform;
+    private final Package pkg;
+
+    public PackageBackedMakeVariableSupplier(Package pkg, String platform) {
+      this.pkg = pkg;
+      this.platform = platform;
+    }
+
+    @Nullable
+    @Override
+    public String getMakeVariable(String variableName) {
+      return pkg.lookupMakeVariable(variableName, platform);
+    }
+
+    @Override
+    public ImmutableMap<String, String> getAllMakeVariables() {
+      return pkg.getAllMakeVariables(platform);
+    }
+  }
+}