Use a new pattern for builtin Provider objects with @SkylarkCallable.
This deprecates the old NativeProvider pattern.
The new pattern is demonstrated using AppleStaticLibraryInfo.
RELNOTES: None.
PiperOrigin-RevId: 194956883
diff --git a/src/main/java/com/google/devtools/build/lib/packages/BuiltinProvider.java b/src/main/java/com/google/devtools/build/lib/packages/BuiltinProvider.java
new file mode 100644
index 0000000..bb12ae3
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/packages/BuiltinProvider.java
@@ -0,0 +1,91 @@
+// Copyright 2018 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.packages;
+
+import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
+import com.google.devtools.build.lib.events.Location;
+import com.google.devtools.build.lib.packages.NativeProvider.NativeKey;
+import com.google.devtools.build.lib.skylarkinterface.SkylarkPrinter;
+import javax.annotation.Nullable;
+
+/**
+ * Base class for declared providers {@see Provider} defined in native code.
+ *
+ * <p>Every subclass of {@link BuiltinProvider} corresponds to a single declared
+ * provider. This is enforced by final {@link #equals(Object)} and {@link #hashCode()}.
+ *
+ * <p>Implementations of native declared providers should subclass this class, and define a method
+ * in the subclass definition to create instances of its corresponding Info object. The method
+ * should be annotated with {@link SkylarkCallable} with {@link SkylarkCallable#selfCall} set to
+ * true, and with {@link SkylarkConstructor} for the info type it constructs.
+ */
+@Immutable
+public abstract class BuiltinProvider<T extends Info> implements Provider {
+ private final NativeKey key;
+ private final String name;
+ private final Class<T> valueClass;
+
+ public Class<T> getValueClass() {
+ return valueClass;
+ }
+
+ public BuiltinProvider(String name, Class<T> valueClass) {
+ @SuppressWarnings("unchecked")
+ Class<? extends BuiltinProvider<?>> clazz = (Class<? extends BuiltinProvider<?>>) getClass();
+ key = new NativeKey(name, clazz);
+ this.name = name;
+ this.valueClass = valueClass;
+ }
+
+ /**
+ * equals() implements singleton class semantics.
+ */
+ @Override
+ public final boolean equals(@Nullable Object other) {
+ return other != null && this.getClass().equals(other.getClass());
+ }
+
+ /**
+ * hashCode() implements singleton class semantics.
+ */
+ @Override
+ public final int hashCode() {
+ return getClass().hashCode();
+ }
+
+ @Override
+ public boolean isExported() {
+ return true;
+ }
+
+ @Override
+ public NativeKey getKey() {
+ return key;
+ }
+
+ @Override
+ public Location getLocation() {
+ return Location.BUILTIN;
+ }
+
+ @Override
+ public String getPrintableName() {
+ return name;
+ }
+
+ @Override
+ public void repr(SkylarkPrinter printer) {
+ printer.append("<function " + getPrintableName() + ">");
+ }
+}
