1 files changed, 105 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/packages/SkylarkInfo.java b/src/main/java/com/google/devtools/build/lib/packages/SkylarkInfo.java
new file mode 100644
index 0000000000..755a5df5f1
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/packages/SkylarkInfo.java
@@ -0,0 +1,105 @@
+// Copyright 2017 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.common.base.Joiner;
+import com.google.common.collect.ImmutableCollection;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Sets;
+import com.google.common.collect.Sets.SetView;
+import com.google.devtools.build.lib.events.Location;
+import com.google.devtools.build.lib.packages.NativeProvider.StructConstructor;
+import com.google.devtools.build.lib.syntax.Concatable;
+import com.google.devtools.build.lib.syntax.EvalException;
+import com.google.devtools.build.lib.syntax.EvalUtils;
+import java.util.Map;
+
+/** Implementation of {@link Info} created from Skylark. */
+public final class SkylarkInfo extends Info implements Concatable {
+  protected final ImmutableMap<String, Object> values;
+
+  public SkylarkInfo(Provider provider, Map<String, Object> kwargs, Location loc) {
+    super(provider, loc);
+    this.values = copyValues(kwargs);
+  }
+
+  public SkylarkInfo(StructConstructor provider, Map<String, Object> values, String message) {
+    super(provider, values, message);
+    this.values = copyValues(values);
+  }
+
+  @Override
+  public Concatter getConcatter() {
+    return StructConcatter.INSTANCE;
+  }
+
+  @Override
+  public Object getValue(String name) {
+    return values.get(name);
+  }
+
+  @Override
+  public boolean hasKey(String name) {
+    return values.containsKey(name);
+  }
+
+  @Override
+  public ImmutableCollection<String> getKeys() {
+    return values.keySet();
+  }
+
+  @Override
+  public boolean isImmutable() {
+    // If the provider is not yet exported the hash code of the object is subject to change
+    if (!getProvider().isExported()) {
+      return false;
+    }
+    for (Object item : values.values()) {
+      if (!EvalUtils.isImmutable(item)) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  private static class StructConcatter implements Concatter {
+    private static final StructConcatter INSTANCE = new StructConcatter();
+
+    private StructConcatter() {}
+
+    @Override
+    public SkylarkInfo concat(Concatable left, Concatable right, Location loc)
+        throws EvalException {
+      SkylarkInfo lval = (SkylarkInfo) left;
+      SkylarkInfo rval = (SkylarkInfo) right;
+      if (!lval.getProvider().equals(rval.getProvider())) {
+        throw new EvalException(
+            loc,
+            String.format(
+                "Cannot concat %s with %s",
+                lval.getProvider().getPrintableName(), rval.getProvider().getPrintableName()));
+      }
+      SetView<String> commonFields = Sets.intersection(lval.values.keySet(), rval.values.keySet());
+      if (!commonFields.isEmpty()) {
+        throw new EvalException(
+            loc,
+            "Cannot concat structs with common field(s): " + Joiner.on(",").join(commonFields));
+      }
+      return new SkylarkInfo(
+          lval.getProvider(),
+          ImmutableMap.<String, Object>builder().putAll(lval.values).putAll(rval.values).build(),
+          loc);
+    }
+  }
+}