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// 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.common.collect.ImmutableMap;
import com.google.devtools.build.lib.events.Location;
import com.google.devtools.build.lib.skylarkbuildapi.StructApi;
import com.google.devtools.build.lib.syntax.EvalException;
import com.google.devtools.build.lib.syntax.SkylarkDict;
import java.util.Map;
/**
* The provider for the built-in type {@code struct}.
*
* <p>Its singleton instance is {@link StructProvider#STRUCT}.
*/
public final class StructProvider extends BuiltinProvider<StructImpl>
implements StructApi.StructProviderApi {
/** "struct" function. */
public static final StructProvider STRUCT = new StructProvider();
StructProvider() {
super("struct", StructImpl.class);
}
@Override
public StructImpl createStruct(SkylarkDict<?, ?> kwargs, Location loc) throws EvalException {
Map<String, Object> kwargsMap = kwargs.getContents(String.class, Object.class, "kwargs");
if (kwargsMap.containsKey("to_json")) {
throw new EvalException(loc, "cannot override built-in struct function 'to_json'");
}
if (kwargsMap.containsKey("to_proto")) {
throw new EvalException(loc, "cannot override built-in struct function 'to_proto'");
}
return SkylarkInfo.createSchemaless(this, kwargsMap, loc);
}
/**
* Creates a struct with the given field values and message format for unknown fields.
*
* <p>The custom message is useful for objects that have fields but aren't exactly used as
* providers, such as the {@code native} object, and the struct fields of {@code ctx} like
* {@code ctx.attr}.
* */
public SkylarkInfo create(
Map<String, Object> values, String errorMessageFormatForUnknownField) {
return SkylarkInfo.createSchemalessWithCustomMessage(
this, values, errorMessageFormatForUnknownField);
}
/** Creates an empty struct with the given location. */
public SkylarkInfo createEmpty(Location loc) {
return SkylarkInfo.createSchemaless(this, ImmutableMap.of(), loc);
}
}