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// 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.common.options;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Maps;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.Collection;
import java.util.Map;
import javax.annotation.concurrent.Immutable;
/**
* This extends IsolatedOptionsData with information that can only be determined once all the {@link
* OptionsBase} subclasses for a parser are known. In particular, this includes expansion
* information.
*/
@Immutable
final class OptionsData extends IsolatedOptionsData {
/**
* Mapping from each Option-annotated field with a {@code String[]} expansion to that expansion.
*/
// TODO(brandjon): This is technically not necessarily immutable due to String[], and should use
// ImmutableList. Either fix this or remove @Immutable.
private final ImmutableMap<Field, String[]> evaluatedExpansions;
/** Construct {@link OptionsData} by extending an {@link IsolatedOptionsData} with new info. */
private OptionsData(IsolatedOptionsData base, Map<Field, String[]> evaluatedExpansions) {
super(base);
this.evaluatedExpansions = ImmutableMap.copyOf(evaluatedExpansions);
}
private static final String[] EMPTY_EXPANSION = new String[] {};
/**
* Returns the expansion of an options field, regardless of whether it was defined using {@link
* Option#expansion} or {@link Option#expansionFunction}. If the field is not an expansion option,
* returns an empty array.
*/
public String[] getEvaluatedExpansion(Field field) {
String[] result = evaluatedExpansions.get(field);
return result != null ? result : EMPTY_EXPANSION;
}
/**
* Constructs an {@link OptionsData} object for a parser that knows about the given {@link
* OptionsBase} classes. In addition to the work done to construct the {@link
* IsolatedOptionsData}, this also computes expansion information.
*/
public static OptionsData from(Collection<Class<? extends OptionsBase>> classes) {
IsolatedOptionsData isolatedData = IsolatedOptionsData.from(classes);
// All that's left is to compute expansions.
Map<Field, String[]> evaluatedExpansionsBuilder = Maps.newHashMap();
for (Map.Entry<String, Field> entry : isolatedData.getAllNamedFields()) {
Field field = entry.getValue();
Option annotation = field.getAnnotation(Option.class);
// Determine either the hard-coded expansion, or the ExpansionFunction class.
String[] constExpansion = annotation.expansion();
Class<? extends ExpansionFunction> expansionFunctionClass = annotation.expansionFunction();
if (constExpansion.length > 0 && usesExpansionFunction(annotation)) {
throw new AssertionError(
"Cannot set both expansion and expansionFunction for option --" + annotation.name());
} else if (constExpansion.length > 0) {
evaluatedExpansionsBuilder.put(field, constExpansion);
} else if (usesExpansionFunction(annotation)) {
if (Modifier.isAbstract(expansionFunctionClass.getModifiers())) {
throw new AssertionError(
"The expansionFunction type " + expansionFunctionClass + " must be a concrete type");
}
// Evaluate the ExpansionFunction.
ExpansionFunction instance;
try {
Constructor<?> constructor = expansionFunctionClass.getConstructor();
instance = (ExpansionFunction) constructor.newInstance();
} catch (Exception e) {
// This indicates an error in the ExpansionFunction, and should be discovered the first
// time it is used.
throw new AssertionError(e);
}
String[] expansion = instance.getExpansion(isolatedData);
evaluatedExpansionsBuilder.put(field, expansion);
}
}
return new OptionsData(isolatedData, evaluatedExpansionsBuilder);
}
}
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