1 // Copyright 2017 The Bazel Authors. All rights reserved. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 package com.google.devtools.common.options; 16 17 import com.google.common.collect.ImmutableList; 18 import com.google.common.collect.ImmutableMap; 19 import java.lang.reflect.Constructor; 20 import java.lang.reflect.Modifier; 21 import java.util.Collection; 22 import java.util.Map; 23 import javax.annotation.concurrent.Immutable; 24 25 /** 26 * This extends IsolatedOptionsData with information that can only be determined once all the {@link 27 * OptionsBase} subclasses for a parser are known. In particular, this includes expansion 28 * information. 29 */ 30 @Immutable 31 final class OptionsData extends IsolatedOptionsData { 32 33 /** Mapping from each option to the (unparsed) options it expands to, if any. */ 34 private final ImmutableMap<OptionDefinition, ImmutableList<String>> evaluatedExpansions; 35 36 /** Construct {@link OptionsData} by extending an {@link IsolatedOptionsData} with new info. */ OptionsData( IsolatedOptionsData base, Map<OptionDefinition, ImmutableList<String>> evaluatedExpansions)37 private OptionsData( 38 IsolatedOptionsData base, Map<OptionDefinition, ImmutableList<String>> evaluatedExpansions) { 39 super(base); 40 this.evaluatedExpansions = ImmutableMap.copyOf(evaluatedExpansions); 41 } 42 43 private static final ImmutableList<String> EMPTY_EXPANSION = ImmutableList.<String>of(); 44 45 /** 46 * Returns the expansion of an options field, regardless of whether it was defined using {@link 47 * Option#expansion} or {@link Option#expansionFunction}. If the field is not an expansion option, 48 * returns an empty array. 49 */ getEvaluatedExpansion(OptionDefinition optionDefinition)50 public ImmutableList<String> getEvaluatedExpansion(OptionDefinition optionDefinition) { 51 ImmutableList<String> result = evaluatedExpansions.get(optionDefinition); 52 return result != null ? result : EMPTY_EXPANSION; 53 } 54 55 /** 56 * Constructs an {@link OptionsData} object for a parser that knows about the given {@link 57 * OptionsBase} classes. In addition to the work done to construct the {@link 58 * IsolatedOptionsData}, this also computes expansion information. If an option has static 59 * expansions or uses an expansion function that takes a Void object, try to precalculate the 60 * expansion here. 61 */ from(Collection<Class<? extends OptionsBase>> classes)62 static OptionsData from(Collection<Class<? extends OptionsBase>> classes) { 63 IsolatedOptionsData isolatedData = IsolatedOptionsData.from(classes); 64 65 // All that's left is to compute expansions. 66 ImmutableMap.Builder<OptionDefinition, ImmutableList<String>> evaluatedExpansionsBuilder = 67 ImmutableMap.builder(); 68 for (Map.Entry<String, OptionDefinition> entry : isolatedData.getAllOptionDefinitions()) { 69 OptionDefinition optionDefinition = entry.getValue(); 70 // Determine either the hard-coded expansion, or the ExpansionFunction class. The 71 // OptionProcessor checks at compile time that these aren't used together. 72 String[] constExpansion = optionDefinition.getOptionExpansion(); 73 Class<? extends ExpansionFunction> expansionFunctionClass = 74 optionDefinition.getExpansionFunction(); 75 if (constExpansion.length > 0) { 76 evaluatedExpansionsBuilder.put(optionDefinition, ImmutableList.copyOf(constExpansion)); 77 } else if (optionDefinition.usesExpansionFunction()) { 78 if (Modifier.isAbstract(expansionFunctionClass.getModifiers())) { 79 throw new AssertionError( 80 "The expansionFunction type " + expansionFunctionClass + " must be a concrete type"); 81 } 82 // Evaluate the ExpansionFunction. 83 ExpansionFunction instance; 84 try { 85 Constructor<?> constructor = expansionFunctionClass.getConstructor(); 86 instance = (ExpansionFunction) constructor.newInstance(); 87 } catch (Exception e) { 88 // This indicates an error in the ExpansionFunction, and should be discovered the first 89 // time it is used. 90 throw new AssertionError(e); 91 } 92 ImmutableList<String> expansion = instance.getExpansion(isolatedData); 93 evaluatedExpansionsBuilder.put(optionDefinition, expansion); 94 } 95 } 96 return new OptionsData(isolatedData, evaluatedExpansionsBuilder.build()); 97 } 98 } 99