// Copyright 2014 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.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.devtools.build.lib.cmdline.Label;
import com.google.devtools.build.lib.packages.Attribute.ComputedDefault;
import com.google.devtools.build.lib.packages.BuildType.Selector;
import com.google.devtools.build.lib.packages.BuildType.SelectorList;
import com.google.devtools.build.lib.syntax.Type;
import com.google.devtools.build.lib.util.Preconditions;
import java.util.Collection;
import java.util.List;
import javax.annotation.Nullable;
/**
* {@link AttributeMap} implementation that returns raw attribute information as contained within
* a {@link Rule} via {@link #getRawAttributeValue}. In particular, configurable attributes
* of the form { config1: "value1", config2: "value2" } are passed through without being resolved
* to a final value when obtained via that method.
*/
public class RawAttributeMapper extends AbstractAttributeMapper {
RawAttributeMapper(
Package pkg, RuleClass ruleClass, Label ruleLabel, AttributeContainer attributes) {
super(pkg, ruleClass, ruleLabel, attributes);
}
public static RawAttributeMapper of(Rule rule) {
return new RawAttributeMapper(
rule.getPackage(),
rule.getRuleClassObject(),
rule.getLabel(),
rule.getAttributeContainer());
}
/**
* Variation of {@link #get} that merges the values of configurable lists together (with
* duplicates removed).
*
* <p>For example, given:
* <pre>
* attr = select({
* ':condition1': [A, B, C],
* ':condition2': [C, D]
* }),
* </pre>
* this returns the value <code>[A, B, C, D]</code>.
*
* <p>If the attribute isn't configurable (e.g. <code>attr = [A, B]</code>), returns
* its raw value.
*
* <p>Throws an {@link IllegalStateException} if the attribute isn't a list type.
*/
@Nullable
public <T> Collection<T> getMergedValues(String attributeName, Type<List<T>> type) {
Preconditions.checkState(type instanceof Type.ListType);
if (!isConfigurable(attributeName)) {
return get(attributeName, type);
}
ImmutableSet.Builder<T> mergedValues = ImmutableSet.builder();
for (Selector<List<T>> selector : getSelectorList(attributeName, type).getSelectors()) {
for (List<T> configuredList : selector.getEntries().values()) {
mergedValues.addAll(configuredList);
}
}
return mergedValues.build();
}
/**
* If the attribute is configurable for this rule instance, returns its configuration
* keys. Else returns an empty list.
*/
public <T> Iterable<Label> getConfigurabilityKeys(String attributeName, Type<T> type) {
SelectorList<T> selectorList = getSelectorList(attributeName, type);
if (selectorList == null) {
return ImmutableList.of();
}
ImmutableList.Builder<Label> builder = ImmutableList.builder();
for (Selector<T> selector : selectorList.getSelectors()) {
builder.addAll(selector.getEntries().keySet());
}
return builder.build();
}
/**
* See {@link #getRawAttributeValue(Rule, Attribute)}.
*
* <p>{@param attrName} must be the name of an {@link Attribute} defined by the {@param rule}'s
* {@link RuleClass}.
*/
@Nullable
public Object getRawAttributeValue(Rule rule, String attrName) {
Attribute attr =
Preconditions.checkNotNull(getAttributeDefinition(attrName), "%s %s", rule, attrName);
return getRawAttributeValue(rule, attr);
}
/**
* Returns the object associated with the {@param rule}'s {@param attr}.
*
* <p>Handles the special case of the "visibility" attribute by returning {@param rule}'s {@link
* RuleVisibility}'s declared labels.
*
* <p>The returned object will be a {@link SelectorList} if the attribute value contains a
* {@code select(...)} expression.
*
* <p>The returned object will be a {@link ComputedDefault} if the rule doesn't explicitly
* declare an attribute value and the rule's class provides a computed default for it.
*
* <p>Otherwise, the returned object will be the type declared by the {@param attr}, or {@code
* null}.
*/
@Nullable
public Object getRawAttributeValue(Rule rule, Attribute attr) {
// This special case for the visibility attribute is needed because its value is replaced
// with an empty list during package loading if it is public or private in order not to visit
// the package called 'visibility'.
if (attr.getName().equals("visibility")) {
return rule.getVisibility().getDeclaredLabels();
}
// If the attribute value contains one or more select(...) expressions, then return
// the SelectorList object representing those expressions.
SelectorList<?> selectorList = getSelectorList(attr.getName(), attr.getType());
if (selectorList != null) {
return selectorList;
}
// If the attribute value is not explicitly declared, and the rule class provides a computed
// default value for it, then we should return the ComputedDefault object.
//
// We check for the existence of a ComputedDefault value because AbstractAttributeMapper#get
// returns either an explicitly declared attribute value or the result of evaluating the
// computed default function, but does not specify which one it is.
ComputedDefault computedDefault = getComputedDefault(attr.getName(), attr.getType());
if (computedDefault != null) {
return computedDefault;
}
return get(attr.getName(), attr.getType());
}
}