// 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.annotations.VisibleForTesting;
import com.google.common.collect.ImmutableList;
import com.google.devtools.build.lib.cmdline.Label;
import com.google.devtools.build.lib.packages.BuildType.SelectorList;
import com.google.devtools.build.lib.syntax.Type;
import javax.annotation.Nullable;
/**
* Base {@link AttributeMap} implementation providing direct, unmanipulated access to
* underlying attribute data as stored within the Rule.
*
* <p>Any instantiable subclass should define a clear policy of what it does with this
* data before exposing it to consumers.
*/
public abstract class AbstractAttributeMapper implements AttributeMap {
private final Package pkg;
private final RuleClass ruleClass;
private final Label ruleLabel;
private final AttributeContainer attributes;
public AbstractAttributeMapper(Package pkg, RuleClass ruleClass, Label ruleLabel,
AttributeContainer attributes) {
this.pkg = pkg;
this.ruleClass = ruleClass;
this.ruleLabel = ruleLabel;
this.attributes = attributes;
}
@Override
public String getName() {
return ruleLabel.getName();
}
@Override
public Label getLabel() {
return ruleLabel;
}
@Nullable
@Override
public <T> T get(String attributeName, Type<T> type) {
int index = getIndexWithTypeCheck(attributeName, type);
Object value = attributes.getAttributeValue(index);
if (value instanceof Attribute.ComputedDefault) {
value = ((Attribute.ComputedDefault) value).getDefault(this);
}
try {
return type.cast(value);
} catch (ClassCastException e) {
// getIndexWithTypeCheck checks the type is right, but unexpected configurable attributes
// can still trigger cast exceptions.
throw new IllegalArgumentException("wrong type for attribute \"" + attributeName + "\" in "
+ ruleClass + " rule " + ruleLabel, e);
}
}
/**
* Returns the given attribute if it's a computed default, null otherwise.
*
* @throws IllegalArgumentException if the given attribute doesn't exist with the specified
* type. This happens whether or not it's a computed default.
*/
@VisibleForTesting // Should be protected
@Nullable
public <T> Attribute.ComputedDefault getComputedDefault(String attributeName, Type<T> type) {
int index = getIndexWithTypeCheck(attributeName, type);
Object value = attributes.getAttributeValue(index);
if (value instanceof Attribute.ComputedDefault) {
return (Attribute.ComputedDefault) value;
} else {
return null;
}
}
@Override
public Iterable<String> getAttributeNames() {
ImmutableList.Builder<String> names = ImmutableList.builder();
for (Attribute a : ruleClass.getAttributes()) {
names.add(a.getName());
}
return names.build();
}
@Nullable
@Override
public Type<?> getAttributeType(String attrName) {
Attribute attr = getAttributeDefinition(attrName);
return attr == null ? null : attr.getType();
}
@Nullable
@Override
public Attribute getAttributeDefinition(String attrName) {
return ruleClass.getAttributeByNameMaybe(attrName);
}
@Override
public boolean isAttributeValueExplicitlySpecified(String attributeName) {
return attributes.isAttributeValueExplicitlySpecified(attributeName);
}
@Override
public String getPackageDefaultHdrsCheck() {
return pkg.getDefaultHdrsCheck();
}
@Override
public Boolean getPackageDefaultTestOnly() {
return pkg.getDefaultTestOnly();
}
@Override
public String getPackageDefaultDeprecation() {
return pkg.getDefaultDeprecation();
}
@Override
public ImmutableList<String> getPackageDefaultCopts() {
return pkg.getDefaultCopts();
}
@Override
public void visitLabels(final AcceptsLabelAttribute observer) throws InterruptedException {
Type.LabelVisitor<Attribute> visitor = new Type.LabelVisitor<Attribute>() {
@Override
public void visit(@Nullable Label label, Attribute attribute) throws InterruptedException {
if (label != null) {
Label absoluteLabel = ruleLabel.resolveRepositoryRelative(label);
observer.acceptLabelAttribute(absoluteLabel, attribute);
}
}
};
for (Attribute attribute : ruleClass.getAttributes()) {
Type<?> type = attribute.getType();
// TODO(bazel-team): clean up the typing / visitation interface so we don't have to
// special-case these types.
if (type != BuildType.OUTPUT && type != BuildType.OUTPUT_LIST
&& type != BuildType.NODEP_LABEL && type != BuildType.NODEP_LABEL_LIST) {
visitLabels(attribute, visitor);
}
}
}
/** Visits all labels reachable from the given attribute. */
protected void visitLabels(Attribute attribute, Type.LabelVisitor<Attribute> visitor)
throws InterruptedException {
Type<?> type = attribute.getType();
Object value = get(attribute.getName(), type);
if (value != null) { // null values are particularly possible for computed defaults.
type.visitLabels(visitor, value, attribute);
}
}
@Override
public final boolean isConfigurable(String attributeName) {
Attribute attrDef = getAttributeDefinition(attributeName);
return attrDef == null ? false : getSelectorList(attributeName, attrDef.getType()) != null;
}
public static <T> boolean isConfigurable(Rule rule, String attributeName, Type<T> type) {
SelectorList<T> selectorMaybe = getSelectorList(
rule.getRuleClassObject(),
rule.getLabel(),
rule.getAttributeContainer(),
attributeName,
type);
return selectorMaybe != null;
}
/**
* Returns a {@link SelectorList} for the given attribute if the attribute is configurable
* for this rule, null otherwise.
*
* @return a {@link SelectorList} if the attribute takes the form
* "attrName = { 'a': value1_of_type_T, 'b': value2_of_type_T }") for this rule, null
* if it takes the form "attrName = value_of_type_T", null if it doesn't exist
* @throws IllegalArgumentException if the attribute is configurable but of the wrong type
*/
@Nullable
protected final <T> SelectorList<T> getSelectorList(String attributeName, Type<T> type) {
return getSelectorList(ruleClass, ruleLabel, attributes, attributeName, type);
}
@Nullable
@SuppressWarnings("unchecked")
protected static <T> SelectorList<T> getSelectorList(
RuleClass ruleClass,
Label ruleLabel,
AttributeContainer attributes,
String attributeName,
Type<T> type) {
Integer index = ruleClass.getAttributeIndex(attributeName);
if (index == null) {
return null;
}
Object attrValue = attributes.getAttributeValue(index);
if (!(attrValue instanceof SelectorList)) {
return null;
}
if (((SelectorList<?>) attrValue).getOriginalType() != type) {
throw new IllegalArgumentException("Attribute " + attributeName + " is not of type " + type
+ " in " + ruleClass + " rule " + ruleLabel);
}
return (SelectorList<T>) attrValue;
}
/**
* Returns the index of the specified attribute, if its type is 'type'. Throws
* an exception otherwise.
*/
private int getIndexWithTypeCheck(String attrName, Type<?> type) {
Integer index = ruleClass.getAttributeIndex(attrName);
if (index == null) {
throw new IllegalArgumentException(
"No such attribute " + attrName + " in " + ruleClass + " rule " + ruleLabel);
}
Attribute attr = ruleClass.getAttribute(index);
if (attr.getType() != type) {
throw new IllegalArgumentException(
"Attribute " + attrName + " is of type " + attr.getType() + " and not of type " + type
+ " in " + ruleClass + " rule " + ruleLabel);
}
return index;
}
/**
* Helper routine that just checks the given attribute has the given type for this rule and
* throws an IllegalException if not.
*/
protected void checkType(String attrName, Type<?> type) {
getIndexWithTypeCheck(attrName, type);
}
@Override
public boolean has(String attrName) {
Attribute attribute = ruleClass.getAttributeByNameMaybe(attrName);
return attribute != null;
}
@Override
public <T> boolean has(String attrName, Type<T> type) {
return getAttributeType(attrName) == type;
}
}