// Copyright 2015 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.skyframe;
import com.google.common.collect.Lists;
import com.google.common.collect.Multimap;
import com.google.devtools.build.lib.cmdline.Label;
import com.google.devtools.build.lib.events.EventHandler;
import com.google.devtools.build.lib.packages.Attribute;
import com.google.devtools.build.lib.packages.BuildFileContainsErrorsException;
import com.google.devtools.build.lib.packages.DependencyFilter;
import com.google.devtools.build.lib.packages.InputFile;
import com.google.devtools.build.lib.packages.NoSuchPackageException;
import com.google.devtools.build.lib.packages.NoSuchTargetException;
import com.google.devtools.build.lib.packages.OutputFile;
import com.google.devtools.build.lib.packages.Package;
import com.google.devtools.build.lib.packages.PackageGroup;
import com.google.devtools.build.lib.packages.Rule;
import com.google.devtools.build.lib.packages.Target;
import com.google.devtools.build.lib.util.Preconditions;
import com.google.devtools.build.skyframe.SkyFunction;
import com.google.devtools.build.skyframe.SkyFunctionException;
import com.google.devtools.build.skyframe.SkyKey;
import com.google.devtools.build.skyframe.SkyValue;
import com.google.devtools.build.skyframe.ValueOrException2;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import javax.annotation.Nullable;
/**
* This class can be extended to define {@link SkyFunction}s that traverse a target and its
* transitive dependencies and return values based on that traversal.
*
* <p>The {@code TProcessedTargets} type parameter represents the result of processing a target and
* its transitive dependencies.
*
* <p>{@code TransitiveBaseTraversalFunction} asks for one to be constructed via {@link
* #processTarget}, and then asks for it to be updated based on the current target's
* attributes' dependencies via {@link #processDeps}, and then asks for it to be updated based
* on the current target' aspects' dependencies via {@link #processDeps}. Finally, it calls
* {@link #computeSkyValue} with the {#code ProcessedTargets} to get the {@link SkyValue} to
* return.
*/
abstract class TransitiveBaseTraversalFunction<TProcessedTargets> implements SkyFunction {
/**
* Returns a {@link SkyKey} corresponding to the traversal of a target specified by {@code label}
* and its transitive dependencies.
*
* <p>Extenders of this class should implement this function to return a key with their
* specialized {@link SkyFunction}'s name.
*
* <p>{@link TransitiveBaseTraversalFunction} calls this for each dependency of a target, and
* then gets their values from the environment.
*
* <p>The key's {@link SkyFunction} may throw at most {@link NoSuchPackageException} and
* {@link NoSuchTargetException}. Other exception types are not handled by {@link
* TransitiveBaseTraversalFunction}.
*/
abstract SkyKey getKey(Label label);
abstract TProcessedTargets processTarget(Label label, TargetAndErrorIfAny targetAndErrorIfAny);
abstract void processDeps(
TProcessedTargets processedTargets,
EventHandler eventHandler,
TargetAndErrorIfAny targetAndErrorIfAny,
Iterable<Entry<SkyKey, ValueOrException2<NoSuchPackageException, NoSuchTargetException>>>
depEntries)
throws InterruptedException;
/**
* Returns a {@link SkyValue} based on the target and any errors it has, and the values
* accumulated across it and a traversal of its transitive dependencies.
*/
abstract SkyValue computeSkyValue(TargetAndErrorIfAny targetAndErrorIfAny,
TProcessedTargets processedTargets);
/**
* Returns a {@link TargetMarkerValue} corresponding to the {@param targetMarkerKey} or {@code
* null} if the value isn't ready.
*/
@Nullable
abstract TargetMarkerValue getTargetMarkerValue(SkyKey targetMarkerKey, Environment env)
throws NoSuchTargetException, NoSuchPackageException, InterruptedException;
@Override
public SkyValue compute(SkyKey key, Environment env)
throws TransitiveBaseTraversalFunctionException, InterruptedException {
Label label = (Label) key.argument();
LoadTargetResults loadTargetResults;
try {
loadTargetResults = loadTarget(env, label);
} catch (NoSuchTargetException e) {
throw new TransitiveBaseTraversalFunctionException(e);
} catch (NoSuchPackageException e) {
throw new TransitiveBaseTraversalFunctionException(e);
}
LoadTargetResultsType loadTargetResultsType = loadTargetResults.getType();
if (loadTargetResultsType.equals(LoadTargetResultsType.VALUES_MISSING)) {
return null;
}
Preconditions.checkState(
loadTargetResultsType.equals(LoadTargetResultsType.TARGET_AND_ERROR_IF_ANY),
loadTargetResultsType);
TargetAndErrorIfAny targetAndErrorIfAny = (TargetAndErrorIfAny) loadTargetResults;
TProcessedTargets processedTargets = processTarget(label, targetAndErrorIfAny);
// Process deps from attributes.
Iterable<SkyKey> labelDepKeys = getLabelDepKeys(targetAndErrorIfAny.getTarget());
Map<SkyKey, ValueOrException2<NoSuchPackageException, NoSuchTargetException>> depMap =
env.getValuesOrThrow(labelDepKeys, NoSuchPackageException.class,
NoSuchTargetException.class);
processDeps(processedTargets, env.getListener(), targetAndErrorIfAny, depMap.entrySet());
if (env.valuesMissing()) {
return null;
}
// Process deps from aspects.
Iterable<SkyKey> labelAspectKeys =
getStrictLabelAspectKeys(targetAndErrorIfAny.getTarget(), depMap, env);
Set<Entry<SkyKey, ValueOrException2<NoSuchPackageException, NoSuchTargetException>>>
labelAspectEntries = env.getValuesOrThrow(labelAspectKeys, NoSuchPackageException.class,
NoSuchTargetException.class).entrySet();
processDeps(processedTargets, env.getListener(), targetAndErrorIfAny, labelAspectEntries);
if (env.valuesMissing()) {
return null;
}
return computeSkyValue(targetAndErrorIfAny, processedTargets);
}
@Override
public String extractTag(SkyKey skyKey) {
return Label.print(((Label) skyKey.argument()));
}
/**
* Return an Iterable of SkyKeys corresponding to the Aspect-related dependencies of target.
*
* <p>This method may return a precise set of aspect keys, but may need to request additional
* dependencies from the env to do so.
*/
private Iterable<SkyKey> getStrictLabelAspectKeys(
Target target,
Map<SkyKey, ValueOrException2<NoSuchPackageException, NoSuchTargetException>> depMap,
Environment env)
throws InterruptedException {
List<SkyKey> depKeys = Lists.newArrayList();
if (target instanceof Rule) {
Map<Label, ValueOrException2<NoSuchPackageException, NoSuchTargetException>> labelDepMap =
new HashMap<>(depMap.size());
for (Entry<SkyKey, ValueOrException2<NoSuchPackageException, NoSuchTargetException>> entry :
depMap.entrySet()) {
labelDepMap.put((Label) entry.getKey().argument(), entry.getValue());
}
Multimap<Attribute, Label> transitions =
((Rule) target).getTransitions(DependencyFilter.NO_NODEP_ATTRIBUTES);
for (Entry<Attribute, Label> entry : transitions.entries()) {
ValueOrException2<NoSuchPackageException, NoSuchTargetException> value =
labelDepMap.get(entry.getValue());
for (Label label :
getAspectLabels((Rule) target, entry.getKey(), entry.getValue(), value, env)) {
depKeys.add(getKey(label));
}
}
}
return depKeys;
}
/** Get the Aspect-related Label deps for the given edge. */
protected abstract Collection<Label> getAspectLabels(
Rule fromRule,
Attribute attr,
Label toLabel,
ValueOrException2<NoSuchPackageException, NoSuchTargetException> toVal,
Environment env)
throws InterruptedException;
private Iterable<SkyKey> getLabelDepKeys(Target target) throws InterruptedException {
List<SkyKey> depKeys = Lists.newArrayList();
for (Label depLabel : getLabelDeps(target)) {
depKeys.add(getKey(depLabel));
}
return depKeys;
}
// TODO(bazel-team): Unify this logic with that in LabelVisitor, and possibly DependencyResolver.
private static Iterable<Label> getLabelDeps(Target target) throws InterruptedException {
final Set<Label> labels = new HashSet<>();
if (target instanceof OutputFile) {
Rule rule = ((OutputFile) target).getGeneratingRule();
labels.add(rule.getLabel());
visitTargetVisibility(target, labels);
} else if (target instanceof InputFile) {
visitTargetVisibility(target, labels);
} else if (target instanceof Rule) {
visitTargetVisibility(target, labels);
visitRule(target, labels);
} else if (target instanceof PackageGroup) {
visitPackageGroup((PackageGroup) target, labels);
}
return labels;
}
private static void visitRule(Target target, Set<Label> labels) throws InterruptedException {
labels.addAll(((Rule) target).getTransitions(DependencyFilter.NO_NODEP_ATTRIBUTES).values());
}
private static void visitTargetVisibility(Target target, Set<Label> labels) {
labels.addAll(target.getVisibility().getDependencyLabels());
}
private static void visitPackageGroup(PackageGroup packageGroup, Set<Label> labels) {
labels.addAll(packageGroup.getIncludes());
}
enum LoadTargetResultsType {
VALUES_MISSING,
TARGET_AND_ERROR_IF_ANY
}
interface LoadTargetResults {
LoadTargetResultsType getType();
}
private static class ValuesMissing implements LoadTargetResults {
private static final ValuesMissing INSTANCE = new ValuesMissing();
private ValuesMissing() {}
@Override
public LoadTargetResultsType getType() {
return LoadTargetResultsType.VALUES_MISSING;
}
}
interface TargetAndErrorIfAny {
boolean isPackageLoadedSuccessfully();
@Nullable NoSuchTargetException getErrorLoadingTarget();
Target getTarget();
}
private static class TargetAndErrorIfAnyImpl implements TargetAndErrorIfAny, LoadTargetResults {
private final boolean packageLoadedSuccessfully;
@Nullable private final NoSuchTargetException errorLoadingTarget;
private final Target target;
private TargetAndErrorIfAnyImpl(boolean packageLoadedSuccessfully,
@Nullable NoSuchTargetException errorLoadingTarget, Target target) {
this.packageLoadedSuccessfully = packageLoadedSuccessfully;
this.errorLoadingTarget = errorLoadingTarget;
this.target = target;
}
@Override
public LoadTargetResultsType getType() {
return LoadTargetResultsType.TARGET_AND_ERROR_IF_ANY;
}
@Override
public boolean isPackageLoadedSuccessfully() {
return packageLoadedSuccessfully;
}
@Override
@Nullable
public NoSuchTargetException getErrorLoadingTarget() {
return errorLoadingTarget;
}
@Override
public Target getTarget() {
return target;
}
}
private LoadTargetResults loadTarget(Environment env, Label label)
throws NoSuchTargetException, NoSuchPackageException, InterruptedException {
SkyKey packageKey = PackageValue.key(label.getPackageIdentifier());
SkyKey targetKey = TargetMarkerValue.key(label);
boolean packageLoadedSuccessfully;
Target target;
NoSuchTargetException errorLoadingTarget = null;
try {
TargetMarkerValue targetValue = getTargetMarkerValue(targetKey, env);
boolean targetValueMissing = targetValue == null;
Preconditions.checkState(targetValueMissing == env.valuesMissing(), targetKey);
if (targetValueMissing) {
return ValuesMissing.INSTANCE;
}
PackageValue packageValue = (PackageValue) env.getValueOrThrow(packageKey,
NoSuchPackageException.class);
if (packageValue == null) {
return ValuesMissing.INSTANCE;
}
Package pkg = packageValue.getPackage();
if (pkg.containsErrors()) {
throw new BuildFileContainsErrorsException(label.getPackageIdentifier());
}
packageLoadedSuccessfully = true;
try {
target = pkg.getTarget(label.getName());
} catch (NoSuchTargetException unexpected) {
// Not expected since the TargetMarkerFunction would have failed earlier if the Target
// was not present.
throw new IllegalStateException(unexpected);
}
} catch (NoSuchTargetException e) {
if (!e.hasTarget()) {
throw e;
}
// We know that a Target may be extracted, but we need to get it out of the Package
// (which is known to be in error).
PackageValue packageValue =
(PackageValue) Preconditions.checkNotNull(env.getValue(packageKey), label);
Package pkg = packageValue.getPackage();
try {
target = pkg.getTarget(label.getName());
} catch (NoSuchTargetException nste) {
throw new IllegalStateException("Expected target to exist", nste);
}
errorLoadingTarget = e;
packageLoadedSuccessfully = false;
}
return new TargetAndErrorIfAnyImpl(packageLoadedSuccessfully, errorLoadingTarget, target);
}
/**
* Used to declare all the exception types that can be wrapped in the exception thrown by
* {@link TransitiveTraversalFunction#compute}.
*/
static class TransitiveBaseTraversalFunctionException extends SkyFunctionException {
/**
* Used to propagate an error from a direct target dependency to the target that depended on
* it.
*/
public TransitiveBaseTraversalFunctionException(NoSuchPackageException e) {
super(e, Transience.PERSISTENT);
}
/**
* In nokeep_going mode, used to propagate an error from a direct target dependency to the
* target that depended on it.
*
* <p>In keep_going mode, used the same way, but only for targets that could not be loaded at
* all (we proceed with transitive loading on targets that contain errors).</p>
*/
public TransitiveBaseTraversalFunctionException(NoSuchTargetException e) {
super(e, Transience.PERSISTENT);
}
}
}