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// Copyright 2016 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.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Maps;
import com.google.devtools.build.lib.actions.Action;
import com.google.devtools.build.lib.actions.ActionAnalysisMetadata;
import com.google.devtools.build.lib.actions.ActionGraph;
import com.google.devtools.build.lib.actions.ActionKeyContext;
import com.google.devtools.build.lib.actions.ActionLookupValue;
import com.google.devtools.build.lib.actions.ActionTemplate;
import com.google.devtools.build.lib.actions.ActionTemplate.ActionTemplateExpansionException;
import com.google.devtools.build.lib.actions.Actions;
import com.google.devtools.build.lib.actions.Actions.GeneratingActions;
import com.google.devtools.build.lib.actions.Artifact;
import com.google.devtools.build.lib.actions.Artifact.TreeFileArtifact;
import com.google.devtools.build.lib.actions.ArtifactPrefixConflictException;
import com.google.devtools.build.lib.actions.MutableActionGraph.ActionConflictException;
import com.google.devtools.build.lib.bugreport.BugReport;
import com.google.devtools.build.lib.events.Event;
import com.google.devtools.build.lib.skyframe.ActionTemplateExpansionValue.ActionTemplateExpansionKey;
import com.google.devtools.build.lib.vfs.PathFragment;
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 java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;
import javax.annotation.Nullable;
/**
* The SkyFunction for {@link ActionTemplateExpansionValue}.
*
* <p>Given an action template, this function resolves its input TreeArtifact, then expands the
* action template into a list of actions using the expanded {@link TreeFileArtifact}s under the
* input TreeArtifact.
*/
public class ActionTemplateExpansionFunction implements SkyFunction {
private final ActionKeyContext actionKeyContext;
ActionTemplateExpansionFunction(ActionKeyContext actionKeyContext) {
this.actionKeyContext = actionKeyContext;
}
@Override
public SkyValue compute(SkyKey skyKey, Environment env)
throws ActionTemplateExpansionFunctionException, InterruptedException {
ActionTemplateExpansionKey key = (ActionTemplateExpansionKey) skyKey.argument();
ActionLookupValue value = (ActionLookupValue) env.getValue(key.getActionLookupKey());
if (value == null) {
// Because of the phase boundary separating analysis and execution, all needed
// ActionLookupValues must have already been evaluated, so a missing ActionLookupValue is
// unexpected. However, we tolerate this case.
BugReport.sendBugReport(new IllegalStateException("Unexpected absent value for " + key));
return null;
}
ActionTemplate<?> actionTemplate = value.getActionTemplate(key.getActionIndex());
TreeArtifactValue treeArtifactValue =
(TreeArtifactValue) env.getValue(actionTemplate.getInputTreeArtifact());
// Input TreeArtifact is not ready yet.
if (env.valuesMissing()) {
return null;
}
Iterable<TreeFileArtifact> inputTreeFileArtifacts = treeArtifactValue.getChildren();
GeneratingActions generatingActions;
try {
// Expand the action template using the list of expanded input TreeFileArtifacts.
// TODO(rduan): Add a check to verify the inputs of expanded actions are subsets of inputs
// of the ActionTemplate.
generatingActions =
checkActionAndArtifactConflicts(
actionTemplate.generateActionForInputArtifacts(inputTreeFileArtifacts, key), key);
} catch (ActionConflictException e) {
e.reportTo(env.getListener());
throw new ActionTemplateExpansionFunctionException(e);
} catch (ArtifactPrefixConflictException e) {
env.getListener().handle(Event.error(e.getMessage()));
throw new ActionTemplateExpansionFunctionException(e);
} catch (ActionTemplateExpansionException e) {
env.getListener().handle(Event.error(e.getMessage()));
throw new ActionTemplateExpansionFunctionException(e);
}
return new ActionTemplateExpansionValue(generatingActions);
}
/** Exception thrown by {@link ActionTemplateExpansionFunction}. */
public static final class ActionTemplateExpansionFunctionException extends SkyFunctionException {
ActionTemplateExpansionFunctionException(ActionConflictException e) {
super(e, Transience.PERSISTENT);
}
ActionTemplateExpansionFunctionException(ArtifactPrefixConflictException e) {
super(e, Transience.PERSISTENT);
}
ActionTemplateExpansionFunctionException(ActionTemplateExpansionException e) {
super(e, Transience.PERSISTENT);
}
}
private GeneratingActions checkActionAndArtifactConflicts(
Iterable<? extends Action> actions, ActionLookupValue.ActionLookupKey actionLookupKey)
throws ActionConflictException, ArtifactPrefixConflictException {
GeneratingActions generatingActions =
Actions.assignOwnersAndFindAndThrowActionConflict(
actionKeyContext, ImmutableList.copyOf(actions), actionLookupKey);
Map<ActionAnalysisMetadata, ArtifactPrefixConflictException> artifactPrefixConflictMap =
findArtifactPrefixConflicts(getMapForConsistencyCheck(generatingActions.getActions()));
if (!artifactPrefixConflictMap.isEmpty()) {
throw artifactPrefixConflictMap.values().iterator().next();
}
return generatingActions;
}
private static Map<Artifact, ActionAnalysisMetadata> getMapForConsistencyCheck(
List<? extends ActionAnalysisMetadata> actions) {
if (actions.isEmpty()) {
return ImmutableMap.of();
}
HashMap<Artifact, ActionAnalysisMetadata> result =
Maps.newHashMapWithExpectedSize(actions.size() * actions.get(0).getOutputs().size());
for (ActionAnalysisMetadata action : actions) {
for (Artifact output : action.getOutputs()) {
result.put(output, action);
}
}
return result;
}
/**
* Finds Artifact prefix conflicts between generated artifacts. An artifact prefix conflict
* happens if one action generates an artifact whose path is a prefix of another artifact's path.
* Those two artifacts cannot exist simultaneously in the output tree.
*
* @param generatingActions a map between generated artifacts and their associated generating
* actions.
* @return a map between actions that generated the conflicting artifacts and their associated
* {@link ArtifactPrefixConflictException}.
*/
private static Map<ActionAnalysisMetadata, ArtifactPrefixConflictException>
findArtifactPrefixConflicts(Map<Artifact, ActionAnalysisMetadata> generatingActions) {
TreeMap<PathFragment, Artifact> artifactPathMap =
new TreeMap<>(Actions.comparatorForPrefixConflicts());
for (Artifact artifact : generatingActions.keySet()) {
artifactPathMap.put(artifact.getExecPath(), artifact);
}
return Actions.findArtifactPrefixConflicts(
new MapBasedImmutableActionGraph(generatingActions), artifactPathMap);
}
private static class MapBasedImmutableActionGraph implements ActionGraph {
private final Map<Artifact, ActionAnalysisMetadata> generatingActions;
MapBasedImmutableActionGraph(Map<Artifact, ActionAnalysisMetadata> generatingActions) {
this.generatingActions = ImmutableMap.copyOf(generatingActions);
}
@Nullable
@Override
public ActionAnalysisMetadata getGeneratingAction(Artifact artifact) {
return generatingActions.get(artifact);
}
}
@Nullable
@Override
public String extractTag(SkyKey skyKey) {
return null;
}
}