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// Copyright 2022 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.base.Preconditions;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Maps;
import com.google.common.collect.Sets;
import com.google.common.eventbus.AllowConcurrentEvents;
import com.google.common.eventbus.EventBus;
import com.google.common.eventbus.Subscribe;
import com.google.devtools.build.lib.actions.PackageRoots;
import com.google.devtools.build.lib.analysis.AnalysisPhaseCompleteEvent;
import com.google.devtools.build.lib.buildtool.SymlinkForest;
import com.google.devtools.build.lib.cmdline.PackageIdentifier;
import com.google.devtools.build.lib.collect.nestedset.NestedSet;
import com.google.devtools.build.lib.packages.Package;
import com.google.devtools.build.lib.server.FailureDetails;
import com.google.devtools.build.lib.server.FailureDetails.FailureDetail;
import com.google.devtools.build.lib.skyframe.TopLevelStatusEvents.TopLevelTargetReadyForSymlinkPlanting;
import com.google.devtools.build.lib.util.AbruptExitException;
import com.google.devtools.build.lib.util.DetailedExitCode;
import com.google.devtools.build.lib.vfs.Path;
import com.google.devtools.build.lib.vfs.Root;
import java.io.IOException;
import java.util.Map;
import java.util.Optional;
import java.util.Set;
import javax.annotation.Nullable;
import javax.annotation.concurrent.GuardedBy;
/**
* An implementation of PackageRoots that allows incremental updating of the packageRootsMap.
*
* <p>This class is also in charge of planting the necessary symlinks.
*/
public class IncrementalPackageRoots implements PackageRoots {
// We only keep track of PackageIdentifier from external repos here as a memory optimization:
// packages belong to the main repository all share the same root, which is singleSourceRoot.
private final Map<PackageIdentifier, Root> threadSafeExternalRepoPackageRootsMap;
@GuardedBy("stateLock")
@Nullable
private Set<NestedSet.Node> handledPackageNestedSets = Sets.newConcurrentHashSet();
@Nullable private Set<Path> plantedExternalRepoLinks = Sets.newConcurrentHashSet();
private final Object stateLock = new Object();
private final Path execroot;
private final Root singleSourceRoot;
private final String prefix;
private final boolean useSiblingRepositoryLayout;
private final boolean allowExternalRepositories;
@Nullable private EventBus eventBus;
private IncrementalPackageRoots(
Path execroot,
Root singleSourceRoot,
EventBus eventBus,
String prefix,
boolean useSiblingRepositoryLayout,
boolean allowExternalRepositories) {
this.threadSafeExternalRepoPackageRootsMap = Maps.newConcurrentMap();
this.execroot = execroot;
this.singleSourceRoot = singleSourceRoot;
this.prefix = prefix;
this.eventBus = eventBus;
this.useSiblingRepositoryLayout = useSiblingRepositoryLayout;
this.allowExternalRepositories = allowExternalRepositories;
}
public static IncrementalPackageRoots createAndRegisterToEventBus(
Path execroot,
Root singleSourceRoot,
EventBus eventBus,
String prefix,
boolean useSiblingRepositoryLayout,
boolean allowExternalRepositories) {
IncrementalPackageRoots incrementalPackageRoots =
new IncrementalPackageRoots(
execroot,
singleSourceRoot,
eventBus,
prefix,
useSiblingRepositoryLayout,
allowExternalRepositories);
eventBus.register(incrementalPackageRoots);
return incrementalPackageRoots;
}
/** Eagerly plant the symlinks to the directories under the single source root. */
public void eagerlyPlantSymlinksToSingleSourceRoot() throws AbruptExitException {
try {
SymlinkForest.eagerlyPlantSymlinkForestSinglePackagePath(
execroot, singleSourceRoot.asPath(), prefix, useSiblingRepositoryLayout);
} catch (IOException e) {
throwAbruptExitException(e);
}
}
/** There is currently no use case for this method, and it should not be called. */
@Override
public Optional<ImmutableMap<PackageIdentifier, Root>> getPackageRootsMap() {
throw new UnsupportedOperationException(
"IncrementalPackageRoots does not provide the package roots map directly.");
}
@Override
public PackageRootLookup getPackageRootLookup() {
return packageId ->
packageId.getRepository().isMain()
? singleSourceRoot
: threadSafeExternalRepoPackageRootsMap.get(packageId);
}
@AllowConcurrentEvents
@Subscribe
public void topLevelTargetReadyForSymlinkPlanting(TopLevelTargetReadyForSymlinkPlanting event)
throws AbruptExitException {
if (allowExternalRepositories) {
registerAndPlantSymlinksForExternalPackages(event.transitivePackagesForSymlinkPlanting());
}
}
@Subscribe
public void analysisFinished(AnalysisPhaseCompleteEvent unused) {
dropIntermediateStatesAndUnregisterFromEventBus();
}
private void registerAndPlantSymlinksForExternalPackages(NestedSet<Package> packages)
throws AbruptExitException {
Set<Path> plantedExternalRepoLinksLocalRef;
synchronized (stateLock) {
if (handledPackageNestedSets == null || !handledPackageNestedSets.add(packages.toNode())) {
return;
}
plantedExternalRepoLinksLocalRef = plantedExternalRepoLinks;
if (plantedExternalRepoLinksLocalRef == null) {
return;
}
}
// To reach this point, this has to be the first and only time we plant the symlinks for this
// NestedSet<Package>. That means it's not possible to reach this after analysis has ended.
for (Package pkg : packages.getLeaves()) {
PackageIdentifier pkgId = pkg.getPackageIdentifier();
if (isExternalRepository(pkgId) && pkg.getSourceRoot().isPresent()) {
threadSafeExternalRepoPackageRootsMap.put(
pkg.getPackageIdentifier(), pkg.getSourceRoot().get());
try {
SymlinkForest.plantSingleSymlinkForExternalRepo(
pkgId.getRepository(),
pkg.getSourceRoot().get().asPath(),
execroot,
useSiblingRepositoryLayout,
plantedExternalRepoLinksLocalRef);
} catch (IOException e) {
throwAbruptExitException(e);
}
}
}
for (NestedSet<Package> transitive : packages.getNonLeaves()) {
registerAndPlantSymlinksForExternalPackages(transitive);
}
}
private static void throwAbruptExitException(IOException e) throws AbruptExitException {
throw new AbruptExitException(
DetailedExitCode.of(
FailureDetail.newBuilder()
.setMessage("Failed to prepare the symlink forest: " + e)
.setSymlinkForest(
FailureDetails.SymlinkForest.newBuilder()
.setCode(FailureDetails.SymlinkForest.Code.CREATION_FAILED))
.build()),
e);
}
private static boolean isExternalRepository(PackageIdentifier pkgId) {
return !pkgId.getRepository().isMain();
}
/**
* Drops the intermediate states and stop receiving new events.
*
* <p>This essentially makes this instance read-only. Should be called when and only when all
* analysis work is done in the build to free up some memory.
*/
private void dropIntermediateStatesAndUnregisterFromEventBus() {
// This instance is retained after a build via ArtifactFactory, so it's important that we remove
// the reference to the eventBus here for it to be GC'ed.
Preconditions.checkNotNull(eventBus).unregister(this);
eventBus = null;
synchronized (stateLock) {
handledPackageNestedSets = null;
plantedExternalRepoLinks = null;
}
}
}