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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 static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;
import static com.google.common.collect.ImmutableSet.toImmutableSet;
import com.google.auto.value.AutoValue;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.MoreObjects;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.ImmutableSortedMap;
import com.google.common.io.BaseEncoding;
import com.google.devtools.build.lib.actions.ActionInput;
import com.google.devtools.build.lib.actions.ActionInputHelper;
import com.google.devtools.build.lib.actions.Artifact.ArchivedTreeArtifact;
import com.google.devtools.build.lib.actions.Artifact.SpecialArtifact;
import com.google.devtools.build.lib.actions.Artifact.TreeFileArtifact;
import com.google.devtools.build.lib.actions.FileArtifactValue;
import com.google.devtools.build.lib.actions.FileContentsProxy;
import com.google.devtools.build.lib.actions.FileStateType;
import com.google.devtools.build.lib.actions.HasDigest;
import com.google.devtools.build.lib.actions.cache.MetadataDigestUtils;
import com.google.devtools.build.lib.concurrent.AbstractQueueVisitor;
import com.google.devtools.build.lib.concurrent.ErrorClassifier;
import com.google.devtools.build.lib.concurrent.NamedForkJoinPool;
import com.google.devtools.build.lib.concurrent.ThreadSafety.ThreadSafe;
import com.google.devtools.build.lib.skyframe.serialization.autocodec.AutoCodec;
import com.google.devtools.build.lib.skyframe.serialization.autocodec.SerializationConstant;
import com.google.devtools.build.lib.util.Fingerprint;
import com.google.devtools.build.lib.vfs.Dirent;
import com.google.devtools.build.lib.vfs.IORuntimeException;
import com.google.devtools.build.lib.vfs.Path;
import com.google.devtools.build.lib.vfs.PathFragment;
import com.google.devtools.build.lib.vfs.Symlinks;
import com.google.devtools.build.skyframe.SkyValue;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.io.IOException;
import java.util.Arrays;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import java.util.concurrent.ForkJoinPool;
import javax.annotation.Nullable;
/**
* Value for TreeArtifacts, which contains a digest and the {@link FileArtifactValue}s of its child
* {@link TreeFileArtifact}s.
*/
public class TreeArtifactValue implements HasDigest, SkyValue {
private static final ForkJoinPool VISITOR_POOL =
NamedForkJoinPool.newNamedPool(
"tree-artifact-visitor", Runtime.getRuntime().availableProcessors());
/**
* Comparator based on exec path which works on {@link ActionInput} as opposed to {@link
* com.google.devtools.build.lib.actions.Artifact}. This way, we can use an {@link ActionInput} to
* search {@link #childData}.
*/
@SerializationConstant @AutoCodec.VisibleForSerialization
static final Comparator<ActionInput> EXEC_PATH_COMPARATOR =
(input1, input2) -> input1.getExecPath().compareTo(input2.getExecPath());
private static final ImmutableSortedMap<TreeFileArtifact, FileArtifactValue> EMPTY_MAP =
childDataBuilder().buildOrThrow();
private static ImmutableSortedMap.Builder<TreeFileArtifact, FileArtifactValue>
childDataBuilder() {
return new ImmutableSortedMap.Builder<>(EXEC_PATH_COMPARATOR);
}
/** Returns an empty {@link TreeArtifactValue}. */
public static TreeArtifactValue empty() {
return EMPTY;
}
/**
* Returns a new {@link Builder} for the given parent tree artifact.
*
* <p>The returned builder only supports adding children under this parent. To build multiple tree
* artifacts at once, use {@link MultiBuilder}.
*/
public static Builder newBuilder(SpecialArtifact parent) {
return new Builder(parent);
}
/** Builder for constructing multiple instances of {@link TreeArtifactValue} at once. */
public static final class MultiBuilder {
private final Map<SpecialArtifact, Builder> map = new HashMap<>();
private MultiBuilder() {}
/**
* Puts a child tree file into this builder under its {@linkplain TreeFileArtifact#getParent
* parent}.
*
* @return {@code this} for convenience
*/
@CanIgnoreReturnValue
public MultiBuilder putChild(TreeFileArtifact child, FileArtifactValue metadata) {
map.computeIfAbsent(child.getParent(), Builder::new).putChild(child, metadata);
return this;
}
/**
* Sets the archived representation and its metadata for the {@linkplain
* ArchivedTreeArtifact#getParent parent} of the provided tree artifact.
*
* <p>Setting an archived representation is only allowed once per {@linkplain SpecialArtifact
* tree artifact}.
*/
@CanIgnoreReturnValue
public MultiBuilder setArchivedRepresentation(
ArchivedTreeArtifact archivedArtifact, FileArtifactValue metadata) {
map.computeIfAbsent(archivedArtifact.getParent(), Builder::new)
.setArchivedRepresentation(ArchivedRepresentation.create(archivedArtifact, metadata));
return this;
}
/**
* Removes all of collected data for a given tree artifact.
*
* <p>No-op if there is no data for a given tree artifact.
*/
@CanIgnoreReturnValue
public MultiBuilder remove(SpecialArtifact treeArtifact) {
checkArgument(treeArtifact.isTreeArtifact(), "Not a tree artifact: %s", treeArtifact);
map.remove(treeArtifact);
return this;
}
/**
* For each unique parent seen by this builder, passes the aggregated metadata to {@link
* TreeArtifactInjector#injectTree}.
*/
public void injectTo(TreeArtifactInjector treeInjector) {
map.forEach((parent, builder) -> treeInjector.injectTree(parent, builder.build()));
}
}
/** Returns a new {@link MultiBuilder}. */
public static MultiBuilder newMultiBuilder() {
return new MultiBuilder();
}
/**
* Archived representation of a tree artifact which contains a representation of the filesystem
* tree starting with the tree artifact directory.
*
* <p>Contains both the {@linkplain ArchivedTreeArtifact artifact} for the archived file and the
* metadata for it.
*/
@AutoValue
public abstract static class ArchivedRepresentation {
public abstract ArchivedTreeArtifact archivedTreeFileArtifact();
public abstract FileArtifactValue archivedFileValue();
public static ArchivedRepresentation create(
ArchivedTreeArtifact archivedTreeFileArtifact, FileArtifactValue fileArtifactValue) {
return new AutoValue_TreeArtifactValue_ArchivedRepresentation(
archivedTreeFileArtifact, fileArtifactValue);
}
}
@SuppressWarnings("WeakerAccess") // Serialization constant.
@SerializationConstant
@AutoCodec.VisibleForSerialization
static final TreeArtifactValue EMPTY =
new TreeArtifactValue(
MetadataDigestUtils.fromMetadata(ImmutableMap.of()),
EMPTY_MAP,
0L,
/*archivedRepresentation=*/ null,
/*materializationExecPath=*/ null,
/*entirelyRemote=*/ false);
private final byte[] digest;
private final ImmutableSortedMap<TreeFileArtifact, FileArtifactValue> childData;
private final long totalChildSize;
/**
* Optional archived representation of the entire tree artifact which can be sent instead of all
* the items in the directory.
*/
@Nullable private final ArchivedRepresentation archivedRepresentation;
/**
* Optional materialization path.
*
* <p>If present, this artifact is a copy of another artifact. It is still tracked as a
* non-symlink by Bazel, but materialized in the local filesystem as a symlink to the original
* artifact, whose contents live at this location. This is used by {@link
* com.google.devtools.build.lib.remote.AbstractActionInputPrefetcher} to implement zero-cost
* copies of remotely stored artifacts.
*/
@Nullable private final PathFragment materializationExecPath;
private final boolean entirelyRemote;
/** A FileArtifactValue used to stand in for a TreeArtifactValue. */
private static final class TreeArtifactCompositeFileArtifactValue extends FileArtifactValue {
private final byte[] digest;
private final boolean isRemote;
@Nullable private final PathFragment materializationExecPath;
TreeArtifactCompositeFileArtifactValue(
byte[] digest, boolean isRemote, @Nullable PathFragment materializationExecPath) {
this.digest = digest;
this.isRemote = isRemote;
this.materializationExecPath = materializationExecPath;
}
@Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (!(o instanceof TreeArtifactCompositeFileArtifactValue)) {
return false;
}
TreeArtifactCompositeFileArtifactValue that = (TreeArtifactCompositeFileArtifactValue) o;
return Arrays.equals(digest, that.digest)
&& Objects.equals(materializationExecPath, that.materializationExecPath);
}
@Override
public int hashCode() {
return Objects.hash(Arrays.hashCode(digest), materializationExecPath);
}
@Override
public FileStateType getType() {
return FileStateType.DIRECTORY;
}
@Override
public byte[] getDigest() {
return digest;
}
@Override
@Nullable
public FileContentsProxy getContentsProxy() {
return null;
}
@Override
public long getSize() {
return 0;
}
@Override
public boolean wasModifiedSinceDigest(Path path) {
return false;
}
@Override
public long getModifiedTime() {
throw new UnsupportedOperationException();
}
@Override
public String toString() {
return MoreObjects.toStringHelper(this)
.add("digest", BaseEncoding.base16().lowerCase().encode(digest))
.add("materializationExecPath", materializationExecPath)
.toString();
}
@Override
protected boolean couldBeModifiedByMetadata(FileArtifactValue o) {
return false;
}
@Override
public boolean isRemote() {
return isRemote;
}
@Override
public Optional<PathFragment> getMaterializationExecPath() {
return Optional.ofNullable(materializationExecPath);
}
}
private TreeArtifactValue(
byte[] digest,
ImmutableSortedMap<TreeFileArtifact, FileArtifactValue> childData,
long totalChildSize,
@Nullable ArchivedRepresentation archivedRepresentation,
@Nullable PathFragment materializationExecPath,
boolean entirelyRemote) {
this.digest = digest;
this.childData = childData;
this.totalChildSize = totalChildSize;
this.archivedRepresentation = archivedRepresentation;
this.materializationExecPath = materializationExecPath;
this.entirelyRemote = entirelyRemote;
}
public FileArtifactValue getMetadata() {
return new TreeArtifactCompositeFileArtifactValue(
digest, entirelyRemote, materializationExecPath);
}
ImmutableSet<PathFragment> getChildPaths() {
return childData.keySet().stream()
.map(TreeFileArtifact::getParentRelativePath)
.collect(toImmutableSet());
}
@Override
public byte[] getDigest() {
return digest.clone();
}
public ImmutableSet<TreeFileArtifact> getChildren() {
return childData.keySet();
}
public long getTotalChildBytes() {
return totalChildSize;
}
/** Return archived representation of the tree artifact (if present). */
public Optional<ArchivedRepresentation> getArchivedRepresentation() {
return Optional.ofNullable(archivedRepresentation);
}
/** Return materialization path (if present). */
public Optional<PathFragment> getMaterializationExecPath() {
return Optional.ofNullable(materializationExecPath);
}
@VisibleForTesting
@Nullable
public ArchivedTreeArtifact getArchivedArtifactForTesting() {
return archivedRepresentation != null
? archivedRepresentation.archivedTreeFileArtifact()
: null;
}
public ImmutableSortedMap<TreeFileArtifact, FileArtifactValue> getChildValues() {
return childData;
}
/** Returns an entry for child with given exec path or null if no such child is present. */
@SuppressWarnings("unchecked")
@Nullable
public Map.Entry<TreeFileArtifact, FileArtifactValue> findChildEntryByExecPath(
PathFragment execPath) {
ActionInput searchToken = ActionInputHelper.fromPath(execPath);
// Not really a copy -- original map is already an ImmutableSortedMap using the same comparator.
ImmutableSortedMap<ActionInput, FileArtifactValue> casted =
ImmutableSortedMap.copyOf(childData, EXEC_PATH_COMPARATOR);
checkState(casted == (Object) childData, "Casting children resulted with a copy");
Map.Entry<? extends ActionInput, FileArtifactValue> entry = casted.floorEntry(searchToken);
return entry != null && entry.getKey().getExecPath().equals(execPath)
? (Map.Entry<TreeFileArtifact, FileArtifactValue>) entry
: null;
}
/** Returns true if the {@link TreeFileArtifact}s are only stored remotely. */
public boolean isEntirelyRemote() {
return entirelyRemote;
}
@Override
public int hashCode() {
return Arrays.hashCode(digest);
}
@Override
public boolean equals(Object other) {
if (this == other) {
return true;
}
if (!(other instanceof TreeArtifactValue)) {
return false;
}
TreeArtifactValue that = (TreeArtifactValue) other;
if (!Arrays.equals(digest, that.digest)) {
return false;
}
return childData.equals(that.childData);
}
@Override
public String toString() {
return MoreObjects.toStringHelper(this)
.add("digest", digest)
.add("childData", childData)
.add("archivedRepresentation", archivedRepresentation)
.add("materializationExecPath", materializationExecPath)
.toString();
}
/**
* Represents a tree artifact that was intentionally omitted, similar to {@link
* FileArtifactValue#OMITTED_FILE_MARKER}.
*/
@SerializationConstant
public static final TreeArtifactValue OMITTED_TREE_MARKER = createMarker("OMITTED_TREE_MARKER");
/**
* A TreeArtifactValue that represents a missing TreeArtifact. This is occasionally useful because
* Java's concurrent collections disallow null members.
*/
public static final TreeArtifactValue MISSING_TREE_ARTIFACT =
createMarker("MISSING_TREE_ARTIFACT");
private static TreeArtifactValue createMarker(String toStringRepresentation) {
return new TreeArtifactValue(
null,
EMPTY_MAP,
0L,
/*archivedRepresentation=*/ null,
/*materializationExecPath=*/ null,
/*entirelyRemote=*/ false) {
@Override
public ImmutableSet<TreeFileArtifact> getChildren() {
throw new UnsupportedOperationException(toString());
}
@Override
public ImmutableSortedMap<TreeFileArtifact, FileArtifactValue> getChildValues() {
throw new UnsupportedOperationException(toString());
}
@Override
public FileArtifactValue getMetadata() {
throw new UnsupportedOperationException(toString());
}
@Override
ImmutableSet<PathFragment> getChildPaths() {
throw new UnsupportedOperationException(toString());
}
@Nullable
@Override
public byte[] getDigest() {
throw new UnsupportedOperationException(toString());
}
@Override
public int hashCode() {
return System.identityHashCode(this);
}
@Override
public boolean equals(Object other) {
return this == other;
}
@Override
public String toString() {
return toStringRepresentation;
}
};
}
/** Visitor for use in {@link #visitTree}. */
@FunctionalInterface
public interface TreeArtifactVisitor {
/**
* Called for every directory entry encountered during tree traversal.
*
* <p>Symlinks are not followed during traversal and are simply reported as {@link
* Dirent.Type#SYMLINK} regardless of whether they point to a file, directory, or are dangling.
*
* <p>{@code type} is guaranteed never to be {@link Dirent.Type#UNKNOWN}, since if this type is
* encountered, {@link IOException} is immediately thrown without invoking the visitor.
*
* <p>If the implementation throws {@link IOException}, traversal is immediately halted and the
* exception is propagated.
*
* <p>This method can be called from multiple threads in parallel during a single call of {@link
* TreeArtifactVisitor#visitTree(Path, TreeArtifactVisitor)}.
*/
@ThreadSafe
void visit(PathFragment parentRelativePath, Dirent.Type type) throws IOException;
}
/** An {@link AbstractQueueVisitor} that visits every file in the tree artifact. */
static class Visitor extends AbstractQueueVisitor {
private final Path parentDir;
private final TreeArtifactVisitor visitor;
Visitor(Path parentDir, TreeArtifactVisitor visitor) {
super(
VISITOR_POOL,
ExecutorOwnership.SHARED,
ExceptionHandlingMode.FAIL_FAST,
ErrorClassifier.DEFAULT);
this.parentDir = checkNotNull(parentDir);
this.visitor = checkNotNull(visitor);
}
void run() throws IOException, InterruptedException {
execute(() -> visitTree(PathFragment.EMPTY_FRAGMENT));
try {
awaitQuiescence(true);
} catch (IORuntimeException e) {
throw e.getCauseIOException();
}
}
// IOExceptions are wrapped in IORuntimeException so that it can be propagated to the main
// thread
private void visitTree(PathFragment subdir) {
try {
for (Dirent dirent : parentDir.getRelative(subdir).readdir(Symlinks.NOFOLLOW)) {
PathFragment parentRelativePath = subdir.getChild(dirent.getName());
Dirent.Type type = dirent.getType();
if (type == Dirent.Type.UNKNOWN) {
throw new IOException(
"Could not determine type of file for "
+ parentRelativePath
+ " under "
+ parentDir);
}
if (type == Dirent.Type.SYMLINK) {
checkSymlink(subdir, parentDir.getRelative(parentRelativePath));
}
visitor.visit(parentRelativePath, type);
if (type == Dirent.Type.DIRECTORY) {
execute(() -> visitTree(parentRelativePath));
}
}
} catch (IOException e) {
// We can't throw checked exceptions here since AQV expects Runnables
throw new IORuntimeException(e);
}
}
}
/**
* Recursively visits all descendants under a directory.
*
* <p>{@link TreeArtifactVisitor#visit} is invoked on {@code visitor} for each directory, file,
* and symlink under the given {@code parentDir}.
*
* <p>This method is intended to provide uniform semantics for constructing a tree artifact,
* including special logic that validates directory entries. Invalid directory entries include a
* symlink that traverses outside of the tree artifact and any entry of {@link
* Dirent.Type#UNKNOWN}, such as a named pipe.
*
* <p>The visitor will be called on multiple threads in parallel. Accordingly, it must be
* thread-safe.
*
* @throws IOException if there is any problem reading or validating outputs under the given tree
* artifact directory, or if {@link TreeArtifactVisitor#visit} throws {@link IOException}
*/
public static void visitTree(Path parentDir, TreeArtifactVisitor treeArtifactVisitor)
throws IOException, InterruptedException {
Visitor visitor = new Visitor(parentDir, treeArtifactVisitor);
visitor.run();
}
private static void checkSymlink(PathFragment subDir, Path path) throws IOException {
PathFragment linkTarget = path.readSymbolicLinkUnchecked();
if (linkTarget.isAbsolute()) {
// We tolerate absolute symlinks here. They will probably be dangling if any downstream
// consumer tries to read them, but let that be downstream's problem.
return;
}
// Visit each path segment of the link target to catch any path traversal outside of the
// TreeArtifact root directory. For example, for TreeArtifact a/b/c, it is possible to have a
// symlink, a/b/c/sym_link that points to ../outside_dir/../c/link_target. Although this symlink
// points to a file under the TreeArtifact, the link target traverses outside of the
// TreeArtifact into a/b/outside_dir.
PathFragment intermediatePath = subDir;
for (String pathSegment : linkTarget.segments()) {
intermediatePath = intermediatePath.getRelative(pathSegment);
if (intermediatePath.containsUplevelReferences()) {
String errorMessage =
String.format(
"A TreeArtifact may not contain relative symlinks whose target paths traverse "
+ "outside of the TreeArtifact, found %s pointing to %s.",
path, linkTarget);
throw new IOException(errorMessage);
}
}
}
/** Builder for a {@link TreeArtifactValue}. */
public static final class Builder {
private final ImmutableSortedMap.Builder<TreeFileArtifact, FileArtifactValue> childData =
childDataBuilder();
private ArchivedRepresentation archivedRepresentation;
private PathFragment materializationExecPath;
private final SpecialArtifact parent;
Builder(SpecialArtifact parent) {
checkArgument(parent.isTreeArtifact(), "%s is not a tree artifact", parent);
this.parent = parent;
}
/**
* Adds a child to this builder.
*
* <p>The child's {@linkplain TreeFileArtifact#getParent parent} <em>must</em> match the parent
* with which this builder was initialized.
*
* <p>Children may be added in any order. The children are sorted prior to constructing the
* final {@link TreeArtifactValue}.
*
* <p>It is illegal to call this method with {@link FileArtifactValue#OMITTED_FILE_MARKER}. When
*
* <p>It is illegal to call this method with {@link FileArtifactValue#OMITTED_FILE_MARKER}. When
* children are omitted, use {@link TreeArtifactValue#OMITTED_TREE_MARKER}.
*
* @return {@code this} for convenience
*/
@CanIgnoreReturnValue
public Builder putChild(TreeFileArtifact child, FileArtifactValue metadata) {
checkArgument(
child.getParent().equals(parent),
"While building TreeArtifactValue for %s, got %s with parent %s",
parent,
child,
child.getParent());
checkArgument(
!FileArtifactValue.OMITTED_FILE_MARKER.equals(metadata),
"Cannot construct TreeArtifactValue for %s because child %s was omitted",
parent,
child);
childData.put(child, metadata);
return this;
}
public Builder setArchivedRepresentation(
ArchivedTreeArtifact archivedTreeArtifact, FileArtifactValue metadata) {
return setArchivedRepresentation(
ArchivedRepresentation.create(archivedTreeArtifact, metadata));
}
@CanIgnoreReturnValue
public Builder setArchivedRepresentation(ArchivedRepresentation archivedRepresentation) {
checkState(
this.archivedRepresentation == null,
"Tried to add 2 archived representations for: %s",
parent);
checkArgument(
parent.equals(archivedRepresentation.archivedTreeFileArtifact().getParent()),
"Cannot add archived representation: %s for a mismatching tree artifact: %s",
archivedRepresentation,
parent);
checkArgument(
!archivedRepresentation.archivedFileValue().equals(FileArtifactValue.OMITTED_FILE_MARKER),
"Cannot add archived representation: %s to %s because it has omitted metadata.",
archivedRepresentation,
parent);
this.archivedRepresentation = archivedRepresentation;
return this;
}
@CanIgnoreReturnValue
public Builder setMaterializationExecPath(PathFragment materializationExecPath) {
checkState(
this.materializationExecPath == null,
"Tried to set materialization exec path multiple times for: %s",
parent);
this.materializationExecPath = materializationExecPath;
return this;
}
/** Builds the final {@link TreeArtifactValue}. */
public TreeArtifactValue build() {
ImmutableSortedMap<TreeFileArtifact, FileArtifactValue> finalChildData =
childData.buildOrThrow();
if (finalChildData.isEmpty()
&& archivedRepresentation == null
&& materializationExecPath == null) {
return EMPTY;
}
Fingerprint fingerprint = new Fingerprint();
boolean entirelyRemote =
archivedRepresentation == null || archivedRepresentation.archivedFileValue().isRemote();
long totalChildSize = 0;
for (Map.Entry<TreeFileArtifact, FileArtifactValue> childData : finalChildData.entrySet()) {
// Digest will be deterministic because children are sorted.
fingerprint.addPath(childData.getKey().getParentRelativePath());
FileArtifactValue metadata = childData.getValue();
metadata.addTo(fingerprint);
// Tolerate a mix of local and remote children (b/152496153#comment80).
entirelyRemote &= metadata.isRemote();
if (metadata.getType() == FileStateType.REGULAR_FILE) {
totalChildSize += metadata.getSize();
}
}
if (archivedRepresentation != null) {
archivedRepresentation.archivedFileValue().addTo(fingerprint);
}
return new TreeArtifactValue(
fingerprint.digestAndReset(),
finalChildData,
totalChildSize,
archivedRepresentation,
materializationExecPath,
entirelyRemote);
}
}
}