// 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.base.Function;
import com.google.common.base.MoreObjects;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Iterables;
import com.google.common.collect.Maps;
import com.google.devtools.build.lib.actions.Artifact;
import com.google.devtools.build.lib.actions.Artifact.TreeFileArtifact;
import com.google.devtools.build.lib.actions.cache.DigestUtils;
import com.google.devtools.build.lib.actions.cache.Metadata;
import com.google.devtools.build.lib.vfs.Path;
import com.google.devtools.build.lib.vfs.PathFragment;
import com.google.devtools.build.skyframe.SkyValue;
import java.io.IOException;
import java.util.Arrays;
import java.util.Map;
import java.util.Set;
import javax.annotation.Nullable;
/**
* Value for TreeArtifacts, which contains a digest and the {@link FileArtifactValue}s of its child
* {@link TreeFileArtifact}s.
*/
class TreeArtifactValue implements SkyValue {
private static final Function<Artifact, PathFragment> PARENT_RELATIVE_PATHS =
new Function<Artifact, PathFragment>() {
@Override
public PathFragment apply(Artifact artifact) {
return artifact.getParentRelativePath();
}
};
private final byte[] digest;
private final Map<TreeFileArtifact, FileArtifactValue> childData;
private TreeArtifactValue(byte[] digest, Map<TreeFileArtifact, FileArtifactValue> childData) {
this.digest = digest;
this.childData = ImmutableMap.copyOf(childData);
}
/**
* Returns a TreeArtifactValue out of the given Artifact-relative path fragments
* and their corresponding FileArtifactValues.
*/
static TreeArtifactValue create(Map<TreeFileArtifact, FileArtifactValue> childFileValues) {
Map<String, Metadata> digestBuilder =
Maps.newHashMapWithExpectedSize(childFileValues.size());
for (Map.Entry<TreeFileArtifact, FileArtifactValue> e : childFileValues.entrySet()) {
digestBuilder.put(
e.getKey().getParentRelativePath().getPathString(),
new Metadata(e.getValue().getDigest()));
}
return new TreeArtifactValue(
DigestUtils.fromMetadata(digestBuilder).getDigestBytesUnsafe(),
ImmutableMap.copyOf(childFileValues));
}
FileArtifactValue getSelfData() {
return FileArtifactValue.createProxy(digest);
}
Metadata getMetadata() {
return new Metadata(digest.clone());
}
Set<PathFragment> getChildPaths() {
return ImmutableSet.copyOf(Iterables.transform(childData.keySet(), PARENT_RELATIVE_PATHS));
}
@Nullable
byte[] getDigest() {
return digest.clone();
}
Iterable<TreeFileArtifact> getChildren() {
return childData.keySet();
}
Map<TreeFileArtifact, FileArtifactValue> getChildValues() {
return childData;
}
@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(TreeArtifactValue.class)
.add("digest", digest)
.add("childData", childData)
.toString();
}
/**
* A TreeArtifactValue that represents a missing TreeArtifact.
* This is occasionally useful because Java's concurrent collections disallow null members.
*/
static final TreeArtifactValue MISSING_TREE_ARTIFACT = new TreeArtifactValue(null,
ImmutableMap.<TreeFileArtifact, FileArtifactValue>of()) {
@Override
FileArtifactValue getSelfData() {
throw new UnsupportedOperationException();
}
@Override
Iterable<TreeFileArtifact> getChildren() {
throw new UnsupportedOperationException();
}
@Override
Map<TreeFileArtifact, FileArtifactValue> getChildValues() {
throw new UnsupportedOperationException();
}
@Override
Metadata getMetadata() {
throw new UnsupportedOperationException();
}
@Override
Set<PathFragment> getChildPaths() {
throw new UnsupportedOperationException();
}
@Nullable
@Override
byte[] getDigest() {
throw new UnsupportedOperationException();
}
@Override
public int hashCode() {
return 24; // my favorite number
}
@Override
public boolean equals(Object other) {
return this == other;
}
@Override
public String toString() {
return "MISSING_TREE_ARTIFACT";
}
};
private static void explodeDirectory(Artifact treeArtifact,
PathFragment pathToExplode, ImmutableSet.Builder<PathFragment> valuesBuilder)
throws IOException {
for (Path subpath : treeArtifact.getPath().getRelative(pathToExplode).getDirectoryEntries()) {
PathFragment canonicalSubpathFragment =
pathToExplode.getChild(subpath.getBaseName()).normalize();
if (subpath.isDirectory()) {
explodeDirectory(treeArtifact,
pathToExplode.getChild(subpath.getBaseName()), valuesBuilder);
} else if (subpath.isSymbolicLink()) {
PathFragment linkTarget = subpath.readSymbolicLinkUnchecked();
valuesBuilder.add(canonicalSubpathFragment);
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.
continue;
}
// We 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 = canonicalSubpathFragment.getParentDirectory();
for (String pathSegment : linkTarget.getSegments()) {
intermediatePath = intermediatePath.getRelative(pathSegment).normalize();
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.",
subpath,
linkTarget);
throw new IOException(errorMessage);
}
}
} else if (subpath.isFile()) {
valuesBuilder.add(canonicalSubpathFragment);
} else {
// We shouldn't ever reach here.
throw new IllegalStateException("Could not determine type of file " + subpath);
}
}
}
/**
* Recursively get all child files in a directory
* (excluding child directories themselves, but including all files in them).
* @throws IOException if there is any problem reading or validating outputs under the given
* tree artifact.
*/
static Set<PathFragment> explodeDirectory(Artifact treeArtifact) throws IOException {
ImmutableSet.Builder<PathFragment> explodedDirectory = ImmutableSet.builder();
explodeDirectory(treeArtifact, PathFragment.EMPTY_FRAGMENT, explodedDirectory);
return explodedDirectory.build();
}
}