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// Copyright 2014 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.devtools.build.lib.cmdline.Label;
import com.google.devtools.build.lib.pkgcache.PathPackageLocator;
import com.google.devtools.build.lib.rules.repository.RepositoryFunction;
import com.google.devtools.build.lib.vfs.Path;
import com.google.devtools.build.lib.vfs.PathFragment;
import com.google.devtools.build.lib.vfs.RootedPath;
import com.google.devtools.build.skyframe.SkyFunction;
import java.util.concurrent.atomic.AtomicReference;
/** Common utilities for dealing with files outside the package roots. */
public class ExternalFilesHelper {
private final AtomicReference<PathPackageLocator> pkgLocator;
private final ExternalFileAction externalFileAction;
// This variable is set to true from multiple threads, but only read once, in the main thread.
// So volatility or an AtomicBoolean is not needed.
private boolean externalFileSeen = false;
/**
* @param pkgLocator an {@link AtomicReference} to a {@link PathPackageLocator} used to
* determine what files are internal.
* @param errorOnExternalFiles If files outside of package paths should be allowed.
*/
public ExternalFilesHelper(
AtomicReference<PathPackageLocator> pkgLocator, boolean errorOnExternalFiles) {
this.pkgLocator = pkgLocator;
if (errorOnExternalFiles) {
this.externalFileAction = ExternalFileAction.ERROR_OUT;
} else {
this.externalFileAction = ExternalFileAction.DEPEND_ON_EXTERNAL_PKG;
}
}
private enum ExternalFileAction {
// Re-check the files when the WORKSPACE file changes.
DEPEND_ON_EXTERNAL_PKG,
// Throw an exception if there is an external file.
ERROR_OUT,
}
boolean isExternalFileSeen() {
return externalFileSeen;
}
static boolean isInternal(RootedPath rootedPath, PathPackageLocator packageLocator) {
// TODO(bazel-team): This is inefficient when there are a lot of package roots or there are a
// lot of external directories. Consider either explicitly preventing this case or using a more
// efficient approach here (e.g. use a trie for determining if a file is under an external
// directory).
return packageLocator.getPathEntries().contains(rootedPath.getRoot());
}
/**
* If this instance is configured with DEPEND_ON_EXTERNAL_PKG and rootedPath is a file that isn't
* under a package root then this adds a dependency on the //external package. If the action is
* ERROR_OUT, it will throw an error instead.
*/
public void maybeHandleExternalFile(RootedPath rootedPath, SkyFunction.Environment env)
throws FileOutsidePackageRootsException {
if (isInternal(rootedPath, pkgLocator.get())) {
return;
}
externalFileSeen = true;
if (externalFileAction == ExternalFileAction.ERROR_OUT) {
throw new FileOutsidePackageRootsException(rootedPath);
}
// The outputBase may be null if we're not actually running a build.
Path outputBase = pkgLocator.get().getOutputBase();
Path relativeExternal = pkgLocator
.get().getOutputBase().getRelative(Label.EXTERNAL_PATH_PREFIX);
if (outputBase != null && !rootedPath.asPath().startsWith(relativeExternal)) {
return;
}
// For files that are under $OUTPUT_BASE/external, add a dependency on the corresponding rule
// so that if the WORKSPACE file changes, the File/DirectoryStateValue will be re-evaluated.
//
// Note that:
// - We don't add a dependency on the parent directory at the package root boundary, so
// the only transitive dependencies from files inside the package roots to external files
// are through symlinks. So the upwards transitive closure of external files is small.
// - The only way other than external repositories for external source files to get into the
// skyframe graph in the first place is through symlinks outside the package roots, which we
// neither want to encourage nor optimize for since it is not common. So the set of external
// files is small.
PathFragment repositoryPath = rootedPath.asPath().relativeTo(relativeExternal);
if (repositoryPath.segmentCount() == 0) {
// We are the top of the repository path (<outputBase>/external), not in an actual external
// repository path.
return;
}
String repositoryName = repositoryPath.getSegment(0);
try {
RepositoryFunction.getRule(repositoryName, env);
} catch (RepositoryFunction.RepositoryNotFoundException ex) {
// The repository we are looking for does not exist so we should depend on the whole
// WORKSPACE file. In that case, the call to RepositoryFunction#getRule(String, Environment)
// already requested all repository functions from the WORKSPACE file from Skyframe as part of
// the resolution. Therefore we are safe to ignore that Exception.
} catch (RepositoryFunction.RepositoryFunctionException ex) {
// This should never happen.
throw new IllegalStateException(
"Repository " + repositoryName + " cannot be resolved for path " + rootedPath, ex);
}
}
}
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