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// Copyright 2018 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.includescanning;
import com.google.devtools.build.lib.actions.ArtifactFactory;
import com.google.devtools.build.lib.concurrent.ThreadSafety.ThreadSafe;
import com.google.devtools.build.lib.vfs.Path;
import com.google.devtools.build.lib.vfs.PathFragment;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
/**
* Cache to store file existence status for include paths. Only paths that are considered immutable
* for the duration of the build (any path outside of blaze-out directory will satisfy that
* criteria) are cached. This information is used by LegacyIncludeScanner class.
*/
@ThreadSafe
class PathExistenceCache {
private final Path execRoot;
private final ArtifactFactory artifactFactory;
private final Map<PathFragment, Boolean> fileExistenceCache = new ConcurrentHashMap<>();
private final Map<PathFragment, Boolean> directoryExistenceCache = new ConcurrentHashMap<>();
PathExistenceCache(Path execRoot, ArtifactFactory artifactFactory) {
this.execRoot = execRoot;
this.artifactFactory = artifactFactory;
}
/** Returns true if given path exists and is a file, false otherwise. */
boolean fileExists(PathFragment execPath, boolean isSource) {
Boolean exists = fileExistenceCache.get(execPath);
if (exists == null) {
// We do a second lookup on failure to avoid generating garbage in the cache hit case.
// The closure captures at least isSource, so the lambda will turn into a heap allocation.
exists =
fileExistenceCache.computeIfAbsent(
execPath,
k -> {
Path path =
isSource
? artifactFactory.getPathFromSourceExecPath(execPath)
: execRoot.getRelative(execPath);
return path.isFile();
});
}
return exists;
}
/** Returns true if given path exists and is a directory, false otherwise. */
boolean directoryExists(PathFragment execPath) {
Boolean exists = directoryExistenceCache.get(execPath);
if (exists == null) {
// We do a second lookup on failure to avoid generating garbage in the cache hit case.
// The closure captures at least execPath, so the lambda will turn into a heap allocation.
exists =
directoryExistenceCache.computeIfAbsent(
execPath,
k -> {
Path path = artifactFactory.getPathFromSourceExecPath(execPath);
return path.isDirectory();
});
}
return exists;
}
}