| // 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; |
| } |
| } |