| // 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.common.base.Preconditions; |
| import com.google.common.base.Verify; |
| import com.google.common.collect.Collections2; |
| import com.google.common.collect.ImmutableList; |
| import com.google.devtools.build.lib.actions.Artifact; |
| import com.google.devtools.build.lib.actions.Artifact.TreeFileArtifact; |
| import com.google.devtools.build.lib.actions.ArtifactSkyKey; |
| import com.google.devtools.build.lib.actions.FileArtifactValue; |
| import com.google.devtools.build.lib.actions.FileValue; |
| import com.google.devtools.build.lib.collect.nestedset.NestedSet; |
| import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder; |
| import com.google.devtools.build.lib.events.Event; |
| import com.google.devtools.build.lib.skyframe.RecursiveFilesystemTraversalValue.ResolvedFile; |
| import com.google.devtools.build.lib.skyframe.RecursiveFilesystemTraversalValue.ResolvedFileFactory; |
| import com.google.devtools.build.lib.skyframe.RecursiveFilesystemTraversalValue.TraversalRequest; |
| import com.google.devtools.build.lib.vfs.Dirent; |
| import com.google.devtools.build.lib.vfs.FileStatus; |
| import com.google.devtools.build.lib.vfs.Path; |
| import com.google.devtools.build.lib.vfs.PathFragment; |
| import com.google.devtools.build.lib.vfs.Root; |
| import com.google.devtools.build.lib.vfs.RootedPath; |
| import com.google.devtools.build.lib.vfs.Symlinks; |
| import com.google.devtools.build.skyframe.SkyFunction; |
| import com.google.devtools.build.skyframe.SkyFunctionException; |
| import com.google.devtools.build.skyframe.SkyKey; |
| import com.google.devtools.build.skyframe.SkyValue; |
| import java.io.IOException; |
| import java.util.ArrayList; |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.HashMap; |
| import java.util.List; |
| import java.util.Map; |
| import javax.annotation.Nullable; |
| |
| /** A {@link SkyFunction} to build {@link RecursiveFilesystemTraversalValue}s. */ |
| public final class RecursiveFilesystemTraversalFunction implements SkyFunction { |
| |
| private static final class MissingDepException extends Exception {} |
| |
| /** Base class for exceptions that {@link RecursiveFilesystemTraversalFunctionException} wraps. */ |
| public abstract static class RecursiveFilesystemTraversalException extends Exception { |
| protected RecursiveFilesystemTraversalException(String message) { |
| super(message); |
| } |
| } |
| |
| /** Thrown when a generated directory's root-relative path conflicts with a package's path. */ |
| public static final class GeneratedPathConflictException extends |
| RecursiveFilesystemTraversalException { |
| GeneratedPathConflictException(TraversalRequest traversal) { |
| super( |
| String.format( |
| "Generated directory %s conflicts with package under the same path. " |
| + "Additional info: %s", |
| traversal.root.asRootedPath().getRootRelativePath().getPathString(), |
| traversal.errorInfo != null ? traversal.errorInfo : traversal.toString())); |
| } |
| } |
| |
| /** |
| * Thrown when the traversal encounters a subdirectory with a BUILD file but is not allowed to |
| * recurse into it. See {@code PackageBoundaryMode#REPORT_ERROR}. |
| */ |
| public static final class CannotCrossPackageBoundaryException extends |
| RecursiveFilesystemTraversalException { |
| CannotCrossPackageBoundaryException(String message) { |
| super(message); |
| } |
| } |
| |
| /** |
| * Thrown when a dangling symlink is attempted to be dereferenced. |
| * |
| * <p>Note: this class is not identical to the one in com.google.devtools.build.lib.view.fileset |
| * and it's not easy to merge the two because of the dependency structure. The other one will |
| * probably be removed along with the rest of the legacy Fileset code. |
| */ |
| public static final class DanglingSymlinkException extends RecursiveFilesystemTraversalException { |
| public final String path; |
| public final String unresolvedLink; |
| |
| public DanglingSymlinkException(String path, String unresolvedLink) { |
| super( |
| String.format( |
| "Found dangling symlink: %s, unresolved path: \"%s\"", path, unresolvedLink)); |
| Preconditions.checkArgument(path != null && !path.isEmpty()); |
| Preconditions.checkArgument(unresolvedLink != null && !unresolvedLink.isEmpty()); |
| this.path = path; |
| this.unresolvedLink = unresolvedLink; |
| } |
| |
| public String getPath() { |
| return path; |
| } |
| } |
| |
| /** Thrown when we encounter errors from underlying File operations */ |
| public static final class FileOperationException extends RecursiveFilesystemTraversalException { |
| public FileOperationException(String message) { |
| super(message); |
| } |
| } |
| |
| /** Exception type thrown by {@link RecursiveFilesystemTraversalFunction#compute}. */ |
| private static final class RecursiveFilesystemTraversalFunctionException extends |
| SkyFunctionException { |
| RecursiveFilesystemTraversalFunctionException(RecursiveFilesystemTraversalException e) { |
| super(e, Transience.PERSISTENT); |
| } |
| } |
| |
| @Override |
| public SkyValue compute(SkyKey skyKey, Environment env) |
| throws RecursiveFilesystemTraversalFunctionException, InterruptedException { |
| TraversalRequest traversal = (TraversalRequest) skyKey.argument(); |
| try { |
| // Stat the traversal root. |
| FileInfo rootInfo = lookUpFileInfo(env, traversal); |
| |
| if (!rootInfo.type.exists()) { |
| // May be a dangling symlink or a non-existent file. Handle gracefully. |
| if (rootInfo.type.isSymlink()) { |
| return resultForDanglingSymlink(traversal.root.asRootedPath(), rootInfo); |
| } else { |
| return RecursiveFilesystemTraversalValue.EMPTY; |
| } |
| } |
| |
| if (rootInfo.type.isFile()) { |
| return resultForFileRoot(traversal.root.asRootedPath(), rootInfo); |
| } else if (rootInfo.type.isDirectory() && rootInfo.metadata instanceof TreeArtifactValue) { |
| final TreeArtifactValue value = (TreeArtifactValue) rootInfo.metadata; |
| ImmutableList.Builder<RecursiveFilesystemTraversalValue> list = ImmutableList.builder(); |
| for (Map.Entry<TreeFileArtifact, FileArtifactValue> entry |
| : value.getChildValues().entrySet()) { |
| RootedPath path = |
| RootedPath.toRootedPath( |
| traversal.root.asRootedPath().getRoot(), entry.getKey().getPath()); |
| list.add(resultForFileRoot( |
| path, |
| // TreeArtifact can't have symbolic inside. So the assumption for FileType.FILE |
| // is always true. |
| new FileInfo(FileType.FILE, entry.getValue(), path, null))); |
| } |
| return resultForDirectory(traversal, rootInfo, list.build()); |
| } |
| |
| // Otherwise the root is a directory or a symlink to one. |
| PkgLookupResult pkgLookupResult = checkIfPackage(env, traversal, rootInfo); |
| traversal = pkgLookupResult.traversal; |
| |
| if (pkgLookupResult.isConflicting()) { |
| // The traversal was requested for an output directory whose root-relative path conflicts |
| // with a source package. We can't handle that, bail out. |
| throw new RecursiveFilesystemTraversalFunctionException( |
| new GeneratedPathConflictException(traversal)); |
| } else if (pkgLookupResult.isPackage() && !traversal.skipTestingForSubpackage) { |
| // The traversal was requested for a directory that defines a package. |
| String msg = |
| traversal.errorInfo |
| + " crosses package boundary into package rooted at " |
| + traversal.root.asRootedPath().getRootRelativePath().getPathString(); |
| switch (traversal.crossPkgBoundaries) { |
| case CROSS: |
| // We are free to traverse the subpackage but we need to display a warning. |
| env.getListener().handle(Event.warn(null, msg)); |
| break; |
| case DONT_CROSS: |
| // We cannot traverse the subpackage and should skip it silently. Return empty results. |
| return RecursiveFilesystemTraversalValue.EMPTY; |
| case REPORT_ERROR: |
| // We cannot traverse the subpackage and should complain loudly (display an error). |
| throw new RecursiveFilesystemTraversalFunctionException( |
| new CannotCrossPackageBoundaryException(msg)); |
| default: |
| throw new IllegalStateException(traversal.toString()); |
| } |
| } |
| |
| // We are free to traverse this directory. |
| Collection<SkyKey> dependentKeys = createRecursiveTraversalKeys(env, traversal); |
| return resultForDirectory( |
| traversal, |
| rootInfo, |
| traverseChildren(env, dependentKeys, /*inline=*/ traversal.isRootGenerated)); |
| } catch (IOException e) { |
| throw new RecursiveFilesystemTraversalFunctionException( |
| new FileOperationException("Error while traversing fileset: " + e.getMessage())); |
| } catch (MissingDepException e) { |
| return null; |
| } |
| } |
| |
| @Override |
| public String extractTag(SkyKey skyKey) { |
| return null; |
| } |
| |
| private static final class FileInfo { |
| final FileType type; |
| final Object metadata; |
| @Nullable final RootedPath realPath; |
| @Nullable final PathFragment unresolvedSymlinkTarget; |
| |
| FileInfo( |
| FileType type, |
| Object metadata, |
| @Nullable RootedPath realPath, |
| @Nullable PathFragment unresolvedSymlinkTarget) { |
| this.type = Preconditions.checkNotNull(type); |
| this.metadata = metadata; |
| this.realPath = realPath; |
| this.unresolvedSymlinkTarget = unresolvedSymlinkTarget; |
| } |
| |
| @Override |
| public String toString() { |
| if (type.isSymlink()) { |
| return String.format("(%s: link_value=%s, real_path=%s)", type, |
| unresolvedSymlinkTarget.getPathString(), realPath); |
| } else { |
| return String.format("(%s: real_path=%s)", type, realPath); |
| } |
| } |
| } |
| |
| private static final FileInfo NON_EXISTENT_FILE_INFO = |
| new FileInfo(FileType.NONEXISTENT, new Integer(0), null, null); |
| |
| private static FileInfo lookUpFileInfo(Environment env, TraversalRequest traversal) |
| throws MissingDepException, IOException, InterruptedException { |
| if (traversal.isRootGenerated) { |
| SkyValue fsVal = null; |
| if (traversal.root.getOutputArtifact() != null) { |
| Artifact artifact = traversal.root.getOutputArtifact(); |
| SkyKey artifactKey = ArtifactSkyKey.key(artifact, true); |
| SkyValue value = env.getValue(artifactKey); |
| if (env.valuesMissing()) { |
| throw new MissingDepException(); |
| } |
| |
| if (value instanceof FileArtifactValue) { |
| fsVal = value; |
| } else if (value instanceof TreeArtifactValue) { |
| fsVal = value; |
| } else { |
| return NON_EXISTENT_FILE_INFO; |
| } |
| } |
| RootedPath realPath = traversal.root.asRootedPath(); |
| if (traversal.strictOutputFiles) { |
| Preconditions.checkNotNull(fsVal, "Strict Fileset output tree has null FileArtifactValue"); |
| return new FileInfo( |
| (fsVal instanceof TreeArtifactValue ? FileType.DIRECTORY : FileType.FILE), |
| fsVal, realPath, null); |
| } else { |
| // FileArtifactValue does not currently track symlinks. If it did, we could potentially |
| // remove some of the filesystem operations we're doing here. |
| Path path = traversal.root.asRootedPath().asPath(); |
| FileStatus noFollowStat = path.stat(Symlinks.NOFOLLOW); |
| FileStatus followStat = path.statIfFound(Symlinks.FOLLOW); |
| FileType type; |
| PathFragment unresolvedLinkTarget = null; |
| if (followStat == null) { |
| type = FileType.DANGLING_SYMLINK; |
| if (!noFollowStat.isSymbolicLink()) { |
| throw new IOException("Expected symlink for " + path + ", but got: " + noFollowStat); |
| } |
| unresolvedLinkTarget = path.readSymbolicLink(); |
| } else if (noFollowStat.isFile()) { |
| type = FileType.FILE; |
| } else if (noFollowStat.isDirectory()) { |
| type = FileType.DIRECTORY; |
| } else { |
| unresolvedLinkTarget = path.readSymbolicLink(); |
| realPath = |
| RootedPath.toRootedPath( |
| Root.absoluteRoot(path.getFileSystem()), path.resolveSymbolicLinks()); |
| type = followStat.isFile() ? FileType.SYMLINK_TO_FILE : FileType.SYMLINK_TO_DIRECTORY; |
| } |
| return new FileInfo( |
| type, fsVal != null ? fsVal : noFollowStat.hashCode(), realPath, unresolvedLinkTarget); |
| } |
| } else { |
| // Stat the file. |
| FileValue fileValue = |
| (FileValue) env.getValueOrThrow( |
| FileValue.key(traversal.root.asRootedPath()), IOException.class); |
| |
| if (env.valuesMissing()) { |
| throw new MissingDepException(); |
| } |
| if (fileValue.exists()) { |
| // If it exists, it may either be a symlink or a file/directory. |
| PathFragment unresolvedLinkTarget = null; |
| FileType type; |
| if (fileValue.isSymlink()) { |
| unresolvedLinkTarget = fileValue.getUnresolvedLinkTarget(); |
| type = fileValue.isDirectory() ? FileType.SYMLINK_TO_DIRECTORY : FileType.SYMLINK_TO_FILE; |
| } else { |
| type = fileValue.isDirectory() ? FileType.DIRECTORY : FileType.FILE; |
| } |
| return new FileInfo( |
| type, fileValue.realFileStateValue(), fileValue.realRootedPath(), unresolvedLinkTarget); |
| } else { |
| // If it doesn't exist, or it's a dangling symlink, we still want to handle that gracefully. |
| return new FileInfo( |
| fileValue.isSymlink() ? FileType.DANGLING_SYMLINK : FileType.NONEXISTENT, |
| fileValue.realFileStateValue(), |
| null, |
| fileValue.isSymlink() ? fileValue.getUnresolvedLinkTarget() : null); |
| } |
| } |
| } |
| |
| private static final class PkgLookupResult { |
| private enum Type { |
| CONFLICT, DIRECTORY, PKG |
| } |
| |
| private final Type type; |
| final TraversalRequest traversal; |
| final FileInfo rootInfo; |
| |
| /** Result for a generated directory that conflicts with a source package. */ |
| static PkgLookupResult conflict(TraversalRequest traversal, FileInfo rootInfo) { |
| return new PkgLookupResult(Type.CONFLICT, traversal, rootInfo); |
| } |
| |
| /** Result for a source or generated directory (not a package). */ |
| static PkgLookupResult directory(TraversalRequest traversal, FileInfo rootInfo) { |
| return new PkgLookupResult(Type.DIRECTORY, traversal, rootInfo); |
| } |
| |
| /** Result for a package, i.e. a directory with a BUILD file. */ |
| static PkgLookupResult pkg(TraversalRequest traversal, FileInfo rootInfo) { |
| return new PkgLookupResult(Type.PKG, traversal, rootInfo); |
| } |
| |
| private PkgLookupResult(Type type, TraversalRequest traversal, FileInfo rootInfo) { |
| this.type = Preconditions.checkNotNull(type); |
| this.traversal = Preconditions.checkNotNull(traversal); |
| this.rootInfo = Preconditions.checkNotNull(rootInfo); |
| } |
| |
| boolean isPackage() { |
| return type == Type.PKG; |
| } |
| |
| boolean isConflicting() { |
| return type == Type.CONFLICT; |
| } |
| |
| @Override |
| public String toString() { |
| return String.format("(%s: info=%s, traversal=%s)", type, rootInfo, traversal); |
| } |
| } |
| |
| /** |
| * Checks whether the {@code traversal}'s path refers to a package directory. |
| * |
| * @return the result of the lookup; it contains potentially new {@link TraversalRequest} and |
| * {@link FileInfo} so the caller should use these instead of the old ones (this happens when |
| * a package is found, but under a different root than expected) |
| */ |
| private static PkgLookupResult checkIfPackage( |
| Environment env, TraversalRequest traversal, FileInfo rootInfo) |
| throws MissingDepException, IOException, InterruptedException { |
| Preconditions.checkArgument(rootInfo.type.exists() && !rootInfo.type.isFile(), |
| "{%s} {%s}", traversal, rootInfo); |
| PackageLookupValue pkgLookup = |
| (PackageLookupValue) |
| getDependentSkyValue(env, |
| PackageLookupValue.key(traversal.root.asRootedPath().getRootRelativePath())); |
| |
| if (pkgLookup.packageExists()) { |
| if (traversal.isRootGenerated) { |
| // The traversal's root was a generated directory, but its root-relative path conflicts with |
| // an existing package. |
| return PkgLookupResult.conflict(traversal, rootInfo); |
| } else { |
| // The traversal's root was a source directory and it defines a package. |
| Root pkgRoot = pkgLookup.getRoot(); |
| if (!pkgRoot.equals(traversal.root.asRootedPath().getRoot())) { |
| // However the root of this package is different from what we expected. stat() the real |
| // BUILD file of that package. |
| traversal = traversal.forChangedRootPath(pkgRoot); |
| rootInfo = lookUpFileInfo(env, traversal); |
| Verify.verify(rootInfo.type.exists(), "{%s} {%s}", traversal, rootInfo); |
| } |
| return PkgLookupResult.pkg(traversal, rootInfo); |
| } |
| } else { |
| // The traversal's root was a directory (source or generated one), no package exists under the |
| // same root-relative path. |
| return PkgLookupResult.directory(traversal, rootInfo); |
| } |
| } |
| |
| /** |
| * List the directory and create {@code SkyKey}s to request contents of its children recursively. |
| * |
| * <p>The returned keys are of type {@link SkyFunctions#RECURSIVE_FILESYSTEM_TRAVERSAL}. |
| */ |
| private static Collection<SkyKey> createRecursiveTraversalKeys( |
| Environment env, TraversalRequest traversal) |
| throws MissingDepException, InterruptedException, IOException { |
| // Use the traversal's path, even if it's a symlink. The contents of the directory, as listed |
| // in the result, must be relative to it. |
| Iterable<Dirent> dirents; |
| if (traversal.isRootGenerated) { |
| // If we're dealing with an output file, read the directory directly instead of creating |
| // filesystem nodes under the output tree. |
| List<Dirent> direntsCollection = |
| new ArrayList<>( |
| traversal.root.asRootedPath().asPath().readdir(Symlinks.FOLLOW)); |
| Collections.sort(direntsCollection); |
| dirents = direntsCollection; |
| } else { |
| dirents = ((DirectoryListingValue) getDependentSkyValue(env, |
| DirectoryListingValue.key(traversal.root.asRootedPath()))).getDirents(); |
| } |
| |
| List<SkyKey> result = new ArrayList<>(); |
| for (Dirent dirent : dirents) { |
| RootedPath childPath = |
| RootedPath.toRootedPath( |
| traversal.root.asRootedPath().getRoot(), |
| traversal.root.asRootedPath().getRootRelativePath().getRelative(dirent.getName())); |
| TraversalRequest childTraversal = traversal.forChildEntry(childPath); |
| result.add(childTraversal); |
| } |
| return result; |
| } |
| |
| /** |
| * Creates result for a dangling symlink. |
| * |
| * @param linkName path to the symbolic link |
| * @param info the {@link FileInfo} associated with the link file |
| */ |
| private static RecursiveFilesystemTraversalValue resultForDanglingSymlink(RootedPath linkName, |
| FileInfo info) { |
| Preconditions.checkState(info.type.isSymlink() && !info.type.exists(), "{%s} {%s}", linkName, |
| info.type); |
| return RecursiveFilesystemTraversalValue.of( |
| ResolvedFileFactory.danglingSymlink(linkName, info.unresolvedSymlinkTarget, info.metadata)); |
| } |
| |
| /** |
| * Creates results for a file or for a symlink that points to one. |
| * |
| * <p>A symlink may be direct (points to a file) or transitive (points at a direct or transitive |
| * symlink). |
| */ |
| private static RecursiveFilesystemTraversalValue resultForFileRoot(RootedPath path, |
| FileInfo info) { |
| Preconditions.checkState(info.type.isFile() && info.type.exists(), "{%s} {%s}", path, |
| info.type); |
| if (info.type.isSymlink()) { |
| return RecursiveFilesystemTraversalValue.of( |
| ResolvedFileFactory.symlinkToFile( |
| info.realPath, path, info.unresolvedSymlinkTarget, info.metadata)); |
| } else { |
| return RecursiveFilesystemTraversalValue.of( |
| ResolvedFileFactory.regularFile(path, info.metadata)); |
| } |
| } |
| |
| private static RecursiveFilesystemTraversalValue resultForDirectory(TraversalRequest traversal, |
| FileInfo rootInfo, Collection<RecursiveFilesystemTraversalValue> subdirTraversals) { |
| // Collect transitive closure of files in subdirectories. |
| NestedSetBuilder<ResolvedFile> paths = NestedSetBuilder.stableOrder(); |
| for (RecursiveFilesystemTraversalValue child : subdirTraversals) { |
| paths.addTransitive(child.getTransitiveFiles()); |
| } |
| ResolvedFile root; |
| if (rootInfo.type.isSymlink()) { |
| NestedSet<ResolvedFile> children = paths.build(); |
| root = |
| ResolvedFileFactory.symlinkToDirectory( |
| rootInfo.realPath, |
| traversal.root.asRootedPath(), |
| rootInfo.unresolvedSymlinkTarget, |
| hashDirectorySymlink(children, rootInfo.metadata)); |
| paths = NestedSetBuilder.<ResolvedFile>stableOrder().addTransitive(children).add(root); |
| } else { |
| root = ResolvedFileFactory.directory(rootInfo.realPath); |
| } |
| return RecursiveFilesystemTraversalValue.of(root, paths.build()); |
| } |
| |
| private static int hashDirectorySymlink(Iterable<ResolvedFile> children, Object metadata) { |
| // If the root is a directory symlink, the associated FileStateValue does not change when the |
| // linked directory's contents change, so we can't use the FileStateValue as metadata like we |
| // do with other ResolvedFile kinds. Instead we compute a metadata hash from the child |
| // elements and return that as the ResolvedFile's metadata hash. |
| |
| // Compute the hash using the method described in Effective Java, 2nd ed., Item 9. |
| int result = 0; |
| for (ResolvedFile c : children) { |
| result = 31 * result + c.getMetadata().hashCode(); |
| } |
| return 31 * result + metadata.hashCode(); |
| } |
| |
| private static SkyValue getDependentSkyValue(Environment env, SkyKey key) |
| throws MissingDepException, InterruptedException { |
| SkyValue value = env.getValue(key); |
| if (env.valuesMissing()) { |
| throw new MissingDepException(); |
| } |
| return value; |
| } |
| |
| /** |
| * Requests Skyframe to compute the dependent values and returns them. |
| * |
| * <p>The keys must all be {@link SkyFunctions#RECURSIVE_FILESYSTEM_TRAVERSAL} keys. |
| */ |
| private Collection<RecursiveFilesystemTraversalValue> traverseChildren( |
| Environment env, Iterable<SkyKey> keys, boolean inline) |
| throws MissingDepException, InterruptedException, |
| RecursiveFilesystemTraversalFunctionException { |
| Map<SkyKey, SkyValue> values; |
| if (inline) { |
| // Don't create Skyframe nodes for a recursive traversal over the output tree. |
| // Instead, inline the recursion in the top-level request. |
| values = new HashMap<>(); |
| for (SkyKey depKey : keys) { |
| values.put(depKey, compute(depKey, env)); |
| } |
| } else { |
| values = env.getValues(keys); |
| } |
| if (env.valuesMissing()) { |
| throw new MissingDepException(); |
| } |
| |
| return Collections2.transform(values.values(), RecursiveFilesystemTraversalValue.class::cast); |
| } |
| |
| /** Type information about the filesystem entry residing at a path. */ |
| enum FileType { |
| /** A regular file. */ |
| FILE { |
| @Override boolean isFile() { return true; } |
| @Override boolean exists() { return true; } |
| @Override public String toString() { return "<f>"; } |
| }, |
| /** |
| * A symlink to a regular file. |
| * |
| * <p>The symlink may be direct (points to a non-symlink (here a file)) or it may be transitive |
| * (points to a direct or transitive symlink). |
| */ |
| SYMLINK_TO_FILE { |
| @Override boolean isFile() { return true; } |
| @Override boolean isSymlink() { return true; } |
| @Override boolean exists() { return true; } |
| @Override public String toString() { return "<lf>"; } |
| }, |
| /** A directory. */ |
| DIRECTORY { |
| @Override boolean isDirectory() { return true; } |
| @Override boolean exists() { return true; } |
| @Override public String toString() { return "<d>"; } |
| }, |
| /** |
| * A symlink to a directory. |
| * |
| * <p>The symlink may be direct (points to a non-symlink (here a directory)) or it may be |
| * transitive (points to a direct or transitive symlink). |
| */ |
| SYMLINK_TO_DIRECTORY { |
| @Override boolean isDirectory() { return true; } |
| @Override boolean isSymlink() { return true; } |
| @Override boolean exists() { return true; } |
| @Override public String toString() { return "<ld>"; } |
| }, |
| /** A dangling symlink, i.e. one whose target is known not to exist. */ |
| DANGLING_SYMLINK { |
| @Override boolean isFile() { throw new UnsupportedOperationException(); } |
| @Override boolean isDirectory() { throw new UnsupportedOperationException(); } |
| @Override boolean isSymlink() { return true; } |
| @Override public String toString() { return "<l?>"; } |
| }, |
| /** A path that does not exist or should be ignored. */ |
| NONEXISTENT { |
| @Override public String toString() { return "<?>"; } |
| }; |
| |
| boolean isFile() { return false; } |
| boolean isDirectory() { return false; } |
| boolean isSymlink() { return false; } |
| boolean exists() { return false; } |
| @Override public abstract String toString(); |
| } |
| } |
