Package io.roastedroot.zerofs

Class FileSystemView

java.lang.Object

io.roastedroot.zerofs.FileSystemView

final class FileSystemView
extends Object

View of a file system with a specific working directory. As all file system operations need to work when given either relative or absolute paths, this class contains the implementation of most file system operations, with relative path operations resolving against the working directory.

A file system has one default view using the file system's working directory. Additional views may be created for use in SecureDirectoryStream instances, which each have a different working directory they use.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static enum	FileSystemView.DeleteMode	Mode for deleting.

Field Summary

Fields

Modifier and Type	Field	Description
private final ZeroFsFileStore	store
private final Directory	workingDirectory
private final ZeroFsPath	workingDirectoryPath

Constructor Summary

Constructors

Constructor	Description
FileSystemView(ZeroFsFileStore store, Directory workingDirectory, ZeroFsPath workingDirectoryPath)	Creates a new file system view.

Method Summary

Modifier and Type	Method	Description
void	checkAccess(ZeroFsPath path)	Checks access to the file at the given path for the given modes.
private void	checkDeletable(File file, FileSystemView.DeleteMode mode, Path path)	Checks that the given file can be deleted, throwing an exception if it can't.
private void	checkEmpty(Directory dir, Path pathForException)	Checks that given directory is empty, throwing DirectoryNotEmptyException if not.
private void	checkMovable(File file, ZeroFsPath path)
private void	checkNotAncestor(File source, Directory destParent, FileSystemView destView)	Checks that source is not an ancestor of dest, throwing an exception if it is.
void	copy(ZeroFsPath source, FileSystemView destView, ZeroFsPath dest, Set<CopyOption> options, boolean move)	Copies or moves the file at the given source path to the given dest path.
Directory	createDirectory(ZeroFsPath path, FileAttribute<?>... attrs)	Creates a new directory at the given path.
private File	createFile(ZeroFsPath path, Supplier<? extends File> fileCreator, boolean failIfExists, FileAttribute<?>... attrs)	Creates a new file at the given path if possible, using the given supplier to create the file.
SymbolicLink	createSymbolicLink(ZeroFsPath path, ZeroFsPath target, FileAttribute<?>... attrs)	Creates a new symbolic link at the given path with the given target.
private void	delete(DirectoryEntry entry, FileSystemView.DeleteMode deleteMode, ZeroFsPath pathForException)	Deletes the given directory entry from its parent directory.
void	deleteFile(ZeroFsPath path, FileSystemView.DeleteMode deleteMode)	Deletes the file at the given absolute path.
<V extends FileAttributeView> V	getFileAttributeView(FileLookup lookup, Class<V> type)	Returns a file attribute view using the given lookup callback.
<V extends FileAttributeView> V	getFileAttributeView(ZeroFsPath path, Class<V> type, Set<? super LinkOption> options)	Returns a file attribute view for the given path in this view.
RegularFile	getOrCreateRegularFile(ZeroFsPath path, Set<OpenOption> options, FileAttribute<?>... attrs)	Gets the regular file at the given path, creating it if it doesn't exist and the given options specify that it should be created.
private RegularFile	getOrCreateRegularFileWithWriteLock(ZeroFsPath path, Set<OpenOption> options, FileAttribute<?>[] attrs)	Gets or creates a new regular file with a write lock (assuming the file does not exist).
ZeroFsPath	getWorkingDirectoryPath()	Returns the path of the working directory at the time this view was created.
boolean	isSameFile(ZeroFsPath path, FileSystemView view2, ZeroFsPath path2)	Returns whether or not the two given paths locate the same file.
private boolean	isSameFileSystem(FileSystemView other)	Returns whether or not this view and the given view belong to the same file system.
void	link(ZeroFsPath link, FileSystemView existingView, ZeroFsPath existing)	Creates a hard link at the given link path to the regular file at the given path.
private static void	lockBoth(Lock sourceWriteLock, Lock destWriteLock)	Acquires both write locks in a way that attempts to avoid the possibility of deadlock.
private void	lockSourceAndCopy(File sourceFile, File copyFile)	Locks source and copy files before copying content.
private DirectoryEntry	lookUp(ZeroFsPath path, Set<? super LinkOption> options)	Looks up the file at the given path without locking.
private RegularFile	lookUpRegularFile(ZeroFsPath path, Set<OpenOption> options)	Looks up the regular file at the given path, throwing an exception if the file isn't a regular file.
(package private) DirectoryEntry	lookUpWithLock(ZeroFsPath path, Set<? super LinkOption> options)	Attempt to look up the file at the given path.
DirectoryStream<Path>	newDirectoryStream(ZeroFsPath dir, DirectoryStream.Filter<? super Path> filter, Set<? super LinkOption> options, ZeroFsPath basePathForStream)	Creates a new directory stream for the directory located by the given path.
private FileTime	now()
private static RegularFile	open(RegularFile file, Set<OpenOption> options)	Opens the given regular file with the given options, truncating it if necessary and incrementing its open count.
<A extends BasicFileAttributes> A	readAttributes(ZeroFsPath path, Class<A> type, Set<? super LinkOption> options)	Reads attributes of the file located by the given path in this view as an object.
Map<String,Object>	readAttributes(ZeroFsPath path, String attributes, Set<? super LinkOption> options)	Reads attributes of the file located by the given path in this view as a map.
ZeroFsPath	readSymbolicLink(ZeroFsPath path)	Returns the target of the symbolic link at the given path.
void	setAttribute(ZeroFsPath path, String attribute, Object value, Set<? super LinkOption> options)	Sets the given attribute to the given value on the file located by the given path in this view.
Map<Name,FileTime>	snapshotModifiedTimes(ZeroFsPath path)	Returns a snapshot mapping the names of each file in the directory at the given path to the last modified time of that file.
SortedSet<Name>	snapshotWorkingDirectoryEntries()	Snapshots the entries of the working directory of this view.
FileSystemState	state()	Returns the file system state.
ZeroFsPath	toRealPath(ZeroFsPath path, PathService pathService, Set<? super LinkOption> options)	Gets the real path to the file located by the given path.
private void	unlockSourceAndCopy(File sourceFile, File copyFile)	Unlocks source and copy files after copying content.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

store

private final ZeroFsFileStore store

workingDirectory

private final Directory workingDirectory

workingDirectoryPath

private final ZeroFsPath workingDirectoryPath

Constructor Details

FileSystemView

public FileSystemView(ZeroFsFileStore store,
 Directory workingDirectory,
 ZeroFsPath workingDirectoryPath)

Creates a new file system view.

Method Details

isSameFileSystem

private boolean isSameFileSystem(FileSystemView other)

Returns whether or not this view and the given view belong to the same file system.

state

public FileSystemState state()

Returns the file system state.

now

private FileTime now()

getWorkingDirectoryPath

public ZeroFsPath getWorkingDirectoryPath()

Returns the path of the working directory at the time this view was created. Does not reflect changes to the path caused by the directory being moved.

lookUpWithLock

DirectoryEntry lookUpWithLock(ZeroFsPath path,
 Set<? super LinkOption> options)
                       throws IOException

Attempt to look up the file at the given path.

Throws:

IOException

lookUp

private DirectoryEntry lookUp(ZeroFsPath path,
 Set<? super LinkOption> options)
                       throws IOException

Looks up the file at the given path without locking.

Throws:

IOException

newDirectoryStream

public DirectoryStream<Path> newDirectoryStream(ZeroFsPath dir,
 DirectoryStream.Filter<? super Path> filter,
 Set<? super LinkOption> options,
 ZeroFsPath basePathForStream)
                                         throws IOException

Creates a new directory stream for the directory located by the given path. The given basePathForStream is that base path that the returned stream will use. This will be the same as dir except for streams created relative to another secure stream.

Throws:

IOException

snapshotWorkingDirectoryEntries

public SortedSet<Name> snapshotWorkingDirectoryEntries()

Snapshots the entries of the working directory of this view.

snapshotModifiedTimes

public Map<Name,FileTime> snapshotModifiedTimes(ZeroFsPath path)
                                         throws IOException

Returns a snapshot mapping the names of each file in the directory at the given path to the last modified time of that file.

Throws:

IOException

isSameFile

public boolean isSameFile(ZeroFsPath path,
 FileSystemView view2,
 ZeroFsPath path2)
                   throws IOException

Returns whether or not the two given paths locate the same file. The second path is located using the given view rather than this file view.

Throws:

IOException

toRealPath

public ZeroFsPath toRealPath(ZeroFsPath path,
 PathService pathService,
 Set<? super LinkOption> options)
                      throws IOException

Gets the real path to the file located by the given path.

Throws:

IOException

createDirectory

public Directory createDirectory(ZeroFsPath path,
 FileAttribute<?>... attrs)
                          throws IOException

Creates a new directory at the given path. The given attributes will be set on the new file if possible.

Throws:

IOException

createSymbolicLink

public SymbolicLink createSymbolicLink(ZeroFsPath path,
 ZeroFsPath target,
 FileAttribute<?>... attrs)
                                throws IOException

Creates a new symbolic link at the given path with the given target. The given attributes will be set on the new file if possible.

Throws:

IOException

createFile

private File createFile(ZeroFsPath path,
 Supplier<? extends File> fileCreator,
 boolean failIfExists,
 FileAttribute<?>... attrs)
                 throws IOException

Creates a new file at the given path if possible, using the given supplier to create the file. Returns the new file. If allowExisting is true and a file already exists at the given path, returns that file. Otherwise, throws FileAlreadyExistsException.

Throws:

IOException

getOrCreateRegularFile

public RegularFile getOrCreateRegularFile(ZeroFsPath path,
 Set<OpenOption> options,
 FileAttribute<?>... attrs)
                                   throws IOException

Gets the regular file at the given path, creating it if it doesn't exist and the given options specify that it should be created.

Throws:

IOException

lookUpRegularFile

private RegularFile lookUpRegularFile(ZeroFsPath path,
 Set<OpenOption> options)
                               throws IOException

Looks up the regular file at the given path, throwing an exception if the file isn't a regular file. Returns null if the file did not exist.

Throws:

IOException

getOrCreateRegularFileWithWriteLock

private RegularFile getOrCreateRegularFileWithWriteLock(ZeroFsPath path,
 Set<OpenOption> options,
 FileAttribute<?>[] attrs)
                                                 throws IOException

Gets or creates a new regular file with a write lock (assuming the file does not exist).

Throws:

IOException

open

private static RegularFile open(RegularFile file,
 Set<OpenOption> options)

Opens the given regular file with the given options, truncating it if necessary and incrementing its open count. Returns the given file.

readSymbolicLink

public ZeroFsPath readSymbolicLink(ZeroFsPath path)
                            throws IOException

Returns the target of the symbolic link at the given path.

Throws:

IOException

checkAccess

public void checkAccess(ZeroFsPath path)
                 throws IOException

Checks access to the file at the given path for the given modes. Since access controls are not implemented for this file system, this just checks that the file exists.

Throws:

IOException

link

public void link(ZeroFsPath link,
 FileSystemView existingView,
 ZeroFsPath existing)
          throws IOException

Creates a hard link at the given link path to the regular file at the given path. The existing file must exist and must be a regular file. The given file system view must belong to the same file system as this view.

Throws:

IOException

deleteFile

public void deleteFile(ZeroFsPath path,
 FileSystemView.DeleteMode deleteMode)
                throws IOException

Deletes the file at the given absolute path.

Throws:

IOException

delete

private void delete(DirectoryEntry entry,
 FileSystemView.DeleteMode deleteMode,
 ZeroFsPath pathForException)
             throws IOException

Deletes the given directory entry from its parent directory.

Throws:

IOException

checkDeletable

private void checkDeletable(File file,
 FileSystemView.DeleteMode mode,
 Path path)
                     throws IOException

Checks that the given file can be deleted, throwing an exception if it can't.

Throws:

IOException

checkEmpty

private void checkEmpty(Directory dir,
 Path pathForException)
                 throws FileSystemException

Checks that given directory is empty, throwing DirectoryNotEmptyException if not.

Throws:

FileSystemException

copy

public void copy(ZeroFsPath source,
 FileSystemView destView,
 ZeroFsPath dest,
 Set<CopyOption> options,
 boolean move)
          throws IOException

Copies or moves the file at the given source path to the given dest path.

Throws:

IOException

checkMovable

private void checkMovable(File file,
 ZeroFsPath path)
                   throws FileSystemException

Throws:

FileSystemException

lockBoth

private static void lockBoth(Lock sourceWriteLock,
 Lock destWriteLock)

Acquires both write locks in a way that attempts to avoid the possibility of deadlock. Note that typically (when only one file system instance is involved), both locks will be the same lock and there will be no issue at all.

checkNotAncestor

private void checkNotAncestor(File source,
 Directory destParent,
 FileSystemView destView)
                       throws IOException

Checks that source is not an ancestor of dest, throwing an exception if it is.

Throws:

IOException

lockSourceAndCopy

private void lockSourceAndCopy(File sourceFile,
 File copyFile)

Locks source and copy files before copying content. Also marks the source file as opened so that its content won't be deleted until after the copy if it is deleted.

unlockSourceAndCopy

private void unlockSourceAndCopy(File sourceFile,
 File copyFile)

Unlocks source and copy files after copying content. Also closes the source file so its content can be deleted if it was deleted.

getFileAttributeView

public <V extends FileAttributeView> V getFileAttributeView(FileLookup lookup,
 Class<V> type)

Returns a file attribute view using the given lookup callback.

getFileAttributeView

public <V extends FileAttributeView> V getFileAttributeView(ZeroFsPath path,
 Class<V> type,
 Set<? super LinkOption> options)

Returns a file attribute view for the given path in this view.

readAttributes

public <A extends BasicFileAttributes> A readAttributes(ZeroFsPath path,
 Class<A> type,
 Set<? super LinkOption> options)
                                                 throws IOException

Reads attributes of the file located by the given path in this view as an object.

Throws:

IOException

readAttributes

public Map<String,Object> readAttributes(ZeroFsPath path,
 String attributes,
 Set<? super LinkOption> options)
                                  throws IOException

Reads attributes of the file located by the given path in this view as a map.

Throws:

IOException

setAttribute

public void setAttribute(ZeroFsPath path,
 String attribute,
 Object value,
 Set<? super LinkOption> options)
                  throws IOException

Sets the given attribute to the given value on the file located by the given path in this view.

Throws:

IOException