Java example source code file (WindowsPath.java)
The WindowsPath.java Java example source code
/*
* Copyright (c) 2008, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package sun.nio.fs;
import java.nio.file.*;
import java.nio.file.attribute.*;
import java.io.*;
import java.net.URI;
import java.util.*;
import java.lang.ref.WeakReference;
import com.sun.nio.file.ExtendedWatchEventModifier;
import static sun.nio.fs.WindowsNativeDispatcher.*;
import static sun.nio.fs.WindowsConstants.*;
/**
* Windows implementation of Path
*/
class WindowsPath extends AbstractPath {
// The maximum path that does not require long path prefix. On Windows
// the maximum path is 260 minus 1 (NUL) but for directories it is 260
// minus 12 minus 1 (to allow for the creation of a 8.3 file in the
// directory).
private static final int MAX_PATH = 247;
// Maximum extended-length path
private static final int MAX_LONG_PATH = 32000;
// FIXME - eliminate this reference to reduce space
private final WindowsFileSystem fs;
// path type
private final WindowsPathType type;
// root component (may be empty)
private final String root;
// normalized path
private final String path;
// the path to use in Win32 calls. This differs from path for relative
// paths and has a long path prefix for all paths longer than MAX_PATH.
private volatile WeakReference<String> pathForWin32Calls;
// offsets into name components (computed lazily)
private volatile Integer[] offsets;
// computed hash code (computed lazily, no need to be volatile)
private int hash;
/**
* Initializes a new instance of this class.
*/
private WindowsPath(WindowsFileSystem fs,
WindowsPathType type,
String root,
String path)
{
this.fs = fs;
this.type = type;
this.root = root;
this.path = path;
}
/**
* Creates a Path by parsing the given path.
*/
static WindowsPath parse(WindowsFileSystem fs, String path) {
WindowsPathParser.Result result = WindowsPathParser.parse(path);
return new WindowsPath(fs, result.type(), result.root(), result.path());
}
/**
* Creates a Path from a given path that is known to be normalized.
*/
static WindowsPath createFromNormalizedPath(WindowsFileSystem fs,
String path,
BasicFileAttributes attrs)
{
try {
WindowsPathParser.Result result =
WindowsPathParser.parseNormalizedPath(path);
if (attrs == null) {
return new WindowsPath(fs,
result.type(),
result.root(),
result.path());
} else {
return new WindowsPathWithAttributes(fs,
result.type(),
result.root(),
result.path(),
attrs);
}
} catch (InvalidPathException x) {
throw new AssertionError(x.getMessage());
}
}
/**
* Creates a WindowsPath from a given path that is known to be normalized.
*/
static WindowsPath createFromNormalizedPath(WindowsFileSystem fs,
String path)
{
return createFromNormalizedPath(fs, path, null);
}
/**
* Special implementation with attached/cached attributes (used to quicken
* file tree traveral)
*/
private static class WindowsPathWithAttributes
extends WindowsPath implements BasicFileAttributesHolder
{
final WeakReference<BasicFileAttributes> ref;
WindowsPathWithAttributes(WindowsFileSystem fs,
WindowsPathType type,
String root,
String path,
BasicFileAttributes attrs)
{
super(fs, type, root, path);
ref = new WeakReference<BasicFileAttributes>(attrs);
}
@Override
public BasicFileAttributes get() {
return ref.get();
}
@Override
public void invalidate() {
ref.clear();
}
// no need to override equals/hashCode.
}
// use this message when throwing exceptions
String getPathForExceptionMessage() {
return path;
}
// use this path for permission checks
String getPathForPermissionCheck() {
return path;
}
// use this path for Win32 calls
// This method will prefix long paths with \\?\ or \\?\UNC as required.
String getPathForWin32Calls() throws WindowsException {
// short absolute paths can be used directly
if (isAbsolute() && path.length() <= MAX_PATH)
return path;
// return cached values if available
WeakReference<String> ref = pathForWin32Calls;
String resolved = (ref != null) ? ref.get() : null;
if (resolved != null) {
// Win32 path already available
return resolved;
}
// resolve against default directory
resolved = getAbsolutePath();
// Long paths need to have "." and ".." removed and be prefixed with
// "\\?\". Note that it is okay to remove ".." even when it follows
// a link - for example, it is okay for foo/link/../bar to be changed
// to foo/bar. The reason is that Win32 APIs to access foo/link/../bar
// will access foo/bar anyway (which differs to Unix systems)
if (resolved.length() > MAX_PATH) {
if (resolved.length() > MAX_LONG_PATH) {
throw new WindowsException("Cannot access file with path exceeding "
+ MAX_LONG_PATH + " characters");
}
resolved = addPrefixIfNeeded(GetFullPathName(resolved));
}
// cache the resolved path (except drive relative paths as the working
// directory on removal media devices can change during the lifetime
// of the VM)
if (type != WindowsPathType.DRIVE_RELATIVE) {
synchronized (path) {
pathForWin32Calls = new WeakReference<String>(resolved);
}
}
return resolved;
}
// return this path resolved against the file system's default directory
private String getAbsolutePath() throws WindowsException {
if (isAbsolute())
return path;
// Relative path ("foo" for example)
if (type == WindowsPathType.RELATIVE) {
String defaultDirectory = getFileSystem().defaultDirectory();
if (isEmpty())
return defaultDirectory;
if (defaultDirectory.endsWith("\\")) {
return defaultDirectory + path;
} else {
StringBuilder sb =
new StringBuilder(defaultDirectory.length() + path.length() + 1);
return sb.append(defaultDirectory).append('\\').append(path).toString();
}
}
// Directory relative path ("\foo" for example)
if (type == WindowsPathType.DIRECTORY_RELATIVE) {
String defaultRoot = getFileSystem().defaultRoot();
return defaultRoot + path.substring(1);
}
// Drive relative path ("C:foo" for example).
if (isSameDrive(root, getFileSystem().defaultRoot())) {
// relative to default directory
String remaining = path.substring(root.length());
String defaultDirectory = getFileSystem().defaultDirectory();
String result;
if (defaultDirectory.endsWith("\\")) {
result = defaultDirectory + remaining;
} else {
result = defaultDirectory + "\\" + remaining;
}
return result;
} else {
// relative to some other drive
String wd;
try {
int dt = GetDriveType(root + "\\");
if (dt == DRIVE_UNKNOWN || dt == DRIVE_NO_ROOT_DIR)
throw new WindowsException("");
wd = GetFullPathName(root + ".");
} catch (WindowsException x) {
throw new WindowsException("Unable to get working directory of drive '" +
Character.toUpperCase(root.charAt(0)) + "'");
}
String result = wd;
if (wd.endsWith("\\")) {
result += path.substring(root.length());
} else {
if (path.length() > root.length())
result += "\\" + path.substring(root.length());
}
return result;
}
}
// returns true if same drive letter
private static boolean isSameDrive(String root1, String root2) {
return Character.toUpperCase(root1.charAt(0)) ==
Character.toUpperCase(root2.charAt(0));
}
// Add long path prefix to path if required
static String addPrefixIfNeeded(String path) {
if (path.length() > MAX_PATH) {
if (path.startsWith("\\\\")) {
path = "\\\\?\\UNC" + path.substring(1, path.length());
} else {
path = "\\\\?\\" + path;
}
}
return path;
}
@Override
public WindowsFileSystem getFileSystem() {
return fs;
}
// -- Path operations --
private boolean isEmpty() {
return path.length() == 0;
}
private WindowsPath emptyPath() {
return new WindowsPath(getFileSystem(), WindowsPathType.RELATIVE, "", "");
}
@Override
public Path getFileName() {
int len = path.length();
// represents empty path
if (len == 0)
return this;
// represents root component only
if (root.length() == len)
return null;
int off = path.lastIndexOf('\\');
if (off < root.length())
off = root.length();
else
off++;
return new WindowsPath(getFileSystem(), WindowsPathType.RELATIVE, "", path.substring(off));
}
@Override
public WindowsPath getParent() {
// represents root component only
if (root.length() == path.length())
return null;
int off = path.lastIndexOf('\\');
if (off < root.length())
return getRoot();
else
return new WindowsPath(getFileSystem(),
type,
root,
path.substring(0, off));
}
@Override
public WindowsPath getRoot() {
if (root.length() == 0)
return null;
return new WindowsPath(getFileSystem(), type, root, root);
}
// package-private
WindowsPathType type() {
return type;
}
// package-private
boolean isUnc() {
return type == WindowsPathType.UNC;
}
boolean needsSlashWhenResolving() {
if (path.endsWith("\\"))
return false;
return path.length() > root.length();
}
@Override
public boolean isAbsolute() {
return type == WindowsPathType.ABSOLUTE || type == WindowsPathType.UNC;
}
static WindowsPath toWindowsPath(Path path) {
if (path == null)
throw new NullPointerException();
if (!(path instanceof WindowsPath)) {
throw new ProviderMismatchException();
}
return (WindowsPath)path;
}
@Override
public WindowsPath relativize(Path obj) {
WindowsPath other = toWindowsPath(obj);
if (this.equals(other))
return emptyPath();
// can only relativize paths of the same type
if (this.type != other.type)
throw new IllegalArgumentException("'other' is different type of Path");
// can only relativize paths if root component matches
if (!this.root.equalsIgnoreCase(other.root))
throw new IllegalArgumentException("'other' has different root");
int bn = this.getNameCount();
int cn = other.getNameCount();
// skip matching names
int n = (bn > cn) ? cn : bn;
int i = 0;
while (i < n) {
if (!this.getName(i).equals(other.getName(i)))
break;
i++;
}
// append ..\ for remaining names in the base
StringBuilder result = new StringBuilder();
for (int j=i; j<bn; j++) {
result.append("..\\");
}
// append remaining names in child
for (int j=i; j<cn; j++) {
result.append(other.getName(j).toString());
result.append("\\");
}
// drop trailing slash in result
result.setLength(result.length()-1);
return createFromNormalizedPath(getFileSystem(), result.toString());
}
@Override
public Path normalize() {
final int count = getNameCount();
if (count == 0 || isEmpty())
return this;
boolean[] ignore = new boolean[count]; // true => ignore name
int remaining = count; // number of names remaining
// multiple passes to eliminate all occurrences of "." and "name/.."
int prevRemaining;
do {
prevRemaining = remaining;
int prevName = -1;
for (int i=0; i<count; i++) {
if (ignore[i])
continue;
String name = elementAsString(i);
// not "." or ".."
if (name.length() > 2) {
prevName = i;
continue;
}
// "." or something else
if (name.length() == 1) {
// ignore "."
if (name.charAt(0) == '.') {
ignore[i] = true;
remaining--;
} else {
prevName = i;
}
continue;
}
// not ".."
if (name.charAt(0) != '.' || name.charAt(1) != '.') {
prevName = i;
continue;
}
// ".." found
if (prevName >= 0) {
// name/<ignored>/.. found so mark name and ".." to be
// ignored
ignore[prevName] = true;
ignore[i] = true;
remaining = remaining - 2;
prevName = -1;
} else {
// Cases:
// C:\<ignored>\..
// \\server\\share\<ignored>\..
// \<ignored>..
if (isAbsolute() || type == WindowsPathType.DIRECTORY_RELATIVE) {
boolean hasPrevious = false;
for (int j=0; j<i; j++) {
if (!ignore[j]) {
hasPrevious = true;
break;
}
}
if (!hasPrevious) {
// all proceeding names are ignored
ignore[i] = true;
remaining--;
}
}
}
}
} while (prevRemaining > remaining);
// no redundant names
if (remaining == count)
return this;
// corner case - all names removed
if (remaining == 0) {
return (root.length() == 0) ? emptyPath() : getRoot();
}
// re-constitute the path from the remaining names.
StringBuilder result = new StringBuilder();
if (root != null)
result.append(root);
for (int i=0; i<count; i++) {
if (!ignore[i]) {
result.append(getName(i));
result.append("\\");
}
}
// drop trailing slash in result
result.setLength(result.length()-1);
return createFromNormalizedPath(getFileSystem(), result.toString());
}
@Override
public WindowsPath resolve(Path obj) {
WindowsPath other = toWindowsPath(obj);
if (other.isEmpty())
return this;
if (other.isAbsolute())
return other;
switch (other.type) {
case RELATIVE: {
String result;
if (path.endsWith("\\") || (root.length() == path.length())) {
result = path + other.path;
} else {
result = path + "\\" + other.path;
}
return new WindowsPath(getFileSystem(), type, root, result);
}
case DIRECTORY_RELATIVE: {
String result;
if (root.endsWith("\\")) {
result = root + other.path.substring(1);
} else {
result = root + other.path;
}
return createFromNormalizedPath(getFileSystem(), result);
}
case DRIVE_RELATIVE: {
if (!root.endsWith("\\"))
return other;
// if different roots then return other
String thisRoot = root.substring(0, root.length()-1);
if (!thisRoot.equalsIgnoreCase(other.root))
return other;
// same roots
String remaining = other.path.substring(other.root.length());
String result;
if (path.endsWith("\\")) {
result = path + remaining;
} else {
result = path + "\\" + remaining;
}
return createFromNormalizedPath(getFileSystem(), result);
}
default:
throw new AssertionError();
}
}
// generate offset array
private void initOffsets() {
if (offsets == null) {
ArrayList<Integer> list = new ArrayList<>();
if (isEmpty()) {
// empty path considered to have one name element
list.add(0);
} else {
int start = root.length();
int off = root.length();
while (off < path.length()) {
if (path.charAt(off) != '\\') {
off++;
} else {
list.add(start);
start = ++off;
}
}
if (start != off)
list.add(start);
}
synchronized (this) {
if (offsets == null)
offsets = list.toArray(new Integer[list.size()]);
}
}
}
@Override
public int getNameCount() {
initOffsets();
return offsets.length;
}
private String elementAsString(int i) {
initOffsets();
if (i == (offsets.length-1))
return path.substring(offsets[i]);
return path.substring(offsets[i], offsets[i+1]-1);
}
@Override
public WindowsPath getName(int index) {
initOffsets();
if (index < 0 || index >= offsets.length)
throw new IllegalArgumentException();
return new WindowsPath(getFileSystem(), WindowsPathType.RELATIVE, "", elementAsString(index));
}
@Override
public WindowsPath subpath(int beginIndex, int endIndex) {
initOffsets();
if (beginIndex < 0)
throw new IllegalArgumentException();
if (beginIndex >= offsets.length)
throw new IllegalArgumentException();
if (endIndex > offsets.length)
throw new IllegalArgumentException();
if (beginIndex >= endIndex)
throw new IllegalArgumentException();
StringBuilder sb = new StringBuilder();
Integer[] nelems = new Integer[endIndex - beginIndex];
for (int i = beginIndex; i < endIndex; i++) {
nelems[i-beginIndex] = sb.length();
sb.append(elementAsString(i));
if (i != (endIndex-1))
sb.append("\\");
}
return new WindowsPath(getFileSystem(), WindowsPathType.RELATIVE, "", sb.toString());
}
@Override
public boolean startsWith(Path obj) {
if (!(Objects.requireNonNull(obj) instanceof WindowsPath))
return false;
WindowsPath other = (WindowsPath)obj;
// if this path has a root component the given path's root must match
if (!this.root.equalsIgnoreCase(other.root)) {
return false;
}
// empty path starts with itself
if (other.isEmpty())
return this.isEmpty();
// roots match so compare elements
int thisCount = getNameCount();
int otherCount = other.getNameCount();
if (otherCount <= thisCount) {
while (--otherCount >= 0) {
String thisElement = this.elementAsString(otherCount);
String otherElement = other.elementAsString(otherCount);
// FIXME: should compare in uppercase
if (!thisElement.equalsIgnoreCase(otherElement))
return false;
}
return true;
}
return false;
}
@Override
public boolean endsWith(Path obj) {
if (!(Objects.requireNonNull(obj) instanceof WindowsPath))
return false;
WindowsPath other = (WindowsPath)obj;
// other path is longer
if (other.path.length() > this.path.length()) {
return false;
}
// empty path ends in itself
if (other.isEmpty()) {
return this.isEmpty();
}
int thisCount = this.getNameCount();
int otherCount = other.getNameCount();
// given path has more elements that this path
if (otherCount > thisCount) {
return false;
}
// compare roots
if (other.root.length() > 0) {
if (otherCount < thisCount)
return false;
// FIXME: should compare in uppercase
if (!this.root.equalsIgnoreCase(other.root))
return false;
}
// match last 'otherCount' elements
int off = thisCount - otherCount;
while (--otherCount >= 0) {
String thisElement = this.elementAsString(off + otherCount);
String otherElement = other.elementAsString(otherCount);
// FIXME: should compare in uppercase
if (!thisElement.equalsIgnoreCase(otherElement))
return false;
}
return true;
}
@Override
public int compareTo(Path obj) {
if (obj == null)
throw new NullPointerException();
String s1 = path;
String s2 = ((WindowsPath)obj).path;
int n1 = s1.length();
int n2 = s2.length();
int min = Math.min(n1, n2);
for (int i = 0; i < min; i++) {
char c1 = s1.charAt(i);
char c2 = s2.charAt(i);
if (c1 != c2) {
c1 = Character.toUpperCase(c1);
c2 = Character.toUpperCase(c2);
if (c1 != c2) {
return c1 - c2;
}
}
}
return n1 - n2;
}
@Override
public boolean equals(Object obj) {
if ((obj != null) && (obj instanceof WindowsPath)) {
return compareTo((Path)obj) == 0;
}
return false;
}
@Override
public int hashCode() {
// OK if two or more threads compute hash
int h = hash;
if (h == 0) {
for (int i = 0; i< path.length(); i++) {
h = 31*h + Character.toUpperCase(path.charAt(i));
}
hash = h;
}
return h;
}
@Override
public String toString() {
return path;
}
// -- file operations --
// package-private
long openForReadAttributeAccess(boolean followLinks)
throws WindowsException
{
int flags = FILE_FLAG_BACKUP_SEMANTICS;
if (!followLinks && getFileSystem().supportsLinks())
flags |= FILE_FLAG_OPEN_REPARSE_POINT;
return CreateFile(getPathForWin32Calls(),
FILE_READ_ATTRIBUTES,
(FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE),
0L,
OPEN_EXISTING,
flags);
}
void checkRead() {
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
sm.checkRead(getPathForPermissionCheck());
}
}
void checkWrite() {
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
sm.checkWrite(getPathForPermissionCheck());
}
}
void checkDelete() {
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
sm.checkDelete(getPathForPermissionCheck());
}
}
@Override
public URI toUri() {
return WindowsUriSupport.toUri(this);
}
@Override
public WindowsPath toAbsolutePath() {
if (isAbsolute())
return this;
// permission check as per spec
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
sm.checkPropertyAccess("user.dir");
}
try {
return createFromNormalizedPath(getFileSystem(), getAbsolutePath());
} catch (WindowsException x) {
throw new IOError(new IOException(x.getMessage()));
}
}
@Override
public WindowsPath toRealPath(LinkOption... options) throws IOException {
checkRead();
String rp = WindowsLinkSupport.getRealPath(this, Util.followLinks(options));
return createFromNormalizedPath(getFileSystem(), rp);
}
@Override
public WatchKey register(WatchService watcher,
WatchEvent.Kind<?>[] events,
WatchEvent.Modifier... modifiers)
throws IOException
{
if (watcher == null)
throw new NullPointerException();
if (!(watcher instanceof WindowsWatchService))
throw new ProviderMismatchException();
// When a security manager is set then we need to make a defensive
// copy of the modifiers and check for the Windows specific FILE_TREE
// modifier. When the modifier is present then check that permission
// has been granted recursively.
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
boolean watchSubtree = false;
final int ml = modifiers.length;
if (ml > 0) {
modifiers = Arrays.copyOf(modifiers, ml);
int i=0;
while (i < ml) {
if (modifiers[i++] == ExtendedWatchEventModifier.FILE_TREE) {
watchSubtree = true;
break;
}
}
}
String s = getPathForPermissionCheck();
sm.checkRead(s);
if (watchSubtree)
sm.checkRead(s + "\\-");
}
return ((WindowsWatchService)watcher).register(this, events, modifiers);
}
}
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