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The UnixPath.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
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package sun.nio.fs;
import java.nio.*;
import java.nio.file.*;
import java.nio.charset.*;
import java.io.*;
import java.net.URI;
import java.util.*;
import java.lang.ref.SoftReference;
import static sun.nio.fs.UnixNativeDispatcher.*;
import static sun.nio.fs.UnixConstants.*;
/**
* Solaris/Linux implementation of java.nio.file.Path
*/
class UnixPath
extends AbstractPath
{
private static ThreadLocal<SoftReference encoder =
new ThreadLocal<SoftReference();
// FIXME - eliminate this reference to reduce space
private final UnixFileSystem fs;
// internal representation
private final byte[] path;
// String representation (created lazily)
private volatile String stringValue;
// cached hashcode (created lazily, no need to be volatile)
private int hash;
// array of offsets of elements in path (created lazily)
private volatile int[] offsets;
UnixPath(UnixFileSystem fs, byte[] path) {
this.fs = fs;
this.path = path;
}
UnixPath(UnixFileSystem fs, String input) {
// removes redundant slashes and checks for invalid characters
this(fs, encode(fs, normalizeAndCheck(input)));
}
// package-private
// removes redundant slashes and check input for invalid characters
static String normalizeAndCheck(String input) {
int n = input.length();
char prevChar = 0;
for (int i=0; i < n; i++) {
char c = input.charAt(i);
if ((c == '/') && (prevChar == '/'))
return normalize(input, n, i - 1);
checkNotNul(input, c);
prevChar = c;
}
if (prevChar == '/')
return normalize(input, n, n - 1);
return input;
}
private static void checkNotNul(String input, char c) {
if (c == '\u0000')
throw new InvalidPathException(input, "Nul character not allowed");
}
private static String normalize(String input, int len, int off) {
if (len == 0)
return input;
int n = len;
while ((n > 0) && (input.charAt(n - 1) == '/')) n--;
if (n == 0)
return "/";
StringBuilder sb = new StringBuilder(input.length());
if (off > 0)
sb.append(input.substring(0, off));
char prevChar = 0;
for (int i=off; i < n; i++) {
char c = input.charAt(i);
if ((c == '/') && (prevChar == '/'))
continue;
checkNotNul(input, c);
sb.append(c);
prevChar = c;
}
return sb.toString();
}
// encodes the given path-string into a sequence of bytes
private static byte[] encode(UnixFileSystem fs, String input) {
SoftReference<CharsetEncoder> ref = encoder.get();
CharsetEncoder ce = (ref != null) ? ref.get() : null;
if (ce == null) {
ce = Util.jnuEncoding().newEncoder()
.onMalformedInput(CodingErrorAction.REPORT)
.onUnmappableCharacter(CodingErrorAction.REPORT);
encoder.set(new SoftReference<CharsetEncoder>(ce));
}
char[] ca = fs.normalizeNativePath(input.toCharArray());
// size output buffer for worse-case size
byte[] ba = new byte[(int)(ca.length * (double)ce.maxBytesPerChar())];
// encode
ByteBuffer bb = ByteBuffer.wrap(ba);
CharBuffer cb = CharBuffer.wrap(ca);
ce.reset();
CoderResult cr = ce.encode(cb, bb, true);
boolean error;
if (!cr.isUnderflow()) {
error = true;
} else {
cr = ce.flush(bb);
error = !cr.isUnderflow();
}
if (error) {
throw new InvalidPathException(input,
"Malformed input or input contains unmappable characters");
}
// trim result to actual length if required
int len = bb.position();
if (len != ba.length)
ba = Arrays.copyOf(ba, len);
return ba;
}
// package-private
byte[] asByteArray() {
return path;
}
// use this path when making system/library calls
byte[] getByteArrayForSysCalls() {
// resolve against default directory if required (chdir allowed or
// file system default directory is not working directory)
if (getFileSystem().needToResolveAgainstDefaultDirectory()) {
return resolve(getFileSystem().defaultDirectory(), path);
} else {
if (!isEmpty()) {
return path;
} else {
// empty path case will access current directory
byte[] here = { '.' };
return here;
}
}
}
// use this message when throwing exceptions
String getPathForExceptionMessage() {
return toString();
}
// use this path for permission checks
String getPathForPermissionCheck() {
if (getFileSystem().needToResolveAgainstDefaultDirectory()) {
return Util.toString(getByteArrayForSysCalls());
} else {
return toString();
}
}
// Checks that the given file is a UnixPath
static UnixPath toUnixPath(Path obj) {
if (obj == null)
throw new NullPointerException();
if (!(obj instanceof UnixPath))
throw new ProviderMismatchException();
return (UnixPath)obj;
}
// create offset list if not already created
private void initOffsets() {
if (offsets == null) {
int count, index;
// count names
count = 0;
index = 0;
if (isEmpty()) {
// empty path has one name
count = 1;
} else {
while (index < path.length) {
byte c = path[index++];
if (c != '/') {
count++;
while (index < path.length && path[index] != '/')
index++;
}
}
}
// populate offsets
int[] result = new int[count];
count = 0;
index = 0;
while (index < path.length) {
byte c = path[index];
if (c == '/') {
index++;
} else {
result[count++] = index++;
while (index < path.length && path[index] != '/')
index++;
}
}
synchronized (this) {
if (offsets == null)
offsets = result;
}
}
}
// returns {@code true} if this path is an empty path
private boolean isEmpty() {
return path.length == 0;
}
// returns an empty path
private UnixPath emptyPath() {
return new UnixPath(getFileSystem(), new byte[0]);
}
@Override
public UnixFileSystem getFileSystem() {
return fs;
}
@Override
public UnixPath getRoot() {
if (path.length > 0 && path[0] == '/') {
return getFileSystem().rootDirectory();
} else {
return null;
}
}
@Override
public UnixPath getFileName() {
initOffsets();
int count = offsets.length;
// no elements so no name
if (count == 0)
return null;
// one name element and no root component
if (count == 1 && path.length > 0 && path[0] != '/')
return this;
int lastOffset = offsets[count-1];
int len = path.length - lastOffset;
byte[] result = new byte[len];
System.arraycopy(path, lastOffset, result, 0, len);
return new UnixPath(getFileSystem(), result);
}
@Override
public UnixPath getParent() {
initOffsets();
int count = offsets.length;
if (count == 0) {
// no elements so no parent
return null;
}
int len = offsets[count-1] - 1;
if (len <= 0) {
// parent is root only (may be null)
return getRoot();
}
byte[] result = new byte[len];
System.arraycopy(path, 0, result, 0, len);
return new UnixPath(getFileSystem(), result);
}
@Override
public int getNameCount() {
initOffsets();
return offsets.length;
}
@Override
public UnixPath getName(int index) {
initOffsets();
if (index < 0)
throw new IllegalArgumentException();
if (index >= offsets.length)
throw new IllegalArgumentException();
int begin = offsets[index];
int len;
if (index == (offsets.length-1)) {
len = path.length - begin;
} else {
len = offsets[index+1] - begin - 1;
}
// construct result
byte[] result = new byte[len];
System.arraycopy(path, begin, result, 0, len);
return new UnixPath(getFileSystem(), result);
}
@Override
public UnixPath 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();
}
// starting offset and length
int begin = offsets[beginIndex];
int len;
if (endIndex == offsets.length) {
len = path.length - begin;
} else {
len = offsets[endIndex] - begin - 1;
}
// construct result
byte[] result = new byte[len];
System.arraycopy(path, begin, result, 0, len);
return new UnixPath(getFileSystem(), result);
}
@Override
public boolean isAbsolute() {
return (path.length > 0 && path[0] == '/');
}
// Resolve child against given base
private static byte[] resolve(byte[] base, byte[] child) {
int baseLength = base.length;
int childLength = child.length;
if (childLength == 0)
return base;
if (baseLength == 0 || child[0] == '/')
return child;
byte[] result;
if (baseLength == 1 && base[0] == '/') {
result = new byte[childLength + 1];
result[0] = '/';
System.arraycopy(child, 0, result, 1, childLength);
} else {
result = new byte[baseLength + 1 + childLength];
System.arraycopy(base, 0, result, 0, baseLength);
result[base.length] = '/';
System.arraycopy(child, 0, result, baseLength+1, childLength);
}
return result;
}
@Override
public UnixPath resolve(Path obj) {
byte[] other = toUnixPath(obj).path;
if (other.length > 0 && other[0] == '/')
return ((UnixPath)obj);
byte[] result = resolve(path, other);
return new UnixPath(getFileSystem(), result);
}
UnixPath resolve(byte[] other) {
return resolve(new UnixPath(getFileSystem(), other));
}
@Override
public UnixPath relativize(Path obj) {
UnixPath other = toUnixPath(obj);
if (other.equals(this))
return emptyPath();
// can only relativize paths of the same type
if (this.isAbsolute() != other.isAbsolute())
throw new IllegalArgumentException("'other' is different type of Path");
// this path is the empty path
if (this.isEmpty())
return other;
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++;
}
int dotdots = bn - i;
if (i < cn) {
// remaining name components in other
UnixPath remainder = other.subpath(i, cn);
if (dotdots == 0)
return remainder;
// other is the empty path
boolean isOtherEmpty = other.isEmpty();
// result is a "../" for each remaining name in base
// followed by the remaining names in other. If the remainder is
// the empty path then we don't add the final trailing slash.
int len = dotdots*3 + remainder.path.length;
if (isOtherEmpty) {
assert remainder.isEmpty();
len--;
}
byte[] result = new byte[len];
int pos = 0;
while (dotdots > 0) {
result[pos++] = (byte)'.';
result[pos++] = (byte)'.';
if (isOtherEmpty) {
if (dotdots > 1) result[pos++] = (byte)'/';
} else {
result[pos++] = (byte)'/';
}
dotdots--;
}
System.arraycopy(remainder.path, 0, result, pos, remainder.path.length);
return new UnixPath(getFileSystem(), result);
} else {
// no remaining names in other so result is simply a sequence of ".."
byte[] result = new byte[dotdots*3 - 1];
int pos = 0;
while (dotdots > 0) {
result[pos++] = (byte)'.';
result[pos++] = (byte)'.';
// no tailing slash at the end
if (dotdots > 1)
result[pos++] = (byte)'/';
dotdots--;
}
return new UnixPath(getFileSystem(), result);
}
}
@Override
public Path normalize() {
final int count = getNameCount();
if (count == 0)
return this;
boolean[] ignore = new boolean[count]; // true => ignore name
int[] size = new int[count]; // length of name
int remaining = count; // number of names remaining
boolean hasDotDot = false; // has at least one ..
boolean isAbsolute = isAbsolute();
// first pass:
// 1. compute length of names
// 2. mark all occurrences of "." to ignore
// 3. and look for any occurrences of ".."
for (int i=0; i<count; i++) {
int begin = offsets[i];
int len;
if (i == (offsets.length-1)) {
len = path.length - begin;
} else {
len = offsets[i+1] - begin - 1;
}
size[i] = len;
if (path[begin] == '.') {
if (len == 1) {
ignore[i] = true; // ignore "."
remaining--;
}
else {
if (path[begin+1] == '.') // ".." found
hasDotDot = true;
}
}
}
// multiple passes to eliminate all occurrences of name/..
if (hasDotDot) {
int prevRemaining;
do {
prevRemaining = remaining;
int prevName = -1;
for (int i=0; i<count; i++) {
if (ignore[i])
continue;
// not a ".."
if (size[i] != 2) {
prevName = i;
continue;
}
int begin = offsets[i];
if (path[begin] != '.' || path[begin+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 {
// Case: /<ignored>/.. so mark ".." as ignored
if (isAbsolute) {
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 isAbsolute ? getFileSystem().rootDirectory() : emptyPath();
}
// compute length of result
int len = remaining - 1;
if (isAbsolute)
len++;
for (int i=0; i<count; i++) {
if (!ignore[i])
len += size[i];
}
byte[] result = new byte[len];
// copy names into result
int pos = 0;
if (isAbsolute)
result[pos++] = '/';
for (int i=0; i<count; i++) {
if (!ignore[i]) {
System.arraycopy(path, offsets[i], result, pos, size[i]);
pos += size[i];
if (--remaining > 0) {
result[pos++] = '/';
}
}
}
return new UnixPath(getFileSystem(), result);
}
@Override
public boolean startsWith(Path other) {
if (!(Objects.requireNonNull(other) instanceof UnixPath))
return false;
UnixPath that = (UnixPath)other;
// other path is longer
if (that.path.length > path.length)
return false;
int thisOffsetCount = getNameCount();
int thatOffsetCount = that.getNameCount();
// other path has no name elements
if (thatOffsetCount == 0 && this.isAbsolute()) {
return that.isEmpty() ? false : true;
}
// given path has more elements that this path
if (thatOffsetCount > thisOffsetCount)
return false;
// same number of elements so must be exact match
if ((thatOffsetCount == thisOffsetCount) &&
(path.length != that.path.length)) {
return false;
}
// check offsets of elements match
for (int i=0; i<thatOffsetCount; i++) {
Integer o1 = offsets[i];
Integer o2 = that.offsets[i];
if (!o1.equals(o2))
return false;
}
// offsets match so need to compare bytes
int i=0;
while (i < that.path.length) {
if (this.path[i] != that.path[i])
return false;
i++;
}
// final check that match is on name boundary
if (i < path.length && this.path[i] != '/')
return false;
return true;
}
@Override
public boolean endsWith(Path other) {
if (!(Objects.requireNonNull(other) instanceof UnixPath))
return false;
UnixPath that = (UnixPath)other;
int thisLen = path.length;
int thatLen = that.path.length;
// other path is longer
if (thatLen > thisLen)
return false;
// other path is the empty path
if (thisLen > 0 && thatLen == 0)
return false;
// other path is absolute so this path must be absolute
if (that.isAbsolute() && !this.isAbsolute())
return false;
int thisOffsetCount = getNameCount();
int thatOffsetCount = that.getNameCount();
// given path has more elements that this path
if (thatOffsetCount > thisOffsetCount) {
return false;
} else {
// same number of elements
if (thatOffsetCount == thisOffsetCount) {
if (thisOffsetCount == 0)
return true;
int expectedLen = thisLen;
if (this.isAbsolute() && !that.isAbsolute())
expectedLen--;
if (thatLen != expectedLen)
return false;
} else {
// this path has more elements so given path must be relative
if (that.isAbsolute())
return false;
}
}
// compare bytes
int thisPos = offsets[thisOffsetCount - thatOffsetCount];
int thatPos = that.offsets[0];
if ((thatLen - thatPos) != (thisLen - thisPos))
return false;
while (thatPos < thatLen) {
if (this.path[thisPos++] != that.path[thatPos++])
return false;
}
return true;
}
@Override
public int compareTo(Path other) {
int len1 = path.length;
int len2 = ((UnixPath) other).path.length;
int n = Math.min(len1, len2);
byte v1[] = path;
byte v2[] = ((UnixPath) other).path;
int k = 0;
while (k < n) {
int c1 = v1[k] & 0xff;
int c2 = v2[k] & 0xff;
if (c1 != c2) {
return c1 - c2;
}
k++;
}
return len1 - len2;
}
@Override
public boolean equals(Object ob) {
if ((ob != null) && (ob instanceof UnixPath)) {
return compareTo((Path)ob) == 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 + (path[i] & 0xff);
}
hash = h;
}
return h;
}
@Override
public String toString() {
// OK if two or more threads create a String
if (stringValue == null) {
stringValue = fs.normalizeJavaPath(Util.toString(path)); // platform encoding
}
return stringValue;
}
// -- file operations --
// package-private
int openForAttributeAccess(boolean followLinks) throws IOException {
int flags = O_RDONLY;
if (!followLinks) {
if (O_NOFOLLOW == 0)
throw new IOException("NOFOLLOW_LINKS is not supported on this platform");
flags |= O_NOFOLLOW;
}
try {
return open(this, flags, 0);
} catch (UnixException x) {
// HACK: EINVAL instead of ELOOP on Solaris 10 prior to u4 (see 6460380)
if (getFileSystem().isSolaris() && x.errno() == EINVAL)
x.setError(ELOOP);
if (x.errno() == ELOOP)
throw new FileSystemException(getPathForExceptionMessage(), null,
x.getMessage() + " or unable to access attributes of symbolic link");
x.rethrowAsIOException(this);
return -1; // keep compile happy
}
}
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 UnixPath toAbsolutePath() {
if (isAbsolute()) {
return this;
}
// The path is relative so need to resolve against default directory,
// taking care not to reveal the user.dir
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
sm.checkPropertyAccess("user.dir");
}
return new UnixPath(getFileSystem(),
resolve(getFileSystem().defaultDirectory(), path));
}
@Override
public Path toRealPath(LinkOption... options) throws IOException {
checkRead();
UnixPath absolute = toAbsolutePath();
// if resolving links then use realpath
if (Util.followLinks(options)) {
try {
byte[] rp = realpath(absolute);
return new UnixPath(getFileSystem(), rp);
} catch (UnixException x) {
x.rethrowAsIOException(this);
}
}
// if not resolving links then eliminate "." and also ".."
// where the previous element is not a link.
UnixPath result = fs.rootDirectory();
for (int i=0; i<absolute.getNameCount(); i++) {
UnixPath element = absolute.getName(i);
// eliminate "."
if ((element.asByteArray().length == 1) && (element.asByteArray()[0] == '.'))
continue;
// cannot eliminate ".." if previous element is a link
if ((element.asByteArray().length == 2) && (element.asByteArray()[0] == '.') &&
(element.asByteArray()[1] == '.'))
{
UnixFileAttributes attrs = null;
try {
attrs = UnixFileAttributes.get(result, false);
} catch (UnixException x) {
x.rethrowAsIOException(result);
}
if (!attrs.isSymbolicLink()) {
result = result.getParent();
if (result == null) {
result = fs.rootDirectory();
}
continue;
}
}
result = result.resolve(element);
}
// check file exists (without following links)
try {
UnixFileAttributes.get(result, false);
} catch (UnixException x) {
x.rethrowAsIOException(result);
}
return result;
}
@Override
public URI toUri() {
return UnixUriUtils.toUri(this);
}
@Override
public WatchKey register(WatchService watcher,
WatchEvent.Kind<?>[] events,
WatchEvent.Modifier... modifiers)
throws IOException
{
if (watcher == null)
throw new NullPointerException();
if (!(watcher instanceof AbstractWatchService))
throw new ProviderMismatchException();
checkRead();
return ((AbstractWatchService)watcher).register(this, events, modifiers);
}
}
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