blob: ffc20aa171d1204c52ff17c4a88bfb180a7281c3 [file] [log] [blame]
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.
*/
// BEGIN android-note
// We've dropped Windows support, except where it's exposed: we still support
// non-Unix separators in serialized File objects, for example, but we don't
// have any code for UNC paths or case-insensitivity.
// We've also changed the JNI interface to better match what the Java actually wants.
// (The JNI implementation is also much simpler.)
// Some methods have been rewritten to reduce unnecessary allocation.
// Some duplication has been factored out.
// END android-note
package java.io;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.security.AccessController;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import org.apache.harmony.luni.util.DeleteOnExit;
import org.apache.harmony.luni.util.PriviAction;
/**
* An "abstract" representation of a file system entity identified by a
* pathname. The pathname may be absolute (relative to the root directory
* of the file system) or relative to the current directory in which the program
* is running.
* <p>
* The actual file referenced by a {@code File} may or may not exist. It may
* also, despite the name {@code File}, be a directory or other non-regular
* file.
* <p>
* This class provides limited functionality for getting/setting file
* permissions, file type, and last modified time.
* <p>
* Although Java doesn't specify a character encoding for filenames, on Android
* Java strings are converted to UTF-8 byte sequences when sending filenames to
* the operating system, and byte sequences returned by the operating system
* (from the various {@code list} methods) are converted to Java strings by
* decoding them as UTF-8 byte sequences.
*
* @see java.io.Serializable
* @see java.lang.Comparable
*/
public class File implements Serializable, Comparable<File> {
private static final long serialVersionUID = 301077366599181567L;
/**
* The system-dependent character used to separate components in filenames ('/').
* Use of this (rather than hard-coding '/') helps portability to other operating systems.
*
* <p>This field is initialized from the system property "file.separator".
* Later changes to that property will have no effect on this field or this class.
*/
public static final char separatorChar;
/**
* The system-dependent string used to separate components in filenames ('/').
* See {@link #separatorChar}.
*/
public static final String separator;
/**
* The system-dependent character used to separate components in search paths (':').
* This is used to split such things as the PATH environment variable and classpath
* system properties into lists of directories to be searched.
*
* <p>This field is initialized from the system property "path.separator".
* Later changes to that property will have no effect on this field or this class.
*/
public static final char pathSeparatorChar;
/**
* The system-dependent string used to separate components in search paths (":").
* See {@link #pathSeparatorChar}.
*/
public static final String pathSeparator;
/**
* The path we return from getPath. This is almost the path we were
* given, but without duplicate adjacent slashes and without trailing
* slashes (except for the special case of the root directory). This
* path may be the empty string.
*/
private String path;
/**
* The path we return from getAbsolutePath, and pass down to native code.
*/
private String absolutePath;
static {
// The default protection domain grants access to these properties.
separatorChar = System.getProperty("file.separator", "/").charAt(0);
pathSeparatorChar = System.getProperty("path.separator", ":").charAt(0);
separator = String.valueOf(separatorChar);
pathSeparator = String.valueOf(pathSeparatorChar);
}
/**
* Constructs a new file using the specified directory and name.
*
* @param dir
* the directory where the file is stored.
* @param name
* the file's name.
* @throws NullPointerException
* if {@code name} is {@code null}.
*/
public File(File dir, String name) {
this(dir == null ? null : dir.getPath(), name);
}
/**
* Constructs a new file using the specified path.
*
* @param path
* the path to be used for the file.
*/
public File(String path) {
init(path);
}
/**
* Constructs a new File using the specified directory path and file name,
* placing a path separator between the two.
*
* @param dirPath
* the path to the directory where the file is stored.
* @param name
* the file's name.
* @throws NullPointerException
* if {@code name} is {@code null}.
*/
public File(String dirPath, String name) {
if (name == null) {
throw new NullPointerException();
}
if (dirPath == null || dirPath.isEmpty()) {
init(name);
} else if (name.isEmpty()) {
init(dirPath);
} else {
init(join(dirPath, name));
}
}
/**
* Constructs a new File using the path of the specified URI. {@code uri}
* needs to be an absolute and hierarchical Unified Resource Identifier with
* file scheme and non-empty path component, but with undefined authority,
* query or fragment components.
*
* @param uri
* the Unified Resource Identifier that is used to construct this
* file.
* @throws IllegalArgumentException
* if {@code uri} does not comply with the conditions above.
* @see #toURI
* @see java.net.URI
*/
public File(URI uri) {
// check pre-conditions
checkURI(uri);
init(uri.getPath());
}
private void init(String dirtyPath) {
// Cache the path and the absolute path.
// We can't call isAbsolute() here (http://b/2486943).
String cleanPath = fixSlashes(dirtyPath);
boolean isAbsolute = cleanPath.length() > 0 && cleanPath.charAt(0) == separatorChar;
if (isAbsolute) {
this.path = this.absolutePath = cleanPath;
} else {
String userDir = AccessController.doPrivileged(new PriviAction<String>("user.dir"));
this.absolutePath = cleanPath.isEmpty() ? userDir : join(userDir, cleanPath);
// We want path to be equal to cleanPath, but we'd like to reuse absolutePath's char[].
this.path = absolutePath.substring(absolutePath.length() - cleanPath.length());
}
}
// Removes duplicate adjacent slashes and any trailing slash.
private String fixSlashes(String origPath) {
// Remove duplicate adjacent slashes.
boolean lastWasSlash = false;
char[] newPath = origPath.toCharArray();
int length = newPath.length;
int newLength = 0;
for (int i = 0; i < length; ++i) {
char ch = newPath[i];
if (ch == '/') {
if (!lastWasSlash) {
newPath[newLength++] = separatorChar;
lastWasSlash = true;
}
} else {
newPath[newLength++] = ch;
lastWasSlash = false;
}
}
// Remove any trailing slash (unless this is the root of the file system).
if (lastWasSlash && newLength > 1) {
newLength--;
}
// Reuse the original string if possible.
return (newLength != length) ? new String(newPath, 0, newLength) : origPath;
}
// Joins two path components, adding a separator only if necessary.
private String join(String prefix, String suffix) {
int prefixLength = prefix.length();
boolean haveSlash = (prefixLength > 0 && prefix.charAt(prefixLength - 1) == separatorChar);
if (!haveSlash) {
haveSlash = (suffix.length() > 0 && suffix.charAt(0) == separatorChar);
}
return haveSlash ? (prefix + suffix) : (prefix + separatorChar + suffix);
}
private void checkURI(URI uri) {
if (!uri.isAbsolute()) {
throw new IllegalArgumentException("URI is not absolute: " + uri);
} else if (!uri.getRawSchemeSpecificPart().startsWith("/")) {
throw new IllegalArgumentException("URI is not hierarchical: " + uri);
}
if (!"file".equals(uri.getScheme())) {
throw new IllegalArgumentException("Expected file scheme in URI: " + uri);
}
String rawPath = uri.getRawPath();
if (rawPath == null || rawPath.isEmpty()) {
throw new IllegalArgumentException("Expected non-empty path in URI: " + uri);
}
if (uri.getRawAuthority() != null) {
throw new IllegalArgumentException("Found authority in URI: " + uri);
}
if (uri.getRawQuery() != null) {
throw new IllegalArgumentException("Found query in URI: " + uri);
}
if (uri.getRawFragment() != null) {
throw new IllegalArgumentException("Found fragment in URI: " + uri);
}
}
/**
* Lists the file system roots. The Java platform may support zero or more
* file systems, each with its own platform-dependent root. Further, the
* canonical pathname of any file on the system will always begin with one
* of the returned file system roots.
*
* @return the array of file system roots.
*/
public static File[] listRoots() {
return new File[] { new File("/") };
}
/**
* Tests whether or not this process is allowed to execute this file.
* Note that this is a best-effort result; the only way to be certain is
* to actually attempt the operation.
*
* @return {@code true} if this file can be executed, {@code false} otherwise.
* @throws SecurityException
* If a security manager exists and
* SecurityManager.checkExec(java.lang.String) disallows read
* permission to this file object
* @see java.lang.SecurityManager#checkExec(String)
*
* @since 1.6
*/
public boolean canExecute() {
if (path.isEmpty()) {
return false;
}
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkExec(path); // Seems bogus, but this is what the RI does.
}
return canExecuteImpl(absolutePath);
}
private static native boolean canExecuteImpl(String path);
/**
* Indicates whether the current context is allowed to read from this file.
*
* @return {@code true} if this file can be read, {@code false} otherwise.
* @throws SecurityException
* if a {@code SecurityManager} is installed and it denies the
* read request.
*/
public boolean canRead() {
if (path.isEmpty()) {
return false;
}
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkRead(path);
}
return canReadImpl(absolutePath);
}
private static native boolean canReadImpl(String path);
/**
* Indicates whether the current context is allowed to write to this file.
*
* @return {@code true} if this file can be written, {@code false}
* otherwise.
* @throws SecurityException
* if a {@code SecurityManager} is installed and it denies the
* write request.
*/
public boolean canWrite() {
if (path.isEmpty()) {
return false;
}
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkWrite(path);
}
return canWriteImpl(absolutePath);
}
private static native boolean canWriteImpl(String path);
/**
* Returns the relative sort ordering of the paths for this file and the
* file {@code another}. The ordering is platform dependent.
*
* @param another
* a file to compare this file to
* @return an int determined by comparing the two paths. Possible values are
* described in the Comparable interface.
* @see Comparable
*/
public int compareTo(File another) {
return this.getPath().compareTo(another.getPath());
}
/**
* Deletes this file. Directories must be empty before they will be deleted.
*
* <p>Note that this method does <i>not</i> throw {@code IOException} on failure.
* Callers must check the return value.
*
* @return {@code true} if this file was deleted, {@code false} otherwise.
* @throws SecurityException
* if a {@code SecurityManager} is installed and it denies the
* request.
* @see java.lang.SecurityManager#checkDelete
*/
public boolean delete() {
if (path.isEmpty()) {
return false;
}
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkDelete(path);
}
return deleteImpl(absolutePath);
}
private static native boolean deleteImpl(String path);
/**
* Schedules this file to be automatically deleted once the virtual machine
* terminates. This will only happen when the virtual machine terminates
* normally as described by the Java Language Specification section 12.9.
*
* @throws SecurityException
* if a {@code SecurityManager} is installed and it denies the
* request.
*/
public void deleteOnExit() {
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkDelete(path);
}
DeleteOnExit.getInstance().addFile(getAbsoluteName());
}
/**
* Compares {@code obj} to this file and returns {@code true} if they
* represent the <em>same</em> object using a path specific comparison.
*
* @param obj
* the object to compare this file with.
* @return {@code true} if {@code obj} is the same as this object,
* {@code false} otherwise.
*/
@Override
public boolean equals(Object obj) {
if (!(obj instanceof File)) {
return false;
}
return path.equals(((File) obj).getPath());
}
/**
* Returns a boolean indicating whether this file can be found on the
* underlying file system.
*
* @return {@code true} if this file exists, {@code false} otherwise.
* @throws SecurityException
* if a {@code SecurityManager} is installed and it denies read
* access to this file.
* @see #getPath
* @see java.lang.SecurityManager#checkRead(FileDescriptor)
*/
public boolean exists() {
if (path.isEmpty()) {
return false;
}
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkRead(path);
}
return existsImpl(absolutePath);
}
private static native boolean existsImpl(String path);
/**
* Returns the absolute path of this file.
*
* @return the absolute file path.
*/
public String getAbsolutePath() {
return absolutePath;
}
/**
* Returns a new file constructed using the absolute path of this file.
*
* @return a new file from this file's absolute path.
* @see java.lang.SecurityManager#checkPropertyAccess
*/
public File getAbsoluteFile() {
return new File(this.getAbsolutePath());
}
/**
* Returns the absolute path of this file with all references resolved. An
* <em>absolute</em> path is one that begins at the root of the file
* system. The canonical path is one in which all references have been
* resolved. For the cases of '..' and '.', where the file system supports
* parent and working directory respectively, these are removed and replaced
* with a direct directory reference. If the file does not exist,
* getCanonicalPath() may not resolve any references and simply returns an
* absolute path name or throws an IOException.
*
* @return the canonical path of this file.
* @throws IOException
* if an I/O error occurs.
*/
public String getCanonicalPath() throws IOException {
// BEGIN android-removed
// Caching the canonical path is bogus. Users facing specific
// performance problems can perform their own caching, with
// eviction strategies that are appropriate for their application.
// A VM-wide cache with no mechanism to evict stale elements is a
// disservice to applications that need up-to-date data.
// String canonPath = FileCanonPathCache.get(absPath);
// if (canonPath != null) {
// return canonPath;
// }
// END android-removed
// TODO: rewrite getCanonicalPath, resolve, and resolveLink.
String result = absolutePath;
if (separatorChar == '/') {
// resolve the full path first
result = resolveLink(result, result.length(), false);
// resolve the parent directories
result = resolve(result);
}
int numSeparators = 1;
for (int i = 0; i < result.length(); ++i) {
if (result.charAt(i) == separatorChar) {
numSeparators++;
}
}
int[] sepLocations = new int[numSeparators];
int rootLoc = 0;
if (separatorChar != '/') {
if (result.charAt(0) == '\\') {
rootLoc = (result.length() > 1 && result.charAt(1) == '\\') ? 1 : 0;
} else {
rootLoc = 2; // skip drive i.e. c:
}
}
char[] newResult = new char[result.length() + 1];
int newLength = 0, lastSlash = 0, foundDots = 0;
sepLocations[lastSlash] = rootLoc;
for (int i = 0; i <= result.length(); ++i) {
if (i < rootLoc) {
newResult[newLength++] = result.charAt(i);
} else {
if (i == result.length() || result.charAt(i) == separatorChar) {
if (i == result.length() && foundDots == 0) {
break;
}
if (foundDots == 1) {
/* Don't write anything, just reset and continue */
foundDots = 0;
continue;
}
if (foundDots > 1) {
/* Go back N levels */
lastSlash = lastSlash > (foundDots - 1) ? lastSlash - (foundDots - 1) : 0;
newLength = sepLocations[lastSlash] + 1;
foundDots = 0;
continue;
}
sepLocations[++lastSlash] = newLength;
newResult[newLength++] = separatorChar;
continue;
}
if (result.charAt(i) == '.') {
foundDots++;
continue;
}
/* Found some dots within text, write them out */
if (foundDots > 0) {
for (int j = 0; j < foundDots; j++) {
newResult[newLength++] = '.';
}
}
newResult[newLength++] = result.charAt(i);
foundDots = 0;
}
}
// remove trailing slash
if (newLength > (rootLoc + 1) && newResult[newLength - 1] == separatorChar) {
newLength--;
}
return new String(newResult, 0, newLength);
}
/*
* Resolve symbolic links in the parent directories.
*/
private static String resolve(String path) throws IOException {
int last = 1;
String linkPath = path;
String bytes;
boolean done;
for (int i = 1; i <= path.length(); i++) {
if (i == path.length() || path.charAt(i) == separatorChar) {
done = i >= path.length() - 1;
// if there is only one segment, do nothing
if (done && linkPath.length() == 1) {
return path;
}
boolean inPlace = false;
if (linkPath.equals(path)) {
bytes = path;
// if there are no symbolic links, truncate the path instead of copying
if (!done) {
inPlace = true;
path = path.substring(0, i);
}
} else {
int nextSize = i - last + 1;
int linkSize = linkPath.length();
if (linkPath.charAt(linkSize - 1) == separatorChar) {
linkSize--;
}
bytes = linkPath.substring(0, linkSize) +
path.substring(last - 1, last - 1 + nextSize);
// the full path has already been resolved
}
if (done) {
return bytes;
}
linkPath = resolveLink(bytes, inPlace ? i : bytes.length(), true);
if (inPlace) {
// path[i] = '/';
path = path.substring(0, i) + '/' + (i + 1 < path.length() ? path.substring(i + 1) : "");
}
last = i + 1;
}
}
throw new InternalError();
}
/*
* Resolve a symbolic link. While the path resolves to an existing path,
* keep resolving. If an absolute link is found, resolve the parent
* directories if resolveAbsolute is true.
*/
private static String resolveLink(String path, int length, boolean resolveAbsolute) throws IOException {
boolean restart = false;
do {
String fragment = path.substring(0, length);
String target = readlink(fragment);
if (target.equals(fragment)) {
break;
}
if (target.charAt(0) == separatorChar) {
// The link target was an absolute path, so we may need to start again.
restart = resolveAbsolute;
path = target + path.substring(length);
} else {
path = path.substring(0, path.lastIndexOf(separatorChar, length - 1) + 1) + target;
}
length = path.length();
} while (existsImpl(path));
// resolve the parent directories
if (restart) {
return resolve(path);
}
return path;
}
private static native String readlink(String filePath);
/**
* Returns a new file created using the canonical path of this file.
* Equivalent to {@code new File(this.getCanonicalPath())}.
*
* @return the new file constructed from this file's canonical path.
* @throws IOException
* if an I/O error occurs.
* @see java.lang.SecurityManager#checkPropertyAccess
*/
public File getCanonicalFile() throws IOException {
return new File(getCanonicalPath());
}
/**
* Returns the name of the file or directory represented by this file.
*
* @return this file's name or an empty string if there is no name part in
* the file's path.
*/
public String getName() {
int separatorIndex = path.lastIndexOf(separator);
return (separatorIndex < 0) ? path : path.substring(separatorIndex + 1, path.length());
}
/**
* Returns the pathname of the parent of this file. This is the path up to
* but not including the last name. {@code null} is returned if there is no
* parent.
*
* @return this file's parent pathname or {@code null}.
*/
public String getParent() {
int length = path.length(), firstInPath = 0;
if (separatorChar == '\\' && length > 2 && path.charAt(1) == ':') {
firstInPath = 2;
}
int index = path.lastIndexOf(separatorChar);
if (index == -1 && firstInPath > 0) {
index = 2;
}
if (index == -1 || path.charAt(length - 1) == separatorChar) {
return null;
}
if (path.indexOf(separatorChar) == index
&& path.charAt(firstInPath) == separatorChar) {
return path.substring(0, index + 1);
}
return path.substring(0, index);
}
/**
* Returns a new file made from the pathname of the parent of this file.
* This is the path up to but not including the last name. {@code null} is
* returned when there is no parent.
*
* @return a new file representing this file's parent or {@code null}.
*/
public File getParentFile() {
String tempParent = getParent();
if (tempParent == null) {
return null;
}
return new File(tempParent);
}
/**
* Returns the path of this file.
*
* @return this file's path.
*/
public String getPath() {
return path;
}
/**
* Returns an integer hash code for the receiver. Any two objects for which
* {@code equals} returns {@code true} must return the same hash code.
*
* @return this files's hash value.
* @see #equals
*/
@Override
public int hashCode() {
return getPath().hashCode() ^ 1234321;
}
/**
* Indicates if this file's pathname is absolute. Whether a pathname is
* absolute is platform specific. On Android, absolute paths start with
* the character '/'.
*
* @return {@code true} if this file's pathname is absolute, {@code false}
* otherwise.
* @see #getPath
*/
public boolean isAbsolute() {
return path.length() > 0 && path.charAt(0) == separatorChar;
}
/**
* Indicates if this file represents a <em>directory</em> on the
* underlying file system.
*
* @return {@code true} if this file is a directory, {@code false}
* otherwise.
* @throws SecurityException
* if a {@code SecurityManager} is installed and it denies read
* access to this file.
*/
public boolean isDirectory() {
if (path.isEmpty()) {
return false;
}
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkRead(path);
}
return isDirectoryImpl(absolutePath);
}
private static native boolean isDirectoryImpl(String path);
/**
* Indicates if this file represents a <em>file</em> on the underlying
* file system.
*
* @return {@code true} if this file is a file, {@code false} otherwise.
* @throws SecurityException
* if a {@code SecurityManager} is installed and it denies read
* access to this file.
*/
public boolean isFile() {
if (path.isEmpty()) {
return false;
}
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkRead(path);
}
return isFileImpl(absolutePath);
}
private static native boolean isFileImpl(String path);
/**
* Returns whether or not this file is a hidden file as defined by the
* operating system. The notion of "hidden" is system-dependent. For Unix
* systems a file is considered hidden if its name starts with a ".". For
* Windows systems there is an explicit flag in the file system for this
* purpose.
*
* @return {@code true} if the file is hidden, {@code false} otherwise.
* @throws SecurityException
* if a {@code SecurityManager} is installed and it denies read
* access to this file.
*/
public boolean isHidden() {
if (path.isEmpty()) {
return false;
}
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkRead(path);
}
return getName().startsWith(".");
}
/**
* Returns the time when this file was last modified, measured in
* milliseconds since January 1st, 1970, midnight.
* Returns 0 if the file does not exist.
*
* @return the time when this file was last modified.
* @throws SecurityException
* if a {@code SecurityManager} is installed and it denies read
* access to this file.
*/
public long lastModified() {
if (path.isEmpty()) {
return 0;
}
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkRead(path);
}
return lastModifiedImpl(absolutePath);
}
private static native long lastModifiedImpl(String path);
/**
* Sets the time this file was last modified, measured in milliseconds since
* January 1st, 1970, midnight.
*
* <p>Note that this method does <i>not</i> throw {@code IOException} on failure.
* Callers must check the return value.
*
* @param time
* the last modification time for this file.
* @return {@code true} if the operation is successful, {@code false}
* otherwise.
* @throws IllegalArgumentException
* if {@code time < 0}.
* @throws SecurityException
* if a {@code SecurityManager} is installed and it denies write
* access to this file.
*/
public boolean setLastModified(long time) {
if (path.isEmpty()) {
return false;
}
if (time < 0) {
throw new IllegalArgumentException("time < 0");
}
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkWrite(path);
}
return setLastModifiedImpl(absolutePath, time);
}
private static native boolean setLastModifiedImpl(String path, long time);
/**
* Equivalent to setWritable(false, false).
*
* @see #setWritable(boolean, boolean)
*/
public boolean setReadOnly() {
return setWritable(false, false);
}
/**
* Manipulates the execute permissions for the abstract path designated by
* this file.
*
* <p>Note that this method does <i>not</i> throw {@code IOException} on failure.
* Callers must check the return value.
*
* @param executable
* To allow execute permission if true, otherwise disallow
* @param ownerOnly
* To manipulate execute permission only for owner if true,
* otherwise for everyone. The manipulation will apply to
* everyone regardless of this value if the underlying system
* does not distinguish owner and other users.
* @return true if and only if the operation succeeded. If the user does not
* have permission to change the access permissions of this abstract
* pathname the operation will fail. If the underlying file system
* does not support execute permission and the value of executable
* is false, this operation will fail.
* @throws SecurityException -
* If a security manager exists and
* SecurityManager.checkWrite(java.lang.String) disallows write
* permission to this file object
* @since 1.6
*/
public boolean setExecutable(boolean executable, boolean ownerOnly) {
if (path.isEmpty()) {
return false;
}
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkWrite(path);
}
return setExecutableImpl(absolutePath, executable, ownerOnly);
}
/**
* Equivalent to setExecutable(executable, true).
* @see #setExecutable(boolean, boolean)
* @since 1.6
*/
public boolean setExecutable(boolean executable) {
return setExecutable(executable, true);
}
private static native boolean setExecutableImpl(String path, boolean executable, boolean ownerOnly);
/**
* Manipulates the read permissions for the abstract path designated by this
* file.
*
* @param readable
* To allow read permission if true, otherwise disallow
* @param ownerOnly
* To manipulate read permission only for owner if true,
* otherwise for everyone. The manipulation will apply to
* everyone regardless of this value if the underlying system
* does not distinguish owner and other users.
* @return true if and only if the operation succeeded. If the user does not
* have permission to change the access permissions of this abstract
* pathname the operation will fail. If the underlying file system
* does not support read permission and the value of readable is
* false, this operation will fail.
* @throws SecurityException -
* If a security manager exists and
* SecurityManager.checkWrite(java.lang.String) disallows write
* permission to this file object
* @since 1.6
*/
public boolean setReadable(boolean readable, boolean ownerOnly) {
if (path.isEmpty()) {
return false;
}
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkWrite(path);
}
return setReadableImpl(absolutePath, readable, ownerOnly);
}
/**
* Equivalent to setReadable(readable, true).
* @see #setReadable(boolean, boolean)
* @since 1.6
*/
public boolean setReadable(boolean readable) {
return setReadable(readable, true);
}
private static native boolean setReadableImpl(String path, boolean readable, boolean ownerOnly);
/**
* Manipulates the write permissions for the abstract path designated by this
* file.
*
* @param writable
* To allow write permission if true, otherwise disallow
* @param ownerOnly
* To manipulate write permission only for owner if true,
* otherwise for everyone. The manipulation will apply to
* everyone regardless of this value if the underlying system
* does not distinguish owner and other users.
* @return true if and only if the operation succeeded. If the user does not
* have permission to change the access permissions of this abstract
* pathname the operation will fail.
* @throws SecurityException -
* If a security manager exists and
* SecurityManager.checkWrite(java.lang.String) disallows write
* permission to this file object
* @since 1.6
*/
public boolean setWritable(boolean writable, boolean ownerOnly) {
if (path.isEmpty()) {
return false;
}
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkWrite(path);
}
return setWritableImpl(absolutePath, writable, ownerOnly);
}
/**
* Equivalent to setWritable(writable, true).
* @see #setWritable(boolean, boolean)
* @since 1.6
*/
public boolean setWritable(boolean writable) {
return setWritable(writable, true);
}
private static native boolean setWritableImpl(String path, boolean writable, boolean ownerOnly);
/**
* Returns the length of this file in bytes.
* Returns 0 if the file does not exist.
* The result for a directory is not defined.
*
* @return the number of bytes in this file.
* @throws SecurityException
* if a {@code SecurityManager} is installed and it denies read
* access to this file.
*/
public long length() {
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkRead(path);
}
return lengthImpl(absolutePath);
}
private static native long lengthImpl(String path);
/**
* Returns an array of strings with the file names in the directory
* represented by this file. The result is {@code null} if this file is not
* a directory.
* <p>
* The entries {@code .} and {@code ..} representing the current and parent
* directory are not returned as part of the list.
*
* @return an array of strings with file names or {@code null}.
* @throws SecurityException
* if a {@code SecurityManager} is installed and it denies read
* access to this file.
* @see #isDirectory
* @see java.lang.SecurityManager#checkRead(FileDescriptor)
*/
public String[] list() {
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkRead(path);
}
if (path.isEmpty()) {
return null;
}
return listImpl(absolutePath);
}
private static native String[] listImpl(String path);
/**
* Gets a list of the files in the directory represented by this file. This
* list is then filtered through a FilenameFilter and the names of files
* with matching names are returned as an array of strings. Returns
* {@code null} if this file is not a directory. If {@code filter} is
* {@code null} then all filenames match.
* <p>
* The entries {@code .} and {@code ..} representing the current and parent
* directories are not returned as part of the list.
*
* @param filter
* the filter to match names against, may be {@code null}.
* @return an array of files or {@code null}.
* @throws SecurityException
* if a {@code SecurityManager} is installed and it denies read
* access to this file.
* @see #getPath
* @see #isDirectory
* @see java.lang.SecurityManager#checkRead(FileDescriptor)
*/
public String[] list(FilenameFilter filter) {
String[] filenames = list();
if (filter == null || filenames == null) {
return filenames;
}
List<String> result = new ArrayList<String>(filenames.length);
for (String filename : filenames) {
if (filter.accept(this, filename)) {
result.add(filename);
}
}
return result.toArray(new String[result.size()]);
}
/**
* Returns an array of files contained in the directory represented by this
* file. The result is {@code null} if this file is not a directory. The
* paths of the files in the array are absolute if the path of this file is
* absolute, they are relative otherwise.
*
* @return an array of files or {@code null}.
* @throws SecurityException
* if a {@code SecurityManager} is installed and it denies read
* access to this file.
* @see #list
* @see #isDirectory
*/
public File[] listFiles() {
return filenamesToFiles(list());
}
/**
* Gets a list of the files in the directory represented by this file. This
* list is then filtered through a FilenameFilter and files with matching
* names are returned as an array of files. Returns {@code null} if this
* file is not a directory. If {@code filter} is {@code null} then all
* filenames match.
* <p>
* The entries {@code .} and {@code ..} representing the current and parent
* directories are not returned as part of the list.
*
* @param filter
* the filter to match names against, may be {@code null}.
* @return an array of files or {@code null}.
* @throws SecurityException
* if a {@code SecurityManager} is installed and it denies read
* access to this file.
* @see #list(FilenameFilter filter)
* @see #getPath
* @see #isDirectory
* @see java.lang.SecurityManager#checkRead(FileDescriptor)
*/
public File[] listFiles(FilenameFilter filter) {
return filenamesToFiles(list(filter));
}
/**
* Gets a list of the files in the directory represented by this file. This
* list is then filtered through a FileFilter and matching files are
* returned as an array of files. Returns {@code null} if this file is not a
* directory. If {@code filter} is {@code null} then all files match.
* <p>
* The entries {@code .} and {@code ..} representing the current and parent
* directories are not returned as part of the list.
*
* @param filter
* the filter to match names against, may be {@code null}.
* @return an array of files or {@code null}.
* @throws SecurityException
* if a {@code SecurityManager} is installed and it denies read
* access to this file.
* @see #getPath
* @see #isDirectory
* @see java.lang.SecurityManager#checkRead(FileDescriptor)
*/
public File[] listFiles(FileFilter filter) {
File[] files = listFiles();
if (filter == null || files == null) {
return files;
}
List<File> result = new ArrayList<File>(files.length);
for (File file : files) {
if (filter.accept(file)) {
result.add(file);
}
}
return result.toArray(new File[result.size()]);
}
/**
* Converts a String[] containing filenames to a File[].
* Note that the filenames must not contain slashes.
* This method is to remove duplication in the implementation
* of File.list's overloads.
*/
private File[] filenamesToFiles(String[] filenames) {
if (filenames == null) {
return null;
}
int count = filenames.length;
File[] result = new File[count];
for (int i = 0; i < count; ++i) {
result[i] = new File(this, filenames[i]);
}
return result;
}
/**
* Creates the directory named by the trailing filename of this file. Does
* not create the complete path required to create this directory.
*
* <p>Note that this method does <i>not</i> throw {@code IOException} on failure.
* Callers must check the return value.
*
* @return {@code true} if the directory has been created, {@code false}
* otherwise.
* @throws SecurityException
* if a {@code SecurityManager} is installed and it denies write
* access for this file.
* @see #mkdirs
*/
public boolean mkdir() {
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkWrite(path);
}
return mkdirImpl(absolutePath);
}
private static native boolean mkdirImpl(String path);
/**
* Creates the directory named by the trailing filename of this file,
* including the complete directory path required to create this directory.
*
* <p>Note that this method does <i>not</i> throw {@code IOException} on failure.
* Callers must check the return value.
*
* @return {@code true} if the necessary directories have been created,
* {@code false} if the target directory already exists or one of
* the directories can not be created.
* @throws SecurityException
* if a {@code SecurityManager} is installed and it denies write
* access for this file.
* @see #mkdir
*/
public boolean mkdirs() {
/* If the terminal directory already exists, answer false */
if (exists()) {
return false;
}
/* If the receiver can be created, answer true */
if (mkdir()) {
return true;
}
String parentDir = getParent();
/* If there is no parent and we were not created, answer false */
if (parentDir == null) {
return false;
}
/* Otherwise, try to create a parent directory and then this directory */
return (new File(parentDir).mkdirs() && mkdir());
}
/**
* Creates a new, empty file on the file system according to the path
* information stored in this file.
*
* <p>Note that this method does <i>not</i> throw {@code IOException} on failure.
* Callers must check the return value.
*
* @return {@code true} if the file has been created, {@code false} if it
* already exists.
* @throws IOException if it's not possible to create the file.
* @throws SecurityException
* if a {@code SecurityManager} is installed and it denies write
* access for this file.
*/
public boolean createNewFile() throws IOException {
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkWrite(path);
}
if (path.isEmpty()) {
throw new IOException("No such file or directory");
}
return createNewFileImpl(absolutePath);
}
private static native boolean createNewFileImpl(String path);
/**
* Creates an empty temporary file using the given prefix and suffix as part
* of the file name. If {@code suffix} is null, {@code .tmp} is used. This
* method is a convenience method that calls
* {@link #createTempFile(String, String, File)} with the third argument
* being {@code null}.
*
* @param prefix
* the prefix to the temp file name.
* @param suffix
* the suffix to the temp file name.
* @return the temporary file.
* @throws IOException
* if an error occurs when writing the file.
*/
public static File createTempFile(String prefix, String suffix) throws IOException {
return createTempFile(prefix, suffix, null);
}
/**
* Creates an empty temporary file in the given directory using the given
* prefix and suffix as part of the file name. If {@code suffix} is null, {@code .tmp} is used.
*
* <p>Note that this method does <i>not</i> call {@link #deleteOnExit}.
*
* @param prefix
* the prefix to the temp file name.
* @param suffix
* the suffix to the temp file name.
* @param directory
* the location to which the temp file is to be written, or
* {@code null} for the default location for temporary files,
* which is taken from the "java.io.tmpdir" system property. It
* may be necessary to set this property to an existing, writable
* directory for this method to work properly.
* @return the temporary file.
* @throws IllegalArgumentException
* if the length of {@code prefix} is less than 3.
* @throws IOException
* if an error occurs when writing the file.
*/
@SuppressWarnings("nls")
public static File createTempFile(String prefix, String suffix,
File directory) throws IOException {
// Force a prefix null check first
if (prefix.length() < 3) {
throw new IllegalArgumentException("prefix must be at least 3 characters");
}
if (suffix == null) {
suffix = ".tmp";
}
File tmpDirFile = directory;
if (tmpDirFile == null) {
String tmpDir = AccessController.doPrivileged(
new PriviAction<String>("java.io.tmpdir", "."));
tmpDirFile = new File(tmpDir);
}
File result;
do {
result = new File(tmpDirFile, prefix + new Random().nextInt() + suffix);
} while (!result.createNewFile());
return result;
}
/**
* Renames this file to {@code newPath}. This operation is supported for both
* files and directories.
*
* <p>Many failures are possible. Some of the more likely failures include:
* <ul>
* <li>Write permission is required on the directories containing both the source and
* destination paths.
* <li>Search permission is required for all parents of both paths.
* <li>Both paths be on the same mount point. On Android, applications are most likely to hit
* this restriction when attempting to copy between internal storage and an SD card.
* </ul>
*
* <p>Note that this method does <i>not</i> throw {@code IOException} on failure.
* Callers must check the return value.
*
* @param newPath the new path.
* @return true on success.
* @throws SecurityException
* if a {@code SecurityManager} is installed and it denies write
* access for this file or {@code newPath}.
*/
public boolean renameTo(File newPath) {
if (path.isEmpty() || newPath.path.isEmpty()) {
return false;
}
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkWrite(path);
security.checkWrite(newPath.path);
}
return renameToImpl(absolutePath, newPath.absolutePath);
}
private static native boolean renameToImpl(String oldPath, String newPath);
/**
* Returns a string containing a concise, human-readable description of this
* file.
*
* @return a printable representation of this file.
*/
@Override
public String toString() {
return path;
}
/**
* Returns a Uniform Resource Identifier for this file. The URI is system
* dependent and may not be transferable between different operating / file
* systems.
*
* @return an URI for this file.
*/
@SuppressWarnings("nls")
public URI toURI() {
String name = getAbsoluteName();
try {
if (!name.startsWith("/")) {
// start with sep.
return new URI("file", null, new StringBuilder(
name.length() + 1).append('/').append(name).toString(),
null, null);
} else if (name.startsWith("//")) {
return new URI("file", "", name, null); // UNC path
}
return new URI("file", null, name, null, null);
} catch (URISyntaxException e) {
// this should never happen
return null;
}
}
/**
* Returns a Uniform Resource Locator for this file. The URL is system
* dependent and may not be transferable between different operating / file
* systems.
*
* @return a URL for this file.
* @throws java.net.MalformedURLException
* if the path cannot be transformed into a URL.
* @deprecated use {@link #toURI} and {@link java.net.URI#toURL} to get
* correct escaping of illegal characters.
*/
@Deprecated
@SuppressWarnings("nls")
public URL toURL() throws java.net.MalformedURLException {
String name = getAbsoluteName();
if (!name.startsWith("/")) {
// start with sep.
return new URL("file", "", -1,
new StringBuilder(name.length() + 1).append('/').append(name).toString(), null);
} else if (name.startsWith("//")) {
return new URL("file:" + name); // UNC path
}
return new URL("file", "", -1, name, null);
}
private String getAbsoluteName() {
File f = getAbsoluteFile();
String name = f.getPath();
if (f.isDirectory() && name.charAt(name.length() - 1) != separatorChar) {
// Directories must end with a slash
name = new StringBuilder(name.length() + 1).append(name)
.append('/').toString();
}
if (separatorChar != '/') { // Must convert slashes.
name = name.replace(separatorChar, '/');
}
return name;
}
private void writeObject(ObjectOutputStream stream) throws IOException {
stream.defaultWriteObject();
stream.writeChar(separatorChar);
}
private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException {
stream.defaultReadObject();
char inSeparator = stream.readChar();
init(path.replace(inSeparator, separatorChar));
}
/**
* Returns the total size in bytes of the partition containing this path.
* Returns 0 if this path does not exist.
*
* @since 1.6
*/
public long getTotalSpace() {
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkPermission(new RuntimePermission("getFileSystemAttributes"));
}
return getTotalSpaceImpl(absolutePath);
}
private static native long getTotalSpaceImpl(String path);
/**
* Returns the number of usable free bytes on the partition containing this path.
* Returns 0 if this path does not exist.
*
* <p>Note that this is likely to be an optimistic over-estimate and should not
* be taken as a guarantee your application can actually write this many bytes.
* On Android (and other Unix-based systems), this method returns the number of free bytes
* available to non-root users, regardless of whether you're actually running as root,
* and regardless of any quota or other restrictions that might apply to the user.
* (The {@code getFreeSpace} method returns the number of bytes potentially available to root.)
*
* @since 1.6
*/
public long getUsableSpace() {
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkPermission(new RuntimePermission("getFileSystemAttributes"));
}
return getUsableSpaceImpl(absolutePath);
}
private static native long getUsableSpaceImpl(String path);
/**
* Returns the number of free bytes on the partition containing this path.
* Returns 0 if this path does not exist.
*
* <p>Note that this is likely to be an optimistic over-estimate and should not
* be taken as a guarantee your application can actually write this many bytes.
*
* @since 1.6
*/
public long getFreeSpace() {
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkPermission(new RuntimePermission("getFileSystemAttributes"));
}
return getFreeSpaceImpl(absolutePath);
}
private static native long getFreeSpaceImpl(String path);
}