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/*
* Copyright (C) 2006 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.os;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.regex.Pattern;
/**
* Tools for managing files. Not for public consumption.
* @hide
*/
public class FileUtils
{
public static final int S_IRWXU = 00700;
public static final int S_IRUSR = 00400;
public static final int S_IWUSR = 00200;
public static final int S_IXUSR = 00100;
public static final int S_IRWXG = 00070;
public static final int S_IRGRP = 00040;
public static final int S_IWGRP = 00020;
public static final int S_IXGRP = 00010;
public static final int S_IRWXO = 00007;
public static final int S_IROTH = 00004;
public static final int S_IWOTH = 00002;
public static final int S_IXOTH = 00001;
/**
* File status information. This class maps directly to the POSIX stat structure.
* @hide
*/
public static final class FileStatus {
public int dev;
public int ino;
public int mode;
public int nlink;
public int uid;
public int gid;
public int rdev;
public long size;
public int blksize;
public long blocks;
public long atime;
public long mtime;
public long ctime;
}
/**
* Get the status for the given path. This is equivalent to the POSIX stat(2) system call.
* @param path The path of the file to be stat'd.
* @param status Optional argument to fill in. It will only fill in the status if the file
* exists.
* @return true if the file exists and false if it does not exist. If you do not have
* permission to stat the file, then this method will return false.
*/
public static native boolean getFileStatus(String path, FileStatus status);
/** Regular expression for safe filenames: no spaces or metacharacters */
private static final Pattern SAFE_FILENAME_PATTERN = Pattern.compile("[\\w%+,./=_-]+");
public static native int setPermissions(String file, int mode, int uid, int gid);
public static native int getPermissions(String file, int[] outPermissions);
/** returns the FAT file system volume ID for the volume mounted
* at the given mount point, or -1 for failure
* @param mount point for FAT volume
* @return volume ID or -1
*/
public static native int getFatVolumeId(String mountPoint);
// copy a file from srcFile to destFile, return true if succeed, return
// false if fail
public static boolean copyFile(File srcFile, File destFile) {
boolean result = false;
try {
InputStream in = new FileInputStream(srcFile);
try {
result = copyToFile(in, destFile);
} finally {
in.close();
}
} catch (IOException e) {
result = false;
}
return result;
}
/**
* Copy data from a source stream to destFile.
* Return true if succeed, return false if failed.
*/
public static boolean copyToFile(InputStream inputStream, File destFile) {
try {
OutputStream out = new FileOutputStream(destFile);
try {
byte[] buffer = new byte[4096];
int bytesRead;
while ((bytesRead = inputStream.read(buffer)) >= 0) {
out.write(buffer, 0, bytesRead);
}
} finally {
out.close();
}
return true;
} catch (IOException e) {
return false;
}
}
/**
* Check if a filename is "safe" (no metacharacters or spaces).
* @param file The file to check
*/
public static boolean isFilenameSafe(File file) {
// Note, we check whether it matches what's known to be safe,
// rather than what's known to be unsafe. Non-ASCII, control
// characters, etc. are all unsafe by default.
return SAFE_FILENAME_PATTERN.matcher(file.getPath()).matches();
}
/**
* Read a text file into a String, optionally limiting the length.
* @param file to read (will not seek, so things like /proc files are OK)
* @param max length (positive for head, negative of tail, 0 for no limit)
* @param ellipsis to add of the file was truncated (can be null)
* @return the contents of the file, possibly truncated
* @throws IOException if something goes wrong reading the file
*/
public static String readTextFile(File file, int max, String ellipsis) throws IOException {
InputStream input = new FileInputStream(file);
try {
if (max > 0) { // "head" mode: read the first N bytes
byte[] data = new byte[max + 1];
int length = input.read(data);
if (length <= 0) return "";
if (length <= max) return new String(data, 0, length);
if (ellipsis == null) return new String(data, 0, max);
return new String(data, 0, max) + ellipsis;
} else if (max < 0) { // "tail" mode: read it all, keep the last N
int len;
boolean rolled = false;
byte[] last = null, data = null;
do {
if (last != null) rolled = true;
byte[] tmp = last; last = data; data = tmp;
if (data == null) data = new byte[-max];
len = input.read(data);
} while (len == data.length);
if (last == null && len <= 0) return "";
if (last == null) return new String(data, 0, len);
if (len > 0) {
rolled = true;
System.arraycopy(last, len, last, 0, last.length - len);
System.arraycopy(data, 0, last, last.length - len, len);
}
if (ellipsis == null || !rolled) return new String(last);
return ellipsis + new String(last);
} else { // "cat" mode: read it all
ByteArrayOutputStream contents = new ByteArrayOutputStream();
int len;
byte[] data = new byte[1024];
do {
len = input.read(data);
if (len > 0) contents.write(data, 0, len);
} while (len == data.length);
return contents.toString();
}
} finally {
input.close();
}
}
}
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