com.peterphi.std.io.FileHelper Maven / Gradle / Ivy
package com.peterphi.std.io;
import com.peterphi.std.system.exec.Exec;
import com.peterphi.std.system.exec.Execed;
import org.apache.commons.io.FileUtils;
import org.apache.log4j.Logger;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.StringReader;
import java.net.URL;
import java.nio.channels.FileChannel;
import java.nio.channels.FileLock;
import java.nio.file.Files;
import java.util.Set;
/**
*
* Title: File Helper
*
*
* Description: File-related helper functions
*
*
* Copyright: Copyright (c) 2006-2009
*
*
*
*
*
* @version $Revision$
*/
public class FileHelper
{
private static final transient Logger log = Logger.getLogger(FileHelper.class);
private FileHelper()
{
} // Prevent instantiation
/**
* Creates a temporary file name
*
* @return File
*/
public static File createTempFile(final String prefix, final String suffix)
{
try
{
File tempFile = File.createTempFile(prefix, suffix);
if (tempFile.exists())
{
if (!tempFile.delete())
throw new RuntimeException("Could not delete new temp file: " + tempFile);
}
return tempFile;
}
catch (IOException e)
{
log.error("[FileHelper] {createTempFile} Error creating temp file: " + e.getMessage(), e);
return null;
}
}
/**
* Ensures that a file is "safe" (this is done by whitelisting a small number of characters)
* This method is mainly designed for producing a filename which bears some resemblance to a user-supplied String while
* removing the risk of being tricked
*
* @param filename
*
* @return
*/
public static String enforceSafeFilename(final String filename)
{
final char safeChar = '.';
char[] chars = filename.toCharArray();
for (int i = 0; i < chars.length; i++)
{
if (!isSafeFilenameCharacter(chars[i]))
chars[i] = safeChar;
}
return String.valueOf(chars);
}
/**
* Determines if a character is a valid "safe filename" character (which we restrict to: alpha, digits, "-", "_" and ".")
*
* @param c
*
* @return
*/
private static boolean isSafeFilenameCharacter(char c)
{
if (Character.isLetterOrDigit(c))
{
return true;
}
else if (c == '-' || c == '_' || c == '.')
{
return true;
}
else
{
return false;
}
}
public static boolean isAbsoluteFile(File f)
{
try
{
return f.isAbsolute();
}
catch (Throwable t)
{
return false;
}
}
public static boolean isAbsoluteFile(String filename)
{
return isAbsoluteFile(new File(filename));
}
public static boolean isAncestor(File root, File f)
{
while (f != null && !f.equals(root))
f = f.getParentFile();
return f != null;
}
public static boolean couldWrite(final File f)
{
if (f == null)
throw new IllegalArgumentException("Must specify a non-null file!");
// If the file exists check if we can write to it
// If the file doesn't exist, try to create it. If we can't then the caller won't be able to write to it if they try
// If the file doesn't exist and the parent directory doesn't exist
if (!f.exists())
{
try
{
if (f.getParentFile().exists())
{
try
{
FileHelper.write(f, "");
// should always exist - test in case there was a silently dropped error
return f.exists();
}
finally
{
if (!f.delete())
log.warn("Could not delete file once written: " + f);
}
}
else
{
log.info("{couldWrite} Could not determine if the file is writable because the parent directory did not exist");
return false;
}
}
catch (IOException e)
{
log.warn("{couldWrite} Error while testing: " + e.getMessage(), e);
return false;
}
}
else
{
return f.canWrite();
}
}
public static void copy(File src, File dest) throws IOException
{
if (!src.exists())
throw new FileNotFoundException("Cannot copy from non-existant source " +
src.getAbsolutePath() +
" to " +
dest.getAbsolutePath());
if (log.isInfoEnabled())
log.info("[FileHelper] {copy} Copying " + src + " to " + dest);
if (src.isDirectory())
{
FileUtils.copyDirectory(src, dest);
}
else
{
if (dest.exists())
{
delete(dest);
}
FileUtils.copyFile(src, dest);
if (log.isTraceEnabled())
{
if (src.length() != dest.length())
{
log.trace("[FileHelper] {copy} src and dest have different sizes at the end of the copy process!");
}
else
{
log.trace("[FileHelper] {copy} Success: src and dest are identically sized");
}
}
}
}
public static void move(File src, File dest) throws IOException
{
if (!src.exists())
throw new FileNotFoundException("Cannot copy from non-existant source " +
src.getAbsolutePath() +
" to " +
dest.getAbsolutePath());
if (log.isInfoEnabled())
log.info("[FileHelper] {move} Moving " + src + " to " + dest);
if (!src.renameTo(dest))
{ // Try a fast move (works if the files are on the same partition)
if (src.isDirectory())
{
FileUtils.copyDirectory(src, dest);
FileUtils.deleteDirectory(src);
}
else
{
FileUtils.copyFile(src, dest);
src.delete();
}
}
}
public static boolean trySymlink(final File from, final File to)
{
try
{
symlink(from, to);
return true;
}
catch (IOException e)
{
log.error("[FileHelper] {trySymlink} Failure: " + e.getMessage(), e);
return false;
}
}
public static void symlink(final File from, final File to) throws IOException
{
try
{
if (!from.exists())
{
throw new FileNotFoundException("Symbolic link source does not exist: " + from);
}
// Delete the destination if necessary
if (to.exists())
if (!to.delete())
throw new IOException("Could not delete file: " + to);
// Launch the link process
final int returnCode = Exec.utilityAs(null, "ln", "-s", from.toString(), to.toString()).waitForExit();
if (returnCode != 0)
{
throw new IOException("ln command returned nonzero return code: " + returnCode);
}
else if (!to.exists())
{
throw new IOException("Symbolic link does not exist (but ln claimed successful execution)");
}
else if (!to.getCanonicalFile().equals(from.getCanonicalFile()))
{
throw new IOException("Link points to the wrong place (to.getCanonicalFile() != from.getCanonicalFile()");
}
}
catch (IOException e)
{
log.error("[FileHelper] {symlink} Failure: " + e.getMessage(), e);
throw e;
}
}
/**
* Safely moves a file from one place to another, ensuring the filesystem is left in a consistent state
*
* @param src
* File The source file
* @param dest
* File The destination file
*
* @return boolean True if the file has been completely moved to the new location, false if it is still in the original
* location
*
* @throws java.lang.SecurityException
* MAY BE THROWN if permission is denied to src or dest
* @deprecated use commons file utils FileUtils.moveDirectoryToDirectory instead
*/
@Deprecated
public static boolean safeMove(File src, File dest) throws SecurityException
{
assert (src.exists());
final boolean createDestIfNotExist = true;
try
{
if (src.isFile())
FileUtils.moveFile(src, dest);
else
FileUtils.moveDirectoryToDirectory(src, dest, createDestIfNotExist);
return true;
}
catch (IOException e)
{
log.error("{safeMove} Error during move operation: " + e.getMessage(), e);
return false;
}
}
/**
* Deletes a local file or directory from the filesystem
*
* @param f
* File The file/directory to delete
*
* @return boolean True if the deletion was a success, otherwise false
*/
public static boolean delete(File f) throws IOException
{
assert (f.exists());
if (f.isDirectory())
{
FileUtils.deleteDirectory(f);
return true;
}
else
{
return f.delete();
}
}
/**
* Determines if 2 files or directories are equivalent by looking inside them
*
* @param one
* File The first file/directory
* @param two
* File The second file/directory
* @param checkName
* boolean Whether names should be identical also
*
* @return boolean True if the files/directories are equivalent, otherwise false
*
* @throws IOException
* On an unhandleable error or a non-file, non-directory input
*/
public static boolean smartEquals(File one, File two, boolean checkName) throws IOException
{
if (checkName)
{
if (!one.getName().equals(two.getName()))
{
return false;
}
}
if (one.isDirectory() == two.isDirectory())
{
if (one.isDirectory())
{
File[] filesOne = one.listFiles();
File[] filesTwo = two.listFiles();
if (filesOne.length == filesTwo.length)
{
if (filesOne.length > 0)
{
for (int i = 0; i < filesOne.length; i++)
{
if (!smartEquals(filesOne[i], filesTwo[i], checkName))
{
return false;
}
}
return true; // all subfiles are equal
}
else
{
return true;
}
}
else
{
return false;
}
} // Otherwise, the File objects are Files
else if (one.isFile() && two.isFile())
{
if (one.length() == two.length())
{
return FileUtils.contentEquals(one, two);
}
else
{
return false;
}
}
else
{
throw new IOException("I don't know how to handle a non-file non-directory File: one=" + one + " two=" + two);
}
} // One is a directory and the other is not
else
{
return false;
}
}
/**
* Reads a PID (Process Id) file
*
* @param f
* File The process Id file (must exist!)
*
* @return String The process Id represented by the file (or -1 if the file doesn't exist)
*
* @throws IOException
* On filesystem-level errors
*/
public static long readPID(File f) throws IOException
{
return readPID(f, false);
}
/**
* Reads a PID (Process Id) file
*
* @param f
* File The process Id file (must exist!)
* @param carefulProcessing
* boolean If true, non-numeric chars are stripped from the PID before it is parsed
*
* @return String The process Id represented by the file (or -1 if the file doesn't exist)
*
* @throws IOException
* On filesystem-level errors
*/
public static long readPID(File f, boolean carefulProcessing) throws IOException
{
if (f.exists())
{
String pidString = cat(f);
if (carefulProcessing)
pidString = pidString.replaceAll("[^0-9]", ""); // Strip out anything that's not a number
else
pidString = pidString.replace("\n", ""); // Just remove newlines
if (pidString.length() > 0)
return Long.parseLong(pidString);
else
return -1;
}
else
{
return -1;
}
}
public static void writePID(File f, long pid) throws IOException
{
writePID(f, Long.toString(pid));
}
public static void writePID(File f, String pid) throws IOException
{
assert (pid != null && pid.length() != 0) : "Must supply a valid PID!";
write(f, pid);
}
public static void write(File f, String contents) throws IOException
{
write(f, new StringReader(contents));
}
public static void write(File f, StringBuilder sb) throws IOException
{
write(f, new StringBuilderReader(sb));
}
public static void write(File f, Reader fr) throws IOException
{
assert (f != null) : "Must supply a file to write to!";
assert (fr != null) : "Must supply a Reader to read from!";
FileWriter fw = new FileWriter(f);
try
{
char[] buffer = new char[4096];
int size = 0;
while ((size = fr.read(buffer)) != -1)
{
fw.write(buffer, 0, size);
}
}
finally
{
fw.close();
fr.close();
}
}
public static String cat(String filename) throws IOException
{
return cat(new File(filename));
}
public static String cat(InputStream is) throws IOException
{
return cat(new InputStreamReader(is), 1024);
}
public static String cat(final URL u) throws IOException
{
return cat(u.openStream());
}
public static String cat(final Reader reader) throws IOException
{
return cat(reader, 1024);
}
public static String cat(final File f) throws IOException
{
FileInputStream fis = new FileInputStream(f);
try
{
return cat(fis);
}
finally
{
fis.close();
}
}
public static String cat(final Reader reader, final int sizeEstimate) throws IOException
{
assert (reader != null) : "Must provide a reader to read from!";
try
{
StringBuilder sb = new StringBuilder(sizeEstimate);
char[] buffer = new char[4096];
int read = 0;
while ((read = reader.read(buffer)) != -1)
{
sb.append(buffer, 0, read);
}
return sb.toString();
}
finally
{
reader.close();
}
}
public static boolean chown(final File f, String owner, String group, boolean recursive) throws IOException
{
if (!f.exists())
throw new FileNotFoundException("Cannot chown a non-existant file!");
if (owner == null)
owner = "";
else if (group == null)
group = "";
final String ownerGroupPair;
if (owner.isEmpty() && group.isEmpty())
throw new IllegalArgumentException("Must specify an owner or a group to change ownership to");
else if (group.isEmpty())
ownerGroupPair = owner;
else
ownerGroupPair = owner + "." + group;
try
{
final String[] cmd;
if (recursive)
cmd = new String[]{"chown", "--recursive", ownerGroupPair, f.getPath()};
else
cmd = new String[]{"chown", ownerGroupPair, f.getPath()};
Execed call = Exec.rootUtility(cmd);
int returnCode = call.waitForExit();
return returnCode == 0;
}
catch (Exception e)
{
log.error("[FileHelper] {chown} Failure: " + e.getMessage(), e);
return false;
}
}
/**
* Performs a chmod (which assumes this system is Linux/UNIX/Solaris/etc), replacing the permissions using octal
*
* @param f
* @param permissions
* REMEMBER TO SPECIFY THIS VALUE IN OCTAL (ie. with a leading zero) IF YOU ARE USING NUMBERS IDENTICAL TO THE
* CHMOD
* COMMAND-LINE REPRESENTATION (eg. 755)
*
* @return
*
* @throws IOException
*/
public static boolean chmod(final File f, final int permissions)
{
return chmod(null, f, permissions);
}
/**
* Performs a chmod (which assumes this system is Linux/UNIX/Solaris/etc), replacing the permissions using octal
*
* @param f
* @param permissions
* REMEMBER TO SPECIFY THIS VALUE IN OCTAL (ie. with a leading zero)
*
* @return
*
* @throws IOException
*/
public static boolean chmod(final String as, final File f, final int permissions)
{
if (!f.exists())
{
log.error("[FileHelper] {chmod} Non-existant file: " + f.getPath());
return false;
}
try
{
Execed call = Exec.utilityAs(as, "chmod", Integer.toOctalString(permissions), f.getPath());
int returnCode = call.waitForExit();
return returnCode == 0;
}
catch (Exception e)
{
log.error("[FileHelper] {chmod} Failure: " + e.getMessage(), e);
return false;
}
}
/**
* Performs a chmod (which assumes this system is Linux/UNIX/Solaris/etc), replacing the permissions on f with
* the permissions on copyOf
*
* @param f
* @param copyOf
* the file to use the permissions from
*
* @return
*
* @throws IOException
*/
public static boolean chmod(File f, File copyOf)
{
return chmod(null, f, copyOf);
}
/**
* Performs a chmod (which assumes this system is Linux/UNIX/Solaris/etc), replacing the permissions on f with
* the permissions on copyOf
*
* @param f
* @param copyOf
* the file to use the permissions from
*
* @return
*
* @throws IOException
*/
public static boolean chmod(String as, File f, File copyOf)
{
if (!f.exists())
{
log.error("[FileHelper] {chmod} Non-existant file: " + f.getPath());
return false;
}
if (!copyOf.exists())
{
log.error("[FileHelper] {chmod} Non-existant file: " + copyOf.getPath());
return false;
}
try
{
Execed call = Exec.utilityAs(as, "chmod", "--reference=" + copyOf.getPath(), f.getPath());
int returnCode = call.waitForExit();
return returnCode == 0;
}
catch (Exception e)
{
log.error("[LockRecord] {chmod} Failure: " + e.getMessage(), e);
return false;
}
}
/**
* Performs a chmod (which assumes this system is Linux/UNIX/Solaris/etc), altering the permissions using symbols (ie. chmod
* o+w)
*
* @param f
* @param set
* The permissions to set on the file
*
* @return
*
* @throws IOException
*/
public static boolean chmod(String as, File f, Set set)
{
return chmod(as, f, set, null);
}
/**
* Performs a chmod (which assumes this system is Linux/UNIX/Solaris/etc), altering the permissions using symbols (ie. chmod
* o+w)
*
* @param f
* @param set
* The permissions to set on the file
*
* @return
*
* @throws IOException
*/
public static boolean chmod(File f, Set set)
{
return chmod(null, f, set);
}
/**
* Performs a chmod (which assumes this system is Linux/UNIX/Solaris/etc), altering the permissions using symbols (ie. chmod
* o+w)
*
* @param f
* @param set
* The permissions to set on the file
* @param clear
* The permissions to modify on the file
*
* @return
*
* @throws IOException
*/
public static boolean chmod(File f, Set set, Set clear)
{
return chmod(null, f, set, clear);
}
/**
* Performs a chmod (which assumes this system is Linux/UNIX/Solaris/etc), altering the permissions using symbols (ie. chmod
* o+w)
*
* @param f
* @param set
* The permissions to set on the file
* @param clear
* The permissions to modify on the file
*
* @return
*
* @throws IOException
*/
public static boolean chmod(String as, File f, Set set, Set clear)
{
if (!f.exists())
{
log.error("[FileHelper] {chmod} Non-existant file: " + f.getPath());
return false;
}
String permissions = ChmodBit.toString(set, clear);
try
{
Execed call = Exec.utilityAs(as, "chmod", permissions, f.getPath());
int returnCode = call.waitForExit();
return returnCode == 0;
}
catch (Exception e)
{
log.error("[LockRecord] {chmod} Failure: " + e.getMessage(), e);
return false;
}
}
public static class LockRecord
{
protected FileOutputStream fos;
protected FileChannel channel;
protected FileLock flock;
public void release()
{
try
{
if (flock != null && flock.isValid())
{
flock.release();
}
if (channel != null && channel.isOpen())
{
channel.close();
}
if (fos != null)
{
fos.close();
}
}
catch (IOException e)
{
// ignore
}
}
}
/**
* Obtains an exclusive lock on the specified file. By calling this method, the caller guarantees it will call the release()
* method of the LockRecord
*
* @param f
* File The file to lock
*
* @return LockRecord The lock record
*/
public static LockRecord lockFile(File f)
{
LockRecord rec = new LockRecord();
try
{
rec.fos = new FileOutputStream(f);
rec.channel = rec.fos.getChannel();
rec.flock = rec.channel.lock();
}
catch (IOException e)
{
log.error("[FileHelper] {lockFile} Error while locking " + f + ". Error: " + e.getMessage(), e);
if (rec != null)
{
rec.release();
}
return null;
}
return rec;
}
/**
* Creates/updates a file with the modify date set to now
*
* @param f
*/
public static void touch(File f) throws IOException
{
if (f.createNewFile())
{
// The modify time is already set
}
else
{
boolean success = f.setLastModified(System.currentTimeMillis());
if (!success)
log.warn("[FileHelper] {touch} Failed to update modify time on " + f);
}
}
/**
* Create a directory and any necessary parent directories, throwing a {@link RuntimeException} on failure
*
* @param f
* the directory to create
*
* @throws RuntimeException
* wrapping the inner IOException if the filesystem cannot create a directory
*/
public static void mkdirs(File f)
{
try
{
Files.createDirectories(f.toPath());
}
catch (IOException e)
{
throw new RuntimeException("Could not create directory: " + e.getMessage(), e);
}
}
}
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