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//
// ========================================================================
// Copyright (c) 1995-2022 Mort Bay Consulting Pty Ltd and others.
// ------------------------------------------------------------------------
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// and Apache License v2.0 which accompanies this distribution.
//
// The Eclipse Public License is available at
// http://www.eclipse.org/legal/epl-v10.html
//
// The Apache License v2.0 is available at
// http://www.opensource.org/licenses/apache2.0.php
//
// You may elect to redistribute this code under either of these licenses.
// ========================================================================
//
package org.eclipse.jetty.util;
import java.io.File;
import java.io.FilenameFilter;
import java.io.IOException;
import java.nio.file.FileVisitOption;
import java.nio.file.FileVisitResult;
import java.nio.file.FileVisitor;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.PathMatcher;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.ArrayList;
import java.util.Collections;
import java.util.EnumSet;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.Timer;
import java.util.TimerTask;
import java.util.function.Predicate;
import org.eclipse.jetty.util.component.AbstractLifeCycle;
import org.eclipse.jetty.util.log.Log;
import org.eclipse.jetty.util.log.Logger;
/**
* Scanner
*
* Utility for scanning a directory for added, removed and changed
* files and reporting these events via registered Listeners.
*/
public class Scanner extends AbstractLifeCycle
{
/**
* When walking a directory, a depth of 1 ensures that
* the directory's descendants are visited, not just the
* directory itself (as a file).
*
* @see Visitor#preVisitDirectory
*/
public static final int DEFAULT_SCAN_DEPTH = 1;
public static final int MAX_SCAN_DEPTH = Integer.MAX_VALUE;
private static final Logger LOG = Log.getLogger(Scanner.class);
private static int __scannerId = 0;
private int _scanInterval;
private int _scanCount = 0;
private final List _listeners = new ArrayList<>();
private final Map _prevScan = new HashMap<>();
private final Map _currentScan = new HashMap<>();
private FilenameFilter _filter;
private final Map> _scannables = new HashMap<>();
private volatile boolean _running = false;
private boolean _reportExisting = true;
private boolean _reportDirs = true;
private Timer _timer;
private TimerTask _task;
private int _scanDepth = DEFAULT_SCAN_DEPTH;
public enum Notification
{
ADDED, CHANGED, REMOVED
}
private final Map _notifications = new HashMap<>();
/**
* PathMatcherSet
*
* A set of PathMatchers for testing Paths against path matching patterns via
* @see IncludeExcludeSet
*/
static class PathMatcherSet extends HashSet implements Predicate
{
@Override
public boolean test(Path p)
{
for (PathMatcher pm : this)
{
if (pm.matches(p))
return true;
}
return false;
}
}
/**
* TimeNSize
*
* Metadata about a file: Last modified time and file size.
*/
static class TimeNSize
{
final long _lastModified;
final long _size;
public TimeNSize(long lastModified, long size)
{
_lastModified = lastModified;
_size = size;
}
@Override
public int hashCode()
{
return (int)_lastModified ^ (int)_size;
}
@Override
public boolean equals(Object o)
{
if (o instanceof TimeNSize)
{
TimeNSize tns = (TimeNSize)o;
return tns._lastModified == _lastModified && tns._size == _size;
}
return false;
}
@Override
public String toString()
{
return "[lm=" + _lastModified + ",s=" + _size + "]";
}
}
/**
* Visitor
*
* A FileVisitor for walking a subtree of paths. The Scanner uses
* this to examine the dirs and files it has been asked to scan.
*/
class Visitor implements FileVisitor
{
Map scanInfoMap;
IncludeExcludeSet rootIncludesExcludes;
Path root;
public Visitor(Path root, IncludeExcludeSet rootIncludesExcludes, Map scanInfoMap)
{
this.root = root;
this.rootIncludesExcludes = rootIncludesExcludes;
this.scanInfoMap = scanInfoMap;
}
@Override
public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs) throws IOException
{
if (!Files.exists(dir))
return FileVisitResult.SKIP_SUBTREE;
File f = dir.toFile();
//if we want to report directories and we haven't already seen it
if (_reportDirs && !scanInfoMap.containsKey(f.getCanonicalPath()))
{
boolean accepted = false;
if (rootIncludesExcludes != null && !rootIncludesExcludes.isEmpty())
{
//accepted if not explicitly excluded and either is explicitly included or there are no explicit inclusions
boolean result = rootIncludesExcludes.test(dir);
if (result)
accepted = true;
}
else
{
if (_filter == null || _filter.accept(f.getParentFile(), f.getName()))
accepted = true;
}
if (accepted)
{
scanInfoMap.put(f.getCanonicalPath(), new TimeNSize(f.lastModified(), f.isDirectory() ? 0 : f.length()));
if (LOG.isDebugEnabled()) LOG.debug("scan accepted dir {} mod={}", f, f.lastModified());
}
}
return FileVisitResult.CONTINUE;
}
@Override
public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException
{
if (!Files.exists(file))
return FileVisitResult.CONTINUE;
File f = file.toFile();
boolean accepted = false;
if (f.isFile() || (f.isDirectory() && _reportDirs && !scanInfoMap.containsKey(f.getCanonicalPath())))
{
if (rootIncludesExcludes != null && !rootIncludesExcludes.isEmpty())
{
//accepted if not explicitly excluded and either is explicitly included or there are no explicit inclusions
boolean result = rootIncludesExcludes.test(file);
if (result)
accepted = true;
}
else if (_filter == null || _filter.accept(f.getParentFile(), f.getName()))
accepted = true;
}
if (accepted)
{
scanInfoMap.put(f.getCanonicalPath(), new TimeNSize(f.lastModified(), f.isDirectory() ? 0 : f.length()));
if (LOG.isDebugEnabled()) LOG.debug("scan accepted {} mod={}", f, f.lastModified());
}
return FileVisitResult.CONTINUE;
}
@Override
public FileVisitResult visitFileFailed(Path file, IOException exc) throws IOException
{
LOG.warn(exc);
return FileVisitResult.CONTINUE;
}
@Override
public FileVisitResult postVisitDirectory(Path dir, IOException exc) throws IOException
{
return FileVisitResult.CONTINUE;
}
}
/**
* Listener
*
* Marker for notifications re file changes.
*/
public interface Listener
{
}
public interface ScanListener extends Listener
{
void scan();
}
public interface DiscreteListener extends Listener
{
void fileChanged(String filename) throws Exception;
void fileAdded(String filename) throws Exception;
void fileRemoved(String filename) throws Exception;
}
public interface BulkListener extends Listener
{
void filesChanged(List filenames) throws Exception;
}
/**
* Listener that notifies when a scan has started and when it has ended.
*/
public interface ScanCycleListener extends Listener
{
void scanStarted(int cycle) throws Exception;
void scanEnded(int cycle) throws Exception;
}
/**
*
*/
public Scanner()
{
}
/**
* Get the scan interval
*
* @return interval between scans in seconds
*/
public synchronized int getScanInterval()
{
return _scanInterval;
}
/**
* Set the scan interval
*
* @param scanInterval pause between scans in seconds, or 0 for no scan after the initial scan.
*/
public synchronized void setScanInterval(int scanInterval)
{
_scanInterval = scanInterval;
schedule();
}
public void setScanDirs(List dirs)
{
_scannables.clear();
if (dirs == null)
return;
for (File f:dirs)
{
addScanDir(f);
}
}
@Deprecated
public synchronized void addScanDir(File dir)
{
if (dir == null)
return;
try
{
if (dir.isDirectory())
addDirectory(dir.toPath());
else
addFile(dir.toPath());
}
catch (Exception e)
{
LOG.warn(e);
}
}
/**
* Add a file to be scanned. The file must not be null, and must exist.
*
* @param p the Path of the file to scan.
* @throws IOException
*/
public synchronized void addFile(Path p) throws IOException
{
if (p == null)
throw new IllegalStateException("Null path");
File f = p.toFile();
if (!f.exists() || f.isDirectory())
throw new IllegalStateException("Not file or doesn't exist: " + f.getCanonicalPath());
_scannables.put(p, null);
}
/**
* Add a directory to be scanned. The directory must not be null and must exist.
*
* @param p the directory to scan.
* @return an IncludeExcludeSet to which the caller can add PathMatcher patterns to match
* @throws IOException
*/
public synchronized IncludeExcludeSet addDirectory(Path p)
throws IOException
{
if (p == null)
throw new IllegalStateException("Null path");
File f = p.toFile();
if (!f.exists() || !f.isDirectory())
throw new IllegalStateException("Not directory or doesn't exist: " + f.getCanonicalPath());
IncludeExcludeSet includesExcludes = _scannables.get(p);
if (includesExcludes == null)
{
includesExcludes = new IncludeExcludeSet<>(PathMatcherSet.class);
_scannables.put(p.toRealPath(), includesExcludes);
}
return includesExcludes;
}
@Deprecated
public List getScanDirs()
{
ArrayList files = new ArrayList<>();
for (Path p : _scannables.keySet())
files.add(p.toFile());
return Collections.unmodifiableList(files);
}
public Set getScannables()
{
return _scannables.keySet();
}
/**
* @param recursive True if scanning is recursive
* @see #setScanDepth(int)
*/
@Deprecated
public void setRecursive(boolean recursive)
{
_scanDepth = recursive ? Integer.MAX_VALUE : 1;
}
/**
* @return True if scanning is recursive
* @see #getScanDepth()
*/
@Deprecated
public boolean getRecursive()
{
return _scanDepth > 1;
}
/**
* Get the scanDepth.
*
* @return the scanDepth
*/
public int getScanDepth()
{
return _scanDepth;
}
/**
* Set the scanDepth.
*
* @param scanDepth the scanDepth to set
*/
public void setScanDepth(int scanDepth)
{
_scanDepth = scanDepth;
}
/**
* Apply a filter to files found in the scan directory.
* Only files matching the filter will be reported as added/changed/removed.
*
* @param filter the filename filter to use
*/
@Deprecated
public void setFilenameFilter(FilenameFilter filter)
{
_filter = filter;
}
/**
* Get any filter applied to files in the scan dir.
*
* @return the filename filter
*/
@Deprecated
public FilenameFilter getFilenameFilter()
{
return _filter;
}
/**
* Whether or not an initial scan will report all files as being
* added.
*
* @param reportExisting if true, all files found on initial scan will be
* reported as being added, otherwise not
*/
public void setReportExistingFilesOnStartup(boolean reportExisting)
{
_reportExisting = reportExisting;
}
public boolean getReportExistingFilesOnStartup()
{
return _reportExisting;
}
/**
* Set if found directories should be reported.
*
* @param dirs true to report directory changes as well
*/
public void setReportDirs(boolean dirs)
{
_reportDirs = dirs;
}
public boolean getReportDirs()
{
return _reportDirs;
}
/**
* Add an added/removed/changed listener
*
* @param listener the listener to add
*/
public synchronized void addListener(Listener listener)
{
if (listener == null)
return;
_listeners.add(listener);
}
/**
* Remove a registered listener
*
* @param listener the Listener to be removed
*/
public synchronized void removeListener(Listener listener)
{
if (listener == null)
return;
_listeners.remove(listener);
}
/**
* Start the scanning action.
*/
@Override
public synchronized void doStart()
{
if (_running)
return;
_running = true;
if (LOG.isDebugEnabled())
LOG.debug("Scanner start: rprtExists={}, depth={}, rprtDirs={}, interval={}, filter={}, scannables={}",
_reportExisting, _scanDepth, _reportDirs, _scanInterval, _filter, _scannables);
if (_reportExisting)
{
// if files exist at startup, report them
scan();
scan(); // scan twice so files reported as stable
}
else
{
//just register the list of existing files and only report changes
scanFiles();
_prevScan.putAll(_currentScan);
}
schedule();
}
public TimerTask newTimerTask()
{
return new TimerTask()
{
@Override
public void run()
{
scan();
}
};
}
public Timer newTimer()
{
return new Timer("Scanner-" + __scannerId++, true);
}
public void schedule()
{
if (_running)
{
if (_timer != null)
_timer.cancel();
if (_task != null)
_task.cancel();
if (getScanInterval() > 0)
{
_timer = newTimer();
_task = newTimerTask();
_timer.schedule(_task, 1010L * getScanInterval(), 1010L * getScanInterval());
}
}
}
/**
* Stop the scanning.
*/
@Override
public synchronized void doStop()
{
if (_running)
{
_running = false;
if (_timer != null)
_timer.cancel();
if (_task != null)
_task.cancel();
_task = null;
_timer = null;
}
}
/**
* Clear the list of scannables. The scanner must first
* be in the stopped state.
*/
public void reset()
{
if (!isStopped())
throw new IllegalStateException("Not stopped");
//clear the scannables
_scannables.clear();
//clear the previous scans
_currentScan.clear();
_prevScan.clear();
}
/**
* @param path tests if the path exists
* @return true if the path exists in one of the scandirs
*/
public boolean exists(String path)
{
for (Path p : _scannables.keySet())
{
if (p.resolve(path).toFile().exists())
return true;
}
return false;
}
/**
* Perform a pass of the scanner and report changes
*/
public synchronized void scan()
{
reportScanStart(++_scanCount);
scanFiles();
reportDifferences(_currentScan, _prevScan);
_prevScan.clear();
_prevScan.putAll(_currentScan);
reportScanEnd(_scanCount);
for (Listener l : _listeners)
{
try
{
if (l instanceof ScanListener)
((ScanListener)l).scan();
}
catch (Throwable e)
{
LOG.warn(e);
}
}
}
/**
* Scan all of the given paths.
*/
public synchronized void scanFiles()
{
_currentScan.clear();
for (Entry> entry : _scannables.entrySet())
{
Path p = entry.getKey();
try
{
Files.walkFileTree(p, EnumSet.allOf(FileVisitOption.class), _scanDepth, new Visitor(p, entry.getValue(), _currentScan));
}
catch (IOException e)
{
LOG.warn("Error scanning files.", e);
}
}
}
/**
* Report the adds/changes/removes to the registered listeners
*
* @param currentScan the info from the most recent pass
* @param oldScan info from the previous pass
*/
private synchronized void reportDifferences(Map currentScan, Map oldScan)
{
// scan the differences and add what was found to the map of notifications:
Set oldScanKeys = new HashSet<>(oldScan.keySet());
// Look for new and changed files
for (Map.Entry entry : currentScan.entrySet())
{
String file = entry.getKey();
if (!oldScanKeys.contains(file))
{
Notification old = _notifications.put(file, Notification.ADDED);
if (old != null)
{
switch (old)
{
case REMOVED:
case CHANGED:
_notifications.put(file, Notification.CHANGED);
}
}
}
else if (!oldScan.get(file).equals(currentScan.get(file)))
{
Notification old = _notifications.put(file, Notification.CHANGED);
if (old == Notification.ADDED)
_notifications.put(file, Notification.ADDED);
}
}
// Look for deleted files
for (String file : oldScan.keySet())
{
if (!currentScan.containsKey(file))
{
Notification old = _notifications.put(file, Notification.REMOVED);
if (old == Notification.ADDED)
_notifications.remove(file);
}
}
if (LOG.isDebugEnabled())
LOG.debug("scanned " + _scannables.keySet() + ": " + _notifications);
// Process notifications
// Only process notifications that are for stable files (ie same in old and current scan).
List bulkChanges = new ArrayList<>();
for (Iterator> iter = _notifications.entrySet().iterator(); iter.hasNext(); )
{
Entry entry = iter.next();
String file = entry.getKey();
// Is the file stable?
if (oldScan.containsKey(file))
{
if (!oldScan.get(file).equals(currentScan.get(file)))
continue;
}
else if (currentScan.containsKey(file))
continue;
// File is stable so notify
Notification notification = entry.getValue();
iter.remove();
bulkChanges.add(file);
switch (notification)
{
case ADDED:
reportAddition(file);
break;
case CHANGED:
reportChange(file);
break;
case REMOVED:
reportRemoval(file);
break;
}
}
if (!bulkChanges.isEmpty())
reportBulkChanges(bulkChanges);
}
private void warn(Object listener, String filename, Throwable th)
{
LOG.warn(listener + " failed on '" + filename, th);
}
/**
* Report a file addition to the registered FileAddedListeners
*
* @param filename the filename
*/
private void reportAddition(String filename)
{
for (Listener l : _listeners)
{
try
{
if (l instanceof DiscreteListener)
((DiscreteListener)l).fileAdded(filename);
}
catch (Throwable e)
{
warn(l, filename, e);
}
}
}
/**
* Report a file removal to the FileRemovedListeners
*
* @param filename the filename
*/
private void reportRemoval(String filename)
{
for (Object l : _listeners)
{
try
{
if (l instanceof DiscreteListener)
((DiscreteListener)l).fileRemoved(filename);
}
catch (Throwable e)
{
warn(l, filename, e);
}
}
}
/**
* Report a file change to the FileChangedListeners
*
* @param filename the filename
*/
private void reportChange(String filename)
{
for (Listener l : _listeners)
{
try
{
if (l instanceof DiscreteListener)
((DiscreteListener)l).fileChanged(filename);
}
catch (Throwable e)
{
warn(l, filename, e);
}
}
}
/**
* Report the list of filenames for which changes were detected.
*
* @param filenames names of all files added/changed/removed
*/
private void reportBulkChanges(List filenames)
{
for (Listener l : _listeners)
{
try
{
if (l instanceof BulkListener)
((BulkListener)l).filesChanged(filenames);
}
catch (Throwable e)
{
warn(l, filenames.toString(), e);
}
}
}
/**
* Call ScanCycleListeners with start of scan
*/
private void reportScanStart(int cycle)
{
for (Listener listener : _listeners)
{
try
{
if (listener instanceof ScanCycleListener)
{
((ScanCycleListener)listener).scanStarted(cycle);
}
}
catch (Exception e)
{
LOG.warn(listener + " failed on scan start for cycle " + cycle, e);
}
}
}
/**
* Call ScanCycleListeners with end of scan.
*/
private void reportScanEnd(int cycle)
{
for (Listener listener : _listeners)
{
try
{
if (listener instanceof ScanCycleListener)
{
((ScanCycleListener)listener).scanEnded(cycle);
}
}
catch (Exception e)
{
LOG.warn(listener + " failed on scan end for cycle " + cycle, e);
}
}
}
}
