| /******************************************************************************* |
| * Copyright (c) 2011 SAP AG and others. |
| * All rights reserved. This program and the accompanying materials |
| * are made available under the terms of the Eclipse Public License v1.0 |
| * which accompanies this distribution, and is available at |
| * http://www.eclipse.org/legal/epl-v10.html |
| * |
| * Contributors: |
| * SAP AG - initial API and implementation |
| *******************************************************************************/ |
| |
| package org.eclipse.tycho.core.locking; |
| |
| import java.io.File; |
| import java.io.IOException; |
| import java.net.MalformedURLException; |
| |
| import org.eclipse.osgi.service.datalocation.Location; |
| import org.eclipse.tycho.locking.facade.FileLocker; |
| import org.eclipse.tycho.locking.facade.LockTimeoutException; |
| |
| public class FileLockerImpl implements FileLocker { |
| |
| private static final String LOCKFILE_SUFFIX = ".tycholock"; |
| |
| private final Location lockFileLocation; |
| final File lockMarkerFile; |
| |
| public FileLockerImpl(File file, Location anyLocation) { |
| try { |
| if (file.isDirectory()) { |
| this.lockMarkerFile = new File(file, LOCKFILE_SUFFIX).getCanonicalFile(); |
| } else { |
| this.lockMarkerFile = new File(file.getParentFile(), file.getName() + LOCKFILE_SUFFIX) |
| .getCanonicalFile(); |
| } |
| if (lockMarkerFile.isDirectory()) { |
| throw new RuntimeException("Lock marker file " + lockMarkerFile + " already exists and is a directory"); |
| } |
| File parentDir = lockMarkerFile.getParentFile(); |
| if (!parentDir.isDirectory() && !parentDir.mkdirs()) { |
| throw new RuntimeException("Could not create parent directory " + parentDir + " of lock marker file"); |
| } |
| this.lockFileLocation = anyLocation.createLocation(null, null, false); |
| this.lockFileLocation.set(lockMarkerFile.toURL(), false, lockMarkerFile.getAbsolutePath()); |
| } catch (MalformedURLException e) { |
| throw new RuntimeException(e); |
| } catch (IOException e) { |
| throw new RuntimeException(e); |
| } |
| } |
| |
| @Override |
| public void lock() { |
| lock(10000L); |
| } |
| |
| @Override |
| public void lock(long timeout) { |
| if (timeout < 0) { |
| throw new IllegalArgumentException("timeout must not be negative"); |
| } |
| boolean success = false; |
| final long waitInterval = 50L; |
| long maxTries = (timeout / waitInterval) + 1; |
| IOException ioException = null; |
| for (long i = 0; i < maxTries; i++) { |
| ioException = null; |
| try { |
| success = lockFileLocation.lock(); |
| } catch (IOException ioe) { |
| // keep trying (and re-throw eventually) |
| ioException = ioe; |
| } |
| if (success) { |
| return; |
| } |
| try { |
| Thread.sleep(waitInterval); |
| } catch (InterruptedException e) { |
| // ignore |
| } |
| } |
| String message = "lock timeout: Could not acquire lock on file " + lockFileLocation.getURL() + " for " |
| + timeout + " msec"; |
| if (ioException != null) { |
| throw new LockTimeoutException(message, ioException); |
| } else { |
| throw new LockTimeoutException(message); |
| } |
| } |
| |
| /* |
| * (non-Javadoc) |
| * |
| * @see org.eclipse.tycho.p2.repository.IFileLocker#release() |
| */ |
| @Override |
| public void release() { |
| lockFileLocation.release(); |
| if (lockMarkerFile.isFile() && !lockMarkerFile.delete()) { |
| // this can happen if another process already holds the lock again |
| lockMarkerFile.deleteOnExit(); |
| } |
| } |
| |
| /* |
| * (non-Javadoc) |
| * |
| * @see org.eclipse.tycho.p2.repository.IFileLocker#isLocked() |
| */ |
| @Override |
| public boolean isLocked() { |
| try { |
| return lockFileLocation.isLocked(); |
| } catch (IOException e) { |
| throw new RuntimeException(e); |
| } |
| } |
| |
| } |