examples/org.eclipse.team.examples.filesystem/src/org/eclipse/team/examples/pessimistic/PessimisticFilesystemProvider.java - gerrit/platform/eclipse.platform.team - Git at Google

 /*******************************************************************************
  * Copyright (c) 2000, 2004 IBM Corporation 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:
  *     IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.team.examples.pessimistic;

 import java.io.*;
 import java.util.*;
 import org.eclipse.core.resources.*;
 import org.eclipse.core.runtime.*;
 import org.eclipse.jface.preference.IPreferenceStore;
 import org.eclipse.team.core.RepositoryProvider;

 /**
  * The <code>PessimisticFilesystemProvider</code> is a repository provider.
  *
  * The provider manages a file named ".pessimistic" in each container it
  * controls.  This is where it stores metadata on which files it controls
  * in that container.  This file is considered to be controlled by the
  * provider and may be deleted.
  *
  * The provider provides very simple checkin/checkout facilities by marking
  * files read-only to check them in and read-write to check them out.  It
  * also supports ignoring derived files.
  */
 public class PessimisticFilesystemProvider extends RepositoryProvider  {
 	/**
 	 * The name of the file used to store metadata on which
 	 * files are controlled by this provider.
 	 */
 	private static final String CONTROL_FILE_NAME= ".pessimistic";
 	/**
 	 * The file modification validator for this provider.
 	 */
 	private IFileModificationValidator validator;
 	/**
 	 * The cache of resources that are currently controlled.
 	 * The cache is a map of parent resource -> set of controlled children.
 	 */
 	private Map fControlledResources;

 	/**
 	 * Creates a new provider, required for team repository extension.
 	 */
 	public PessimisticFilesystemProvider() {
 		validator = new PessimisticModificationValidator(this);
 		fControlledResources= new HashMap(1);
 	}

 	/**
 	 * Adds the resources to the control of this provider.
 	 */
 	public void addToControl(final IResource[] resources, IProgressMonitor monitor) {
 		if (PessimisticFilesystemProviderPlugin.getInstance().isDebugging()) {
 			System.out.println("Add to control:");
 			if (resources != null) {
 				for (int i= 0; i < resources.length; i++) {
 					System.out.println("\t" + resources[i]);
 				}
 			} else {
 				System.out.println("null resources");
 			}
 		}
 		if (resources == null || resources.length == 0) {
 			return;
 		}
 		final Set toAdd= new HashSet(resources.length);
 		IWorkspaceRunnable runnable= new IWorkspaceRunnable() {
 			public void run(IProgressMonitor monitor) throws CoreException {
 				for (int i = 0; i < resources.length; i++) {
 					IResource resource= resources[i];
 					if (!isControlled(resource)) {
 						toAdd.add(resource);
 					}
 				}
 				Map byParent= sortByParent(toAdd);

 				monitor.beginTask("Adding to control", 1000);
 				for (Iterator i= byParent.keySet().iterator(); i.hasNext();) {
 					IContainer parent= (IContainer) i.next();
 					Set controlledResources= (Set)fControlledResources.get(parent);
 					if (controlledResources == null) {
 						controlledResources= new HashSet(1);
 						fControlledResources.put(parent, controlledResources);
 					}
 					controlledResources.addAll((Set)byParent.get(parent));
 					writeControlFile(parent, monitor);
 				}
 				monitor.done();
 			}
 		};
 		run(runnable, monitor);
 		fireStateChanged(toAdd, false);
 	}

 	/**
 	 * Removes the resources from the control of this provider.
 	 */
 	public void removeFromControl(final IResource[] resources, IProgressMonitor monitor) {
 		if (PessimisticFilesystemProviderPlugin.getInstance().isDebugging()) {
 			System.out.println("Remove from control:");
 			if (resources != null) {
 				for (int i= 0; i < resources.length; i++) {
 					System.out.println("\t" + resources[i]);
 				}
 			} else {
 				System.out.println("null resources");
 			}
 		}
 		if (resources == null || resources.length == 0) {
 			return;
 		}
 		final Set toRemove= new HashSet(resources.length);
 		IWorkspaceRunnable runnable= new IWorkspaceRunnable() {
 			public void run(IProgressMonitor monitor) throws CoreException {
 				for (int i = 0; i < resources.length; i++) {
 					IResource resource= resources[i];
 					if (isControlled(resource)) {
 						toRemove.add(resource);
 					}
 				}
 				Map byParent= sortByParent(toRemove);

 				monitor.beginTask("Removing from control", 1000);
 				for (Iterator i= byParent.keySet().iterator(); i.hasNext();) {
 					IContainer parent= (IContainer) i.next();
 					Set controlledResources= (Set)fControlledResources.get(parent);
 					if (controlledResources == null) {
 						deleteControlFile(parent, monitor);
 					} else {
 						Set toRemove= (Set)byParent.get(parent);
 						controlledResources.removeAll(toRemove);
 						if (controlledResources.isEmpty()) {
 							fControlledResources.remove(parent);
 							deleteControlFile(parent, monitor);
 						} else {
 							writeControlFile(parent, monitor);
 						}
 						for (Iterator j= controlledResources.iterator(); j.hasNext();) {
 							IResource resource= (IResource) j.next();
 							if (!resource.exists()) {
 								j.remove();
 							}
 						}
 					}
 				}
 				monitor.done();
 			}
 		};
 		run(runnable, monitor);
 		fireStateChanged(toRemove, false);
 	}

 	/*
 	 * Returns a map of IContainer -> Set of IResource.
 	 */
 	private Map sortByParent(Set resources) {
 		Map byParent= new HashMap(1);
 		for (Iterator i = resources.iterator(); i.hasNext();) {
 			IResource resource= (IResource) i.next();
 			IContainer parent= resource.getParent();
 			Set set= (Set)byParent.get(parent);
 			if (set == null) {
 				set= new HashSet(1);
 				byParent.put(parent, set);
 			}
 			set.add(resource);
 		}
 		return byParent;
 	}

 	/*
 	 * Deletes the control file for the given container.
 	 */
 	private void deleteControlFile(final IContainer container, IProgressMonitor monitor) {
 		IWorkspaceRunnable runnable= new IWorkspaceRunnable() {
 			public void run(IProgressMonitor monitor) throws CoreException {
 				IFile controlFile= getControlFile(container, monitor);
 				monitor.beginTask("Deleting control file " + controlFile, 1);
 				if (controlFile.exists()) {
 					controlFile.delete(true, false, monitor);
 				}
 				monitor.done();
 			}
 		};
 		run(runnable, monitor);
 	}

 	/*
 	 * Answers the control file for the given container.  If the control
 	 * file exists, but is a directory, it will be deleted!
 	 */
 	private IFile getControlFile(IContainer container, IProgressMonitor monitor) throws CoreException {
 		IResource child= container.findMember(CONTROL_FILE_NAME);
 		if (child != null) {
 			if (child.getType() == IResource.FILE) {
 				return (IFile)child;
 			} else {
 				child.delete(true, monitor);
 			}
 		}
 		IFile controlFile= container.getFile(new Path(CONTROL_FILE_NAME));
 		monitor.beginTask("Creating control file " + controlFile, 2);
 		controlFile.create(new ByteArrayInputStream(new byte[0]), true, monitor);
 		controlFile.setDerived(true);
 		controlFile.setTeamPrivateMember(true);
 		monitor.done();
 		return controlFile;
 	}

 	/*
 	 * Reads the contents of a control file, answering the set of
 	 * resources that was specified in the file.
 	 */
 	private Set readControlFile(IFile controlFile) {
 		Set controlledResources= new HashSet(1);
 		if (controlFile.exists()) {
 			InputStream in= null;
 			try {
 				try {
 					in= ((IFile)controlFile).getContents(true);
 				} catch (CoreException e) {
 					PessimisticFilesystemProviderPlugin.getInstance().logError(e, "Could not open stream on control file: " + controlFile);
 				}
 				DataInputStream dIn= new DataInputStream(in);
 				int count= 0;
 				try {
 					count= dIn.readInt();
 				} catch (IOException e) {
 					// could be empty
 				}
 				if (count > 0) {
 					try {
 						for(int i= 0; i < count; i++) {
 							String name= dIn.readUTF();
 							IResource resource= getProject().findMember(new Path(name));
 							if (resource != null) {
 								controlledResources.add(resource);
 							}
 						}
 					} catch (IOException e) {
 						// corrupt control file
 						try {
 							controlFile.delete(true, null);
 						} catch (CoreException ce) {
 							PessimisticFilesystemProviderPlugin.getInstance().logError(ce, "Could not delete corrupt control file: " + controlFile);
 						}
 					}
 				}
 			} finally {
 				if (in != null) {
 					try {
 						in.close();
 					} catch (IOException e) {
 						PessimisticFilesystemProviderPlugin.getInstance().logError(e, "Problems closing input stream on control file: " + controlFile);
 					}
 				}
 			}
 		}
 		return controlledResources;
 	}

 	/*
 	 * Writes the currently controled resources to the control file for the container.
 	 */
 	private void writeControlFile(IContainer container, IProgressMonitor monitor) throws CoreException {
 		IFile controlFile= getControlFile(container, monitor);
 		Set controlledResources= (Set)fControlledResources.get(container);
 		InputStream contents= generateControlFileContents(controlledResources);
 		monitor.beginTask("Writing control file " + controlFile, 1000);
 		if (contents == null) {
 			controlFile.delete(true, false, monitor);
 		} else {
 			controlFile.setContents(contents, true, false, monitor);
 		}
 		monitor.done();
 	}

 	/*
 	 * Generates an InputStream on a byte array which specifies
 	 * the resources given in controlledResources.
 	 */
 	private InputStream generateControlFileContents(Set controlledResources) {
 		if (controlledResources == null || controlledResources.isEmpty()) {
 			return null;
 		}
 		ByteArrayOutputStream byteOut= new ByteArrayOutputStream();
 		DataOutputStream out= new DataOutputStream(byteOut);
 		try {
 			out.writeInt(controlledResources.size());
 			for (Iterator i= controlledResources.iterator(); i.hasNext();) {
 				IResource resource= (IResource) i.next();
 				out.writeUTF(resource.getProjectRelativePath().toString());
 			}
 			out.flush();
 		} catch (IOException e) {
 			PessimisticFilesystemProviderPlugin.getInstance().logError(e, "Unexpected problems during content generation");
 		}
 		return new ByteArrayInputStream(byteOut.toByteArray());
 	}

 	/*
 	 * @see IProjectNature#setProject(IProject)
 	 */
 	public void setProject(IProject project) {
 		if (PessimisticFilesystemProviderPlugin.getInstance().isDebugging()) {
 			System.out.println("Set project to " + project);
 		}
 		super.setProject(project);
 		configureProject();
 	}

 	/*
 	 * @see IRepositoryProvider#getID()
 	 */
 	public String getID() {
 		return PessimisticFilesystemProviderPlugin.NATURE_ID;
 	}

 	/*
 	 * @see IRepositoryProvider#getFileModificationValidator()
 	 */
 	public IFileModificationValidator getFileModificationValidator() {
 		return validator;
 	}

 	/*
 	 * @see IRepositoryProvider#deconfigure()
 	 */
 	public void deconfigure() {
 		if (PessimisticFilesystemProviderPlugin.getInstance().isDebugging()) {
 			System.out.println("Deconfigure " + getProject());
 		}

 		fControlledResources.clear();
 		fireStateChanged(getSubtreeMembers(getProject()), true);
 	}

 	/*
 	 * @see IRepositoryProvider#configure()
 	 */
 	public void configureProject() {
 		if (PessimisticFilesystemProviderPlugin.getInstance().isDebugging()) {
 			System.out.println("Configure " + getProject());
 		}

 		readControlFiles();
 		fireStateChanged(getSubtreeMembers(getProject()), true);
 	}

 	/*
 	 * Reads the control files located in the project
 	 */
 	private void readControlFiles() {
 		IProject project= getProject();
 		Set set= new HashSet(1);
 		set.add(project);
 		fControlledResources.put(project.getParent(), set);
 		try {
 			getProject().accept(new IResourceVisitor() {
 				public boolean visit(IResource resource) throws CoreException {
 					if (resource.getType() == IResource.FILE) {
 						if (CONTROL_FILE_NAME.equals(resource.getName())) {
 							Set controlledResources= readControlFile((IFile)resource);
 							fControlledResources.put(resource.getParent(), controlledResources);
 						}
 						return false;
 					}
 					return true;
 				}
 			});
 		} catch (CoreException e) {
 			PessimisticFilesystemProviderPlugin.getInstance().logError(e, "Problems traversing resource tree");
 		}
 	}

 	/**
 	 * Checks the resources in by marking them read-only.
 	 */
 	public void checkin(final IResource[] resources, IProgressMonitor monitor) {
 		if (PessimisticFilesystemProviderPlugin.getInstance().isDebugging()) {
 			System.out.println("Check in:");
 			if (resources != null) {
 				for (int i= 0; i < resources.length; i++) {
 					System.out.println("\t" + resources[i]);
 				}
 			} else {
 				System.out.println("null resources");
 			}
 		}
 		if (resources == null || resources.length == 0) {
 			return;
 		}
 		final Set modified= new HashSet(1);
 		IWorkspaceRunnable runnable= new IWorkspaceRunnable() {
 			public void run(IProgressMonitor monitor) throws CoreException {
 				monitor.beginTask("Checking in resources", 1000);
 				for(int i= 0; i < resources.length; i++) {
 					IResource resource= resources[i];
 					if (isControlled(resource)) {
 						if (resource.exists()) {
 							resource.setReadOnly(true);
 							modified.add(resource);
 						}
 					}
 				}
 				monitor.done();
 			}
 		};
 		run(runnable, monitor);
 		fireStateChanged(modified, false);
 	}

 	/**
 	 * Unchecks the resources out.  In this provider this operation is
 	 * equivalent to checkin.
 	 *
 	 * @see PessimisticFilesystemProvider#checkin(IResource[], IProgressMonitor)
 	 */
 	public void uncheckout(final IResource[] resources, IProgressMonitor monitor) {
 		if (PessimisticFilesystemProviderPlugin.getInstance().isDebugging()) {
 			System.out.println("Uncheckout:");
 			if (resources != null) {
 				for (int i= 0; i < resources.length; i++) {
 					System.out.println("\t" + resources[i]);
 				}
 			} else {
 				System.out.println("null resources");
 			}
 		}
 		if (resources == null || resources.length == 0) {
 			return;
 		}
 		final Set modified= new HashSet(1);
 		IWorkspaceRunnable runnable= new IWorkspaceRunnable() {
 			public void run(IProgressMonitor monitor) throws CoreException {
 				monitor.beginTask("Unchecking in resources", 1000);
 				for(int i= 0; i < resources.length; i++) {
 					IResource resource= resources[i];
 					if (isControlled(resource)) {
 						if (resource.exists()) {
 							resource.setReadOnly(true);
 							modified.add(resource);
 						}
 					}
 				}
 				monitor.done();
 			}
 		};
 		run(runnable, monitor);
 		fireStateChanged(modified, false);
 	}

 	/**
 	 * Checks the resources out by marking the resources read-write.
 	 */
 	public void checkout(final IResource[] resources, IProgressMonitor monitor) {
 		if (PessimisticFilesystemProviderPlugin.getInstance().isDebugging()) {
 			System.out.println("Check out:");
 			if (resources != null) {
 				for (int i= 0; i < resources.length; i++) {
 					System.out.println("\t" + resources[i]);
 				}
 			} else {
 				System.out.println("null resources");
 			}
 		}
 		if (resources == null || resources.length == 0) {
 			return;
 		}
 		final Set modified= new HashSet(1);
 		IWorkspaceRunnable runnable= new IWorkspaceRunnable() {
 			public void run(IProgressMonitor monitor) throws CoreException {
 				monitor.beginTask("Checking out resources", 1000);
 				for(int i= 0; i < resources.length; i++) {
 					IResource resource= resources[i];
 					if (isControlled(resource)) {
 						if(resource.exists()) {
 							resource.setReadOnly(false);
 							modified.add(resource);
 						}
 					}
 				}
 				monitor.done();
 			}
 		};
 		run(runnable, monitor);
 		fireStateChanged(modified, false);
 	}

 	/**
 	 * Answers <code>true</code> if and only if the resource is
 	 * not <code>null</code>, controlled, not ignored, and checked out.
 	 * Otherwise this method answers <code>false</code>.
 	 */
 	public boolean isCheckedout(IResource resource) {
 		if (PessimisticFilesystemProviderPlugin.getInstance().isDebugging()) {
 			System.out.println("Is checked out: " + resource);
 		}
 		if (resource == null) {
 			return false;
 		}
 		if (!isControlled(resource)) {
 			return false;
 		}
 		if (isIgnored(resource)) {
 			return false;
 		}
 		return !resource.isReadOnly();
 	}

 	/**
 	 * Answers <code>true</code> if the resource is not <code>null</code>,
 	 * and is controlled, <code>false</code> otherwise.
 	 */
 	public boolean isControlled(IResource resource) {
 		if (PessimisticFilesystemProviderPlugin.getInstance().isDebugging()) {
 			System.out.println("Is controlled: " + resource);
 		}
 		if (resource == null) {
 			return false;
 		}
 		IProject project= getProject();
 		if (!project.equals(resource.getProject())) {
 			return false;
 		}
 		Set controlled= (Set)fControlledResources.get(resource.getParent());
 		if (controlled == null) {
 			return false;
 		}
 		return controlled.contains(resource);
 	}

 	/**
 	 * Answers <code>true</code> if the resource is ignored.
 	 * Resources are ignored if they are derived.
 	 * Will return <code>false</code> when a resource is derived, but
 	 * has explicitly been added to the control of this provider.
 	 */
 	public boolean isIgnored (IResource resource) {
 		if (PessimisticFilesystemProviderPlugin.getInstance().isDebugging()) {
 			System.out.println("Is ignored: " + resource);
 		}
 		if (resource.isDerived()) {
 			if (isControlled(resource)) {
 				return false;
 			}
 			return true;
 		}
 		return false;
 	}

 	/**
 	 * Answers <code>true</code> if the preference to change the content
 	 * of the file has been set to <code>true</code>, <code>false</code>
 	 * otherwise.
 	 */
 	public boolean hasContentChanged(IResource resource) {
 		if (PessimisticFilesystemProviderPlugin.getInstance().isDebugging()) {
 			System.out.println("Has content change: " + resource);
 		}

 		IPreferenceStore preferences= PessimisticFilesystemProviderPlugin.getInstance().getPreferenceStore();
 		boolean change= preferences.getBoolean(IPessimisticFilesystemConstants.PREF_TOUCH_DURING_VALIDATE_EDIT);
 		if (change) {
 			try {
 				if(resource.getType() == IResource.FILE) {
 					try {
 						appendText((IFile)resource, getRandomSnippet(), false);
 					} catch (IOException e1) {
 					}
 				} else {
 					resource.touch(null);
 				}
 			} catch (CoreException e) {
 				PessimisticFilesystemProviderPlugin.getInstance().logError(e, "Problems touching resource: " + resource);
 			}
 		}
 		return change;
 	}

 	public void appendText(IFile file, String text, boolean prepend) throws CoreException, IOException {
 		String contents = getFileContents(file);
 		StringBuffer buffer = new StringBuffer();
 		if (prepend) {
 			buffer.append(text);
 		}
 		buffer.append(contents);
 		if (!prepend) {
 			buffer.append(System.getProperty("line.separator") + text);
 		}
 		file.setContents(new ByteArrayInputStream(buffer.toString().getBytes()), false, false, null);
 	}

 	public static String getFileContents(IFile file) throws IOException, CoreException {
 		StringBuffer buf = new StringBuffer();
 		Reader reader = new InputStreamReader(new BufferedInputStream(file.getContents()));
 		try {
 			int c;
 			while ((c = reader.read()) != -1) buf.append((char)c);
 		} finally {
 			reader.close();
 		}
 		return buf.toString();
 	}

 	public static String getRandomSnippet() {
 		switch ((int) Math.round(Math.random() * 10)) {
 			case 0 :
 				return "este e' o meu conteudo (portuguese)";
 			case 1 :
 				return "Dann brauchen wir aber auch einen deutschen Satz!";
 			case 2 :
 				return "I'll be back";
 			case 3 :
 				return "don't worry, be happy";
 			case 4 :
 				return "there is no imagination for more sentences";
 			case 5 :
 				return "customize yours";
 			case 6 :
 				return "foo";
 			case 7 :
 				return "bar";
 			case 8 :
 				return "foobar";
 			case 9 :
 				return "case 9";
 			default :
 				return "these are my contents";
 		}
 	}

 	/*
 	 * Notifies listeners that the state of the resources has changed.
 	 *
 	 * @param resources	A collection of resources whose state has changed.
 	 * @param queueAfterWorkspaceOperation	If <code>true</code>, indicates that the
 	 * 						notification should occur after the current workspace runnable
 	 * 						has completed.
 	 */
 	private void fireStateChanged(final Collection resources, boolean queueAfterWorkspaceOperation) {
 		if (resources == null || resources.isEmpty()) {
 			return;
 		}

 		if (queueAfterWorkspaceOperation) {
 			Thread t= new Thread(new Runnable() {
 				public void run() {
 					try {
 						ResourcesPlugin.getWorkspace().run(
 							new IWorkspaceRunnable() {
 								public void run(IProgressMonitor monitor) throws CoreException {
 								}
 							},
 							null);
 					} catch (CoreException e) {
 						PessimisticFilesystemProviderPlugin.getInstance().logError(e, "Problem during empty runnable");
 					}
 					fireStateChanged(resources, false);
 				}
 			});
 			t.start();
 		} else {
 			PessimisticFilesystemProviderPlugin.getInstance().fireResourcesChanged(
 				(IResource[])resources.toArray(new IResource[resources.size()]));
 		}
 	}

 	/*
 	 * Answers a collection of all of the resources contained below
 	 * the given resource and the resource itself.
 	 */
 	private Collection getSubtreeMembers(IResource resource) {
 		final Set resources= new HashSet(1);
 		IResourceVisitor visitor= new IResourceVisitor() {
 			public boolean visit(IResource resource) throws CoreException {
 				switch (resource.getType()) {
 					case IResource.PROJECT:
 					case IResource.FOLDER:
 					case IResource.FILE:
 						resources.add(resource);
 						return true;
 				}
 				return true;
 			}
 		};
 		try {
 			resource.accept(visitor);
 		} catch (CoreException e) {
 			PessimisticFilesystemProviderPlugin.getInstance().logError(e, "Problem during resource visiting");
 		}
 		return resources;
 	}

 	/*
 	 * Runs a workspace operation reporting errors to the PessimisticFilesystemProviderPlugin.
 	 */
 	private void run(IWorkspaceRunnable runnable, IProgressMonitor monitor) {
 		try {
 			ResourcesPlugin.getWorkspace().run(runnable, monitor);
 		} catch (CoreException e) {
 			PessimisticFilesystemProviderPlugin.getInstance().logError(e, "Problems during workspace operation.");
 		}
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2000, 2004 IBM Corporation 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:
	* IBM Corporation - initial API and implementation
	*******************************************************************************/
	package org.eclipse.team.examples.pessimistic;

	import java.io.*;
	import java.util.*;
	import org.eclipse.core.resources.*;
	import org.eclipse.core.runtime.*;
	import org.eclipse.jface.preference.IPreferenceStore;
	import org.eclipse.team.core.RepositoryProvider;

	/**
	* The <code>PessimisticFilesystemProvider</code> is a repository provider.
	*
	* The provider manages a file named ".pessimistic" in each container it
	* controls. This is where it stores metadata on which files it controls
	* in that container. This file is considered to be controlled by the
	* provider and may be deleted.
	*
	* The provider provides very simple checkin/checkout facilities by marking
	* files read-only to check them in and read-write to check them out. It
	* also supports ignoring derived files.
	*/
	public class PessimisticFilesystemProvider extends RepositoryProvider {
	/**
	* The name of the file used to store metadata on which
	* files are controlled by this provider.
	*/
	private static final String CONTROL_FILE_NAME= ".pessimistic";
	/**
	* The file modification validator for this provider.
	*/
	private IFileModificationValidator validator;
	/**
	* The cache of resources that are currently controlled.
	* The cache is a map of parent resource -> set of controlled children.
	*/
	private Map fControlledResources;

	/**
	* Creates a new provider, required for team repository extension.
	*/
	public PessimisticFilesystemProvider() {
	validator = new PessimisticModificationValidator(this);
	fControlledResources= new HashMap(1);
	}

	/**
	* Adds the resources to the control of this provider.
	*/
	public void addToControl(final IResource[] resources, IProgressMonitor monitor) {
	if (PessimisticFilesystemProviderPlugin.getInstance().isDebugging()) {
	System.out.println("Add to control:");
	if (resources != null) {
	for (int i= 0; i < resources.length; i++) {
	System.out.println("\t" + resources[i]);
	}
	} else {
	System.out.println("null resources");
	}
	}
	if (resources == null \|\| resources.length == 0) {
	return;
	}
	final Set toAdd= new HashSet(resources.length);
	IWorkspaceRunnable runnable= new IWorkspaceRunnable() {
	public void run(IProgressMonitor monitor) throws CoreException {
	for (int i = 0; i < resources.length; i++) {
	IResource resource= resources[i];
	if (!isControlled(resource)) {
	toAdd.add(resource);
	}
	}
	Map byParent= sortByParent(toAdd);

	monitor.beginTask("Adding to control", 1000);
	for (Iterator i= byParent.keySet().iterator(); i.hasNext();) {
	IContainer parent= (IContainer) i.next();
	Set controlledResources= (Set)fControlledResources.get(parent);
	if (controlledResources == null) {
	controlledResources= new HashSet(1);
	fControlledResources.put(parent, controlledResources);
	}
	controlledResources.addAll((Set)byParent.get(parent));
	writeControlFile(parent, monitor);
	}
	monitor.done();
	}
	};
	run(runnable, monitor);
	fireStateChanged(toAdd, false);
	}

	/**
	* Removes the resources from the control of this provider.
	*/
	public void removeFromControl(final IResource[] resources, IProgressMonitor monitor) {
	if (PessimisticFilesystemProviderPlugin.getInstance().isDebugging()) {
	System.out.println("Remove from control:");
	if (resources != null) {
	for (int i= 0; i < resources.length; i++) {
	System.out.println("\t" + resources[i]);
	}
	} else {
	System.out.println("null resources");
	}
	}
	if (resources == null \|\| resources.length == 0) {
	return;
	}
	final Set toRemove= new HashSet(resources.length);
	IWorkspaceRunnable runnable= new IWorkspaceRunnable() {
	public void run(IProgressMonitor monitor) throws CoreException {
	for (int i = 0; i < resources.length; i++) {
	IResource resource= resources[i];
	if (isControlled(resource)) {
	toRemove.add(resource);
	}
	}
	Map byParent= sortByParent(toRemove);

	monitor.beginTask("Removing from control", 1000);
	for (Iterator i= byParent.keySet().iterator(); i.hasNext();) {
	IContainer parent= (IContainer) i.next();
	Set controlledResources= (Set)fControlledResources.get(parent);
	if (controlledResources == null) {
	deleteControlFile(parent, monitor);
	} else {
	Set toRemove= (Set)byParent.get(parent);
	controlledResources.removeAll(toRemove);
	if (controlledResources.isEmpty()) {
	fControlledResources.remove(parent);
	deleteControlFile(parent, monitor);
	} else {
	writeControlFile(parent, monitor);
	}
	for (Iterator j= controlledResources.iterator(); j.hasNext();) {
	IResource resource= (IResource) j.next();
	if (!resource.exists()) {
	j.remove();
	}
	}
	}
	}
	monitor.done();
	}
	};
	run(runnable, monitor);
	fireStateChanged(toRemove, false);
	}

	/*
	* Returns a map of IContainer -> Set of IResource.
	*/
	private Map sortByParent(Set resources) {
	Map byParent= new HashMap(1);
	for (Iterator i = resources.iterator(); i.hasNext();) {
	IResource resource= (IResource) i.next();
	IContainer parent= resource.getParent();
	Set set= (Set)byParent.get(parent);
	if (set == null) {
	set= new HashSet(1);
	byParent.put(parent, set);
	}
	set.add(resource);
	}
	return byParent;
	}

	/*
	* Deletes the control file for the given container.
	*/
	private void deleteControlFile(final IContainer container, IProgressMonitor monitor) {
	IWorkspaceRunnable runnable= new IWorkspaceRunnable() {
	public void run(IProgressMonitor monitor) throws CoreException {
	IFile controlFile= getControlFile(container, monitor);
	monitor.beginTask("Deleting control file " + controlFile, 1);
	if (controlFile.exists()) {
	controlFile.delete(true, false, monitor);
	}
	monitor.done();
	}
	};
	run(runnable, monitor);
	}

	/*
	* Answers the control file for the given container. If the control
	* file exists, but is a directory, it will be deleted!
	*/
	private IFile getControlFile(IContainer container, IProgressMonitor monitor) throws CoreException {
	IResource child= container.findMember(CONTROL_FILE_NAME);
	if (child != null) {
	if (child.getType() == IResource.FILE) {
	return (IFile)child;
	} else {
	child.delete(true, monitor);
	}
	}
	IFile controlFile= container.getFile(new Path(CONTROL_FILE_NAME));
	monitor.beginTask("Creating control file " + controlFile, 2);
	controlFile.create(new ByteArrayInputStream(new byte[0]), true, monitor);
	controlFile.setDerived(true);
	controlFile.setTeamPrivateMember(true);
	monitor.done();
	return controlFile;
	}

	/*
	* Reads the contents of a control file, answering the set of
	* resources that was specified in the file.
	*/
	private Set readControlFile(IFile controlFile) {
	Set controlledResources= new HashSet(1);
	if (controlFile.exists()) {
	InputStream in= null;
	try {
	try {
	in= ((IFile)controlFile).getContents(true);
	} catch (CoreException e) {
	PessimisticFilesystemProviderPlugin.getInstance().logError(e, "Could not open stream on control file: " + controlFile);
	}
	DataInputStream dIn= new DataInputStream(in);
	int count= 0;
	try {
	count= dIn.readInt();
	} catch (IOException e) {
	// could be empty
	}
	if (count > 0) {
	try {
	for(int i= 0; i < count; i++) {
	String name= dIn.readUTF();
	IResource resource= getProject().findMember(new Path(name));
	if (resource != null) {
	controlledResources.add(resource);
	}
	}
	} catch (IOException e) {
	// corrupt control file
	try {
	controlFile.delete(true, null);
	} catch (CoreException ce) {
	PessimisticFilesystemProviderPlugin.getInstance().logError(ce, "Could not delete corrupt control file: " + controlFile);
	}
	}
	}
	} finally {
	if (in != null) {
	try {
	in.close();
	} catch (IOException e) {
	PessimisticFilesystemProviderPlugin.getInstance().logError(e, "Problems closing input stream on control file: " + controlFile);
	}
	}
	}
	}
	return controlledResources;
	}

	/*
	* Writes the currently controled resources to the control file for the container.
	*/
	private void writeControlFile(IContainer container, IProgressMonitor monitor) throws CoreException {
	IFile controlFile= getControlFile(container, monitor);
	Set controlledResources= (Set)fControlledResources.get(container);
	InputStream contents= generateControlFileContents(controlledResources);
	monitor.beginTask("Writing control file " + controlFile, 1000);
	if (contents == null) {
	controlFile.delete(true, false, monitor);
	} else {
	controlFile.setContents(contents, true, false, monitor);
	}
	monitor.done();
	}

	/*
	* Generates an InputStream on a byte array which specifies
	* the resources given in controlledResources.
	*/
	private InputStream generateControlFileContents(Set controlledResources) {
	if (controlledResources == null \|\| controlledResources.isEmpty()) {
	return null;
	}
	ByteArrayOutputStream byteOut= new ByteArrayOutputStream();
	DataOutputStream out= new DataOutputStream(byteOut);
	try {
	out.writeInt(controlledResources.size());
	for (Iterator i= controlledResources.iterator(); i.hasNext();) {
	IResource resource= (IResource) i.next();
	out.writeUTF(resource.getProjectRelativePath().toString());
	}
	out.flush();
	} catch (IOException e) {
	PessimisticFilesystemProviderPlugin.getInstance().logError(e, "Unexpected problems during content generation");
	}
	return new ByteArrayInputStream(byteOut.toByteArray());
	}

	/*
	* @see IProjectNature#setProject(IProject)
	*/
	public void setProject(IProject project) {
	if (PessimisticFilesystemProviderPlugin.getInstance().isDebugging()) {
	System.out.println("Set project to " + project);
	}
	super.setProject(project);
	configureProject();
	}

	/*
	* @see IRepositoryProvider#getID()
	*/
	public String getID() {
	return PessimisticFilesystemProviderPlugin.NATURE_ID;
	}

	/*
	* @see IRepositoryProvider#getFileModificationValidator()
	*/
	public IFileModificationValidator getFileModificationValidator() {
	return validator;
	}

	/*
	* @see IRepositoryProvider#deconfigure()
	*/
	public void deconfigure() {
	if (PessimisticFilesystemProviderPlugin.getInstance().isDebugging()) {
	System.out.println("Deconfigure " + getProject());
	}

	fControlledResources.clear();
	fireStateChanged(getSubtreeMembers(getProject()), true);
	}

	/*
	* @see IRepositoryProvider#configure()
	*/
	public void configureProject() {
	if (PessimisticFilesystemProviderPlugin.getInstance().isDebugging()) {
	System.out.println("Configure " + getProject());
	}

	readControlFiles();
	fireStateChanged(getSubtreeMembers(getProject()), true);
	}

	/*
	* Reads the control files located in the project
	*/
	private void readControlFiles() {
	IProject project= getProject();
	Set set= new HashSet(1);
	set.add(project);
	fControlledResources.put(project.getParent(), set);
	try {
	getProject().accept(new IResourceVisitor() {
	public boolean visit(IResource resource) throws CoreException {
	if (resource.getType() == IResource.FILE) {
	if (CONTROL_FILE_NAME.equals(resource.getName())) {
	Set controlledResources= readControlFile((IFile)resource);
	fControlledResources.put(resource.getParent(), controlledResources);
	}
	return false;
	}
	return true;
	}
	});
	} catch (CoreException e) {
	PessimisticFilesystemProviderPlugin.getInstance().logError(e, "Problems traversing resource tree");
	}
	}

	/**
	* Checks the resources in by marking them read-only.
	*/
	public void checkin(final IResource[] resources, IProgressMonitor monitor) {
	if (PessimisticFilesystemProviderPlugin.getInstance().isDebugging()) {
	System.out.println("Check in:");
	if (resources != null) {
	for (int i= 0; i < resources.length; i++) {
	System.out.println("\t" + resources[i]);
	}
	} else {
	System.out.println("null resources");
	}
	}
	if (resources == null \|\| resources.length == 0) {
	return;
	}
	final Set modified= new HashSet(1);
	IWorkspaceRunnable runnable= new IWorkspaceRunnable() {
	public void run(IProgressMonitor monitor) throws CoreException {
	monitor.beginTask("Checking in resources", 1000);
	for(int i= 0; i < resources.length; i++) {
	IResource resource= resources[i];
	if (isControlled(resource)) {
	if (resource.exists()) {
	resource.setReadOnly(true);
	modified.add(resource);
	}
	}
	}
	monitor.done();
	}
	};
	run(runnable, monitor);
	fireStateChanged(modified, false);
	}

	/**
	* Unchecks the resources out. In this provider this operation is
	* equivalent to checkin.
	*
	* @see PessimisticFilesystemProvider#checkin(IResource[], IProgressMonitor)
	*/
	public void uncheckout(final IResource[] resources, IProgressMonitor monitor) {
	if (PessimisticFilesystemProviderPlugin.getInstance().isDebugging()) {
	System.out.println("Uncheckout:");
	if (resources != null) {
	for (int i= 0; i < resources.length; i++) {
	System.out.println("\t" + resources[i]);
	}
	} else {
	System.out.println("null resources");
	}
	}
	if (resources == null \|\| resources.length == 0) {
	return;
	}
	final Set modified= new HashSet(1);
	IWorkspaceRunnable runnable= new IWorkspaceRunnable() {
	public void run(IProgressMonitor monitor) throws CoreException {
	monitor.beginTask("Unchecking in resources", 1000);
	for(int i= 0; i < resources.length; i++) {
	IResource resource= resources[i];
	if (isControlled(resource)) {
	if (resource.exists()) {
	resource.setReadOnly(true);
	modified.add(resource);
	}
	}
	}
	monitor.done();
	}
	};
	run(runnable, monitor);
	fireStateChanged(modified, false);
	}

	/**
	* Checks the resources out by marking the resources read-write.
	*/
	public void checkout(final IResource[] resources, IProgressMonitor monitor) {
	if (PessimisticFilesystemProviderPlugin.getInstance().isDebugging()) {
	System.out.println("Check out:");
	if (resources != null) {
	for (int i= 0; i < resources.length; i++) {
	System.out.println("\t" + resources[i]);
	}
	} else {
	System.out.println("null resources");
	}
	}
	if (resources == null \|\| resources.length == 0) {
	return;
	}
	final Set modified= new HashSet(1);
	IWorkspaceRunnable runnable= new IWorkspaceRunnable() {
	public void run(IProgressMonitor monitor) throws CoreException {
	monitor.beginTask("Checking out resources", 1000);
	for(int i= 0; i < resources.length; i++) {
	IResource resource= resources[i];
	if (isControlled(resource)) {
	if(resource.exists()) {
	resource.setReadOnly(false);
	modified.add(resource);
	}
	}
	}
	monitor.done();
	}
	};
	run(runnable, monitor);
	fireStateChanged(modified, false);
	}

	/**
	* Answers <code>true</code> if and only if the resource is
	* not <code>null</code>, controlled, not ignored, and checked out.
	* Otherwise this method answers <code>false</code>.
	*/
	public boolean isCheckedout(IResource resource) {
	if (PessimisticFilesystemProviderPlugin.getInstance().isDebugging()) {
	System.out.println("Is checked out: " + resource);
	}
	if (resource == null) {
	return false;
	}
	if (!isControlled(resource)) {
	return false;
	}
	if (isIgnored(resource)) {
	return false;
	}
	return !resource.isReadOnly();
	}

	/**
	* Answers <code>true</code> if the resource is not <code>null</code>,
	* and is controlled, <code>false</code> otherwise.
	*/
	public boolean isControlled(IResource resource) {
	if (PessimisticFilesystemProviderPlugin.getInstance().isDebugging()) {
	System.out.println("Is controlled: " + resource);
	}
	if (resource == null) {
	return false;
	}
	IProject project= getProject();
	if (!project.equals(resource.getProject())) {
	return false;
	}
	Set controlled= (Set)fControlledResources.get(resource.getParent());
	if (controlled == null) {
	return false;
	}
	return controlled.contains(resource);
	}

	/**
	* Answers <code>true</code> if the resource is ignored.
	* Resources are ignored if they are derived.
	* Will return <code>false</code> when a resource is derived, but
	* has explicitly been added to the control of this provider.
	*/
	public boolean isIgnored (IResource resource) {
	if (PessimisticFilesystemProviderPlugin.getInstance().isDebugging()) {
	System.out.println("Is ignored: " + resource);
	}
	if (resource.isDerived()) {
	if (isControlled(resource)) {
	return false;
	}
	return true;
	}
	return false;
	}

	/**
	* Answers <code>true</code> if the preference to change the content
	* of the file has been set to <code>true</code>, <code>false</code>
	* otherwise.
	*/
	public boolean hasContentChanged(IResource resource) {
	if (PessimisticFilesystemProviderPlugin.getInstance().isDebugging()) {
	System.out.println("Has content change: " + resource);
	}

	IPreferenceStore preferences= PessimisticFilesystemProviderPlugin.getInstance().getPreferenceStore();
	boolean change= preferences.getBoolean(IPessimisticFilesystemConstants.PREF_TOUCH_DURING_VALIDATE_EDIT);
	if (change) {
	try {
	if(resource.getType() == IResource.FILE) {
	try {
	appendText((IFile)resource, getRandomSnippet(), false);
	} catch (IOException e1) {
	}
	} else {
	resource.touch(null);
	}
	} catch (CoreException e) {
	PessimisticFilesystemProviderPlugin.getInstance().logError(e, "Problems touching resource: " + resource);
	}
	}
	return change;
	}

	public void appendText(IFile file, String text, boolean prepend) throws CoreException, IOException {
	String contents = getFileContents(file);
	StringBuffer buffer = new StringBuffer();
	if (prepend) {
	buffer.append(text);
	}
	buffer.append(contents);
	if (!prepend) {
	buffer.append(System.getProperty("line.separator") + text);
	}
	file.setContents(new ByteArrayInputStream(buffer.toString().getBytes()), false, false, null);
	}

	public static String getFileContents(IFile file) throws IOException, CoreException {
	StringBuffer buf = new StringBuffer();
	Reader reader = new InputStreamReader(new BufferedInputStream(file.getContents()));
	try {
	int c;
	while ((c = reader.read()) != -1) buf.append((char)c);
	} finally {
	reader.close();
	}
	return buf.toString();
	}

	public static String getRandomSnippet() {
	switch ((int) Math.round(Math.random() * 10)) {
	case 0 :
	return "este e' o meu conteudo (portuguese)";
	case 1 :
	return "Dann brauchen wir aber auch einen deutschen Satz!";
	case 2 :
	return "I'll be back";
	case 3 :
	return "don't worry, be happy";
	case 4 :
	return "there is no imagination for more sentences";
	case 5 :
	return "customize yours";
	case 6 :
	return "foo";
	case 7 :
	return "bar";
	case 8 :
	return "foobar";
	case 9 :
	return "case 9";
	default :
	return "these are my contents";
	}
	}

	/*
	* Notifies listeners that the state of the resources has changed.
	*
	* @param resources A collection of resources whose state has changed.
	* @param queueAfterWorkspaceOperation If <code>true</code>, indicates that the
	* notification should occur after the current workspace runnable
	* has completed.
	*/
	private void fireStateChanged(final Collection resources, boolean queueAfterWorkspaceOperation) {
	if (resources == null \|\| resources.isEmpty()) {
	return;
	}

	if (queueAfterWorkspaceOperation) {
	Thread t= new Thread(new Runnable() {
	public void run() {
	try {
	ResourcesPlugin.getWorkspace().run(
	new IWorkspaceRunnable() {
	public void run(IProgressMonitor monitor) throws CoreException {
	}
	},
	null);
	} catch (CoreException e) {
	PessimisticFilesystemProviderPlugin.getInstance().logError(e, "Problem during empty runnable");
	}
	fireStateChanged(resources, false);
	}
	});
	t.start();
	} else {
	PessimisticFilesystemProviderPlugin.getInstance().fireResourcesChanged(
	(IResource[])resources.toArray(new IResource[resources.size()]));
	}
	}

	/*
	* Answers a collection of all of the resources contained below
	* the given resource and the resource itself.
	*/
	private Collection getSubtreeMembers(IResource resource) {
	final Set resources= new HashSet(1);
	IResourceVisitor visitor= new IResourceVisitor() {
	public boolean visit(IResource resource) throws CoreException {
	switch (resource.getType()) {
	case IResource.PROJECT:
	case IResource.FOLDER:
	case IResource.FILE:
	resources.add(resource);
	return true;
	}
	return true;
	}
	};
	try {
	resource.accept(visitor);
	} catch (CoreException e) {
	PessimisticFilesystemProviderPlugin.getInstance().logError(e, "Problem during resource visiting");
	}
	return resources;
	}

	/*
	* Runs a workspace operation reporting errors to the PessimisticFilesystemProviderPlugin.
	*/
	private void run(IWorkspaceRunnable runnable, IProgressMonitor monitor) {
	try {
	ResourcesPlugin.getWorkspace().run(runnable, monitor);
	} catch (CoreException e) {
	PessimisticFilesystemProviderPlugin.getInstance().logError(e, "Problems during workspace operation.");
	}
	}
	}