/*******************************************************************************
* Copyright (c) 2000, 2010 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
* Anton Leherbauer (Wind River Systems)
*******************************************************************************/
package org.eclipse.cdt.internal.ui.viewsupport;
import java.util.HashMap;
import java.util.Map;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.ListenerList;
import org.eclipse.core.runtime.Status;
import org.eclipse.core.runtime.jobs.ILock;
import org.eclipse.core.runtime.jobs.Job;
import org.eclipse.jface.text.ISelectionValidator;
import org.eclipse.jface.text.ITextSelection;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.ISelectionChangedListener;
import org.eclipse.jface.viewers.ISelectionProvider;
import org.eclipse.jface.viewers.SelectionChangedEvent;
import org.eclipse.ui.ISelectionListener;
import org.eclipse.ui.IWorkbenchPart;
import org.eclipse.ui.texteditor.ITextEditor;
import org.eclipse.cdt.core.dom.ast.IASTTranslationUnit;
import org.eclipse.cdt.core.model.ILanguage;
import org.eclipse.cdt.core.model.IWorkingCopy;
import org.eclipse.cdt.ui.CUIPlugin;
import org.eclipse.cdt.internal.core.model.ASTCache.ASTRunnable;
import org.eclipse.cdt.internal.ui.editor.ASTProvider;
/**
* Infrastructure to share an AST for editor post selection listeners.
*/
public class SelectionListenerWithASTManager {
private static SelectionListenerWithASTManager fgDefault;
/**
* @return Returns the default manager instance.
*/
public static SelectionListenerWithASTManager getDefault() {
if (fgDefault == null) {
fgDefault= new SelectionListenerWithASTManager();
}
return fgDefault;
}
private final static class PartListenerGroup {
private ITextEditor fPart;
private ISelectionListener fPostSelectionListener;
private ISelectionChangedListener fSelectionListener;
private Job fCurrentJob;
private ListenerList fAstListeners;
/** Rule to make sure only one job is running at a time */
private final ILock fJobLock= Job.getJobManager().newLock();
private ISelectionValidator fValidator;
public PartListenerGroup(ITextEditor editorPart) {
fPart= editorPart;
fCurrentJob= null;
fAstListeners= new ListenerList(ListenerList.IDENTITY);
fSelectionListener= new ISelectionChangedListener() {
public void selectionChanged(SelectionChangedEvent event) {
ISelection selection= event.getSelection();
if (selection instanceof ITextSelection) {
fireSelectionChanged((ITextSelection) selection);
}
}
};
fPostSelectionListener= new ISelectionListener() {
public void selectionChanged(IWorkbenchPart part, ISelection selection) {
if (part == fPart && selection instanceof ITextSelection)
firePostSelectionChanged((ITextSelection) selection);
}
};
}
public boolean isEmpty() {
return fAstListeners.isEmpty();
}
public void install(ISelectionListenerWithAST listener) {
if (isEmpty()) {
fPart.getEditorSite().getPage().addPostSelectionListener(fPostSelectionListener);
ISelectionProvider selectionProvider= fPart.getSelectionProvider();
if (selectionProvider != null) {
selectionProvider.addSelectionChangedListener(fSelectionListener);
if (selectionProvider instanceof ISelectionValidator) {
fValidator= (ISelectionValidator) selectionProvider;
}
}
}
fAstListeners.add(listener);
}
public void uninstall(ISelectionListenerWithAST listener) {
fAstListeners.remove(listener);
if (isEmpty()) {
fPart.getEditorSite().getPage().removePostSelectionListener(fPostSelectionListener);
ISelectionProvider selectionProvider= fPart.getSelectionProvider();
if (selectionProvider != null) {
selectionProvider.removeSelectionChangedListener(fSelectionListener);
}
fValidator= null;
}
}
public void fireSelectionChanged(final ITextSelection selection) {
if (fCurrentJob != null) {
fCurrentJob.cancel();
}
}
public void firePostSelectionChanged(final ITextSelection selection) {
if (fCurrentJob != null) {
fCurrentJob.cancel();
}
final IWorkingCopy workingCopy = CUIPlugin.getDefault().getWorkingCopyManager().getWorkingCopy(fPart.getEditorInput());
if (workingCopy == null)
return;
fCurrentJob= new Job(Messages.SelectionListenerWithASTManager_jobName) {
@Override
public IStatus run(IProgressMonitor monitor) {
try {
// Try to acquire the lock
while (!monitor.isCanceled() && !fJobLock.acquire(10)) {}
if (!monitor.isCanceled() && isSelectionValid(selection)) {
return calculateASTandInform(workingCopy, selection, monitor);
}
} catch (InterruptedException e) {
} finally {
if (fJobLock.getDepth() != 0)
fJobLock.release();
}
return Status.OK_STATUS;
}
};
fCurrentJob.setPriority(Job.DECORATE);
fCurrentJob.setSystem(true);
fCurrentJob.schedule();
}
/**
* Verify that selection is still valid.
*
* @param selection
* @return <code>true</code> if selection is valid
*/
protected boolean isSelectionValid(ITextSelection selection) {
return fValidator == null || fValidator.isValid(selection);
}
protected IStatus calculateASTandInform(final IWorkingCopy workingCopy, final ITextSelection selection, final IProgressMonitor monitor) {
return ASTProvider.getASTProvider().runOnAST(workingCopy, ASTProvider.WAIT_ACTIVE_ONLY, monitor, new ASTRunnable() {
public IStatus runOnAST(ILanguage lang, IASTTranslationUnit astRoot) {
if (astRoot != null && !monitor.isCanceled() && isSelectionValid(selection)) {
Object[] listeners;
synchronized (PartListenerGroup.this) {
listeners= fAstListeners.getListeners();
}
for (int i= 0; i < listeners.length; i++) {
final Object l = listeners[i];
try {
((ISelectionListenerWithAST) l).selectionChanged(fPart, selection, astRoot);
} catch (RuntimeException e) {
CUIPlugin.log(e);
fAstListeners.remove(l);
} catch (OutOfMemoryError e) {
CUIPlugin.log(e);
fAstListeners.remove(l);
}
}
return Status.OK_STATUS;
}
return Status.CANCEL_STATUS;
}
});
}
}
private Map<ITextEditor, PartListenerGroup> fListenerGroups;
private SelectionListenerWithASTManager() {
fListenerGroups= new HashMap<ITextEditor, PartListenerGroup>();
}
/**
* Registers a selection listener for the given editor part.
* @param part The editor part to listen to.
* @param listener The listener to register.
*/
public void addListener(ITextEditor part, ISelectionListenerWithAST listener) {
synchronized (this) {
PartListenerGroup partListener= fListenerGroups.get(part);
if (partListener == null) {
partListener= new PartListenerGroup(part);
fListenerGroups.put(part, partListener);
}
partListener.install(listener);
}
}
/**
* Unregisters a selection listener.
* @param part The editor part the listener was registered.
* @param listener The listener to unregister.
*/
public void removeListener(ITextEditor part, ISelectionListenerWithAST listener) {
synchronized (this) {
PartListenerGroup partListener= fListenerGroups.get(part);
if (partListener != null) {
partListener.uninstall(listener);
if (partListener.isEmpty()) {
fListenerGroups.remove(part);
}
}
}
}
}