dart/editor/tools/plugins/com.google.dart.tools.ui/src/com/google/dart/tools/ui/internal/viewsupport/ProblemMarkerManager.java

/*
 * Copyright (c) 2011, the Dart project authors.
 * 
 * Licensed under the Eclipse Public License v1.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 * 
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */
package com.google.dart.tools.ui.internal.viewsupport;

import com.google.dart.tools.ui.DartToolsPlugin;
import com.google.dart.tools.ui.internal.text.editor.CompilationUnitAnnotationModelEvent;
import com.google.dart.tools.ui.internal.util.SWTUtil;

import org.eclipse.core.resources.IMarker;
import org.eclipse.core.resources.IMarkerDelta;
import org.eclipse.core.resources.IProject;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.resources.IResourceChangeEvent;
import org.eclipse.core.resources.IResourceChangeListener;
import org.eclipse.core.resources.IResourceDelta;
import org.eclipse.core.resources.IResourceDeltaVisitor;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.ListenerList;
import org.eclipse.jface.text.source.AnnotationModelEvent;
import org.eclipse.jface.text.source.IAnnotationModel;
import org.eclipse.jface.text.source.IAnnotationModelListener;
import org.eclipse.jface.text.source.IAnnotationModelListenerExtension;
import org.eclipse.swt.widgets.Display;

import java.util.HashSet;

/**
 * Listens to resource deltas and filters for marker changes of type IMarker.PROBLEM Viewers showing
 * error ticks should register as listener to this type.
 */
public class ProblemMarkerManager implements IResourceChangeListener, IAnnotationModelListener,
    IAnnotationModelListenerExtension {

  /**
   * Visitors used to look if the element change delta contains a marker change.
   */
  private static class ProjectErrorVisitor implements IResourceDeltaVisitor {

    private HashSet<IResource> fChangedElements;

    public ProjectErrorVisitor(HashSet<IResource> changedElements) {
      fChangedElements = changedElements;
    }

    @Override
    public boolean visit(IResourceDelta delta) throws CoreException {
      IResource res = delta.getResource();
      if (res instanceof IProject && delta.getKind() == IResourceDelta.CHANGED) {
        IProject project = (IProject) res;
        if (!project.isAccessible()) {
          // only track open Java projects
          return false;
        }
      }
      checkInvalidate(delta, res);
      return true;
    }

    private void checkInvalidate(IResourceDelta delta, IResource resource) {
      int kind = delta.getKind();
      if (kind == IResourceDelta.REMOVED || kind == IResourceDelta.ADDED
          || (kind == IResourceDelta.CHANGED && isErrorDelta(delta))) {
        // invalidate the resource and all parents
        while (resource.getType() != IResource.ROOT && fChangedElements.add(resource)) {
          resource = resource.getParent();
        }
      }
    }

    private boolean isErrorDelta(IResourceDelta delta) {
      if ((delta.getFlags() & IResourceDelta.MARKERS) != 0) {
        IMarkerDelta[] markerDeltas = delta.getMarkerDeltas();
        for (int i = 0; i < markerDeltas.length; i++) {
          if (markerDeltas[i].isSubtypeOf(IMarker.PROBLEM)) {
            int kind = markerDeltas[i].getKind();
            if (kind == IResourceDelta.ADDED || kind == IResourceDelta.REMOVED) {
              return true;
            }
            int severity = markerDeltas[i].getAttribute(IMarker.SEVERITY, -1);
            int newSeverity = markerDeltas[i].getMarker().getAttribute(IMarker.SEVERITY, -1);
            if (newSeverity != severity) {
              return true;
            }
          }
        }
      }
      return false;
    }
  }

  private ListenerList fListeners;

  public ProblemMarkerManager() {
    fListeners = new ListenerList();
  }

  /**
   * Adds a listener for problem marker changes.
   */
  public void addListener(IProblemChangedListener listener) {
    if (fListeners.isEmpty()) {
      DartToolsPlugin.getWorkspace().addResourceChangeListener(this);
      DartToolsPlugin.getDefault().getCompilationUnitDocumentProvider().addGlobalAnnotationModelListener(
          this);
    }
    fListeners.add(listener);
  }

  /*
   * (non-Javadoc)
   * 
   * @see IAnnotationModelListenerExtension#modelChanged(AnnotationModelEvent)
   */
  @Override
  public void modelChanged(AnnotationModelEvent event) {
    if (event instanceof CompilationUnitAnnotationModelEvent) {
      CompilationUnitAnnotationModelEvent cuEvent = (CompilationUnitAnnotationModelEvent) event;
      if (cuEvent.includesProblemMarkerAnnotationChanges()) {
        IResource[] changes = new IResource[] {cuEvent.getUnderlyingResource()};
        fireChanges(changes, false);
      }
    }
  }

  /*
   * (non-Javadoc)
   * 
   * @see IAnnotationModelListener#modelChanged(IAnnotationModel)
   */
  @Override
  public void modelChanged(IAnnotationModel model) {
    // no action
  }

  /**
   * Removes a <code>IProblemChangedListener</code>.
   */
  public void removeListener(IProblemChangedListener listener) {
    fListeners.remove(listener);
    if (fListeners.isEmpty()) {
      DartToolsPlugin.getWorkspace().removeResourceChangeListener(this);
      DartToolsPlugin.getDefault().getCompilationUnitDocumentProvider().removeGlobalAnnotationModelListener(
          this);
    }
  }

  /*
   * @see IResourceChangeListener#resourceChanged
   */
  @Override
  public void resourceChanged(IResourceChangeEvent event) {
    HashSet<IResource> changedElements = new HashSet<IResource>();

    try {
      IResourceDelta delta = event.getDelta();
      if (delta != null) {
        delta.accept(new ProjectErrorVisitor(changedElements));
      }
    } catch (CoreException e) {
      DartToolsPlugin.log(e.getStatus());
    }

    if (!changedElements.isEmpty()) {
      IResource[] changes = changedElements.toArray(new IResource[changedElements.size()]);
      fireChanges(changes, true);
    }
  }

  private void fireChanges(final IResource[] changes, final boolean isMarkerChange) {
    Display display = SWTUtil.getStandardDisplay();
    if (display != null && !display.isDisposed()) {
      display.asyncExec(new Runnable() {
        @Override
        public void run() {
          Object[] listeners = fListeners.getListeners();
          for (int i = 0; i < listeners.length; i++) {
            IProblemChangedListener curr = (IProblemChangedListener) listeners[i];
            curr.problemsChanged(changes, isMarkerChange);
          }
        }
      });
    }
  }

}