org.eclipse.egit.ui.internal.selection.RepositorySourceProvider.java Source code

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Here is the source code for org.eclipse.egit.ui.internal.selection.RepositorySourceProvider.java

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/*******************************************************************************
 * Copyright (C) 2016 Thomas Wolf <thomas.wolf@paranor.ch>
 *
 * 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
 *******************************************************************************/
package org.eclipse.egit.ui.internal.selection;

import java.lang.ref.WeakReference;
import java.util.Collections;
import java.util.Map;

import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.ui.AbstractSourceProvider;
import org.eclipse.ui.ISelectionListener;
import org.eclipse.ui.ISources;
import org.eclipse.ui.IWindowListener;
import org.eclipse.ui.IWorkbenchPart;
import org.eclipse.ui.IWorkbenchWindow;
import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.services.IServiceLocator;

/**
 * An {@link AbstractSourceProvider} that provides the current repository (based
 * on the current selection) as a variable in an Eclipse
 * {@link org.eclipse.core.expressions.IEvaluationContext}. To avoid interfering
 * with repository removal, which in EGit relies on {@link WeakReference}
 * semantics, the variable provides not the {@link Repository} directly but its
 * git directory as a string, which can then be used to obtain the
 * {@link Repository} instance via
 * {@link org.eclipse.egit.core.RepositoryCache#getRepository(java.io.File)}. If
 * no repository can be determined, the variable's value is the empty string.
 */
public class RepositorySourceProvider extends AbstractSourceProvider
        implements ISelectionListener, IWindowListener {

    /**
     * Key for the new variable in the
     * {@link org.eclipse.core.expressions.IEvaluationContext}; may be used in a
     * &lt;with> element in plugin.xml to reference the variable.
     */
    public static final String REPOSITORY_PROPERTY = "org.eclipse.egit.ui.currentRepository"; //$NON-NLS-1$

    /**
     * Use a weak reference here to not preclude repository removal.
     */
    private WeakReference<Repository> repositoryRef;

    @Override
    public void initialize(IServiceLocator locator) {
        super.initialize(locator);
        PlatformUI.getWorkbench().addWindowListener(this);
    }

    @Override
    public void dispose() {
        PlatformUI.getWorkbench().removeWindowListener(this);
        repositoryRef = null;
    }

    @Override
    public Map getCurrentState() {
        @SuppressWarnings("resource")
        Repository repository = repositoryRef == null ? null : repositoryRef.get();
        if (repository == null) {
            return Collections.singletonMap(REPOSITORY_PROPERTY, ""); //$NON-NLS-1$
        }
        return Collections.singletonMap(REPOSITORY_PROPERTY, repository.getDirectory().getAbsolutePath());
    }

    @Override
    public String[] getProvidedSourceNames() {
        return new String[] { REPOSITORY_PROPERTY };
    }

    @Override
    public void selectionChanged(IWorkbenchPart part, ISelection selection) {
        Repository newRepository;
        if (selection == null) {
            newRepository = null;
        } else {
            newRepository = SelectionUtils.getRepository(SelectionUtils.getStructuredSelection(selection));
        }
        @SuppressWarnings("resource")
        Repository currentRepository = repositoryRef == null ? null : repositoryRef.get();
        if (currentRepository == null && repositoryRef != null) {
            repositoryRef = null;
            if (newRepository == null) {
                // Last evaluation was non-null, but that repo has since gone.
                fireSourceChanged(ISources.ACTIVE_WORKBENCH_WINDOW, REPOSITORY_PROPERTY, ""); //$NON-NLS-1$
                return;
            }
        }
        if (currentRepository != newRepository) {
            if (newRepository != null) {
                repositoryRef = new WeakReference<>(newRepository);
                fireSourceChanged(ISources.ACTIVE_WORKBENCH_WINDOW, REPOSITORY_PROPERTY,
                        newRepository.getDirectory().getAbsolutePath());
            } else {
                repositoryRef = null;
                fireSourceChanged(ISources.ACTIVE_WORKBENCH_WINDOW, REPOSITORY_PROPERTY, ""); //$NON-NLS-1$
            }
        }
    }

    @Override
    public void windowActivated(IWorkbenchWindow window) {
        window.getSelectionService().addSelectionListener(this);
    }

    @Override
    public void windowDeactivated(IWorkbenchWindow window) {
        window.getSelectionService().removeSelectionListener(this);
    }

    @Override
    public void windowClosed(IWorkbenchWindow window) {
        // Nothing to do
    }

    @Override
    public void windowOpened(IWorkbenchWindow window) {
        // Nothing to do
    }

}