bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/contexts/ContextService.java - platform/eclipse.platform.ui - Git at Google

 /*******************************************************************************
  * Copyright (c) 2005, 2015 IBM Corporation and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
  * which accompanies this distribution, and is available at
  * https://www.eclipse.org/legal/epl-2.0/
  *
  * SPDX-License-Identifier: EPL-2.0
  *
  * Contributors:
  *     IBM Corporation - initial API and implementation
  *     Lars Vogel <Lars.Vogel@vogella.com> - Bug 472654
  *******************************************************************************/
 package org.eclipse.ui.internal.contexts;

 import java.util.Collection;
 import java.util.HashMap;
 import java.util.Iterator;
 import javax.inject.Inject;
 import org.eclipse.core.commands.contexts.Context;
 import org.eclipse.core.commands.contexts.ContextManager;
 import org.eclipse.core.commands.contexts.IContextManagerListener;
 import org.eclipse.core.expressions.EvaluationResult;
 import org.eclipse.core.expressions.Expression;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.e4.core.commands.ExpressionContext;
 import org.eclipse.e4.core.contexts.IEclipseContext;
 import org.eclipse.e4.core.contexts.RunAndTrack;
 import org.eclipse.e4.ui.services.EContextService;
 import org.eclipse.swt.widgets.Shell;
 import org.eclipse.ui.ISourceProvider;
 import org.eclipse.ui.ISources;
 import org.eclipse.ui.contexts.IContextActivation;
 import org.eclipse.ui.contexts.IContextService;
 import org.eclipse.ui.internal.WorkbenchPlugin;

 /**
  * <p>
  * Provides services related to contexts in the Eclipse workbench. This provides
  * access to contexts.
  * </p>
  *
  * @since 3.1
  */
 public final class ContextService implements IContextService {

 	private HashMap<IContextActivation, UpdateExpression> activationToRat = new HashMap<>();

 	/**
 	 * The central authority for determining which context we should use.
 	 */
 	private final ContextAuthority contextAuthority;

 	/**
 	 * The context manager that supports this service. This value is never
 	 * <code>null</code>.
 	 */
 	private ContextManager contextManager;

 	@Inject
 	private EContextService contextService;

 	@Inject
 	private IEclipseContext eclipseContext;

 	/**
 	 * The persistence class for this context service.
 	 */
 	private final ContextPersistence contextPersistence;

 	/**
 	 * Constructs a new instance of <code>ContextService</code> using a context
 	 * manager.
 	 *
 	 * @param contextManager The context manager to use; must not be
 	 *                       <code>null</code>.
 	 */
 	@Inject
 	public ContextService(final ContextManager contextManager) {
 		if (contextManager == null) {
 			throw new NullPointerException("Cannot create a context service with a null manager"); //$NON-NLS-1$
 		}
 		this.contextManager = contextManager;
 		this.contextAuthority = new ContextAuthority(contextManager, this);
 		this.contextPersistence = new ContextPersistence(contextManager);
 	}

 	@Override
 	public void deferUpdates(boolean defer) {
 		contextManager.deferUpdates(defer);
 		contextService.deferUpdates(defer);
 	}

 	@Override
 	public IContextActivation activateContext(final String contextId) {
 		return activateContext(contextId, null);
 	}

 	private class UpdateExpression extends RunAndTrack {
 		boolean updating = true;

 		private String contextId;
 		private Expression expression;

 		EvaluationResult cached = null;

 		public UpdateExpression(String contextId, Expression expression) {
 			this.contextId = contextId;
 			this.expression = expression;
 		}

 		@Override
 		public boolean changed(IEclipseContext context) {
 			if (!updating) {
 				return false;
 			}
 			ExpressionContext ctx = new ExpressionContext(eclipseContext);
 			try {
 				if (updating) {
 					EvaluationResult result = expression.evaluate(ctx);
 					if (cached != null && (cached == result
 							|| (cached != EvaluationResult.FALSE && result != EvaluationResult.FALSE))) {
 						return updating;
 					}
 					if (result != EvaluationResult.FALSE) {
 						runExternalCode(() -> contextService.activateContext(contextId));
 					} else if (cached != null) {
 						runExternalCode(() -> contextService.deactivateContext(contextId));
 					}
 					cached = result;
 				}
 			} catch (CoreException e) {
 				// contextService.deactivateContext(contextId);
 				WorkbenchPlugin.log("Failed to update " + contextId, e); //$NON-NLS-1$
 			}
 			return updating;
 		}
 	}

 	@Override
 	public IContextActivation activateContext(final String contextId, final Expression expression) {

 		final IContextActivation activation = new ContextActivation(contextId, expression, this);
 		contextAuthority.activateContext(activation);
 		if (expression == null) {
 			contextService.activateContext(contextId);
 		} else {
 			final UpdateExpression runnable = new UpdateExpression(contextId, expression);
 			activationToRat.put(activation, runnable);
 			eclipseContext.runAndTrack(runnable);
 		}
 		return activation;
 	}

 	@Override
 	public IContextActivation activateContext(String contextId, Expression expression, boolean global) {
 		return activateContext(contextId, expression);
 	}

 	@Override
 	public IContextActivation activateContext(final String contextId, final Expression expression,
 			final int sourcePriority) {
 		return activateContext(contextId, expression);
 	}

 	@Override
 	public void addContextManagerListener(final IContextManagerListener listener) {
 		contextManager.addContextManagerListener(listener);
 	}

 	@Override
 	public void addSourceProvider(final ISourceProvider provider) {
 		contextAuthority.addSourceProvider(provider);
 	}

 	@Override
 	public void deactivateContext(final IContextActivation activation) {
 		if (activation != null && activation.getContextService() == this) {
 			final UpdateExpression rat = activationToRat.remove(activation);
 			if (rat != null) {
 				rat.updating = false;
 				if (rat.cached != null && rat.cached != EvaluationResult.FALSE) {
 					contextService.deactivateContext(activation.getContextId());
 				}
 			} else {
 				contextService.deactivateContext(activation.getContextId());
 			}
 			contextAuthority.deactivateContext(activation);
 		}
 	}

 	@Override
 	public void deactivateContexts(final Collection activations) {
 		try {
 			deferUpdates(true);
 			final Iterator<?> activationItr = activations.iterator();
 			while (activationItr.hasNext()) {
 				final IContextActivation activation = (IContextActivation) activationItr.next();
 				deactivateContext(activation);
 			}
 		} finally {
 			deferUpdates(false);
 		}
 	}

 	@Override
 	public void dispose() {
 		contextPersistence.dispose();
 		contextAuthority.dispose();
 	}

 	@Override
 	public Collection getActiveContextIds() {
 		return contextService.getActiveContextIds();
 	}

 	@Override
 	public Context getContext(final String contextId) {
 		return contextService.getContext(contextId);
 	}

 	@Override
 	public Collection getDefinedContextIds() {
 		return contextManager.getDefinedContextIds();
 	}

 	@Override
 	public Context[] getDefinedContexts() {
 		return contextManager.getDefinedContexts();
 	}

 	@Override
 	public int getShellType(final Shell shell) {
 		return contextAuthority.getShellType(shell);
 	}

 	@Override
 	public void readRegistry() {
 		// contextPersistence.read();
 	}

 	@Override
 	public boolean registerShell(final Shell shell, final int type) {
 		return contextAuthority.registerShell(shell, type);
 	}

 	@Override
 	public void removeContextManagerListener(final IContextManagerListener listener) {
 		contextManager.removeContextManagerListener(listener);
 	}

 	@Override
 	public void removeSourceProvider(final ISourceProvider provider) {
 		contextAuthority.removeSourceProvider(provider);
 	}

 	@Override
 	public boolean unregisterShell(final Shell shell) {
 		return contextAuthority.unregisterShell(shell);
 	}

 	/**
 	 * <p>
 	 * Bug 95792. A mechanism by which the key binding architecture can force an
 	 * update of the contexts (based on the active shell) before trying to execute a
 	 * command. This mechanism is required for GTK+ only.
 	 * </p>
 	 * <p>
 	 * DO NOT CALL THIS METHOD.
 	 * </p>
 	 */
 	public void updateShellKludge() {
 		contextAuthority.updateShellKludge();
 	}

 	/**
 	 * <p>
 	 * Bug 95792. A mechanism by which the key binding architecture can force an
 	 * update of the contexts (based on the active shell) before trying to execute a
 	 * command. This mechanism is required for GTK+ only.
 	 * </p>
 	 * <p>
 	 * DO NOT CALL THIS METHOD.
 	 * </p>
 	 *
 	 * @param shell The shell that should be considered active; must not be
 	 *              <code>null</code>.
 	 */
 	public void updateShellKludge(final Shell shell) {
 		final Shell currentActiveShell = contextAuthority.getActiveShell();
 		if (currentActiveShell != shell) {
 			contextAuthority.sourceChanged(ISources.ACTIVE_SHELL, ISources.ACTIVE_SHELL_NAME, shell);
 		}
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2005, 2015 IBM Corporation and others.
	*
	* This program and the accompanying materials
	* are made available under the terms of the Eclipse Public License 2.0
	* which accompanies this distribution, and is available at
	* https://www.eclipse.org/legal/epl-2.0/
	*
	* SPDX-License-Identifier: EPL-2.0
	*
	* Contributors:
	* IBM Corporation - initial API and implementation
	* Lars Vogel <Lars.Vogel@vogella.com> - Bug 472654
	*******************************************************************************/
	package org.eclipse.ui.internal.contexts;

	import java.util.Collection;
	import java.util.HashMap;
	import java.util.Iterator;
	import javax.inject.Inject;
	import org.eclipse.core.commands.contexts.Context;
	import org.eclipse.core.commands.contexts.ContextManager;
	import org.eclipse.core.commands.contexts.IContextManagerListener;
	import org.eclipse.core.expressions.EvaluationResult;
	import org.eclipse.core.expressions.Expression;
	import org.eclipse.core.runtime.CoreException;
	import org.eclipse.e4.core.commands.ExpressionContext;
	import org.eclipse.e4.core.contexts.IEclipseContext;
	import org.eclipse.e4.core.contexts.RunAndTrack;
	import org.eclipse.e4.ui.services.EContextService;
	import org.eclipse.swt.widgets.Shell;
	import org.eclipse.ui.ISourceProvider;
	import org.eclipse.ui.ISources;
	import org.eclipse.ui.contexts.IContextActivation;
	import org.eclipse.ui.contexts.IContextService;
	import org.eclipse.ui.internal.WorkbenchPlugin;

	/**
	* <p>
	* Provides services related to contexts in the Eclipse workbench. This provides
	* access to contexts.
	* </p>
	*
	* @since 3.1
	*/
	public final class ContextService implements IContextService {

	private HashMap<IContextActivation, UpdateExpression> activationToRat = new HashMap<>();

	/**
	* The central authority for determining which context we should use.
	*/
	private final ContextAuthority contextAuthority;

	/**
	* The context manager that supports this service. This value is never
	* <code>null</code>.
	*/
	private ContextManager contextManager;

	@Inject
	private EContextService contextService;

	@Inject
	private IEclipseContext eclipseContext;

	/**
	* The persistence class for this context service.
	*/
	private final ContextPersistence contextPersistence;

	/**
	* Constructs a new instance of <code>ContextService</code> using a context
	* manager.
	*
	* @param contextManager The context manager to use; must not be
	* <code>null</code>.
	*/
	@Inject
	public ContextService(final ContextManager contextManager) {
	if (contextManager == null) {
	throw new NullPointerException("Cannot create a context service with a null manager"); //$NON-NLS-1$
	}
	this.contextManager = contextManager;
	this.contextAuthority = new ContextAuthority(contextManager, this);
	this.contextPersistence = new ContextPersistence(contextManager);
	}

	@Override
	public void deferUpdates(boolean defer) {
	contextManager.deferUpdates(defer);
	contextService.deferUpdates(defer);
	}

	@Override
	public IContextActivation activateContext(final String contextId) {
	return activateContext(contextId, null);
	}

	private class UpdateExpression extends RunAndTrack {
	boolean updating = true;

	private String contextId;
	private Expression expression;

	EvaluationResult cached = null;

	public UpdateExpression(String contextId, Expression expression) {
	this.contextId = contextId;
	this.expression = expression;
	}

	@Override
	public boolean changed(IEclipseContext context) {
	if (!updating) {
	return false;
	}
	ExpressionContext ctx = new ExpressionContext(eclipseContext);
	try {
	if (updating) {
	EvaluationResult result = expression.evaluate(ctx);
	if (cached != null && (cached == result
	\|\| (cached != EvaluationResult.FALSE && result != EvaluationResult.FALSE))) {
	return updating;
	}
	if (result != EvaluationResult.FALSE) {
	runExternalCode(() -> contextService.activateContext(contextId));
	} else if (cached != null) {
	runExternalCode(() -> contextService.deactivateContext(contextId));
	}
	cached = result;
	}
	} catch (CoreException e) {
	// contextService.deactivateContext(contextId);
	WorkbenchPlugin.log("Failed to update " + contextId, e); //$NON-NLS-1$
	}
	return updating;
	}
	}

	@Override
	public IContextActivation activateContext(final String contextId, final Expression expression) {

	final IContextActivation activation = new ContextActivation(contextId, expression, this);
	contextAuthority.activateContext(activation);
	if (expression == null) {
	contextService.activateContext(contextId);
	} else {
	final UpdateExpression runnable = new UpdateExpression(contextId, expression);
	activationToRat.put(activation, runnable);
	eclipseContext.runAndTrack(runnable);
	}
	return activation;
	}

	@Override
	public IContextActivation activateContext(String contextId, Expression expression, boolean global) {
	return activateContext(contextId, expression);
	}

	@Override
	public IContextActivation activateContext(final String contextId, final Expression expression,
	final int sourcePriority) {
	return activateContext(contextId, expression);
	}

	@Override
	public void addContextManagerListener(final IContextManagerListener listener) {
	contextManager.addContextManagerListener(listener);
	}

	@Override
	public void addSourceProvider(final ISourceProvider provider) {
	contextAuthority.addSourceProvider(provider);
	}

	@Override
	public void deactivateContext(final IContextActivation activation) {
	if (activation != null && activation.getContextService() == this) {
	final UpdateExpression rat = activationToRat.remove(activation);
	if (rat != null) {
	rat.updating = false;
	if (rat.cached != null && rat.cached != EvaluationResult.FALSE) {
	contextService.deactivateContext(activation.getContextId());
	}
	} else {
	contextService.deactivateContext(activation.getContextId());
	}
	contextAuthority.deactivateContext(activation);
	}
	}

	@Override
	public void deactivateContexts(final Collection activations) {
	try {
	deferUpdates(true);
	final Iterator<?> activationItr = activations.iterator();
	while (activationItr.hasNext()) {
	final IContextActivation activation = (IContextActivation) activationItr.next();
	deactivateContext(activation);
	}
	} finally {
	deferUpdates(false);
	}
	}

	@Override
	public void dispose() {
	contextPersistence.dispose();
	contextAuthority.dispose();
	}

	@Override
	public Collection getActiveContextIds() {
	return contextService.getActiveContextIds();
	}

	@Override
	public Context getContext(final String contextId) {
	return contextService.getContext(contextId);
	}

	@Override
	public Collection getDefinedContextIds() {
	return contextManager.getDefinedContextIds();
	}

	@Override
	public Context[] getDefinedContexts() {
	return contextManager.getDefinedContexts();
	}

	@Override
	public int getShellType(final Shell shell) {
	return contextAuthority.getShellType(shell);
	}

	@Override
	public void readRegistry() {
	// contextPersistence.read();
	}

	@Override
	public boolean registerShell(final Shell shell, final int type) {
	return contextAuthority.registerShell(shell, type);
	}

	@Override
	public void removeContextManagerListener(final IContextManagerListener listener) {
	contextManager.removeContextManagerListener(listener);
	}

	@Override
	public void removeSourceProvider(final ISourceProvider provider) {
	contextAuthority.removeSourceProvider(provider);
	}

	@Override
	public boolean unregisterShell(final Shell shell) {
	return contextAuthority.unregisterShell(shell);
	}

	/**
	* <p>
	* Bug 95792. A mechanism by which the key binding architecture can force an
	* update of the contexts (based on the active shell) before trying to execute a
	* command. This mechanism is required for GTK+ only.
	* </p>
	* <p>
	* DO NOT CALL THIS METHOD.
	* </p>
	*/
	public void updateShellKludge() {
	contextAuthority.updateShellKludge();
	}

	/**
	* <p>
	* Bug 95792. A mechanism by which the key binding architecture can force an
	* update of the contexts (based on the active shell) before trying to execute a
	* command. This mechanism is required for GTK+ only.
	* </p>
	* <p>
	* DO NOT CALL THIS METHOD.
	* </p>
	*
	* @param shell The shell that should be considered active; must not be
	* <code>null</code>.
	*/
	public void updateShellKludge(final Shell shell) {
	final Shell currentActiveShell = contextAuthority.getActiveShell();
	if (currentActiveShell != shell) {
	contextAuthority.sourceChanged(ISources.ACTIVE_SHELL, ISources.ACTIVE_SHELL_NAME, shell);
	}
	}
	}