dsf/org.eclipse.cdt.dsf.ui/src/org/eclipse/cdt/dsf/debug/internal/ui/ExpressionInformationControlCreator.java - cdt/org.eclipse.cdt - Git at Google

 /*******************************************************************************
  * Copyright (c) 2008, 2014 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
  *     Wind River Systems - adapted for DSF
  *     Marc-Andre Laperle (Ericsson) - Remember hover size when expanded (Bug 417559)
  *******************************************************************************/
 package org.eclipse.cdt.dsf.debug.internal.ui;

 import org.eclipse.cdt.dsf.debug.service.IExpressions.IExpressionDMContext;
 import org.eclipse.cdt.dsf.debug.ui.IDsfDebugUIConstants;
 import org.eclipse.cdt.dsf.internal.ui.DsfUIPlugin;
 import org.eclipse.debug.internal.ui.SWTFactory;
 import org.eclipse.debug.internal.ui.viewers.model.provisional.IPresentationContext;
 import org.eclipse.debug.internal.ui.viewers.model.provisional.IViewerInputRequestor;
 import org.eclipse.debug.internal.ui.viewers.model.provisional.IViewerInputUpdate;
 import org.eclipse.debug.internal.ui.viewers.model.provisional.IViewerUpdate;
 import org.eclipse.debug.internal.ui.viewers.model.provisional.IViewerUpdateListener;
 import org.eclipse.debug.internal.ui.viewers.model.provisional.PresentationContext;
 import org.eclipse.debug.internal.ui.viewers.model.provisional.TreeModelViewer;
 import org.eclipse.debug.internal.ui.viewers.model.provisional.ViewerInputService;
 import org.eclipse.debug.internal.ui.views.variables.details.DefaultDetailPane;
 import org.eclipse.debug.internal.ui.views.variables.details.DetailPaneProxy;
 import org.eclipse.debug.internal.ui.views.variables.details.IDetailPaneContainer;
 import org.eclipse.debug.ui.AbstractDebugView;
 import org.eclipse.debug.ui.IDebugUIConstants;
 import org.eclipse.jface.dialogs.IDialogSettings;
 import org.eclipse.jface.preference.JFacePreferences;
 import org.eclipse.jface.resource.ColorRegistry;
 import org.eclipse.jface.text.AbstractInformationControl;
 import org.eclipse.jface.text.IInformationControl;
 import org.eclipse.jface.text.IInformationControlCreator;
 import org.eclipse.jface.text.IInformationControlExtension2;
 import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.jface.viewers.StructuredViewer;
 import org.eclipse.jface.viewers.TreeSelection;
 import org.eclipse.jface.viewers.ViewerFilter;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.custom.SashForm;
 import org.eclipse.swt.events.SelectionEvent;
 import org.eclipse.swt.events.SelectionListener;
 import org.eclipse.swt.graphics.Color;
 import org.eclipse.swt.graphics.Point;
 import org.eclipse.swt.layout.GridData;
 import org.eclipse.swt.layout.GridLayout;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Layout;
 import org.eclipse.swt.widgets.Shell;
 import org.eclipse.swt.widgets.Tree;
 import org.eclipse.ui.IWorkbenchPage;
 import org.eclipse.ui.IWorkbenchPartSite;
 import org.eclipse.ui.PlatformUI;
 import org.eclipse.ui.themes.ITheme;

 /**
  * Creates an information control to display an expression in a hover control.
  * <br/> This class is derivative work from JDT's <code>ExpressionInformationControlCreator</code>.
  *
  * @noextend This class is not intended to be subclassed by clients.
  *
  * @since 2.1
  */
 @SuppressWarnings("restriction")
 public class ExpressionInformationControlCreator implements IInformationControlCreator {

 	/**
 	 * A presentation context for the expression hover control.
 	 * Implements equals and hashCode based on id comparison.
 	 */
 	private static final class ExpressionHoverPresentationContext extends PresentationContext {

 		private ExpressionHoverPresentationContext(String id) {
 			super(id);
 		}

 		@Override
 		public boolean equals(Object obj) {
 			if (this == obj) {
 				return true;
 			}
 			if (obj instanceof ExpressionHoverPresentationContext) {
 				if (getId().equals(((PresentationContext) obj).getId())) {
 					return true;
 				}
 			}
 			return false;
 		}

 		@Override
 		public int hashCode() {
 			return getId().hashCode();
 		}
 	}

 	class ExpressionInformationControl extends AbstractInformationControl
 			implements IInformationControlExtension2, IViewerInputRequestor {

 		/**
 		 * Dialog setting key for height
 		 */
 		private static final String HEIGHT = "HEIGHT"; //$NON-NLS-1$

 		/**
 		 * Dialog setting key for width.
 		 */
 		private static final String WIDTH = "WIDTH"; //$NON-NLS-1$

 		/**
 		 * Dialog setting key for tree sash weight
 		 */
 		private static final String SASH_WEIGHT_TREE = "SashWeightTree"; //$NON-NLS-1$

 		/**
 		 * Dialog setting key for details sash weight
 		 */
 		private static final String SASH_WEIGHT_DETAILS = "SashWeightDetails"; //$NON-NLS-1$

 		/**
 		 * Variable to display.
 		 */
 		private Object fVariable;

 		private TreeModelViewer fViewer;
 		private SashForm fSashForm;
 		private Composite fDetailPaneComposite;
 		private DetailPaneProxy fDetailPane;
 		private Tree fTree;
 		private IViewerUpdateListener fViewerUpdateListener;

 		private ViewerInputService fInputService;

 		private IInformationControlCreator fInformationControlCreator;

 		/**
 		 * Inner class implementing IDetailPaneContainer methods.  Handles changes to detail
 		 * pane and provides limited access to the detail pane proxy.
 		 */
 		private class DetailPaneContainer implements IDetailPaneContainer {

 			/*
 			 * @see org.eclipse.debug.internal.ui.views.variables.details.IDetailPaneContainer#getCurrentPaneID()
 			 */
 			@Override
 			public String getCurrentPaneID() {
 				return fDetailPane.getCurrentPaneID();
 			}

 			/*
 			 * @see org.eclipse.debug.internal.ui.views.variables.details.IDetailPaneContainer#getCurrentSelection()
 			 */
 			@Override
 			public IStructuredSelection getCurrentSelection() {
 				return (IStructuredSelection) fViewer.getSelection();
 			}

 			/*
 			 * @see org.eclipse.debug.internal.ui.views.variables.details.IDetailPaneContainer#refreshDetailPaneContents()
 			 */
 			@Override
 			public void refreshDetailPaneContents() {
 				fDetailPane.display(getCurrentSelection());
 			}

 			/*
 			 * @see org.eclipse.debug.internal.ui.views.variables.details.IDetailPaneContainer#getParentComposite()
 			 */
 			@Override
 			public Composite getParentComposite() {
 				return fDetailPaneComposite;
 			}

 			/*
 			 * @see org.eclipse.debug.internal.ui.views.variables.details.IDetailPaneContainer#getWorkbenchPartSite()
 			 */
 			@Override
 			public IWorkbenchPartSite getWorkbenchPartSite() {
 				return null;
 			}

 			/*
 			 * @see org.eclipse.debug.internal.ui.views.variables.details.IDetailPaneContainer#paneChanged(java.lang.String)
 			 */
 			@Override
 			public void paneChanged(String newPaneID) {
 				if (DefaultDetailPane.ID.equals(newPaneID)) {
 					fDetailPane.getCurrentControl()
 							.setBackground(getShell().getDisplay().getSystemColor(SWT.COLOR_INFO_BACKGROUND));
 				}
 			}

 		}

 		/**
 		 * Constructs a new control in the given shell.
 		 *
 		 * @param parentShell shell
 		 * @param resize whether resize is supported
 		 */
 		ExpressionInformationControl(Shell parentShell, boolean resize) {
 			super(parentShell, resize);
 			create();
 		}

 		/**
 		 * Override the size constraints so that it can be as big as
 		 * when the hover was last displayed (IDialogSettings).
 		 */
 		@Override
 		public Point computeSizeConstraints(int widthInChars, int heightInChars) {
 			// Bug 417559: The TextViewerHoverManager constrains the size of a newly created
 			// ExpressionInformationControl by 100 chars by 12 chars (602x182). The control
 			// size can be expanded beyond that, however when re-created it will still be constrained.
 			// By removing the constraint in the presence of a non-null IDialogSettings,
 			// the size gets restored properly even when previously expanded.
 			Point dialogSettingsSize = getDialogSettingsSize();
 			if (dialogSettingsSize != null) {
 				return dialogSettingsSize;
 			}
 			return super.computeSizeConstraints(widthInChars, heightInChars);
 		}

 		@Override
 		public Point computeSizeHint() {
 			Point dialogSettingsSize = getDialogSettingsSize();
 			if (dialogSettingsSize != null) {
 				return dialogSettingsSize;
 			}
 			return super.computeSizeHint();
 		}

 		private Point getDialogSettingsSize() {
 			IDialogSettings settings = getDialogSettings(false);
 			if (settings != null) {
 				int x = getIntSetting(settings, WIDTH);
 				if (x > 0) {
 					int y = getIntSetting(settings, HEIGHT);
 					if (y > 0) {
 						return new Point(x, y);
 					}
 				}
 			}

 			return null;
 		}

 		@Override
 		public void setSize(int width, int height) {
 			if (!isResizable() && fDetailPaneComposite != null) {
 				// add height of details pane
 				height += fDetailPaneComposite.computeSize(SWT.DEFAULT, SWT.DEFAULT).y;
 			}
 			super.setSize(width, height);
 		}

 		/**
 		 * Returns the dialog settings for this hover or <code>null</code> if none
 		 *
 		 * @param create whether to create the settings
 		 */
 		private IDialogSettings getDialogSettings(boolean create) {
 			IDialogSettings settings = DsfUIPlugin.getDefault().getDialogSettings();
 			IDialogSettings section = settings.getSection(this.getClass().getName());
 			if (section == null & create) {
 				section = settings.addNewSection(this.getClass().getName());
 			}
 			return section;
 		}

 		/**
 		 * Returns an integer value in the given dialog settings or -1 if none.
 		 *
 		 * @param settings dialog settings
 		 * @param key key
 		 * @return value or -1 if not present
 		 */
 		private int getIntSetting(IDialogSettings settings, String key) {
 			try {
 				return settings.getInt(key);
 			} catch (NumberFormatException e) {
 				return -1;
 			}
 		}

 		@Override
 		public void dispose() {
 			persistSettings(getShell());
 			super.dispose();
 		}

 		/**
 		 * Persists dialog settings.
 		 *
 		 * @param shell
 		 */
 		private void persistSettings(Shell shell) {
 			if (shell != null && !shell.isDisposed()) {
 				if (isResizable()) {
 					IDialogSettings settings = getDialogSettings(true);
 					Point size = shell.getSize();
 					settings.put(WIDTH, size.x);
 					settings.put(HEIGHT, size.y);
 					int[] weights = fSashForm.getWeights();
 					if (weights.length == 1) {
 						settings.put(SASH_WEIGHT_TREE, weights[0]);
 					} else if (weights.length == 2) {
 						settings.put(SASH_WEIGHT_TREE, weights[0]);
 						settings.put(SASH_WEIGHT_DETAILS, weights[1]);
 					}
 				}
 			}
 		}

 		@Override
 		public void setVisible(boolean visible) {
 			if (!visible) {
 				if (fViewer != null && fViewerUpdateListener != null) {
 					// Remove update listener to avoid refreshing variables that were
 					// previously shown in a hover at every step
 					// Bug 438367
 					fViewer.removeViewerUpdateListener(fViewerUpdateListener);
 					fViewerUpdateListener = null;
 				}

 				persistSettings(getShell());
 			}
 			super.setVisible(visible);
 		}

 		@Override
 		protected void createContent(Composite parent) {

 			fSashForm = new SashForm(parent, parent.getStyle());
 			fSashForm.setOrientation(SWT.VERTICAL);

 			// update presentation context
 			AbstractDebugView view = getViewToEmulate();
 			IPresentationContext context = new ExpressionHoverPresentationContext(
 					IDsfDebugUIConstants.ID_EXPRESSION_HOVER);
 			if (view != null) {
 				// copy over properties
 				IPresentationContext copy = ((TreeModelViewer) view.getViewer()).getPresentationContext();
 				try {
 					String[] properties = copy.getProperties();
 					for (int i = 0; i < properties.length; i++) {
 						String key = properties[i];
 						context.setProperty(key, copy.getProperty(key));
 					}
 				} catch (NoSuchMethodError e) {
 					// ignore
 				}
 			}

 			fViewer = new TreeModelViewer(fSashForm, SWT.MULTI | SWT.VIRTUAL | SWT.FULL_SELECTION, context);
 			fViewer.setAutoExpandLevel(fExpansionLevel);

 			if (view != null) {
 				// copy over filters
 				StructuredViewer structuredViewer = (StructuredViewer) view.getViewer();
 				if (structuredViewer != null) {
 					ViewerFilter[] filters = structuredViewer.getFilters();
 					for (int i = 0; i < filters.length; i++) {
 						fViewer.addFilter(filters[i]);
 					}
 				}
 			}
 			fInputService = new ViewerInputService(fViewer, this);
 			fTree = fViewer.getTree();

 			if (fShowDetailPane) {
 				fDetailPaneComposite = SWTFactory.createComposite(fSashForm, 1, 1, GridData.FILL_BOTH);
 				Layout layout = fDetailPaneComposite.getLayout();
 				if (layout instanceof GridLayout) {
 					GridLayout gl = (GridLayout) layout;
 					gl.marginHeight = 0;
 					gl.marginWidth = 0;
 				}

 				fDetailPane = new DetailPaneProxy(new DetailPaneContainer());
 				fDetailPane.display(null); // Bring up the default pane so the user doesn't see an empty composite

 				fTree.addSelectionListener(new SelectionListener() {
 					@Override
 					public void widgetSelected(SelectionEvent e) {
 						fDetailPane.display((IStructuredSelection) fViewer.getSelection());
 					}

 					@Override
 					public void widgetDefaultSelected(SelectionEvent e) {
 					}
 				});
 			}

 			initSashWeights();

 			// add update listener to auto-select and display details of root expression
 			fViewerUpdateListener = new IViewerUpdateListener() {
 				@Override
 				public void viewerUpdatesComplete() {
 					fViewer.getDisplay().timerExec(100, () -> {
 						if (!fViewer.getTree().isDisposed()) {
 							TreeSelection selection = (TreeSelection) fViewer.getSelection();
 							if (selection.isEmpty()) {
 								selection = new TreeSelection(fViewer.getTopElementPath());
 							}
 							fViewer.setSelection(selection);
 							if (fDetailPane != null) {
 								fDetailPane.display(selection);
 							}
 						}
 					});
 				}

 				@Override
 				public void viewerUpdatesBegin() {
 				}

 				@Override
 				public void updateStarted(IViewerUpdate update) {
 				}

 				@Override
 				public void updateComplete(IViewerUpdate update) {
 				}
 			};

 			fViewer.addViewerUpdateListener(fViewerUpdateListener);

 			ITheme currentTheme = PlatformUI.getWorkbench().getThemeManager().getCurrentTheme();
 			ColorRegistry colorRegistry = currentTheme.getColorRegistry();

 			Color fg = colorRegistry.get(JFacePreferences.INFORMATION_FOREGROUND_COLOR);
 			if (fg == null) {
 				fg = getShell().getDisplay().getSystemColor(SWT.COLOR_INFO_FOREGROUND);
 			}

 			Color bg = colorRegistry.get(JFacePreferences.INFORMATION_BACKGROUND_COLOR);
 			if (bg == null) {
 				bg = getShell().getDisplay().getSystemColor(SWT.COLOR_INFO_BACKGROUND);
 			}

 			setForegroundColor(fg);
 			setBackgroundColor(bg);
 		}

 		/**
 		 * Attempts to find an appropriate view to emulate, this will either be the
 		 * variables view or the expressions view.
 		 * @return a view to emulate or <code>null</code>
 		 */
 		private AbstractDebugView getViewToEmulate() {
 			IWorkbenchPage page = PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage();
 			AbstractDebugView expressionsView = (AbstractDebugView) page.findView(IDebugUIConstants.ID_EXPRESSION_VIEW);
 			if (expressionsView != null && expressionsView.isVisible()) {
 				return expressionsView;
 			}
 			AbstractDebugView variablesView = (AbstractDebugView) page.findView(IDebugUIConstants.ID_VARIABLE_VIEW);
 			if (variablesView != null && variablesView.isVisible()) {
 				return variablesView;
 			}
 			if (expressionsView != null) {
 				return expressionsView;
 			}
 			return variablesView;
 		}

 		/**
 		 * Initializes the sash form weights from the preference store (using default values if
 		 * no sash weights were stored previously).
 		 */
 		protected void initSashWeights() {
 			IDialogSettings settings = getDialogSettings(false);
 			if (settings != null) {
 				int tree = getIntSetting(settings, SASH_WEIGHT_TREE);
 				if (tree > 0) {
 					if (fDetailPane != null) {
 						int details = getIntSetting(settings, SASH_WEIGHT_DETAILS);
 						if (details <= 0) {
 							details = tree / 2;
 						}
 						fSashForm.setWeights(new int[] { tree, details });
 					} else {
 						fSashForm.setWeights(new int[] { tree });
 					}
 				}
 			}
 		}

 		@Override
 		public void setForegroundColor(Color foreground) {
 			super.setForegroundColor(foreground);
 			if (fDetailPaneComposite != null) {
 				fDetailPaneComposite.setForeground(foreground);
 			}
 			fTree.setForeground(foreground);
 		}

 		@Override
 		public void setBackgroundColor(Color background) {
 			super.setBackgroundColor(background);
 			if (fDetailPaneComposite != null) {
 				fDetailPaneComposite.setBackground(background);
 			}
 			fTree.setBackground(background);
 		}

 		@Override
 		public void setFocus() {
 			super.setFocus();
 			fTree.setFocus();
 		}

 		/*
 		 * @see org.eclipse.jface.text.IInformationControlExtension#hasContents()
 		 */
 		@Override
 		public boolean hasContents() {
 			return fVariable != null;
 		}

 		/*
 		 * @see org.eclipse.jface.text.IInformationControlExtension2#setInput(java.lang.Object)
 		 */
 		@Override
 		public void setInput(Object input) {
 			if (input instanceof IExpressionDMContext) {
 				fVariable = input;
 				fInputService.resolveViewerInput(input);
 			}
 		}

 		@Override
 		public IInformationControlCreator getInformationPresenterControlCreator() {
 			if (fInformationControlCreator == null) {
 				fInformationControlCreator = new ExpressionInformationControlCreator(fShowDetailPane, fExpansionLevel) {
 					@Override
 					public IInformationControl createInformationControl(Shell shell) {
 						return new ExpressionInformationControl(shell, true);
 					}
 				};
 			}
 			return fInformationControlCreator;
 		}

 		@Override
 		public void viewerInputComplete(IViewerInputUpdate update) {
 			fViewer.setInput(fVariable = update.getInputElement());
 		}

 	}

 	protected final boolean fShowDetailPane;
 	protected final int fExpansionLevel;

 	/**
 	 * Create default expression information control creator.
 	 * <p>
 	 * Same as {@code ExpressionInformationControlCreator(true, 1)}.
 	 * </p>
 	 */
 	public ExpressionInformationControlCreator() {
 		this(true, 1);
 	}

 	/**
 	 * Create expression information control creator with customization options.
 	 *
 	 * @param showDetailPane  if <code>true</code> the detail pane will be shown
 	 * @param expansionLevel  tree level to which the expression should be expanded by default
 	 */
 	public ExpressionInformationControlCreator(boolean showDetailPane, int expansionLevel) {
 		fShowDetailPane = showDetailPane;
 		fExpansionLevel = expansionLevel;
 	}

 	/*
 	 * @see org.eclipse.jface.text.IInformationControlCreator#createInformationControl(org.eclipse.swt.widgets.Shell)
 	 */
 	@Override
 	public IInformationControl createInformationControl(Shell parent) {
 		return new ExpressionInformationControl(parent, false);
 	}

 }
	/*******************************************************************************
	* Copyright (c) 2008, 2014 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
	* Wind River Systems - adapted for DSF
	* Marc-Andre Laperle (Ericsson) - Remember hover size when expanded (Bug 417559)
	*******************************************************************************/
	package org.eclipse.cdt.dsf.debug.internal.ui;

	import org.eclipse.cdt.dsf.debug.service.IExpressions.IExpressionDMContext;
	import org.eclipse.cdt.dsf.debug.ui.IDsfDebugUIConstants;
	import org.eclipse.cdt.dsf.internal.ui.DsfUIPlugin;
	import org.eclipse.debug.internal.ui.SWTFactory;
	import org.eclipse.debug.internal.ui.viewers.model.provisional.IPresentationContext;
	import org.eclipse.debug.internal.ui.viewers.model.provisional.IViewerInputRequestor;
	import org.eclipse.debug.internal.ui.viewers.model.provisional.IViewerInputUpdate;
	import org.eclipse.debug.internal.ui.viewers.model.provisional.IViewerUpdate;
	import org.eclipse.debug.internal.ui.viewers.model.provisional.IViewerUpdateListener;
	import org.eclipse.debug.internal.ui.viewers.model.provisional.PresentationContext;
	import org.eclipse.debug.internal.ui.viewers.model.provisional.TreeModelViewer;
	import org.eclipse.debug.internal.ui.viewers.model.provisional.ViewerInputService;
	import org.eclipse.debug.internal.ui.views.variables.details.DefaultDetailPane;
	import org.eclipse.debug.internal.ui.views.variables.details.DetailPaneProxy;
	import org.eclipse.debug.internal.ui.views.variables.details.IDetailPaneContainer;
	import org.eclipse.debug.ui.AbstractDebugView;
	import org.eclipse.debug.ui.IDebugUIConstants;
	import org.eclipse.jface.dialogs.IDialogSettings;
	import org.eclipse.jface.preference.JFacePreferences;
	import org.eclipse.jface.resource.ColorRegistry;
	import org.eclipse.jface.text.AbstractInformationControl;
	import org.eclipse.jface.text.IInformationControl;
	import org.eclipse.jface.text.IInformationControlCreator;
	import org.eclipse.jface.text.IInformationControlExtension2;
	import org.eclipse.jface.viewers.IStructuredSelection;
	import org.eclipse.jface.viewers.StructuredViewer;
	import org.eclipse.jface.viewers.TreeSelection;
	import org.eclipse.jface.viewers.ViewerFilter;
	import org.eclipse.swt.SWT;
	import org.eclipse.swt.custom.SashForm;
	import org.eclipse.swt.events.SelectionEvent;
	import org.eclipse.swt.events.SelectionListener;
	import org.eclipse.swt.graphics.Color;
	import org.eclipse.swt.graphics.Point;
	import org.eclipse.swt.layout.GridData;
	import org.eclipse.swt.layout.GridLayout;
	import org.eclipse.swt.widgets.Composite;
	import org.eclipse.swt.widgets.Layout;
	import org.eclipse.swt.widgets.Shell;
	import org.eclipse.swt.widgets.Tree;
	import org.eclipse.ui.IWorkbenchPage;
	import org.eclipse.ui.IWorkbenchPartSite;
	import org.eclipse.ui.PlatformUI;
	import org.eclipse.ui.themes.ITheme;

	/**
	* Creates an information control to display an expression in a hover control.
	* <br/> This class is derivative work from JDT's <code>ExpressionInformationControlCreator</code>.
	*
	* @noextend This class is not intended to be subclassed by clients.
	*
	* @since 2.1
	*/
	@SuppressWarnings("restriction")
	public class ExpressionInformationControlCreator implements IInformationControlCreator {

	/**
	* A presentation context for the expression hover control.
	* Implements equals and hashCode based on id comparison.
	*/
	private static final class ExpressionHoverPresentationContext extends PresentationContext {

	private ExpressionHoverPresentationContext(String id) {
	super(id);
	}

	@Override
	public boolean equals(Object obj) {
	if (this == obj) {
	return true;
	}
	if (obj instanceof ExpressionHoverPresentationContext) {
	if (getId().equals(((PresentationContext) obj).getId())) {
	return true;
	}
	}
	return false;
	}

	@Override
	public int hashCode() {
	return getId().hashCode();
	}
	}

	class ExpressionInformationControl extends AbstractInformationControl
	implements IInformationControlExtension2, IViewerInputRequestor {

	/**
	* Dialog setting key for height
	*/
	private static final String HEIGHT = "HEIGHT"; //$NON-NLS-1$

	/**
	* Dialog setting key for width.
	*/
	private static final String WIDTH = "WIDTH"; //$NON-NLS-1$

	/**
	* Dialog setting key for tree sash weight
	*/
	private static final String SASH_WEIGHT_TREE = "SashWeightTree"; //$NON-NLS-1$

	/**
	* Dialog setting key for details sash weight
	*/
	private static final String SASH_WEIGHT_DETAILS = "SashWeightDetails"; //$NON-NLS-1$

	/**
	* Variable to display.
	*/
	private Object fVariable;

	private TreeModelViewer fViewer;
	private SashForm fSashForm;
	private Composite fDetailPaneComposite;
	private DetailPaneProxy fDetailPane;
	private Tree fTree;
	private IViewerUpdateListener fViewerUpdateListener;

	private ViewerInputService fInputService;

	private IInformationControlCreator fInformationControlCreator;

	/**
	* Inner class implementing IDetailPaneContainer methods. Handles changes to detail
	* pane and provides limited access to the detail pane proxy.
	*/
	private class DetailPaneContainer implements IDetailPaneContainer {

	/*
	* @see org.eclipse.debug.internal.ui.views.variables.details.IDetailPaneContainer#getCurrentPaneID()
	*/
	@Override
	public String getCurrentPaneID() {
	return fDetailPane.getCurrentPaneID();
	}

	/*
	* @see org.eclipse.debug.internal.ui.views.variables.details.IDetailPaneContainer#getCurrentSelection()
	*/
	@Override
	public IStructuredSelection getCurrentSelection() {
	return (IStructuredSelection) fViewer.getSelection();
	}

	/*
	* @see org.eclipse.debug.internal.ui.views.variables.details.IDetailPaneContainer#refreshDetailPaneContents()
	*/
	@Override
	public void refreshDetailPaneContents() {
	fDetailPane.display(getCurrentSelection());
	}

	/*
	* @see org.eclipse.debug.internal.ui.views.variables.details.IDetailPaneContainer#getParentComposite()
	*/
	@Override
	public Composite getParentComposite() {
	return fDetailPaneComposite;
	}

	/*
	* @see org.eclipse.debug.internal.ui.views.variables.details.IDetailPaneContainer#getWorkbenchPartSite()
	*/
	@Override
	public IWorkbenchPartSite getWorkbenchPartSite() {
	return null;
	}

	/*
	* @see org.eclipse.debug.internal.ui.views.variables.details.IDetailPaneContainer#paneChanged(java.lang.String)
	*/
	@Override
	public void paneChanged(String newPaneID) {
	if (DefaultDetailPane.ID.equals(newPaneID)) {
	fDetailPane.getCurrentControl()
	.setBackground(getShell().getDisplay().getSystemColor(SWT.COLOR_INFO_BACKGROUND));
	}
	}

	}

	/**
	* Constructs a new control in the given shell.
	*
	* @param parentShell shell
	* @param resize whether resize is supported
	*/
	ExpressionInformationControl(Shell parentShell, boolean resize) {
	super(parentShell, resize);
	create();
	}

	/**
	* Override the size constraints so that it can be as big as
	* when the hover was last displayed (IDialogSettings).
	*/
	@Override
	public Point computeSizeConstraints(int widthInChars, int heightInChars) {
	// Bug 417559: The TextViewerHoverManager constrains the size of a newly created
	// ExpressionInformationControl by 100 chars by 12 chars (602x182). The control
	// size can be expanded beyond that, however when re-created it will still be constrained.
	// By removing the constraint in the presence of a non-null IDialogSettings,
	// the size gets restored properly even when previously expanded.
	Point dialogSettingsSize = getDialogSettingsSize();
	if (dialogSettingsSize != null) {
	return dialogSettingsSize;
	}
	return super.computeSizeConstraints(widthInChars, heightInChars);
	}

	@Override
	public Point computeSizeHint() {
	Point dialogSettingsSize = getDialogSettingsSize();
	if (dialogSettingsSize != null) {
	return dialogSettingsSize;
	}
	return super.computeSizeHint();
	}

	private Point getDialogSettingsSize() {
	IDialogSettings settings = getDialogSettings(false);
	if (settings != null) {
	int x = getIntSetting(settings, WIDTH);
	if (x > 0) {
	int y = getIntSetting(settings, HEIGHT);
	if (y > 0) {
	return new Point(x, y);
	}
	}
	}

	return null;
	}

	@Override
	public void setSize(int width, int height) {
	if (!isResizable() && fDetailPaneComposite != null) {
	// add height of details pane
	height += fDetailPaneComposite.computeSize(SWT.DEFAULT, SWT.DEFAULT).y;
	}
	super.setSize(width, height);
	}

	/**
	* Returns the dialog settings for this hover or <code>null</code> if none
	*
	* @param create whether to create the settings
	*/
	private IDialogSettings getDialogSettings(boolean create) {
	IDialogSettings settings = DsfUIPlugin.getDefault().getDialogSettings();
	IDialogSettings section = settings.getSection(this.getClass().getName());
	if (section == null & create) {
	section = settings.addNewSection(this.getClass().getName());
	}
	return section;
	}

	/**
	* Returns an integer value in the given dialog settings or -1 if none.
	*
	* @param settings dialog settings
	* @param key key
	* @return value or -1 if not present
	*/
	private int getIntSetting(IDialogSettings settings, String key) {
	try {
	return settings.getInt(key);
	} catch (NumberFormatException e) {
	return -1;
	}
	}

	@Override
	public void dispose() {
	persistSettings(getShell());
	super.dispose();
	}

	/**
	* Persists dialog settings.
	*
	* @param shell
	*/
	private void persistSettings(Shell shell) {
	if (shell != null && !shell.isDisposed()) {
	if (isResizable()) {
	IDialogSettings settings = getDialogSettings(true);
	Point size = shell.getSize();
	settings.put(WIDTH, size.x);
	settings.put(HEIGHT, size.y);
	int[] weights = fSashForm.getWeights();
	if (weights.length == 1) {
	settings.put(SASH_WEIGHT_TREE, weights[0]);
	} else if (weights.length == 2) {
	settings.put(SASH_WEIGHT_TREE, weights[0]);
	settings.put(SASH_WEIGHT_DETAILS, weights[1]);
	}
	}
	}
	}

	@Override
	public void setVisible(boolean visible) {
	if (!visible) {
	if (fViewer != null && fViewerUpdateListener != null) {
	// Remove update listener to avoid refreshing variables that were
	// previously shown in a hover at every step
	// Bug 438367
	fViewer.removeViewerUpdateListener(fViewerUpdateListener);
	fViewerUpdateListener = null;
	}

	persistSettings(getShell());
	}
	super.setVisible(visible);
	}

	@Override
	protected void createContent(Composite parent) {

	fSashForm = new SashForm(parent, parent.getStyle());
	fSashForm.setOrientation(SWT.VERTICAL);

	// update presentation context
	AbstractDebugView view = getViewToEmulate();
	IPresentationContext context = new ExpressionHoverPresentationContext(
	IDsfDebugUIConstants.ID_EXPRESSION_HOVER);
	if (view != null) {
	// copy over properties
	IPresentationContext copy = ((TreeModelViewer) view.getViewer()).getPresentationContext();
	try {
	String[] properties = copy.getProperties();
	for (int i = 0; i < properties.length; i++) {
	String key = properties[i];
	context.setProperty(key, copy.getProperty(key));
	}
	} catch (NoSuchMethodError e) {
	// ignore
	}
	}

	fViewer = new TreeModelViewer(fSashForm, SWT.MULTI \| SWT.VIRTUAL \| SWT.FULL_SELECTION, context);
	fViewer.setAutoExpandLevel(fExpansionLevel);

	if (view != null) {
	// copy over filters
	StructuredViewer structuredViewer = (StructuredViewer) view.getViewer();
	if (structuredViewer != null) {
	ViewerFilter[] filters = structuredViewer.getFilters();
	for (int i = 0; i < filters.length; i++) {
	fViewer.addFilter(filters[i]);
	}
	}
	}
	fInputService = new ViewerInputService(fViewer, this);
	fTree = fViewer.getTree();

	if (fShowDetailPane) {
	fDetailPaneComposite = SWTFactory.createComposite(fSashForm, 1, 1, GridData.FILL_BOTH);
	Layout layout = fDetailPaneComposite.getLayout();
	if (layout instanceof GridLayout) {
	GridLayout gl = (GridLayout) layout;
	gl.marginHeight = 0;
	gl.marginWidth = 0;
	}

	fDetailPane = new DetailPaneProxy(new DetailPaneContainer());
	fDetailPane.display(null); // Bring up the default pane so the user doesn't see an empty composite

	fTree.addSelectionListener(new SelectionListener() {
	@Override
	public void widgetSelected(SelectionEvent e) {
	fDetailPane.display((IStructuredSelection) fViewer.getSelection());
	}

	@Override
	public void widgetDefaultSelected(SelectionEvent e) {
	}
	});
	}

	initSashWeights();

	// add update listener to auto-select and display details of root expression
	fViewerUpdateListener = new IViewerUpdateListener() {
	@Override
	public void viewerUpdatesComplete() {
	fViewer.getDisplay().timerExec(100, () -> {
	if (!fViewer.getTree().isDisposed()) {
	TreeSelection selection = (TreeSelection) fViewer.getSelection();
	if (selection.isEmpty()) {
	selection = new TreeSelection(fViewer.getTopElementPath());
	}
	fViewer.setSelection(selection);
	if (fDetailPane != null) {
	fDetailPane.display(selection);
	}
	}
	});
	}

	@Override
	public void viewerUpdatesBegin() {
	}

	@Override
	public void updateStarted(IViewerUpdate update) {
	}

	@Override
	public void updateComplete(IViewerUpdate update) {
	}
	};

	fViewer.addViewerUpdateListener(fViewerUpdateListener);

	ITheme currentTheme = PlatformUI.getWorkbench().getThemeManager().getCurrentTheme();
	ColorRegistry colorRegistry = currentTheme.getColorRegistry();

	Color fg = colorRegistry.get(JFacePreferences.INFORMATION_FOREGROUND_COLOR);
	if (fg == null) {
	fg = getShell().getDisplay().getSystemColor(SWT.COLOR_INFO_FOREGROUND);
	}

	Color bg = colorRegistry.get(JFacePreferences.INFORMATION_BACKGROUND_COLOR);
	if (bg == null) {
	bg = getShell().getDisplay().getSystemColor(SWT.COLOR_INFO_BACKGROUND);
	}

	setForegroundColor(fg);
	setBackgroundColor(bg);
	}

	/**
	* Attempts to find an appropriate view to emulate, this will either be the
	* variables view or the expressions view.
	* @return a view to emulate or <code>null</code>
	*/
	private AbstractDebugView getViewToEmulate() {
	IWorkbenchPage page = PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage();
	AbstractDebugView expressionsView = (AbstractDebugView) page.findView(IDebugUIConstants.ID_EXPRESSION_VIEW);
	if (expressionsView != null && expressionsView.isVisible()) {
	return expressionsView;
	}
	AbstractDebugView variablesView = (AbstractDebugView) page.findView(IDebugUIConstants.ID_VARIABLE_VIEW);
	if (variablesView != null && variablesView.isVisible()) {
	return variablesView;
	}
	if (expressionsView != null) {
	return expressionsView;
	}
	return variablesView;
	}

	/**
	* Initializes the sash form weights from the preference store (using default values if
	* no sash weights were stored previously).
	*/
	protected void initSashWeights() {
	IDialogSettings settings = getDialogSettings(false);
	if (settings != null) {
	int tree = getIntSetting(settings, SASH_WEIGHT_TREE);
	if (tree > 0) {
	if (fDetailPane != null) {
	int details = getIntSetting(settings, SASH_WEIGHT_DETAILS);
	if (details <= 0) {
	details = tree / 2;
	}
	fSashForm.setWeights(new int[] { tree, details });
	} else {
	fSashForm.setWeights(new int[] { tree });
	}
	}
	}
	}

	@Override
	public void setForegroundColor(Color foreground) {
	super.setForegroundColor(foreground);
	if (fDetailPaneComposite != null) {
	fDetailPaneComposite.setForeground(foreground);
	}
	fTree.setForeground(foreground);
	}

	@Override
	public void setBackgroundColor(Color background) {
	super.setBackgroundColor(background);
	if (fDetailPaneComposite != null) {
	fDetailPaneComposite.setBackground(background);
	}
	fTree.setBackground(background);
	}

	@Override
	public void setFocus() {
	super.setFocus();
	fTree.setFocus();
	}

	/*
	* @see org.eclipse.jface.text.IInformationControlExtension#hasContents()
	*/
	@Override
	public boolean hasContents() {
	return fVariable != null;
	}

	/*
	* @see org.eclipse.jface.text.IInformationControlExtension2#setInput(java.lang.Object)
	*/
	@Override
	public void setInput(Object input) {
	if (input instanceof IExpressionDMContext) {
	fVariable = input;
	fInputService.resolveViewerInput(input);
	}
	}

	@Override
	public IInformationControlCreator getInformationPresenterControlCreator() {
	if (fInformationControlCreator == null) {
	fInformationControlCreator = new ExpressionInformationControlCreator(fShowDetailPane, fExpansionLevel) {
	@Override
	public IInformationControl createInformationControl(Shell shell) {
	return new ExpressionInformationControl(shell, true);
	}
	};
	}
	return fInformationControlCreator;
	}

	@Override
	public void viewerInputComplete(IViewerInputUpdate update) {
	fViewer.setInput(fVariable = update.getInputElement());
	}

	}

	protected final boolean fShowDetailPane;
	protected final int fExpansionLevel;

	/**
	* Create default expression information control creator.
	* <p>
	* Same as {@code ExpressionInformationControlCreator(true, 1)}.
	* </p>
	*/
	public ExpressionInformationControlCreator() {
	this(true, 1);
	}

	/**
	* Create expression information control creator with customization options.
	*
	* @param showDetailPane if <code>true</code> the detail pane will be shown
	* @param expansionLevel tree level to which the expression should be expanded by default
	*/
	public ExpressionInformationControlCreator(boolean showDetailPane, int expansionLevel) {
	fShowDetailPane = showDetailPane;
	fExpansionLevel = expansionLevel;
	}

	/*
	* @see org.eclipse.jface.text.IInformationControlCreator#createInformationControl(org.eclipse.swt.widgets.Shell)
	*/
	@Override
	public IInformationControl createInformationControl(Shell parent) {
	return new ExpressionInformationControl(parent, false);
	}

	}