core/plugins/org.eclipse.dltk.ui/src/org/eclipse/dltk/internal/ui/text/hover/AbstractScriptEditorTextHover.java

/*******************************************************************************
 * Copyright (c) 2000, 2007 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
 *
 
 *******************************************************************************/
package org.eclipse.dltk.internal.ui.text.hover;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URL;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.FileLocator;
import org.eclipse.core.runtime.Platform;
import org.eclipse.dltk.core.DLTKLanguageManager;
import org.eclipse.dltk.core.ICodeAssist;
import org.eclipse.dltk.core.IDLTKLanguageToolkit;
import org.eclipse.dltk.core.IModelElement;
import org.eclipse.dltk.core.ModelException;
import org.eclipse.dltk.internal.ui.editor.EditorUtility;
import org.eclipse.dltk.internal.ui.text.HTMLTextPresenter;
import org.eclipse.dltk.internal.ui.text.ScriptWordFinder;
import org.eclipse.dltk.ui.DLTKUIPlugin;
import org.eclipse.dltk.ui.IWorkingCopyManager;
import org.eclipse.dltk.ui.PreferenceConstants;
import org.eclipse.dltk.ui.text.completion.HTMLPrinter;
import org.eclipse.dltk.ui.text.hover.IScriptEditorTextHover;
import org.eclipse.jface.preference.IPreferenceStore;
import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.DefaultInformationControl;
import org.eclipse.jface.text.IInformationControl;
import org.eclipse.jface.text.IInformationControlCreator;
import org.eclipse.jface.text.IRegion;
import org.eclipse.jface.text.ITextHoverExtension;
import org.eclipse.jface.text.ITextViewer;
import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.FontData;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.ui.IEditorInput;
import org.eclipse.ui.IEditorPart;
import org.eclipse.ui.editors.text.EditorsUI;
import org.osgi.framework.Bundle;

/**
 * Abstract class for providing hover information for Script elements.
 */
public abstract class AbstractScriptEditorTextHover implements
		IScriptEditorTextHover, ITextHoverExtension {

	/**
	 * The style sheet (css).
	 */
	private static String fgCSSStyles;
	private IEditorPart fEditor;
	private IPreferenceStore fStore;

	public void setPreferenceStore(IPreferenceStore store) {
		fStore = store;
	}

	/**
	 * @return the fStore
	 */
	protected IPreferenceStore getPreferenceStore() {
		return fStore;
	}

	public void setEditor(IEditorPart editor) {
		fEditor = editor;
	}

	protected IEditorPart getEditor() {
		return fEditor;
	}

	protected ICodeAssist getCodeAssist() {
		if (fEditor != null) {
			IEditorInput input = fEditor.getEditorInput();

			IWorkingCopyManager manager = DLTKUIPlugin.getDefault()
					.getWorkingCopyManager();
			return manager.getWorkingCopy(input, false);
		}

		return null;
	}

	public IRegion getHoverRegion(final ITextViewer textViewer, int offset) {

		// final IRegion[] result = new IRegion[] { ScriptWordFinder.findWord(
		// textViewer.getDocument(), offset) };
		//
		// textViewer.getTextWidget().getDisplay().syncExec(new Runnable() {
		// public void run() {
		// Point selection = textViewer.getSelectedRange();
		// int off = selection.x;
		// int len = selection.y;
		//
		// if (len > 0) {
		// result[0] = new Region(off, len);
		// }
		// }
		// });
		//
		// return result[0];
		return ScriptWordFinder.findWord(textViewer.getDocument(), offset);
	}

	public String getHoverInfo(ITextViewer textViewer, IRegion hoverRegion) {

		String nature = null;
		try {
			IModelElement inputModelElement = EditorUtility
					.getEditorInputModelElement(this.fEditor, false);
			if (inputModelElement == null)
				return null;
			IDLTKLanguageToolkit toolkit = DLTKLanguageManager
					.getLanguageToolkit(inputModelElement);
			if (toolkit == null) {
				return null;
			}
			nature = toolkit.getNatureId();
		} catch (CoreException e) {
			return null;
		}
		if (nature == null) {
			return null;
		}

		ICodeAssist resolve = getCodeAssist();
		if (resolve != null) {
			try {
				String content = null;
				try {
					content = textViewer.getDocument().get(
							hoverRegion.getOffset(), hoverRegion.getLength());
				} catch (BadLocationException e) {
				}

				IModelElement[] result = resolve.codeSelect(hoverRegion
						.getOffset(), hoverRegion.getLength());

				if (result == null) {
					return null;
				}

				int nResults = result.length;

				if (nResults == 0) {
					if (content != null) {
						return getHoverInfo(nature, content);
					}
					return null;
				}

				return getHoverInfo(nature, result);

			} catch (ModelException x) {
				return null;
			}
		}
		return null;
	}

	/**
	 * Provides hover information for the given Script elements.
	 * 
	 * @param modelElements
	 *            the Script elements for which to provide hover information
	 * @return the hover information string
	 * 
	 */
	protected String getHoverInfo(String nature, IModelElement[] modelElements) {
		return null;
	}

	/**
	 * Provides hover information for the keyword.
	 * 
	 * @param content
	 *            text of the keyword
	 * @return the hover information string
	 * 
	 */
	protected String getHoverInfo(String nature, String content) {
		return null;
	}

	public IInformationControlCreator getHoverControlCreator() {
		return new IInformationControlCreator() {
			public IInformationControl createInformationControl(Shell parent) {
				return new DefaultInformationControl(parent, SWT.NONE,
						new HTMLTextPresenter(true),
						EditorsUI.getTooltipAffordanceString());
			}
		};
	}

	/**
	 * Returns the tool tip affordance string.
	 * 
	 * @return the affordance string or <code>null</code> if disabled or no
	 *         key binding is defined
	 * 
	 */
//	protected String getTooltipAffordanceString() {
//		if (this.getPreferenceStore() == null) {
//			return "{0}";
//		}
//		if (fBindingService == null
//				|| !getPreferenceStore().getBoolean(
//						PreferenceConstants.EDITOR_SHOW_TEXT_HOVER_AFFORDANCE))
//			return null;
//
//		String keySequence = fBindingService
//				.getBestActiveBindingFormattedFor(IScriptEditorActionDefinitionIds.SHOW_DOCUMENTATION);
//		if (keySequence == null)
//			return null;
//
//		return Messages.format(
//				ScriptHoverMessages.ScriptTextHover_makeStickyHint,
//				keySequence == null ? "" : keySequence); //$NON-NLS-1$
//	}

	/**
	 * Returns the style sheet.
	 * 
	 * 
	 */
	protected static String getStyleSheet() {
		if (fgCSSStyles == null) {
			Bundle bundle = Platform.getBundle(DLTKUIPlugin.getPluginId());
			URL url = bundle.getEntry("/DocumentationHoverStyleSheet.css"); //$NON-NLS-1$
			if (url != null) {
				try {
					url = FileLocator.toFileURL(url);
					BufferedReader reader = new BufferedReader(
							new InputStreamReader(url.openStream()));
					StringBuffer buffer = new StringBuffer(200);
					String line = reader.readLine();
					while (line != null) {
						buffer.append(line);
						buffer.append('\n');
						line = reader.readLine();
					}
					fgCSSStyles = buffer.toString();
				} catch (IOException ex) {
					DLTKUIPlugin.log(ex);
				}
			}
		}
		String css = fgCSSStyles;
		if (css != null) {
			FontData fontData = JFaceResources.getFontRegistry().getFontData(
					PreferenceConstants.APPEARANCE_DOCUMENTATION_FONT)[0];
			css = HTMLPrinter.convertTopLevelFont(css, fontData);
		}
		return css;
	}
}