content: /*******************************************************************************
   * Copyright (c) 2000, 2008 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
   *
   * Contributors:
   *     IBM Corporation - initial API and implementation
   *******************************************************************************/
  
  package org.eclipse.wst.jsdt.internal.ui.javaeditor;
  
  import java.util.HashMap;
  import java.util.Map;
  import java.util.ResourceBundle;
  
  import org.eclipse.jface.dialogs.MessageDialog;
  import org.eclipse.jface.text.BadLocationException;
  import org.eclipse.jface.text.IDocument;
  import org.eclipse.jface.text.IRegion;
  import org.eclipse.jface.text.ITextOperationTarget;
  import org.eclipse.jface.text.ITextSelection;
  import org.eclipse.jface.text.ITypedRegion;
  import org.eclipse.jface.text.Region;
  import org.eclipse.jface.text.TextUtilities;
  import org.eclipse.jface.text.source.ISourceViewer;
  import org.eclipse.jface.text.source.SourceViewerConfiguration;
  import org.eclipse.jface.viewers.ISelection;
  import org.eclipse.swt.custom.BusyIndicator;
  import org.eclipse.swt.widgets.Display;
  import org.eclipse.swt.widgets.Shell;
  import org.eclipse.ui.texteditor.ITextEditor;
  import org.eclipse.ui.texteditor.TextEditorAction;
  import org.eclipse.wst.jsdt.internal.ui.JavaScriptPlugin;
  
  
  /**
   * An action which toggles comment prefixes on the selected lines.
   *
   * 
   */
  public final class ToggleCommentAction extends TextEditorAction {
  
  	/** The text operation target */
  	private ITextOperationTarget fOperationTarget;
  	/** The document partitioning */
  	private String fDocumentPartitioning;
  	/** The comment prefixes */
  	private Map fPrefixesMap;
  
  	/**
  	 * Creates and initializes the action for the given text editor. The action
  	 * configures its visual representation from the given resource bundle.
  	 *
  	 * @param bundle the resource bundle
  	 * @param prefix a prefix to be prepended to the various resource keys
  	 *   (described in <code>ResourceAction</code> constructor), or
  	 *   <code>null</code> if none
  	 * @param editor the text editor
  	 * @see org.eclipse.ui.texteditor.ResourceAction#ResourceAction(ResourceBundle, String, int)
  	 */
  	public ToggleCommentAction(ResourceBundle bundle, String prefix, ITextEditor editor) {
  		super(bundle, prefix, editor);
  	}
  
  	/**
  	 * Implementation of the <code>IAction</code> prototype. Checks if the selected
  	 * lines are all commented or not and uncomments/comments them respectively.
  	 */
  	public void run() {
  		if (fOperationTarget == null || fDocumentPartitioning == null || fPrefixesMap == null)
  			return;
  
  		ITextEditor editor= getTextEditor();
  		if (editor == null)
  			return;
  
  		if (!validateEditorInputState())
  			return;
  
  		final int operationCode;
  		if (isSelectionCommented(editor.getSelectionProvider().getSelection()))
  			operationCode= ITextOperationTarget.STRIP_PREFIX;
  		else
  			operationCode= ITextOperationTarget.PREFIX;
  
  		Shell shell= editor.getSite().getShell();
  		if (!fOperationTarget.canDoOperation(operationCode)) {
  			if (shell != null)
  				MessageDialog.openError(shell, JavaEditorMessages.ToggleComment_error_title, JavaEditorMessages.ToggleComment_error_message);
  			return;
  		}
  
  		Display display= null;
  		if (shell != null && !shell.isDisposed())
  			display= shell.getDisplay();
  
  		BusyIndicator.showWhile(display, new Runnable() {
  			public void run() {
  				fOperationTarget.doOperation(operationCode);
  			}
  		});
  	}
  
  	/**
  	 * Is the given selection single-line commented?
  	 *
  	 * @param selection Selection to check
  	 * @return <code>true</code> iff all selected lines are commented
  	 */
  	private boolean isSelectionCommented(ISelection selection) {
  		if (!(selection instanceof ITextSelection))
  			return false;
  
  		ITextSelection textSelection= (ITextSelection) selection;
  		if (textSelection.getStartLine() < 0 || textSelection.getEndLine() < 0)
  			return false;
  
  		IDocument document= getTextEditor().getDocumentProvider().getDocument(getTextEditor().getEditorInput());
  
  		try {
  
  			IRegion block= getTextBlockFromSelection(textSelection, document);
  			ITypedRegion[] regions= TextUtilities.computePartitioning(document, fDocumentPartitioning, block.getOffset(), block.getLength(), false);
  
  			int lineCount= 0;
  			int[] lines= new int[regions.length * 2]; // [startline, endline, startline, endline, ...]
  			for (int i= 0, j= 0; i < regions.length; i++, j+= 2) {
  				// start line of region
  				lines[j]= getFirstCompleteLineOfRegion(regions[i], document);
  				// end line of region
  				int length= regions[i].getLength();
  				int offset= regions[i].getOffset() + length;
  				if (length > 0)
  					offset--;
  				lines[j + 1]= (lines[j] == -1 ? -1 : document.getLineOfOffset(offset));
  				lineCount += lines[j + 1] - lines[j] + 1;
  			}
  
  			// Perform the check
  			for (int i= 0, j= 0; i < regions.length; i++, j += 2) {
  				String[] prefixes= (String[]) fPrefixesMap.get(regions[i].getType());
  				if (prefixes != null && prefixes.length > 0 && lines[j] >= 0 && lines[j + 1] >= 0)
  					if (!isBlockCommented(lines[j], lines[j + 1], prefixes, document))
  						return false;
  			}
  
  			return true;
  
  		} catch (BadLocationException x) {
  			// should not happen
  			JavaScriptPlugin.log(x);
  		}
  
  		return false;
  	}
  
  	/**
  	 * Creates a region describing the text block (something that starts at
  	 * the beginning of a line) completely containing the current selection.
  	 *
  	 * @param selection The selection to use
  	 * @param document The document
  	 * @return the region describing the text block comprising the given selection
  	 */
  	private IRegion getTextBlockFromSelection(ITextSelection selection, IDocument document) {
  
  		try {
  			IRegion line= document.getLineInformationOfOffset(selection.getOffset());
  			int length= selection.getLength() == 0 ? line.getLength() : selection.getLength() + (selection.getOffset() - line.getOffset());
  			return new Region(line.getOffset(), length);
  
  		} catch (BadLocationException x) {
  			// should not happen
  			JavaScriptPlugin.log(x);
  		}
  
  		return null;
  	}
  
  	/**
  	 * Returns the index of the first line whose start offset is in the given text range.
  	 *
  	 * @param region the text range in characters where to find the line
  	 * @param document The document
  	 * @return the first line whose start index is in the given range, -1 if there is no such line
  	 */
  	private int getFirstCompleteLineOfRegion(IRegion region, IDocument document) {
  
  		try {
  
  			int startLine= document.getLineOfOffset(region.getOffset());
  
  			int offset= document.getLineOffset(startLine);
  			if (offset >= region.getOffset())
  				return startLine;
  
  			offset= document.getLineOffset(startLine + 1);
  			return (offset > region.getOffset() + region.getLength() ? -1 : startLine + 1);
  
  		} catch (BadLocationException x) {
  			// should not happen
  			JavaScriptPlugin.log(x);
  		}
  
  		return -1;
  	}
  
  	/**
  	 * Determines whether each line is prefixed by one of the prefixes.
  	 *
  	 * @param startLine Start line in document
  	 * @param endLine End line in document
  	 * @param prefixes Possible comment prefixes
  	 * @param document The document
  	 * @return <code>true</code> iff each line from <code>startLine</code>
  	 *             to and including <code>endLine</code> is prepended by one
  	 *             of the <code>prefixes</code>, ignoring whitespace at the
  	 *             begin of line
  	 */
  	private boolean isBlockCommented(int startLine, int endLine, String[] prefixes, IDocument document) {
  
  		try {
  
  			// check for occurrences of prefixes in the given lines
  			for (int i= startLine; i <= endLine; i++) {
  
  				IRegion line= document.getLineInformation(i);
  				String text= document.get(line.getOffset(), line.getLength());
  
  				int[] found= TextUtilities.indexOf(prefixes, text, 0);
  
  				if (found[0] == -1)
  					// found a line which is not commented
  					return false;
  
  				String s= document.get(line.getOffset(), found[0]);
  				s= s.trim();
  				if (s.length() != 0)
  					// found a line which is not commented
  					return false;
  
  			}
  
  			return true;
  
  		} catch (BadLocationException x) {
  			// should not happen
  			JavaScriptPlugin.log(x);
  		}
  
  		return false;
  	}
  
  	/**
  	 * Implementation of the <code>IUpdate</code> prototype method discovers
  	 * the operation through the current editor's
  	 * <code>ITextOperationTarget</code> adapter, and sets the enabled state
  	 * accordingly.
  	 */
  	public void update() {
  		super.update();
  
  		if (!canModifyEditor()) {
  			setEnabled(false);
  			return;
  		}
  
  		ITextEditor editor= getTextEditor();
  		if (fOperationTarget == null && editor != null)
  			fOperationTarget= (ITextOperationTarget) editor.getAdapter(ITextOperationTarget.class);
  
  		boolean isEnabled= (fOperationTarget != null && fOperationTarget.canDoOperation(ITextOperationTarget.PREFIX) && fOperationTarget.canDoOperation(ITextOperationTarget.STRIP_PREFIX));
  		setEnabled(isEnabled);
  	}
  
  	/*
  	 * @see TextEditorAction#setEditor(ITextEditor)
  	 */
  	public void setEditor(ITextEditor editor) {
  		super.setEditor(editor);
  		fOperationTarget= null;
  	}
  
  	public void configure(ISourceViewer sourceViewer, SourceViewerConfiguration configuration) {
  		fPrefixesMap= null;
  
  		String[] types= configuration.getConfiguredContentTypes(sourceViewer);
  		Map prefixesMap= new HashMap(types.length);
  		for (int i= 0; i < types.length; i++) {
  			String type= types[i];
  			String[] prefixes= configuration.getDefaultPrefixes(sourceViewer, type);
  			if (prefixes != null && prefixes.length > 0) {
  				int emptyPrefixes= 0;
  				for (int j= 0; j < prefixes.length; j++)
  					if (prefixes[j].length() == 0)
  						emptyPrefixes++;
  
  				if (emptyPrefixes > 0) {
  					String[] nonemptyPrefixes= new String[prefixes.length - emptyPrefixes];
  					for (int j= 0, k= 0; j < prefixes.length; j++) {
  						String prefix= prefixes[j];
  						if (prefix.length() != 0) {
  							nonemptyPrefixes[k]= prefix;
  							k++;
  						}
  					}
  					prefixes= nonemptyPrefixes;
  				}
  
  				prefixesMap.put(type, prefixes);
  			}
  		}
  		fDocumentPartitioning= configuration.getConfiguredDocumentPartitioning(sourceViewer);
  		fPrefixesMap= prefixesMap;
  	}
  }
  