/*******************************************************************************
* Copyright (c) 2013 Red Hat Inc.
* 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:
* Red Hat Inc. - initial API and implementation
*******************************************************************************/
package org.eclipse.linuxtools.internal.systemtap.ui.ide.handlers;
import org.eclipse.core.commands.AbstractHandler;
import org.eclipse.core.commands.ExecutionEvent;
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.viewers.ISelection;
import org.eclipse.linuxtools.internal.systemtap.ui.ide.Localization;
import org.eclipse.linuxtools.internal.systemtap.ui.ide.editors.stp.STPPartitionScanner;
import org.eclipse.linuxtools.systemtap.graphing.ui.widgets.ExceptionErrorDialog;
import org.eclipse.swt.custom.BusyIndicator;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.ui.handlers.HandlerUtil;
import org.eclipse.ui.texteditor.ITextEditor;
/**
* Handler for command in charge of toggling comment prefixes. Based on
* org.eclipse.cdt.internal.ui.actions.ToggleCommentAction.
*/
public class ToggleCommentHandler extends AbstractHandler {
/** The text operation target */
private ITextOperationTarget operationTarget;
/**
* Checks if the selected lines are all commented or not and
* uncomments/comments them respectively.
*/
@Override
public Object execute(ExecutionEvent event) {
ITextEditor editor = (ITextEditor) HandlerUtil.getActiveEditor(event);
if (editor == null || !editor.isEditable()) {
return null;
}
updateOpTarget(editor);
if (operationTarget == null) {
return null;
}
ISelection selection = editor.getSelectionProvider().getSelection();
IDocument document = editor.getDocumentProvider().getDocument(
editor.getEditorInput());
final int operationCode;
if (isSelectionCommented(selection, document)) {
operationCode = ITextOperationTarget.STRIP_PREFIX;
} else {
operationCode = ITextOperationTarget.PREFIX;
}
Shell shell = editor.getSite().getShell();
if (!operationTarget.canDoOperation(operationCode)) {
if (shell != null) {
MessageDialog.openError(shell,
Localization.getString("ToggleComment_error_title"), //$NON-NLS-1$
Localization.getString("ToggleComment_error_message")); //$NON-NLS-1$
}
return null;
}
Display display = null;
if (shell != null && !shell.isDisposed()) {
display = shell.getDisplay();
}
BusyIndicator.showWhile(display, () -> operationTarget.doOperation(operationCode));
return null;
}
/**
* Creates a region describing the text block (something that starts at the
* beginning of a line) completely containing the current selection.
*
* Note, the implementation has to match org.eclipse.jface.text.TextViewer;
* .getTextBlockFromSelection().
*
* @param selection The selection to use
* @param document The document
* @return the region describing the text block comprising the given
* selection
* @throws BadLocationException
*/
public IRegion getTextBlockFromSelection(ITextSelection selection,
IDocument document) throws BadLocationException {
int start = document.getLineOffset(selection.getStartLine());
int end;
int endLine = selection.getEndLine();
if (document.getNumberOfLines() > endLine + 1) {
end = document.getLineOffset(endLine + 1);
} else {
end = document.getLength();
}
return new Region(start, end - start);
}
/**
* Is the given selection on the specified document single-line commented?
*
* @param selection Selection to check
* @param document The document
* @return <code>true</code> iff all selected lines are commented
*/
public boolean isSelectionCommented(ISelection selection,
IDocument document) {
if (!(selection instanceof ITextSelection)) {
return false;
}
ITextSelection textSelection = (ITextSelection) selection;
if (textSelection.getStartLine() < 0 || textSelection.getEndLine() < 0) {
return false;
}
try {
IRegion block = getTextBlockFromSelection(textSelection, document);
ITypedRegion[] regions = TextUtilities.computePartitioning(
document, STPPartitionScanner.STP_PARTITIONING,
block.getOffset(), block.getLength(), false);
int[] lines = new int[regions.length * 2]; // [startline, endline,
// startline, endline,
// ...]
// For each partition in the text selection, figure out the
// startline and endline.
// Count the number of lines that are selected.
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--;
}
// If there is no startline for this region (startline = -1),
// then there is no endline,
// otherwise, get the line number of the endline and store it in
// the array.
lines[j + 1] = (lines[j] == -1 ? -1 : document
.getLineOfOffset(offset));
assert i < regions.length;
assert j < regions.length * 2;
}
// Perform the check
boolean hasComment = false;
for (int i = 0, j = 0; i < regions.length; i++, j += 2) {
String prefix = "//"; //$NON-NLS-1$
if (lines[j] >= 0 && lines[j + 1] >= 0) {
if (isBlockCommented(lines[j], lines[j + 1], prefix,
document)) {
hasComment = true;
} else if (!isBlockEmpty(lines[j], lines[j + 1], document)) {
return false;
}
}
}
return hasComment;
} catch (BadLocationException e) {
ExceptionErrorDialog.openError(e.getLocalizedMessage(), e);
}
return false;
}
/**
* 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
*/
public 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 e) {
ExceptionErrorDialog.openError(e.getLocalizedMessage(), e);
}
return -1;
}
/**
* Determines whether each line is empty
*
* @param startLine Start line in document
* @param endLine End line in document
* @param document The document
* @return <code>true</code> if each line from <code>startLine</code> to and
* including <code>endLine</code> is empty
*/
public boolean isBlockEmpty(int startLine, int endLine, IDocument document) {
try {
for (int i = startLine; i <= endLine; i++) {
IRegion line = document.getLineInformation(i);
String text = document.get(line.getOffset(), line.getLength());
boolean isEmptyLine = text.trim().length() == 0;
if (!isEmptyLine) {
return false;
}
}
return true;
} catch (BadLocationException e) {
ExceptionErrorDialog.openError(e.getLocalizedMessage(), e);
}
return false;
}
/**
* Determines whether each line is prefixed by one of the prefixes.
*
* @param startLine Start line in document
* @param endLine End line in document
* @param prefix Comment prefix
* @param document The document
* @return <code>true</code> iff each line from <code>startLine</code> to
* and including <code>endLine</code> is prepended by the
* <code>prefix</code>, ignoring whitespace at the begin of line
*/
public boolean isBlockCommented(int startLine, int endLine, String prefix,
IDocument document) {
try {
// Check for occurrences of prefixes in the given lines
boolean hasComment = false;
for (int i = startLine; i <= endLine; i++) {
IRegion line = document.getLineInformation(i);
String text = document.get(line.getOffset(), line.getLength());
boolean isEmptyLine = text.trim().length() == 0;
if (isEmptyLine) {
continue;
}
int prefixIndex = text.indexOf(prefix, 0);
if (prefixIndex == -1) {
// Found a line which is not commented
return false;
}
String s = document.get(line.getOffset(), prefixIndex);
s = s.trim();
if (s.length() != 0) {
// Found a line which is not commented
return false;
}
hasComment = true;
}
return hasComment;
} catch (BadLocationException e) {
ExceptionErrorDialog.openError(e.getLocalizedMessage(), e);
}
return false;
}
/**
* Update text operation target based on the specified text editor.
*
* @param editor ITextEditor editor to associate operation target to.
*/
private void updateOpTarget(ITextEditor editor) {
if (editor != null) {
operationTarget = editor.getAdapter(ITextOperationTarget.class);
}
}
}