[Rubyeclipse-commit] org.rubypeople.rdt.ui/src/org/rubypeople/rdt/internal/ui/text/comment RubyCommentAutoIndentStrategy.java,NONE,1.1

[Christopher W. <caw...@us...>]

Update of /cvsroot/rubyeclipse/org.rubypeople.rdt.ui/src/org/rubypeople/rdt/internal/ui/text/comment
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv21910/src/org/rubypeople/rdt/internal/ui/text/comment

Added Files:
	RubyCommentAutoIndentStrategy.java 
Log Message:
implement ticket #74 - auto-extend comments under particular conditions

--- NEW FILE: RubyCommentAutoIndentStrategy.java ---
package org.rubypeople.rdt.internal.ui.text.comment;

import org.eclipse.jface.text.Assert;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.DefaultIndentLineAutoEditStrategy;
import org.eclipse.jface.text.DocumentCommand;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.IRegion;
import org.eclipse.jface.text.Region;
import org.eclipse.jface.text.TextUtilities;

public class RubyCommentAutoIndentStrategy extends
		DefaultIndentLineAutoEditStrategy {

	private String fPartitioning;

	public RubyCommentAutoIndentStrategy(String partitioning) {
		fPartitioning = partitioning;
	}

	public void customizeDocumentCommand(IDocument document,
			DocumentCommand command) {
		if (command.text != null) {
			if (command.length == 0) {
				String[] lineDelimiters = document.getLegalLineDelimiters();
				int index = TextUtilities
						.endsWith(lineDelimiters, command.text);
				if (index > -1) {
					// ends with line delimiter
					if (lineDelimiters[index].equals(command.text))
						// just the line delimiter
						indentAfterNewLine(document, command);
					return;
				}
			}
		}
	}

	/**
	 * Copies the indentation of the previous line and adds a #.
	 * 
	 * @param d
	 *            the document to work on
	 * @param c
	 *            the command to deal with
	 */
	private void indentAfterNewLine(IDocument d, DocumentCommand c) {

		int offset = c.offset;
		if (offset == -1 || d.getLength() == 0)
			return;

		try {
			int p = (offset == d.getLength() ? offset - 1 : offset);
				
			int lineNumber = d.getLineOfOffset(p);
			IRegion line = d.getLineInformation(lineNumber);
			if (lineNumber != 0) { // If first line, extend the comment
				String nextLine = getLine(d, lineNumber + 1); // otherwise check next line
				if (!(isComment(nextLine) || isClassDefinition(nextLine)
						|| isMethodDeclaration(nextLine)
						|| isAttributeCall(nextLine) || isAliasCall(nextLine)
						|| isModuleDeclaration(nextLine) || isConstantAssignment(nextLine))) { // if next line is commonly documented element, continue comment
					String previousLine = getLine(d, lineNumber - 1);
					if (!isComment(previousLine)) // last, if the previous line was a comment (so two lines in a row now), extend comments
						return;
				}
			}
			int lineOffset = line.getOffset();
			int firstNonWS = findEndOfWhiteSpace(d, lineOffset, offset);
			Assert.isTrue(firstNonWS >= lineOffset,
					"indentation must not be negative"); //$NON-NLS-1$

			StringBuffer buf = new StringBuffer(c.text);
			IRegion prefix = findPrefixRange(d, line);
			String indentation = d.get(prefix.getOffset(), prefix.getLength());
			int lengthToAdd = Math.min(offset - prefix.getOffset(), prefix
					.getLength());

			buf.append(indentation.substring(0, lengthToAdd));

			// move the caret behind the prefix, even if we do not have to
			// insert it.
			if (lengthToAdd < prefix.getLength())
				c.caretOffset = offset + prefix.getLength() - lengthToAdd;
			c.text = buf.toString();

		} catch (BadLocationException excp) {
			// stop work
		}
	}

	private boolean isComment(String nextLineText) {
		return nextLineText.matches("^\\s*#.*");
	}

	private boolean isClassDefinition(String nextLineText) {
		return nextLineText.matches("^\\s*class\\s+.+\\s*");
	}

	private boolean isAliasCall(String nextLineText) {
		return nextLineText.matches("^\\s*alias\\s+.+\\s*");
	}

	private boolean isModuleDeclaration(String nextLineText) {
		return nextLineText.matches("^\\s*module\\s+.+\\s*");
	}

	private boolean isMethodDeclaration(String nextLineText) {
		return nextLineText.matches("^\\s*def\\s+.+\\s*");
	}

	private boolean isAttributeCall(String nextLineText) {
		return nextLineText.matches("^\\s*attr.+\\s*");
	}

	private boolean isConstantAssignment(String nextLineText) {
		return nextLineText.matches("^\\s*[A-Z_]+\\s?=\\s+.+\\s*");
	}

	private String getLine(IDocument d, int lineNum) throws BadLocationException {
		IRegion nextLineRegion = d.getLineInformation(lineNum + 1);
		return d.get(nextLineRegion.getOffset(), nextLineRegion.getLength());
	}

	/**
	 * Returns the range of the comment prefix on the given line in
	 * <code>document</code>. The prefix greedily matches the following regex
	 * pattern: <code>\w*#\w*</code>, that is, any number of whitespace
	 * characters, followed by an pound symbol ('#'), followed by any number of
	 * whitespace characters.
	 * 
	 * @param document
	 *            the document to which <code>line</code> refers
	 * @param line
	 *            the line from which to extract the prefix range
	 * @return an <code>IRegion</code> describing the range of the prefix on
	 *         the given line
	 * @throws BadLocationException
	 *             if accessing the document fails
	 */
	private IRegion findPrefixRange(IDocument document, IRegion line)
			throws BadLocationException {
		int lineOffset = line.getOffset();
		int lineEnd = lineOffset + line.getLength();
		int indentEnd = findEndOfWhiteSpace(document, lineOffset, lineEnd);
		if (indentEnd < lineEnd && document.getChar(indentEnd) == '#') {
			indentEnd++;
			while (indentEnd < lineEnd && document.getChar(indentEnd) == ' ')
				indentEnd++;
		}
		return new Region(lineOffset, indentEnd - lineOffset);
	}

}