FunctionReferenceRule.java

/*******************************************************************************
 * Copyright (c) 2013, 2016 Andrew Gvozdev 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:
 *     Andrew Gvozdev - Initial API and implementation
 *******************************************************************************/
package org.eclipse.cdt.make.internal.ui.text.makefile;

import org.eclipse.cdt.make.internal.core.makefile.gnu.GNUMakefileConstants;
import org.eclipse.jface.text.rules.ICharacterScanner;
import org.eclipse.jface.text.rules.IToken;
import org.eclipse.jface.text.rules.IWordDetector;
import org.eclipse.jface.text.rules.Token;
import org.eclipse.jface.text.rules.WordRule;

public class FunctionReferenceRule extends WordRule {
	/** Buffer used for pattern detection. */
	private StringBuilder fBuffer= new StringBuilder();
	private String startSeq;
	private String endSeq;

	@SuppressWarnings("nls")
	private final static String[] functions = {
		"subst", "patsubst", "strip", "findstring",
		"filter", "filter-out", "sort",
		"word", "words", "wordlist", "firstword", "lastword",
		"dir", "notdir",
		"suffix", "basename", "addsuffix", "addprefix",
		"join", "wildcard", "realpath", "abspath",
		"if", "or", "and", "foreach",
		"call", "value", "eval", "origin", "flavor",
		"shell", "error", "warning", "info",
	};

	private static class TagDetector implements IWordDetector {
		private char openBracket;
		private char closedBracket;
		private boolean isClosedBracket = false;
		private int bracketNesting = 0;

		public TagDetector(String endSeq) {
			if (endSeq.length() > 0 && endSeq.charAt(0) == '}') {
				openBracket = '{';
				closedBracket = '}';
			} else {
				openBracket = '(';
				closedBracket = ')';
			}
		}
		@Override
		public boolean isWordStart(char c) {
			isClosedBracket = c == closedBracket;
			return isClosedBracket || c == '$';
		}
		@Override
		public boolean isWordPart(char c) {
			return !isClosedBracket && (c == '$' || c == openBracket || Character.isJavaIdentifierPart(c) || c == '-');
		}
		public boolean isBracket(char c) {
			return "(){}".contains(Character.toString(c)); //$NON-NLS-1$
		}
	}

	public FunctionReferenceRule(IToken token, String startSeq, String endSeq) {
		super(new TagDetector(endSeq));
		this.startSeq = startSeq;
		this.endSeq = endSeq;
		for (String f : functions) {
			addWord(startSeq + f, token);
			addWord('$' + startSeq + f, token);
		}
		addWord(endSeq, token);
	}

	@Override
	public IToken evaluate(ICharacterScanner scanner) {
		TagDetector tagDetector = (TagDetector)fDetector;
		int c = scanner.read();
		if (c == tagDetector.closedBracket) {
			if (tagDetector.bracketNesting > 0) {
				tagDetector.bracketNesting--;
				return fWords.get(endSeq);
			}
			return fDefaultToken;
		}

		if (c != ICharacterScanner.EOF && fDetector.isWordStart((char) c)) {
			if (fColumn == UNDEFINED || (fColumn == scanner.getColumn() - 1)) {

				fBuffer.setLength(0);
				do {
					fBuffer.append((char) c);
					c = scanner.read();
				} while (c != ICharacterScanner.EOF && fDetector.isWordPart((char) c));
				scanner.unread();

				String buffer= fBuffer.toString();

				IToken token= fWords.get(buffer);

				if (token != null) {
					if (buffer.equals(startSeq + GNUMakefileConstants.FUNCTION_CALL) || buffer.equals('$' + startSeq + GNUMakefileConstants.FUNCTION_CALL)) {
						if ((char)scanner.read() == ' ') {
							do {
								c = scanner.read();
							} while (((TagDetector) fDetector).isBracket((char)c) || fDetector.isWordPart((char) c));
						}
						scanner.unread();
					}
					((TagDetector)fDetector).bracketNesting++;
					return token;
				}

				if (fDefaultToken.isUndefined())
					unreadBuffer(scanner);

				return fDefaultToken;
			}
		}

		scanner.unread();
		return Token.UNDEFINED;
	}

	@Override
	protected void unreadBuffer(ICharacterScanner scanner) {
		for (int i= fBuffer.length() - 1; i >= 0; i--)
			scanner.unread();
	}
}