FilterUtils.java

/*******************************************************************************
 * Copyright (c) 2006-2013, Cloudsmith Inc.
 * The code, documentation and other materials contained herein have been
 * licensed under the Eclipse Public License - v 1.0 by the copyright holder
 * listed above, as the Initial Contributor under such license. The text of
 * such license is available at www.eclipse.org.
 ******************************************************************************/

package org.eclipse.buckminster.core.helpers;

import java.util.StringTokenizer;

import org.eclipse.buckminster.core.TargetPlatform;
import org.eclipse.buckminster.osgi.filter.Filter;
import org.eclipse.buckminster.osgi.filter.FilterFactory;
import org.osgi.framework.InvalidSyntaxException;

public class FilterUtils {
	public static class MatchAll {
		public MatchAll(String v) {
		}

		@Override
		public boolean equals(Object o) {
			return true;
		}

		@Override
		public int hashCode() {
			return MATCH_ALL.hashCode();
		}

		@Override
		public String toString() {
			return MATCH_ALL;
		}
	}

	public static final String MATCH_ALL = "*"; //$NON-NLS-1$

	public static final MatchAll MATCH_ALL_OBJ = new MatchAll(MATCH_ALL);

	public static Filter createFilter(String os, String ws, String arch, String nl) {
		StringBuilder bld = new StringBuilder();

		int cnt = 0;
		if (addProperty(bld, TargetPlatform.TARGET_OS, os))
			cnt++;
		if (addProperty(bld, TargetPlatform.TARGET_WS, ws))
			cnt++;
		if (addProperty(bld, TargetPlatform.TARGET_ARCH, arch))
			cnt++;
		if (addProperty(bld, TargetPlatform.TARGET_NL, nl))
			cnt++;

		if (cnt > 0) {
			if (cnt > 1) {
				StringBuilder and = new StringBuilder(bld.length() + 3);
				and.append("(&"); //$NON-NLS-1$
				and.append(bld);
				and.append(')');
				bld = and;
			}
			try {
				return FilterFactory.newInstance(bld.toString());
			} catch (InvalidSyntaxException e) {
				// This should never happen
				//
				throw new RuntimeException(e);
			}
		}
		return null;
	}

	public static Filter replaceAttributeNames(org.osgi.framework.Filter filter, String from, String to) {
		if (filter == null)
			return null;
		try {
			return FilterFactory.newInstance(replaceAttributeNames(filter.toString(), from, to));
		} catch (InvalidSyntaxException e) {
			// This should never happen since we don't change the actual syntax
			//
			throw new RuntimeException(e);
		}
	}

	/**
	 * This method will parse the filter and potentially change the names of the
	 * attributes in that filter. No values will be replaced. Attributes named
	 * <code>from</code> or attributes that uses a dotted notation where
	 * <code>from</code> is one of the elements will have <code>from</code>
	 * replaced with <code>to</code>.
	 * 
	 * @param filter
	 *            An LDAP filter in string format
	 * @param from
	 *            The attribute name to replace
	 * @param to
	 *            The new attribute name
	 * @return A string where the needed replacements has been made.
	 */
	public static String replaceAttributeNames(String filter, String from, String to) {
		if (filter == null)
			return null;

		StringBuilder bld = new StringBuilder();
		boolean lastWasFilterStart = false;
		boolean lastWasEscape = false;
		StringTokenizer tokens = new StringTokenizer(filter, "\\&|!~<>=(). \t\r\f\n", true); //$NON-NLS-1$
		while (tokens.hasMoreTokens()) {
			String token = tokens.nextToken();
			if (lastWasFilterStart && token.equals(from))
				bld.append(to);
			else
				bld.append(token);

			if (token.length() == 1) {
				if (lastWasEscape)
					lastWasEscape = false;
				else {
					char c = token.charAt(0);
					if (Character.isWhitespace(c))
						continue;

					if (c == '(')
						lastWasFilterStart = true;
					else
						lastWasEscape = (c == '\\');
				}
			} else {
				lastWasEscape = false;
				lastWasFilterStart = false;
			}
		}
		return bld.toString();
	}

	private static boolean addProperty(StringBuilder bld, String key, String value) {
		value = TextUtils.notEmptyTrimmedString(value);
		if (value == null)
			return false;

		int bldStart = bld.length();
		int top = value.length();
		boolean startNew = true;
		boolean multi = false;
		for (int idx = 0; idx < top; ++idx) {
			if (startNew) {
				if (idx > 0) {
					bld.append(')');
					multi = true;
				}
				bld.append('(');
				bld.append(key);
				bld.append('=');
				startNew = false;
			}
			char c = value.charAt(idx);
			switch (c) {
				case '(':
				case ')':
				case '\\':
					bld.append('\\');
					bld.append(c);
					continue;
				case ',':
					startNew = true;
					continue;
			}
			bld.append(c);
		}

		bld.append(')');
		if (multi) {
			String expr = bld.substring(bldStart);
			bld.setLength(bldStart);
			bld.append("(|"); //$NON-NLS-1$
			bld.append(expr);
			bld.append(')');
		}
		return true;
	}
}