Support boolean operators in search queries

This adds very basic support for boolean search queries such as "video
or movie" or "lin and not linux". However, nested queries such as
"(video or movie) and editing" are not (yet) supported.
Signed-off-by: Lukas Fleischer <lfleischer@archlinux.org>

web/lib/pkgfuncs.inc.php

@@ -602,21 +602,38 @@ function pkg_search_page($SID="") {
 		else {
 			/* Search by name and description (default). */
 			$count = 0;
+			$q_where .= "AND (";
+			$op = "";
 
 			foreach (str_getcsv($_GET['K'], ' ') as $term) {
 				if ($term == "") {
 					continue;
 				}
+				if ($count > 0 && strtolower($term) == "and") {
+					$op = "AND ";
+					continue;
+				}
+				if ($count > 0 && strtolower($term) == "or") {
+					$op = "OR ";
+					continue;
+				}
+			        if ($count > 0 && strtolower($term) == "not") {
+					$op .= "NOT ";
+					continue;
+				}
 
 				$term = "%" . addcslashes($term, '%_') . "%";
-				$q_where .= "AND (Packages.Name LIKE " . $dbh->quote($term) . " OR ";
+				$q_where .= $op . " (Packages.Name LIKE " . $dbh->quote($term) . " OR ";
 				$q_where .= "Description LIKE " . $dbh->quote($term) . ") ";
 
 				$count++;
 				if ($count >= 20) {
 					break;
 				}
+				$op = "AND ";
 			}
+
+			$q_where .= ") ";
 		}
 	}