Retain escape sequences in lexer, fixes #5 (#21)

Retain escape sequences in lexer, fixes #5

\\ is preserved in Lexer, leaving it to later stages to decide
what masking is to be used.

Author: adamdickmeiss

src/main/java/org/z3950/zing/cql/CQLGenerator.java

@@ -204,7 +204,7 @@ private String generate_base_relation() throws MissingParameterException {
     private String generate_term() {
 	switch (rnd.nextInt(10)) {
 	case 0: return "cat";
-	case 1: return "\"cat\"";
+	case 1: return "\"cat\\\"";  // A term with both bare quotes and escaped quotes
 	case 2: return "comp.os.linux";
 	case 3: return "xml:element";
 	case 4: return "<xml.element>";

src/main/java/org/z3950/zing/cql/CQLLexer.java

@@ -69,19 +69,15 @@ else if (comp.equals("<>")) {
       //remember quote char
       char mark = c;
       qi++;
-      boolean escaped = false;
       buf.setLength(0); //reset buffer
-      while (qi < ql) {
-        if (!escaped && qs.charAt(qi) == mark) //terminator
-          break;
-        if (escaped && strchr("*?^\\", qs.charAt(qi))) //no escaping for d-quote
-          buf.append("\\");
-        if (!escaped && qs.charAt(qi) == '\\') { //escape-char
-          escaped = true;
+      while (qi < ql && qs.charAt(qi) != mark) {
+        if (qs.charAt(qi) == '\\') { //escape-char
+          if (qi == ql - 1) {
+            break; //unterminated
+          }
+          buf.append(qs.charAt(qi));
           qi++;
-          continue;
         }
-        escaped = false; //reset escape
         buf.append(qs.charAt(qi));
         qi++;
       }

src/main/java/org/z3950/zing/cql/CQLTermNode.java

@@ -229,7 +229,7 @@ static String maybeQuote(String str) {
 	    str.indexOf('/') != -1 ||
 	    str.indexOf('(') != -1 ||
 	    str.indexOf(')') != -1) {
-	    str = '"' + str.replace("\"", "\\\"") + '"';
+	    str = '"' + str.replaceAll("(?<!\\\\)\"", "\\\\\"") + '"';
 	}
 
 	return str;

src/test/resources/regression/06/03.xcql

@@ -3,5 +3,5 @@
   <relation>
     <value>=</value>
   </relation>
-  <term>^cat says "fish"</term>
+  <term>^cat says \"fish\"</term>
 </searchClause>

src/test/resources/regression/06/06.xcql

@@ -3,5 +3,5 @@
   <relation>
     <value>=</value>
   </relation>
-  <term>^cat*fishdog"horse?</term>
+  <term>^cat*fishdog\"horse?</term>
 </searchClause>

src/test/resources/regression/12/01.xcql

@@ -3,5 +3,5 @@
   <relation>
     <value>=</value>
   </relation>
-  <term>term\*\?\^</term>
+  <term>te\rm\*\?\^</term>
 </searchClause>