JsEscapeFunction.java revision 56ed4167b942ec265f9cee70ac4d71d10b3835ce 
1/*
2 * Copyright (C) 2010 Google Inc.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.google.clearsilver.jsilver.functions.escape;
18
19
20/**
21 * This Javascript escapes the string so it will be valid data for placement into a Javascript
22 * string. This converts characters such as ", ', and \ into their Javascript string safe
23 * equivilants \", \', and \\.
24 *
25 * This behaves in the same way as the ClearSilver js_escape function.
26 *
27 * This implementation has been optimized for performance.
28 */
29public class JsEscapeFunction extends SimpleEscapingFunction {
30
31  private static final char[] DIGITS = "0123456789ABCDEF".toCharArray();
32
33  private static final char[] ESCAPE_CHARS;
34
35  private static final char[] UNQUOTED_ESCAPE_CHARS;
36
37  static {
38    char[] SPECIAL_CHARS = {'/', '"', '\'', '\\', '>', '<', '&', ';'};
39    char[] UNQUOTED_SPECIAL_CHARS = {'/', '"', '\'', '\\', '>', '<', '&', ';', '=', ' '};
40
41    ESCAPE_CHARS = new char[32 + SPECIAL_CHARS.length];
42    UNQUOTED_ESCAPE_CHARS = new char[33 + UNQUOTED_SPECIAL_CHARS.length];
43    for (int n = 0; n < 32; n++) {
44      ESCAPE_CHARS[n] = (char) n;
45      UNQUOTED_ESCAPE_CHARS[n] = (char) n;
46    }
47
48    System.arraycopy(SPECIAL_CHARS, 0, ESCAPE_CHARS, 32, SPECIAL_CHARS.length);
49
50    UNQUOTED_ESCAPE_CHARS[32] = 0x7F;
51    System.arraycopy(UNQUOTED_SPECIAL_CHARS, 0, UNQUOTED_ESCAPE_CHARS, 33,
52        UNQUOTED_SPECIAL_CHARS.length);
53  }
54
55  /**
56   * isUnquoted should be true if the function is escaping a string that will appear inside an
57   * unquoted JS attribute (like onClick or onMouseover).
58   *
59   */
60  public JsEscapeFunction(boolean isAttrUnquoted) {
61    if (isAttrUnquoted) {
62      super.setEscapeChars(UNQUOTED_ESCAPE_CHARS);
63    } else {
64      super.setEscapeChars(ESCAPE_CHARS);
65    }
66  }
67
68  @Override
69  protected String getEscapeString(char c) {
70    return "\\x" + DIGITS[(c >> 4) & 0xF] + DIGITS[c & 0xF];
71  }
72}
73