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1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5/**
6 * @fileoverview This is a simple template engine inspired by JsTemplates
7 * optimized for i18n.
8 *
9 * It currently supports three handlers:
10 *
11 *   * i18n-content which sets the textContent of the element.
12 *
13 *     <span i18n-content="myContent"></span>
14 *
15 *   * i18n-options which generates <option> elements for a <select>.
16 *
17 *     <select i18n-options="myOptionList"></select>
18 *
19 *   * i18n-values is a list of attribute-value or property-value pairs.
20 *     Properties are prefixed with a '.' and can contain nested properties.
21 *
22 *     <span i18n-values="title:myTitle;.style.fontSize:fontSize"></span>
23 *
24 * This file is a copy of i18n_template.js, with minor tweaks to support using
25 * load_time_data.js. It should replace i18n_template.js eventually.
26 */
27
28var i18nTemplate = (function() {
29  /**
30   * This provides the handlers for the templating engine. The key is used as
31   * the attribute name and the value is the function that gets called for every
32   * single node that has this attribute.
33   * @type {Object}
34   */
35  var handlers = {
36    /**
37     * This handler sets the textContent of the element.
38     * @param {HTMLElement} element The node to modify.
39     * @param {string} key The name of the value in the dictionary.
40     * @param {LoadTimeData} dictionary The dictionary of strings to draw from.
41     */
42    'i18n-content': function(element, key, dictionary) {
43      element.textContent = dictionary.getString(key);
44    },
45
46    /**
47     * This handler adds options to a <select> element.
48     * @param {HTMLElement} select The node to modify.
49     * @param {string} key The name of the value in the dictionary. It should
50     *     identify an array of values to initialize an <option>. Each value,
51     *     if a pair, represents [content, value]. Otherwise, it should be a
52     *     content string with no value.
53     * @param {LoadTimeData} dictionary The dictionary of strings to draw from.
54     */
55    'i18n-options': function(select, key, dictionary) {
56      var options = dictionary.getValue(key);
57      options.forEach(function(optionData) {
58        var option = typeof optionData == 'string' ?
59            new Option(optionData) :
60            new Option(optionData[1], optionData[0]);
61        select.appendChild(option);
62      });
63    },
64
65    /**
66     * This is used to set HTML attributes and DOM properties. The syntax is:
67     *   attributename:key;
68     *   .domProperty:key;
69     *   .nested.dom.property:key
70     * @param {HTMLElement} element The node to modify.
71     * @param {string} attributeAndKeys The path of the attribute to modify
72     *     followed by a colon, and the name of the value in the dictionary.
73     *     Multiple attribute/key pairs may be separated by semicolons.
74     * @param {LoadTimeData} dictionary The dictionary of strings to draw from.
75     */
76    'i18n-values': function(element, attributeAndKeys, dictionary) {
77      var parts = attributeAndKeys.replace(/\s/g, '').split(/;/);
78      parts.forEach(function(part) {
79        if (!part)
80          return;
81
82        var attributeAndKeyPair = part.match(/^([^:]+):(.+)$/);
83        if (!attributeAndKeyPair)
84          throw new Error('malformed i18n-values: ' + attributeAndKeys);
85
86        var propName = attributeAndKeyPair[1];
87        var propExpr = attributeAndKeyPair[2];
88
89        var value = dictionary.getValue(propExpr);
90
91        // Allow a property of the form '.foo.bar' to assign a value into
92        // element.foo.bar.
93        if (propName[0] == '.') {
94          var path = propName.slice(1).split('.');
95          var targetObject = element;
96          while (targetObject && path.length > 1) {
97            targetObject = targetObject[path.shift()];
98          }
99          if (targetObject) {
100            targetObject[path] = value;
101            // In case we set innerHTML (ignoring others) we need to
102            // recursively check the content.
103            if (path == 'innerHTML')
104              process(element, dictionary);
105          }
106        } else {
107          element.setAttribute(propName, value);
108        }
109      });
110    }
111  };
112
113  var attributeNames = Object.keys(handlers);
114  var selector = '[' + attributeNames.join('],[') + ']';
115
116  /**
117   * Processes a DOM tree with the {@code dictionary} map.
118   * @param {HTMLElement} node The root of the DOM tree to process.
119   * @param {LoadTimeData} dictionary The dictionary to draw from.
120   */
121  function process(node, dictionary) {
122    var elements = node.querySelectorAll(selector);
123    for (var element, i = 0; element = elements[i]; i++) {
124      for (var j = 0; j < attributeNames.length; j++) {
125        var name = attributeNames[j];
126        var attribute = element.getAttribute(name);
127        if (attribute != null)
128          handlers[name](element, attribute, dictionary);
129      }
130    }
131  }
132
133  return {
134    process: process
135  };
136}());
137