Lady’s Gitweb - Gitweb/blob - static/js/adjust-timezone.js

   1 // Copyright (C) 2011, John 'Warthog9' Hawley <warthog9@eaglescrag.net>
   2 //               2011, Jakub Narebski <jnareb@gmail.com>
   3
   4 /**
   5  * @fileOverview Manipulate dates in gitweb output, adjusting timezone
   6  * @license GPLv2 or later
   7  */
   8
   9 /**
  10  * Get common timezone, add UI for changing timezones, and adjust
  11  * dates to use requested common timezone.
  12  *
  13  * This function is called during onload event (added to window.onload).
  14  *
  15  * @param {String} tzDefault: default timezone, if there is no cookie
  16  * @param {Object} tzCookieInfo: object literal with info about cookie to store timezone
  17  * @param {String} tzCookieInfo.name: name of cookie to store timezone
  18  * @param {String} tzClassName: denotes elements with date to be adjusted
  19  */
  20 function onloadTZSetup(tzDefault, tzCookieInfo, tzClassName) {
  21         var tzCookieTZ = getCookie(tzCookieInfo.name, tzCookieInfo);
  22         var tz = tzDefault;
  23
  24         if (tzCookieTZ) {
  25                 // set timezone to value saved in a cookie
  26                 tz = tzCookieTZ;
  27                 // refresh cookie, so its expiration counts from last use of gitweb
  28                 setCookie(tzCookieInfo.name, tzCookieTZ, tzCookieInfo);
  29         }
  30
  31         // add UI for changing timezone
  32         addChangeTZ(tz, tzCookieInfo, tzClassName);
  33
  34         // server-side of gitweb produces datetime in UTC,
  35         // so if tz is 'utc' there is no need for changes
  36         var nochange = tz === 'utc';
  37
  38         // adjust dates to use specified common timezone
  39         fixDatetimeTZ(tz, tzClassName, nochange);
  40 }
  41
  42
  43 /* ...................................................................... */
  44 /* Changing dates to use requested timezone */
  45
  46 /**
  47  * Replace RFC-2822 dates contained in SPAN elements with tzClassName
  48  * CSS class with equivalent dates in given timezone.
  49  *
  50  * @param {String} tz: numeric timezone in '(-|+)HHMM' format, or 'utc', or 'local'
  51  * @param {String} tzClassName: specifies elements to be changed
  52  * @param {Boolean} nochange: markup for timezone change, but don't change it
  53  */
  54 function fixDatetimeTZ(tz, tzClassName, nochange) {
  55         // sanity check, method should be ensured by common-lib.js
  56         if (!document.getElementsByClassName) {
  57                 return;
  58         }
  59
  60         // translate to timezone in '(-|+)HHMM' format
  61         tz = normalizeTimezoneInfo(tz);
  62
  63         // NOTE: result of getElementsByClassName should probably be cached
  64         var classesFound = document.getElementsByClassName(tzClassName, "span");
  65         for (var i = 0, len = classesFound.length; i < len; i++) {
  66                 var curElement = classesFound[i];
  67
  68                 curElement.title = 'Click to change timezone';
  69                 if (!nochange) {
  70                         // we use *.firstChild.data (W3C DOM) instead of *.innerHTML
  71                         // as the latter doesn't always work everywhere in every browser
  72                         var epoch = parseRFC2822Date(curElement.firstChild.data);
  73                         var adjusted = formatDateRFC2882(epoch, tz);
  74
  75                         curElement.firstChild.data = adjusted;
  76                 }
  77         }
  78 }
  79
  80
  81 /* ...................................................................... */
  82 /* Adding triggers, generating timezone menu, displaying and hiding */
  83
  84 /**
  85  * Adds triggers for UI to change common timezone used for dates in
  86  * gitweb output: it marks up and/or creates item to click to invoke
  87  * timezone change UI, creates timezone UI fragment to be attached,
  88  * and installs appropriate onclick trigger (via event delegation).
  89  *
  90  * @param {String} tzSelected: pre-selected timezone,
  91  *                             'utc' or 'local' or '(-|+)HHMM'
  92  * @param {Object} tzCookieInfo: object literal with info about cookie to store timezone
  93  * @param {String} tzClassName: specifies elements to install trigger
  94  */
  95 function addChangeTZ(tzSelected, tzCookieInfo, tzClassName) {
  96         // make link to timezone UI discoverable
  97         addCssRule('.'+tzClassName + ':hover',
  98                    'text-decoration: underline; cursor: help;');
  99
 100         // create form for selecting timezone (to be saved in a cookie)
 101         var tzSelectFragment = document.createDocumentFragment();
 102         tzSelectFragment = createChangeTZForm(tzSelectFragment,
 103                                               tzSelected, tzCookieInfo, tzClassName);
 104
 105         // event delegation handler for timezone selection UI (clicking on entry)
 106         // see http://www.nczonline.net/blog/2009/06/30/event-delegation-in-javascript/
 107         // assumes that there is no existing document.onclick handler
 108         document.onclick = function onclickHandler(event) {
 109                 //IE doesn't pass in the event object
 110                 event = event || window.event;
 111
 112                 //IE uses srcElement as the target
 113                 var target = event.target || event.srcElement;
 114
 115                 switch (target.className) {
 116                 case tzClassName:
 117                         // don't display timezone menu if it is already displayed
 118                         if (tzSelectFragment.childNodes.length > 0) {
 119                                 displayChangeTZForm(target, tzSelectFragment);
 120                         }
 121                         break;
 122                 } // end switch
 123         };
 124 }
 125
 126 /**
 127  * Create DocumentFragment with UI for changing common timezone in
 128  * which dates are shown in.
 129  *
 130  * @param {DocumentFragment} documentFragment: where attach UI
 131  * @param {String} tzSelected: default (pre-selected) timezone
 132  * @param {Object} tzCookieInfo: object literal with info about cookie to store timezone
 133  * @returns {DocumentFragment}
 134  */
 135 function createChangeTZForm(documentFragment, tzSelected, tzCookieInfo, tzClassName) {
 136         var div = document.createElement("div");
 137         div.className = 'popup';
 138
 139         /* '<div class="close-button" title="(click on this box to close)">X</div>' */
 140         var closeButton = document.createElement('div');
 141         closeButton.className = 'close-button';
 142         closeButton.title = '(click on this box to close)';
 143         closeButton.appendChild(document.createTextNode('X'));
 144         closeButton.onclick = closeTZFormHandler(documentFragment, tzClassName);
 145         div.appendChild(closeButton);
 146
 147         /* 'Select timezone: <br clear="all">' */
 148         div.appendChild(document.createTextNode('Select timezone: '));
 149         var br = document.createElement('br');
 150         br.clear = 'all';
 151         div.appendChild(br);
 152
 153         /* '<select name="tzoffset">
 154          *    ...
 155          *    <option value="-0700">UTC-07:00</option>
 156          *    <option value="-0600">UTC-06:00</option>
 157          *    ...
 158          *  </select>' */
 159         var select = document.createElement("select");
 160         select.name = "tzoffset";
 161         //select.style.clear = 'all';
 162         select.appendChild(generateTZOptions(tzSelected));
 163         select.onchange = selectTZHandler(documentFragment, tzCookieInfo, tzClassName);
 164         div.appendChild(select);
 165
 166         documentFragment.appendChild(div);
 167
 168         return documentFragment;
 169 }
 170
 171
 172 /**
 173  * Hide (remove from DOM) timezone change UI, ensuring that it is not
 174  * garbage collected and that it can be re-enabled later.
 175  *
 176  * @param {DocumentFragment} documentFragment: contains detached UI
 177  * @param {HTMLSelectElement} target: select element inside of UI
 178  * @param {String} tzClassName: specifies element where UI was installed
 179  * @returns {DocumentFragment} documentFragment
 180  */
 181 function removeChangeTZForm(documentFragment, target, tzClassName) {
 182         // find containing element, where we appended timezone selection UI
 183         // `target' is somewhere inside timezone menu
 184         var container = target.parentNode, popup = target;
 185         while (container &&
 186                container.className !== tzClassName) {
 187                 popup = container;
 188                 container = container.parentNode;
 189         }
 190         // safety check if we found correct container,
 191         // and if it isn't deleted already
 192         if (!container || !popup ||
 193             container.className !== tzClassName ||
 194             popup.className     !== 'popup') {
 195                 return documentFragment;
 196         }
 197
 198         // timezone selection UI was appended as last child
 199         // see also displayChangeTZForm function
 200         var removed = popup.parentNode.removeChild(popup);
 201         if (documentFragment.firstChild !== removed) { // the only child
 202                 // re-append it so it would be available for next time
 203                 documentFragment.appendChild(removed);
 204         }
 205         // all of inline style was added by this script
 206         // it is not really needed to remove it, but it is a good practice
 207         container.removeAttribute('style');
 208
 209         return documentFragment;
 210 }
 211
 212
 213 /**
 214  * Display UI for changing common timezone for dates in gitweb output.
 215  * To be used from 'onclick' event handler.
 216  *
 217  * @param {HTMLElement} target: where to install/display UI
 218  * @param {DocumentFragment} tzSelectFragment: timezone selection UI
 219  */
 220 function displayChangeTZForm(target, tzSelectFragment) {
 221         // for absolute positioning to be related to target element
 222         target.style.position = 'relative';
 223         target.style.display = 'inline-block';
 224
 225         // show/display UI for changing timezone
 226         target.appendChild(tzSelectFragment);
 227 }
 228
 229
 230 /* ...................................................................... */
 231 /* List of timezones for timezone selection menu */
 232
 233 /**
 234  * Generate list of timezones for creating timezone select UI
 235  *
 236  * @returns {Object[]} list of e.g. { value: '+0100', descr: 'GMT+01:00' }
 237  */
 238 function generateTZList() {
 239         var timezones = [
 240                 { value: "utc",   descr: "UTC/GMT"},
 241                 { value: "local", descr: "Local (per browser)"}
 242         ];
 243
 244         // generate all full hour timezones (no fractional timezones)
 245         for (var x = -12, idx = timezones.length; x <= +14; x++, idx++) {
 246                 var hours = (x >= 0 ? '+' : '-') + padLeft(x >=0 ? x : -x, 2);
 247                 timezones[idx] = { value: hours + '00', descr: 'UTC' + hours + ':00'};
 248                 if (x === 0) {
 249                         timezones[idx].descr = 'UTC\u00B100:00'; // 'UTC&plusmn;00:00'
 250                 }
 251         }
 252
 253         return timezones;
 254 }
 255
 256 /**
 257  * Generate <options> elements for timezone select UI
 258  *
 259  * @param {String} tzSelected: default timezone
 260  * @returns {DocumentFragment} list of options elements to appendChild
 261  */
 262 function generateTZOptions(tzSelected) {
 263         var elems = document.createDocumentFragment();
 264         var timezones = generateTZList();
 265
 266         for (var i = 0, len = timezones.length; i < len; i++) {
 267                 var tzone = timezones[i];
 268                 var option = document.createElement("option");
 269                 if (tzone.value === tzSelected) {
 270                         option.defaultSelected = true;
 271                 }
 272                 option.value = tzone.value;
 273                 option.appendChild(document.createTextNode(tzone.descr));
 274
 275                 elems.appendChild(option);
 276         }
 277
 278         return elems;
 279 }
 280
 281
 282 /* ...................................................................... */
 283 /* Event handlers and/or their generators */
 284
 285 /**
 286  * Create event handler that select timezone and closes timezone select UI.
 287  * To be used as $('select[name="tzselect"]').onchange handler.
 288  *
 289  * @param {DocumentFragment} tzSelectFragment: timezone selection UI
 290  * @param {Object} tzCookieInfo: object literal with info about cookie to store timezone
 291  * @param {String} tzCookieInfo.name: name of cookie to save result of selection
 292  * @param {String} tzClassName: specifies element where UI was installed
 293  * @returns {Function} event handler
 294  */
 295 function selectTZHandler(tzSelectFragment, tzCookieInfo, tzClassName) {
 296         //return function selectTZ(event) {
 297         return function (event) {
 298                 event = event || window.event;
 299                 var target = event.target || event.srcElement;
 300
 301                 var selected = target.options.item(target.selectedIndex);
 302                 removeChangeTZForm(tzSelectFragment, target, tzClassName);
 303
 304                 if (selected) {
 305                         selected.defaultSelected = true;
 306                         setCookie(tzCookieInfo.name, selected.value, tzCookieInfo);
 307                         fixDatetimeTZ(selected.value, tzClassName);
 308                 }
 309         };
 310 }
 311
 312 /**
 313  * Create event handler that closes timezone select UI.
 314  * To be used e.g. as $('.closebutton').onclick handler.
 315  *
 316  * @param {DocumentFragment} tzSelectFragment: timezone selection UI
 317  * @param {String} tzClassName: specifies element where UI was installed
 318  * @returns {Function} event handler
 319  */
 320 function closeTZFormHandler(tzSelectFragment, tzClassName) {
 321         //return function closeTZForm(event) {
 322         return function (event) {
 323                 event = event || window.event;
 324                 var target = event.target || event.srcElement;
 325
 326                 removeChangeTZForm(tzSelectFragment, target, tzClassName);
 327         };
 328 }
 329
 330 /* end of adjust-timezone.js */