gitweb/static/js/adjust-timezone.js
// Copyright (C) 2011, John 'Warthog9' Hawley <warthog9@eaglescrag.net>
// 2011, Jakub Narebski <jnareb@gmail.com>
/**
* @fileOverview Manipulate dates in gitweb output, adjusting timezone
* @license GPLv2 or later
*/
/**
* Get common timezone, add UI for changing timezones, and adjust
* dates to use requested common timezone.
*
* This function is called during onload event (added to window.onload).
*
* @param {String} tzDefault: default timezone, if there is no cookie
* @param {Object} tzCookieInfo: object literal with info about cookie to store timezone
* @param {String} tzCookieInfo.name: name of cookie to store timezone
* @param {String} tzClassName: denotes elements with date to be adjusted
*/
function onloadTZSetup(tzDefault, tzCookieInfo, tzClassName) {
var tzCookieTZ = getCookie(tzCookieInfo.name, tzCookieInfo);
var tz = tzDefault;
if (tzCookieTZ) {
// set timezone to value saved in a cookie
tz = tzCookieTZ;
// refresh cookie, so its expiration counts from last use of gitweb
setCookie(tzCookieInfo.name, tzCookieTZ, tzCookieInfo);
}
// add UI for changing timezone
addChangeTZ(tz, tzCookieInfo, tzClassName);
// server-side of gitweb produces datetime in UTC,
// so if tz is 'utc' there is no need for changes
var nochange = tz === 'utc';
// adjust dates to use specified common timezone
fixDatetimeTZ(tz, tzClassName, nochange);
}
/* ...................................................................... */
/* Changing dates to use requested timezone */
/**
* Replace RFC-2822 dates contained in SPAN elements with tzClassName
* CSS class with equivalent dates in given timezone.
*
* @param {String} tz: numeric timezone in '(-|+)HHMM' format, or 'utc', or 'local'
* @param {String} tzClassName: specifies elements to be changed
* @param {Boolean} nochange: markup for timezone change, but don't change it
*/
function fixDatetimeTZ(tz, tzClassName, nochange) {
// sanity check, method should be ensured by common-lib.js
if (!document.getElementsByClassName) {
return;
}
// translate to timezone in '(-|+)HHMM' format
tz = normalizeTimezoneInfo(tz);
// NOTE: result of getElementsByClassName should probably be cached
var classesFound = document.getElementsByClassName(tzClassName, "span");
for (var i = 0, len = classesFound.length; i < len; i++) {
var curElement = classesFound[i];
curElement.title = 'Click to change timezone';
if (!nochange) {
// we use *.firstChild.data (W3C DOM) instead of *.innerHTML
// as the latter doesn't always work everywhere in every browser
var epoch = parseRFC2822Date(curElement.firstChild.data);
var adjusted = formatDateRFC2882(epoch, tz);
curElement.firstChild.data = adjusted;
}
}
}
/* ...................................................................... */
/* Adding triggers, generating timezone menu, displaying and hiding */
/**
* Adds triggers for UI to change common timezone used for dates in
* gitweb output: it marks up and/or creates item to click to invoke
* timezone change UI, creates timezone UI fragment to be attached,
* and installs appropriate onclick trigger (via event delegation).
*
* @param {String} tzSelected: pre-selected timezone,
* 'utc' or 'local' or '(-|+)HHMM'
* @param {Object} tzCookieInfo: object literal with info about cookie to store timezone
* @param {String} tzClassName: specifies elements to install trigger
*/
function addChangeTZ(tzSelected, tzCookieInfo, tzClassName) {
// make link to timezone UI discoverable
addCssRule('.'+tzClassName + ':hover',
'text-decoration: underline; cursor: help;');
// create form for selecting timezone (to be saved in a cookie)
var tzSelectFragment = document.createDocumentFragment();
tzSelectFragment = createChangeTZForm(tzSelectFragment,
tzSelected, tzCookieInfo, tzClassName);
// event delegation handler for timezone selection UI (clicking on entry)
// see http://www.nczonline.net/blog/2009/06/30/event-delegation-in-javascript/
// assumes that there is no existing document.onclick handler
document.onclick = function onclickHandler(event) {
//IE doesn't pass in the event object
event = event || window.event;
//IE uses srcElement as the target
var target = event.target || event.srcElement;
switch (target.className) {
case tzClassName:
// don't display timezone menu if it is already displayed
if (tzSelectFragment.childNodes.length > 0) {
displayChangeTZForm(target, tzSelectFragment);
}
break;
} // end switch
};
}
/**
* Create DocumentFragment with UI for changing common timezone in
* which dates are shown in.
*
* @param {DocumentFragment} documentFragment: where attach UI
* @param {String} tzSelected: default (pre-selected) timezone
* @param {Object} tzCookieInfo: object literal with info about cookie to store timezone
* @returns {DocumentFragment}
*/
function createChangeTZForm(documentFragment, tzSelected, tzCookieInfo, tzClassName) {
var div = document.createElement("div");
div.className = 'popup';
/* '<div class="close-button" title="(click on this box to close)">X</div>' */
var closeButton = document.createElement('div');
closeButton.className = 'close-button';
closeButton.title = '(click on this box to close)';
closeButton.appendChild(document.createTextNode('X'));
closeButton.onclick = closeTZFormHandler(documentFragment, tzClassName);
div.appendChild(closeButton);
/* 'Select timezone: <br clear="all">' */
div.appendChild(document.createTextNode('Select timezone: '));
var br = document.createElement('br');
br.clear = 'all';
div.appendChild(br);
/* '<select name="tzoffset">
* ...
* <option value="-0700">UTC-07:00</option>
* <option value="-0600">UTC-06:00</option>
* ...
* </select>' */
var select = document.createElement("select");
select.name = "tzoffset";
//select.style.clear = 'all';
select.appendChild(generateTZOptions(tzSelected));
select.onchange = selectTZHandler(documentFragment, tzCookieInfo, tzClassName);
div.appendChild(select);
documentFragment.appendChild(div);
return documentFragment;
}
/**
* Hide (remove from DOM) timezone change UI, ensuring that it is not
* garbage collected and that it can be re-enabled later.
*
* @param {DocumentFragment} documentFragment: contains detached UI
* @param {HTMLSelectElement} target: select element inside of UI
* @param {String} tzClassName: specifies element where UI was installed
* @returns {DocumentFragment} documentFragment
*/
function removeChangeTZForm(documentFragment, target, tzClassName) {
// find containing element, where we appended timezone selection UI
// `target' is somewhere inside timezone menu
var container = target.parentNode, popup = target;
while (container &&
container.className !== tzClassName) {
popup = container;
container = container.parentNode;
}
// safety check if we found correct container,
// and if it isn't deleted already
if (!container || !popup ||
container.className !== tzClassName ||
popup.className !== 'popup') {
return documentFragment;
}
// timezone selection UI was appended as last child
// see also displayChangeTZForm function
var removed = popup.parentNode.removeChild(popup);
if (documentFragment.firstChild !== removed) { // the only child
// re-append it so it would be available for next time
documentFragment.appendChild(removed);
}
// all of inline style was added by this script
// it is not really needed to remove it, but it is a good practice
container.removeAttribute('style');
return documentFragment;
}
/**
* Display UI for changing common timezone for dates in gitweb output.
* To be used from 'onclick' event handler.
*
* @param {HTMLElement} target: where to install/display UI
* @param {DocumentFragment} tzSelectFragment: timezone selection UI
*/
function displayChangeTZForm(target, tzSelectFragment) {
// for absolute positioning to be related to target element
target.style.position = 'relative';
target.style.display = 'inline-block';
// show/display UI for changing timezone
target.appendChild(tzSelectFragment);
}
/* ...................................................................... */
/* List of timezones for timezone selection menu */
/**
* Generate list of timezones for creating timezone select UI
*
* @returns {Object[]} list of e.g. { value: '+0100', descr: 'GMT+01:00' }
*/
function generateTZList() {
var timezones = [
{ value: "utc", descr: "UTC/GMT"},
{ value: "local", descr: "Local (per browser)"}
];
// generate all full hour timezones (no fractional timezones)
for (var x = -12, idx = timezones.length; x <= +14; x++, idx++) {
var hours = (x >= 0 ? '+' : '-') + padLeft(x >=0 ? x : -x, 2);
timezones[idx] = { value: hours + '00', descr: 'UTC' + hours + ':00'};
if (x === 0) {
timezones[idx].descr = 'UTC\u00B100:00'; // 'UTC±00:00'
}
}
return timezones;
}
/**
* Generate <options> elements for timezone select UI
*
* @param {String} tzSelected: default timezone
* @returns {DocumentFragment} list of options elements to appendChild
*/
function generateTZOptions(tzSelected) {
var elems = document.createDocumentFragment();
var timezones = generateTZList();
for (var i = 0, len = timezones.length; i < len; i++) {
var tzone = timezones[i];
var option = document.createElement("option");
if (tzone.value === tzSelected) {
option.defaultSelected = true;
}
option.value = tzone.value;
option.appendChild(document.createTextNode(tzone.descr));
elems.appendChild(option);
}
return elems;
}
/* ...................................................................... */
/* Event handlers and/or their generators */
/**
* Create event handler that select timezone and closes timezone select UI.
* To be used as $('select[name="tzselect"]').onchange handler.
*
* @param {DocumentFragment} tzSelectFragment: timezone selection UI
* @param {Object} tzCookieInfo: object literal with info about cookie to store timezone
* @param {String} tzCookieInfo.name: name of cookie to save result of selection
* @param {String} tzClassName: specifies element where UI was installed
* @returns {Function} event handler
*/
function selectTZHandler(tzSelectFragment, tzCookieInfo, tzClassName) {
//return function selectTZ(event) {
return function (event) {
event = event || window.event;
var target = event.target || event.srcElement;
var selected = target.options.item(target.selectedIndex);
removeChangeTZForm(tzSelectFragment, target, tzClassName);
if (selected) {
selected.defaultSelected = true;
setCookie(tzCookieInfo.name, selected.value, tzCookieInfo);
fixDatetimeTZ(selected.value, tzClassName);
}
};
}
/**
* Create event handler that closes timezone select UI.
* To be used e.g. as $('.closebutton').onclick handler.
*
* @param {DocumentFragment} tzSelectFragment: timezone selection UI
* @param {String} tzClassName: specifies element where UI was installed
* @returns {Function} event handler
*/
function closeTZFormHandler(tzSelectFragment, tzClassName) {
//return function closeTZForm(event) {
return function (event) {
event = event || window.event;
var target = event.target || event.srcElement;
removeChangeTZForm(tzSelectFragment, target, tzClassName);
};
}
/* end of adjust-timezone.js */