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Fixed localStorage availability test (for real this time), and asynchronified embed.js

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I spent some time fixing the latter because browsers have started warning that synchronous XMLHttpRequest calls on the "main thread" (as Firefox calls it) are deprecated. Since the days of such calls seems to be numbered, I decided to act sooner rather than later.  All PCjs XMLHttpRequests go through a single library function (weblib.loadResource), which accepts an fAsync parameter, and the only code that is still allowed to pass false for that parameter are "emergency" shutdown requests (which I believe browsers must still allow).
This commit is contained in:
Jeff Parsons 2014-10-28 17:12:24 -07:00 • committed by jeffpar
commit e0487bccd8
9 changed files with 1397 additions and 1245 deletions
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134
my_modules/shared/lib/weblib.js
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@ -147,7 +147,7 @@ var web = {};
*
* @param {string} sURL
* @param {boolean} [fAsync] is true for an asynchronous request
* @param {Object|null} [data] for a POST request (default is a GET request)
* @param {Object} [data] for a POST request (default is a GET request)
* @param {Component} [componentNotify]
* @param {function(...)} [fnNotify]
* @param {number|string|null|Object|Array} [pNotify] optional fnNotify info parameter
@ -174,13 +174,14 @@ web.loadResource = function(sURL, fAsync, data, componentNotify, fnNotify, pNoti
xmlHTTP.onreadystatechange = function() {
if (xmlHTTP.readyState === 4) {
/*
* The following line is recommended for WebKit, as a work-around to prevent the handler firing multiple
* The following line was recommended for WebKit, as a work-around to prevent the handler firing multiple
* times when debugging. Unfortunately, that's not the only XMLHttpRequest problem that occurs when
* debugging, so I think the WebKit problem is deeper than that. When we have multiple XMLHttpRequests
* pending, any debugging activity means most of them simply get dropped on floor, so what may actually be
* happening are mis-notifications rather than redundant notifications.
*/
*
xmlHTTP.onreadystatechange = undefined;
*/
sURLData = xmlHTTP.responseText;
if (xmlHTTP.status == 200) {
Component.log("xmlHTTP.onreadystatechange(" + sURL + "): returned " + sURLData.length + " bytes");
@ -189,7 +190,13 @@ web.loadResource = function(sURL, fAsync, data, componentNotify, fnNotify, pNoti
nErrorCode = xmlHTTP.status || -1;
Component.log("xmlHTTP.onreadystatechange(" + sURL + "): error code " + nErrorCode);
}
if (componentNotify && fnNotify) fnNotify.call(componentNotify, sURLName, sURLData, nErrorCode, pNotify);
if (fnNotify) {
if (!componentNotify) {
fnNotify(sURLName, sURLData, nErrorCode, pNotify);
} else {
fnNotify.call(componentNotify, sURLName, sURLData, nErrorCode, pNotify);
}
}
}
};
}
@ -219,7 +226,13 @@ web.loadResource = function(sURL, fAsync, data, componentNotify, fnNotify, pNoti
nErrorCode = xmlHTTP.status || -1;
Component.log("web.loadResource(" + sURL + "): error code " + nErrorCode);
}
if (componentNotify && fnNotify) fnNotify.call(componentNotify, sURLName, sURLData, nErrorCode, pNotify);
if (fnNotify) {
if (!componentNotify) {
fnNotify(sURLName, sURLData, nErrorCode, pNotify);
} else {
fnNotify.call(componentNotify, sURLName, sURLData, nErrorCode, pNotify);
}
}
response = [nErrorCode, sURLData];
}
return response;
@ -326,6 +339,49 @@ web.promptUser = function(sPrompt, sDefault)
return sResponse;
};
/**
* fLocalStorage
*
* true if localStorage support exists, is enabled, and works; "falsey" otherwise
*
* @type {boolean|undefined}
*/
web.fLocalStorage;
/**
* hasLocalStorage
*
* true if localStorage support exists, is enabled, and works; false otherwise
*
* @return {boolean}
*/
web.hasLocalStorage = function() {
if (web.fLocalStorage === undefined) {
var f;
var sTest = 'PCjs.localStorage';
try {
window.localStorage.setItem(sTest, sTest);
f = (window.localStorage.getItem(sTest) === sTest);
window.localStorage.removeItem(sTest);
} catch(e) {
web.logLocalStorageError(e);
f = false;
}
web.fLocalStorage = f;
}
return web.fLocalStorage;
};
/**
* logLocalStorageError(e)
*
* @param {Error} e is an exception
*/
web.logLocalStorageError = function(e)
{
Component.log(e.message, "localStorage error");
};
/**
* getLocalStorageItem(sKey)
*
@ -337,14 +393,10 @@ web.promptUser = function(sPrompt, sDefault)
web.getLocalStorageItem = function(sKey)
{
var sValue;
if (window) {
try {
/*
* A try/catch block is required, because if the user has disabled localStorage, some browsers feel the need
* to throw an exception on any attempt to access it, even when using "typeof".
*/
sValue = window.localStorage.getItem(sKey);
} catch(e) {}
try {
sValue = window.localStorage.getItem(sKey);
} catch(e) {
web.logLocalStorageError(e);
}
return sValue;
};
@ -354,23 +406,51 @@ web.getLocalStorageItem = function(sKey)
*
* @param {string} sKey
* @param {string} sValue
* return {boolean} true if localStorage is available, false if not
* @return {boolean} true if localStorage is available, false if not
*/
web.setLocalStorageItem = function(sKey, sValue)
{
if (window) {
try {
/*
* A try/catch block is required, because if the user has disabled localStorage, some browsers feel the need
* to throw an exception on any attempt to access it, even when using "typeof".
*/
window.localStorage.setItem(sKey, sValue);
return true;
} catch(e) {}
try {
window.localStorage.setItem(sKey, sValue);
return true;
} catch(e) {
web.logLocalStorageError(e);
}
return false;
};
/**
* removeLocalStorageItem(sKey)
*
* @param {string} sKey
*/
web.removeLocalStorageItem = function(sKey)
{
try {
window.localStorage.removeItem(sKey);
} catch(e) {
web.logLocalStorageError(e);
}
};
/**
* getLocalStorageKeys()
*
* @return {Array}
*/
web.getLocalStorageKeys = function()
{
var a = [];
try {
for (var i = 0, c = window.localStorage.length; i < c; i++) {
a.push(window.localStorage.key(i));
}
} catch(e) {
web.logLocalStorageError(e);
}
return a;
};
/**
* reloadPage()
*/
@ -545,6 +625,7 @@ web.aPageEventHandlers = {
'exit': [] // list of window 'onunload' handlers (although we prefer to use 'onbeforeunload' if possible)
};
web.fPageReady = false; // set once the browser's first page initialization has occurred
web.fPageEventsEnabled = true;
/**
@ -635,6 +716,11 @@ web.doPageEvent = function(afn)
*/
web.enablePageEvents = function(fEnable)
{
if (!web.fPageEventsEnabled && fEnable) {
web.fPageEventsEnabled = true;
if (web.fPageReady) web.sendPageEvent('init');
return;
}
web.fPageEventsEnabled = fEnable;
};
@ -652,7 +738,7 @@ web.sendPageEvent = function(sEvent)
}
};
web.onPageEvent('onload', function onPageLoad() { web.doPageEvent(web.aPageEventHandlers['init']); });
web.onPageEvent('onload', function onPageLoad() { web.fPageReady = true; web.doPageEvent(web.aPageEventHandlers['init']); });
web.onPageEvent('onpageshow', function onPageShow() { web.doPageEvent(web.aPageEventHandlers['show']); });
web.onPageEvent(web.isUserAgent("Opera") || web.isUserAgent("iOS")? 'onunload' : 'onbeforeunload', function onPageUnload() { web.doPageEvent(web.aPageEventHandlers['exit']); });