/**
* @license
* Copyright The Closure Library Authors.
* SPDX-License-Identifier: Apache-2.0
*/
/**
* @fileoverview Browser history stack management class.
*
* The goog.History object allows a page to create history state without leaving
* the current document. This allows users to, for example, hit the browser's
* back button without leaving the current page.
*
* The history object can be instantiated in one of two modes. In user visible
* mode, the current history state is shown in the browser address bar as a
* document location fragment (the portion of the URL after the '#'). These
* addresses can be bookmarked, copied and pasted into another browser, and
* modified directly by the user like any other URL.
*
* If the history object is created in invisible mode, the user can still
* affect the state using the browser forward and back buttons, but the current
* state is not displayed in the browser address bar. These states are not
* bookmarkable or editable.
*
* It is possible to use both types of history object on the same page, but not
* currently recommended due to browser deficiencies.
*
* Tested to work in:
* <ul>
* <li>Firefox 1.0-4.0
* <li>Internet Explorer 5.5-9.0
* <li>Opera 9+
* <li>Safari 4+
* </ul>
*
* @see ../demos/history1.html
* @see ../demos/history2.html
*/
/* Some browser specific implementation notes:
*
* Firefox (through version 2.0.0.1):
*
* Ideally, navigating inside the hidden iframe could be done using
* about:blank#state instead of a real page on the server. Setting the hash on
* about:blank creates history entries, but the hash is not recorded and is lost
* when the user hits the back button. This is true in Opera as well. A blank
* HTML page must be provided for invisible states to be recorded in the iframe
* hash.
*
* After leaving the page with the History object and returning to it (by
* hitting the back button from another site), the last state of the iframe is
* overwritten. The most recent state is saved in a hidden input field so the
* previous state can be restored.
*
* Firefox does not store the previous value of dynamically generated input
* elements. To save the state, the hidden element must be in the HTML document,
* either in the original source or added with document.write. If a reference
* to the input element is not provided as a constructor argument, then the
* history object creates one using document.write, in which case the history
* object must be created from a script in the body element of the page.
*
* Manually editing the address field to a different hash link prevents further
* updates to the address bar. The page continues to work as normal, but the
* address shown will be incorrect until the page is reloaded.
*
* NOTE(user): It should be noted that Firefox will URL encode any non-regular
* ascii character, along with |space|, ", <, and >, when added to the fragment.
* If you expect these characters in your tokens you should consider that
* setToken('<b>') would result in the history fragment "%3Cb%3E", and
* "espére" would show "esp%E8re". (IE allows unicode characters in the
* fragment)
*
* TODO(user): Should we encapsulate this escaping into the API for visible
* history and encode all characters that aren't supported by Firefox? It also
* needs to be optional so apps can elect to handle the escaping themselves.
*
*
* Internet Explorer (through version 7.0):
*
* IE does not modify the history stack when the document fragment is changed.
* We create history entries instead by using document.open and document.write
* into a hidden iframe.
*
* IE destroys the history stack when navigating from /foo.html#someFragment to
* /foo.html. The workaround is to always append the # to the URL. This is
* somewhat unfortunate when loading the page without any # specified, because
* a second "click" sound will play on load as the fragment is automatically
* appended. If the hash is always present, this can be avoided.
*
* Manually editing the hash in the address bar in IE6 and then hitting the back
* button can replace the page with a blank page. This is a Bad User Experience,
* but probably not preventable.
*
* IE also has a bug when the page is loaded via a server redirect, setting
* a new hash value on the window location will force a page reload. This will
* happen the first time setToken is called with a new token. The only known
* workaround is to force a client reload early, for example by setting
* window.location.hash = window.location.hash, which will otherwise be a no-op.
*
* Internet Explorer 8.0, Webkit 532.1 and Gecko 1.9.2:
*
* IE8 has introduced the support to the HTML5 onhashchange event, which means
* we don't have to do any polling to detect fragment changes. Chrome and
* Firefox have added it on their newer builds, wekbit 532.1 and gecko 1.9.2.
* http://www.w3.org/TR/html5/history.html
* NOTE(goto): it is important to note that the document needs to have the
* <!DOCTYPE html> tag to enable the IE8 HTML5 mode. If the tag is not present,
* IE8 will enter IE7 compatibility mode (which can also be enabled manually).
*
* Opera (through version 9.02):
*
* Navigating through pages at a rate faster than some threshold causes Opera
* to cancel all outstanding timeouts and intervals, including the location
* polling loop. Since this condition cannot be detected, common input events
* are captured to cause the loop to restart.
*
* location.replace is adding a history entry inside setHash_, despite
* documentation that suggests it should not.
*
*
* Safari (through version 2.0.4):
*
* After hitting the back button, the location.hash property is no longer
* readable from JavaScript. This is fixed in later WebKit builds, but not in
* currently shipping Safari. For now, the only recourse is to disable history
* states in Safari. Pages are still navigable via the History object, but the
* back button cannot restore previous states.
*
* Safari sets history states on navigation to a hashlink, but doesn't allow
* polling of the hash, so following actual anchor links in the page will create
* useless history entries. Using location.replace does not seem to prevent
* this. Not a terribly good user experience, but fixed in later Webkits.
*
*
* WebKit (nightly version 420+):
*
* This almost works. Returning to a page with an invisible history object does
* not restore the old state, however, and there is no pageshow event that fires
* in this browser. Holding off on finding a solution for now.
*
*
* HTML5 capable browsers (Firefox 4, Chrome, Safari 5)
*
* No known issues. The goog.history.Html5History class provides a simpler
* implementation more suitable for recent browsers. These implementations
* should be merged so the history class automatically invokes the correct
* implementation.
*/
goog.provide('goog.History');
goog.provide('goog.History.Event');
goog.provide('goog.History.EventType');
goog.require('goog.Timer');
goog.require('goog.asserts');
goog.require('goog.dom');
goog.require('goog.dom.InputType');
goog.require('goog.dom.safe');
/** @suppress {extraRequire} */
goog.require('goog.events.Event');
goog.require('goog.events.EventHandler');
goog.require('goog.events.EventTarget');
goog.require('goog.events.EventType');
goog.require('goog.history.Event');
goog.require('goog.history.EventType');
goog.require('goog.html.SafeHtml');
goog.require('goog.html.TrustedResourceUrl');
goog.require('goog.html.uncheckedconversions');
goog.require('goog.labs.userAgent.device');
goog.require('goog.memoize');
goog.require('goog.string');
goog.require('goog.string.Const');
goog.require('goog.userAgent');
goog.requireType('goog.events.BrowserEvent');
/**
* A history management object. Can be instantiated in user-visible mode (uses
* the address fragment to manage state) or in hidden mode. This object should
* be created from a script in the document body before the document has
* finished loading.
*
* To store the hidden states in browsers other than IE, a hidden iframe is
* used. It must point to a valid html page on the same domain (which can and
* probably should be blank.)
*
* Sample instantiation and usage:
*
* <pre>
* // Instantiate history to use the address bar for state.
* var h = new goog.History();
* goog.events.listen(h, goog.history.EventType.NAVIGATE, navCallback);
* h.setEnabled(true);
*
* // Any changes to the location hash will call the following function.
* function navCallback(e) {
* alert('Navigated to state "' + e.token + '"');
* }
*
* // The history token can also be set from code directly.
* h.setToken('foo');
* </pre>
*
* @param {boolean=} opt_invisible True to use hidden history states instead of
* the user-visible location hash.
* @param {!goog.html.TrustedResourceUrl=} opt_blankPageUrl A URL to a
* blank page on the same server. Required if opt_invisible is true.
* This URL is also used as the src for the iframe used to track history
* state in IE (if not specified the iframe is not given a src attribute).
* Access is Denied error may occur in IE7 if the window's URL's scheme
* is https, and this URL is not specified.
* @param {HTMLInputElement=} opt_input The hidden input element to be used to
* store the history token. If not provided, a hidden input element will
* be created using document.write.
* @param {HTMLIFrameElement=} opt_iframe The hidden iframe that will be used by
* IE for pushing history state changes, or by all browsers if opt_invisible
* is true. If not provided, a hidden iframe element will be created using
* document.write.
* @constructor
* @extends {goog.events.EventTarget}
*/
goog.History = function(
opt_invisible, opt_blankPageUrl, opt_input, opt_iframe) {
'use strict';
goog.events.EventTarget.call(this);
if (opt_invisible && !opt_blankPageUrl) {
throw new Error(
'Can\'t use invisible history without providing a blank page.');
}
let input;
if (opt_input) {
input = opt_input;
} else {
const inputId = 'history_state' + goog.History.historyCount_;
const inputHtml = goog.html.SafeHtml.create('input', {
type: goog.dom.InputType.TEXT,
name: inputId,
id: inputId,
style: goog.string.Const.from('display:none')
});
goog.dom.safe.documentWrite(document, inputHtml);
input = goog.dom.getElement(inputId);
}
/**
* An input element that stores the current iframe state. Used to restore
* the state when returning to the page on non-IE browsers.
* @type {HTMLInputElement}
* @private
*/
this.hiddenInput_ = /** @type {HTMLInputElement} */ (input);
/**
* The window whose location contains the history token fragment. This is
* the window that contains the hidden input. It's typically the top window.
* It is not necessarily the same window that the js code is loaded in.
* @type {Window}
* @private
*/
this.window_ = opt_input ?
goog.dom.getWindow(goog.dom.getOwnerDocument(opt_input)) :
window;
/**
* The base URL for the hidden iframe. Must refer to a document in the
* same domain as the main page.
* @type {!goog.html.TrustedResourceUrl|undefined}
* @private
*/
this.iframeSrc_ = opt_blankPageUrl;
if (goog.userAgent.IE && !opt_blankPageUrl) {
if (window.location.protocol == 'https') {
this.iframeSrc_ = goog.html.TrustedResourceUrl.fromConstant(
goog.string.Const.from('https:///'));
} else {
this.iframeSrc_ = goog.html.TrustedResourceUrl.fromConstant(
goog.string.Const.from('javascript:""'));
}
}
/**
* A timer for polling the current history state for changes.
* @type {goog.Timer}
* @private
*/
this.timer_ = new goog.Timer(goog.History.PollingType.NORMAL);
this.registerDisposable(this.timer_);
/**
* True if the state tokens are displayed in the address bar, false for hidden
* history states.
* @type {boolean}
* @private
*/
this.userVisible_ = !opt_invisible;
/**
* An object to keep track of the history event listeners.
* @type {goog.events.EventHandler<!goog.History>}
* @private
*/
this.eventHandler_ = new goog.events.EventHandler(this);
if (opt_invisible || goog.History.LEGACY_IE) {
let iframe;
if (opt_iframe) {
iframe = opt_iframe;
} else {
const iframeId = 'history_iframe' + goog.History.historyCount_;
// Using a "sandbox" attribute on the iframe might be possible, but
// this HTML didn't initially have it and when it was refactored
// to SafeHtml it was kept without it.
const iframeHtml =
goog.html.SafeHtml.createIframe(this.iframeSrc_, null, {
id: iframeId,
style: goog.string.Const.from('display:none'),
sandbox: undefined
});
goog.dom.safe.documentWrite(document, iframeHtml);
iframe = goog.dom.getElement(iframeId);
}
/**
* Internet Explorer uses a hidden iframe for all history changes. Other
* browsers use the iframe only for pushing invisible states.
* @type {HTMLIFrameElement}
* @private
*/
this.iframe_ = /** @type {HTMLIFrameElement} */ (iframe);
/**
* Whether the hidden iframe has had a document written to it yet in this
* session.
* @type {boolean}
* @private
*/
this.unsetIframe_ = true;
}
if (goog.History.LEGACY_IE) {
// IE relies on the hidden input to restore the history state from previous
// sessions, but input values are only restored after window.onload. Set up
// a callback to poll the value after the onload event.
this.eventHandler_.listen(
this.window_, goog.events.EventType.LOAD, this.onDocumentLoaded);
/**
* IE-only variable for determining if the document has loaded.
* @type {boolean}
* @protected
*/
this.documentLoaded = false;
/**
* IE-only variable for storing whether the history object should be enabled
* once the document finishes loading.
* @type {boolean}
* @private
*/
this.shouldEnable_ = false;
}
// Set the initial history state.
if (this.userVisible_) {
this.setHash_(this.getToken(), true);
} else {
this.setIframeToken_(this.hiddenInput_.value);
}
goog.History.historyCount_++;
};
goog.inherits(goog.History, goog.events.EventTarget);
/**
* Status of when the object is active and dispatching events.
* @type {boolean}
* @private
*/
goog.History.prototype.enabled_ = false;
/**
* Whether the object is performing polling with longer intervals. This can
* occur for instance when setting the location of the iframe when in invisible
* mode and the server that is hosting the blank html page is down. In FF, this
* will cause the location of the iframe to no longer be accessible, with
* permision denied exceptions being thrown on every access of the history
* token. When this occurs, the polling interval is elongated. This causes
* exceptions to be thrown at a lesser rate while allowing for the history
* object to resurrect itself when the html page becomes accessible.
* @type {boolean}
* @private
*/
goog.History.prototype.longerPolling_ = false;
/**
* The last token set by the history object, used to poll for changes.
* @type {?string}
* @private
*/
goog.History.prototype.lastToken_ = null;
/**
* Whether the browser supports HTML5 history management's onhashchange event.
* {@link http://www.w3.org/TR/html5/history.html}. IE 9 in compatibility mode
* indicates that onhashchange is in window, but testing reveals the event
* isn't actually fired.
* @return {boolean} Whether onhashchange is supported.
*/
goog.History.isOnHashChangeSupported = goog.memoize(function() {
'use strict';
return goog.userAgent.IE ? goog.userAgent.isDocumentModeOrHigher(8) :
'onhashchange' in goog.global;
});
/**
* Whether the current browser is Internet Explorer prior to version 8. Many IE
* specific workarounds developed before version 8 are unnecessary in more
* current versions.
* @type {boolean}
*/
goog.History.LEGACY_IE =
goog.userAgent.IE && !goog.userAgent.isDocumentModeOrHigher(8);
/**
* Whether the browser always requires the hash to be present. Internet Explorer
* before version 8 will reload the HTML page if the hash is omitted.
* @type {boolean}
*/
goog.History.HASH_ALWAYS_REQUIRED = goog.History.LEGACY_IE;
/**
* If not null, polling in the user invisible mode will be disabled until this
* token is seen. This is used to prevent a race condition where the iframe
* hangs temporarily while the location is changed.
* @type {?string}
* @private
*/
goog.History.prototype.lockedToken_ = null;
/** @override */
goog.History.prototype.disposeInternal = function() {
'use strict';
goog.History.superClass_.disposeInternal.call(this);
this.eventHandler_.dispose();
this.setEnabled(false);
};
/**
* Starts or stops the History polling loop. When enabled, the History object
* will immediately fire an event for the current location. The caller can set
* up event listeners between the call to the constructor and the call to
* setEnabled.
*
* On IE, actual startup may be delayed until the iframe and hidden input
* element have been loaded and can be polled. This behavior is transparent to
* the caller.
*
* @param {boolean} enable Whether to enable the history polling loop.
*/
goog.History.prototype.setEnabled = function(enable) {
'use strict';
if (enable == this.enabled_) {
return;
}
if (goog.History.LEGACY_IE && !this.documentLoaded) {
// Wait until the document has actually loaded before enabling the
// object or any saved state from a previous session will be lost.
this.shouldEnable_ = enable;
return;
}
if (enable) {
if (goog.userAgent.GECKO) {
// Firefox will not restore the correct state after navigating away from
// and then back to the page with the history object. This can be fixed
// by restarting the history object on the pageshow event.
this.eventHandler_.listen(this.window_, 'pageshow', this.onShow_);
}
// TODO(goto): make HTML5 and invisible history work by listening to the
// iframe # changes instead of the window.
if (goog.History.isOnHashChangeSupported() && this.userVisible_) {
this.eventHandler_.listen(
this.window_, goog.events.EventType.HASHCHANGE, this.onHashChange_);
this.enabled_ = true;
this.dispatchEvent(new goog.history.Event(this.getToken(), false));
} else if (
!(goog.userAgent.IE && !goog.labs.userAgent.device.isMobile()) ||
this.documentLoaded) {
// Start dispatching history events if all necessary loading has
// completed (always true for browsers other than IE.)
this.eventHandler_.listen(
this.timer_, goog.Timer.TICK, goog.bind(this.check_, this, true));
this.enabled_ = true;
// Initialize last token at startup except on IE < 8, where the last token
// must only be set in conjunction with IFRAME updates, or the IFRAME will
// start out of sync and remove any pre-existing URI fragment.
if (!goog.History.LEGACY_IE) {
this.lastToken_ = this.getToken();
this.dispatchEvent(new goog.history.Event(this.getToken(), false));
}
this.timer_.start();
}
} else {
this.enabled_ = false;
this.eventHandler_.removeAll();
this.timer_.stop();
}
};
/**
* Callback for the window onload event in IE. This is necessary to read the
* value of the hidden input after restoring a history session. The value of
* input elements is not viewable until after window onload for some reason (the
* iframe state is similarly unavailable during the loading phase.) If
* setEnabled is called before the iframe has completed loading, the history
* object will actually be enabled at this point.
* @protected
*/
goog.History.prototype.onDocumentLoaded = function() {
'use strict';
this.documentLoaded = true;
if (this.hiddenInput_.value) {
// Any saved value in the hidden input can only be read after the document
// has been loaded due to an IE limitation. Restore the previous state if
// it has been set.
this.setIframeToken_(this.hiddenInput_.value, true);
}
this.setEnabled(this.shouldEnable_);
};
/**
* Handler for the Gecko pageshow event. Restarts the history object so that the
* correct state can be restored in the hash or iframe.
* @param {goog.events.BrowserEvent} e The browser event.
* @private
*/
goog.History.prototype.onShow_ = function(e) {
'use strict';
// NOTE(user): persisted is a property passed in the pageshow event that
// indicates whether the page is being persisted from the cache or is being
// loaded for the first time.
if (e.getBrowserEvent()['persisted']) {
this.setEnabled(false);
this.setEnabled(true);
}
};
/**
* Handles HTML5 onhashchange events on browsers where it is supported.
* This is very similar to {@link #check_}, except that it is not executed
* continuously. It is only used when
* `goog.History.isOnHashChangeSupported()` is true.
* @param {goog.events.BrowserEvent} e The browser event.
* @private
*/
goog.History.prototype.onHashChange_ = function(e) {
'use strict';
const hash = this.getLocationFragment_(this.window_);
if (hash != this.lastToken_) {
this.update_(hash, true);
}
};
/**
* @return {string} The current token.
*/
goog.History.prototype.getToken = function() {
'use strict';
if (this.lockedToken_ != null) {
return this.lockedToken_;
} else if (this.userVisible_) {
return this.getLocationFragment_(this.window_);
} else {
return this.getIframeToken_() || '';
}
};
/**
* Sets the history state. When user visible states are used, the URL fragment
* will be set to the provided token. Sometimes it is necessary to set the
* history token before the document title has changed, in this case IE's
* history drop down can be out of sync with the token. To get around this
* problem, the app can pass in a title to use with the hidden iframe.
* @param {string} token The history state identifier.
* @param {string=} opt_title Optional title used when setting the hidden iframe
* title in IE.
*/
goog.History.prototype.setToken = function(token, opt_title) {
'use strict';
this.setHistoryState_(token, false, opt_title);
};
/**
* Replaces the current history state without affecting the rest of the history
* stack.
* @param {string} token The history state identifier.
* @param {string=} opt_title Optional title used when setting the hidden iframe
* title in IE.
*/
goog.History.prototype.replaceToken = function(token, opt_title) {
'use strict';
this.setHistoryState_(token, true, opt_title);
};
/**
* Gets the location fragment for the current URL. We don't use location.hash
* directly as the browser helpfully urlDecodes the string for us which can
* corrupt the tokens. For example, if we want to store: label/%2Froot it would
* be returned as label//root.
* @param {Window} win The window object to use.
* @return {string} The fragment.
* @private
*/
goog.History.prototype.getLocationFragment_ = function(win) {
'use strict';
const href = win.location.href;
const index = href.indexOf('#');
return index < 0 ? '' : href.substring(index + 1);
};
/**
* Sets the history state. When user visible states are used, the URL fragment
* will be set to the provided token. Setting opt_replace to true will cause the
* navigation to occur, but will replace the current history entry without
* affecting the length of the stack.
*
* @param {string} token The history state identifier.
* @param {boolean} replace Set to replace the current history entry instead of
* appending a new history state.
* @param {string=} opt_title Optional title used when setting the hidden iframe
* title in IE.
* @private
*/
goog.History.prototype.setHistoryState_ = function(token, replace, opt_title) {
'use strict';
if (this.getToken() != token) {
if (this.userVisible_) {
this.setHash_(token, replace);
if (!goog.History.isOnHashChangeSupported()) {
if (goog.userAgent.IE && !goog.labs.userAgent.device.isMobile()) {
// IE must save state using the iframe.
this.setIframeToken_(token, replace, opt_title);
}
}
// This condition needs to be called even if
// goog.History.isOnHashChangeSupported() is true so the NAVIGATE event
// fires sychronously.
if (this.enabled_) {
this.check_(false);
}
} else {
// Fire the event immediately so that setting history is synchronous, but
// set a suspendToken so that polling doesn't trigger a 'back'.
this.setIframeToken_(token, replace);
this.lockedToken_ = this.lastToken_ = this.hiddenInput_.value = token;
this.dispatchEvent(new goog.history.Event(token, false));
}
}
};
/**
* Sets or replaces the URL fragment. The token does not need to be URL encoded
* according to the URL specification, though certain characters (like newline)
* are automatically stripped.
*
* If opt_replace is not set, non-IE browsers will append a new entry to the
* history list. Setting the hash does not affect the history stack in IE
* (unless there is a pre-existing named anchor for that hash.)
*
* Older versions of Webkit cannot query the location hash, but it still can be
* set. If we detect one of these versions, always replace instead of creating
* new history entries.
*
* window.location.replace replaces the current state from the history stack.
* http://www.whatwg.org/specs/web-apps/current-work/#dom-location-replace
* http://www.whatwg.org/specs/web-apps/current-work/#replacement-enabled
*
* @param {string} token The new string to set.
* @param {boolean=} opt_replace Set to true to replace the current token
* without appending a history entry.
* @private
*/
goog.History.prototype.setHash_ = function(token, opt_replace) {
'use strict';
// If the page uses a BASE element, setting location.hash directly will
// navigate away from the current document. Also, the original URL path may
// possibly change from HTML5 history pushState. To account for these, the
// full path is always specified.
const loc = this.window_.location;
let url = loc.href.split('#')[0];
// If a hash has already been set, then removing it programmatically will
// reload the page. Once there is a hash, we won't remove it.
const hasHash = goog.string.contains(loc.href, '#');
if (goog.History.HASH_ALWAYS_REQUIRED || hasHash || token) {
url += '#' + token;
}
if (url != loc.href) {
const safeUrl =
goog.html.uncheckedconversions
.safeUrlFromStringKnownToSatisfyTypeContract(
goog.string.Const.from('URL taken from location.href.'), url);
if (opt_replace) {
goog.dom.safe.replaceLocation(loc, safeUrl);
} else {
goog.dom.safe.setLocationHref(loc, safeUrl);
}
}
};
/**
* Sets the hidden iframe state. On IE, this is accomplished by writing a new
* document into the iframe. In Firefox, the iframe's URL fragment stores the
* state instead.
*
* Older versions of webkit cannot set the iframe, so ignore those browsers.
*
* @param {string} token The new string to set.
* @param {boolean=} opt_replace Set to true to replace the current iframe state
* without appending a new history entry.
* @param {string=} opt_title Optional title used when setting the hidden iframe
* title in IE.
* @private
*/
goog.History.prototype.setIframeToken_ = function(
token, opt_replace, opt_title) {
'use strict';
if (this.unsetIframe_ || token != this.getIframeToken_()) {
this.unsetIframe_ = false;
token = goog.string.urlEncode(token);
if (goog.userAgent.IE) {
// Caching the iframe document results in document permission errors after
// leaving the page and returning. Access it anew each time instead.
const doc = goog.dom.getFrameContentDocument(this.iframe_);
doc.open('text/html', opt_replace ? 'replace' : undefined);
const iframeSourceHtml = goog.html.SafeHtml.concat(
goog.html.SafeHtml.create(
'title', {}, (opt_title || this.window_.document.title)),
goog.html.SafeHtml.create('body', {}, token));
goog.dom.safe.documentWrite(doc, iframeSourceHtml);
doc.close();
} else {
goog.asserts.assertInstanceof(
this.iframeSrc_, goog.html.TrustedResourceUrl,
'this.iframeSrc_ must be set on calls to setIframeToken_');
const url =
goog.html.TrustedResourceUrl.unwrap(
/** @type {!goog.html.TrustedResourceUrl} */ (this.iframeSrc_)) +
'#' + token;
// In Safari, it is possible for the contentWindow of the iframe to not
// be present when the page is loading after a reload.
const contentWindow = this.iframe_.contentWindow;
if (contentWindow) {
if (opt_replace) {
goog.dom.safe.replaceLocation(contentWindow.location, url);
} else {
goog.dom.safe.setLocationHref(contentWindow.location, url);
}
}
}
}
};
/**
* Return the current state string from the hidden iframe. On internet explorer,
* this is stored as a string in the document body. Other browsers use the
* location hash of the hidden iframe.
*
* Older versions of webkit cannot access the iframe location, so always return
* null in that case.
*
* @return {?string} The state token saved in the iframe (possibly null if the
* iframe has never loaded.).
* @private
*/
goog.History.prototype.getIframeToken_ = function() {
'use strict';
if (goog.userAgent.IE) {
const doc = goog.dom.getFrameContentDocument(this.iframe_);
return doc.body ? goog.string.urlDecode(doc.body.innerHTML) : null;
} else {
// In Safari, it is possible for the contentWindow of the iframe to not
// be present when the page is loading after a reload.
const contentWindow = this.iframe_.contentWindow;
if (contentWindow) {
let hash;
try {
// Iframe tokens are urlEncoded
hash = goog.string.urlDecode(this.getLocationFragment_(contentWindow));
} catch (e) {
// An exception will be thrown if the location of the iframe can not be
// accessed (permission denied). This can occur in FF if the server
// that is hosting the blank html page goes down and then a new history
// token is set. The iframe will navigate to an error page, and the
// location of the iframe can no longer be accessed. Due to the polling,
// this will cause constant exceptions to be thrown. In this case,
// we enable longer polling. We do not have to attempt to reset the
// iframe token because (a) we already fired the NAVIGATE event when
// setting the token, (b) we can rely on the locked token for current
// state, and (c) the token is still in the history and
// accesible on forward/back.
if (!this.longerPolling_) {
this.setLongerPolling_(true);
}
return null;
}
// There was no exception when getting the hash so turn off longer polling
// if it is on.
if (this.longerPolling_) {
this.setLongerPolling_(false);
}
return hash || null;
} else {
return null;
}
}
};
/**
* Checks the state of the document fragment and the iframe title to detect
* navigation changes. If `goog.HistoryisOnHashChangeSupported()` is
* `false`, then this runs approximately twenty times per second.
* @param {boolean} isNavigation True if the event was initiated by a browser
* action, false if it was caused by a setToken call. See
* {@link goog.history.Event}.
* @private
*/
goog.History.prototype.check_ = function(isNavigation) {
'use strict';
if (this.userVisible_) {
const hash = this.getLocationFragment_(this.window_);
if (hash != this.lastToken_) {
this.update_(hash, isNavigation);
}
}
// Old IE uses the iframe for both visible and non-visible versions.
if (!this.userVisible_ || goog.History.LEGACY_IE) {
const token = this.getIframeToken_() || '';
if (this.lockedToken_ == null || token == this.lockedToken_) {
this.lockedToken_ = null;
if (token != this.lastToken_) {
this.update_(token, isNavigation);
}
}
}
};
/**
* Updates the current history state with a given token. Called after a change
* to the location or the iframe state is detected by poll_.
*
* @param {string} token The new history state.
* @param {boolean} isNavigation True if the event was initiated by a browser
* action, false if it was caused by a setToken call. See
* {@link goog.history.Event}.
* @private
*/
goog.History.prototype.update_ = function(token, isNavigation) {
'use strict';
this.lastToken_ = this.hiddenInput_.value = token;
if (this.userVisible_) {
if (goog.History.LEGACY_IE) {
this.setIframeToken_(token);
}
this.setHash_(token);
} else {
this.setIframeToken_(token);
}
this.dispatchEvent(new goog.history.Event(this.getToken(), isNavigation));
};
/**
* Sets if the history oject should use longer intervals when polling.
*
* @param {boolean} longerPolling Whether to enable longer polling.
* @private
*/
goog.History.prototype.setLongerPolling_ = function(longerPolling) {
'use strict';
if (this.longerPolling_ != longerPolling) {
this.timer_.setInterval(
longerPolling ? goog.History.PollingType.LONG :
goog.History.PollingType.NORMAL);
}
this.longerPolling_ = longerPolling;
};
/**
* Opera cancels all outstanding timeouts and intervals after any rapid
* succession of navigation events, including the interval used to detect
* navigation events. This function restarts the interval so that navigation can
* continue. Ideally, only events which would be likely to cause a navigation
* change (mousedown and keydown) would be bound to this function. Since Opera
* seems to ignore keydown events while the alt key is pressed (such as
* alt-left or right arrow), this function is also bound to the much more
* frequent mousemove event. This way, when the update loop freezes, it will
* unstick itself as the user wiggles the mouse in frustration.
* @private
*/
goog.History.prototype.operaDefibrillator_ = function() {
'use strict';
this.timer_.stop();
this.timer_.start();
};
/**
* List of user input event types registered in Opera to restart the history
* timer (@see goog.History#operaDefibrillator_).
* @type {Array<string>}
* @private
*/
goog.History.INPUT_EVENTS_ = [
goog.events.EventType.MOUSEDOWN, goog.events.EventType.KEYDOWN,
goog.events.EventType.MOUSEMOVE
];
/**
* Counter for the number of goog.History objects that have been instantiated.
* Used to create unique IDs.
* @type {number}
* @private
*/
goog.History.historyCount_ = 0;
/**
* Types of polling. The values are in ms of the polling interval.
* @enum {number}
*/
goog.History.PollingType = {
NORMAL: 150,
LONG: 10000
};
/**
* Constant for the history change event type.
* @enum {string}
* @deprecated Use goog.history.EventType.
*/
goog.History.EventType = goog.history.EventType;
/**
* Constant for the history change event type.
* @constructor
* @deprecated Use goog.history.Event.
* @final
*/
goog.History.Event = goog.history.Event;
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