forked from mirrors/gecko-dev
86 lines
2.5 KiB
JavaScript
86 lines
2.5 KiB
JavaScript
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this file,
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* You can obtain one at http://mozilla.org/MPL/2.0/. */
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"use strict";
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this.EXPORTED_SYMBOLS = ["TabStateCache"];
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/**
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* A cache for tabs data.
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*
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* This cache implements a weak map from tabs (as XUL elements)
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* to tab data (as objects).
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*
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* Note that we should never cache private data, as:
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* - that data is used very seldom by SessionStore;
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* - caching private data in addition to public data is memory consuming.
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*/
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this.TabStateCache = Object.freeze({
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/**
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* Retrieves cached data for a given |tab| or associated |browser|.
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*
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* @param browserOrTab (xul:tab or xul:browser)
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* The tab or browser to retrieve cached data for.
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* @return (object)
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* The cached data stored for the given |tab|
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* or associated |browser|.
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*/
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get: function (browserOrTab) {
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return TabStateCacheInternal.get(browserOrTab);
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},
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/**
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* Updates cached data for a given |tab| or associated |browser|.
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*
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* @param browserOrTab (xul:tab or xul:browser)
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* The tab or browser belonging to the given tab data.
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* @param newData (object)
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* The new data to be stored for the given |tab|
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* or associated |browser|.
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*/
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update: function (browserOrTab, newData) {
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TabStateCacheInternal.update(browserOrTab, newData);
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}
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});
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var TabStateCacheInternal = {
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_data: new WeakMap(),
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/**
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* Retrieves cached data for a given |tab| or associated |browser|.
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*
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* @param browserOrTab (xul:tab or xul:browser)
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* The tab or browser to retrieve cached data for.
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* @return (object)
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* The cached data stored for the given |tab|
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* or associated |browser|.
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*/
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get: function (browserOrTab) {
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return this._data.get(browserOrTab.permanentKey);
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},
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/**
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* Updates cached data for a given |tab| or associated |browser|.
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*
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* @param browserOrTab (xul:tab or xul:browser)
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* The tab or browser belonging to the given tab data.
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* @param newData (object)
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* The new data to be stored for the given |tab|
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* or associated |browser|.
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*/
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update: function (browserOrTab, newData) {
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let data = this._data.get(browserOrTab.permanentKey) || {};
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for (let key of Object.keys(newData)) {
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let value = newData[key];
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if (value === null) {
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delete data[key];
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} else {
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data[key] = value;
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}
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}
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this._data.set(browserOrTab.permanentKey, data);
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}
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};
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