81b4761e6e
This was added in PR 7793, which has now been present in a number of PDF.js releases (from version `v1.7.225`). Hence we should be able to remove it now, considering that the migration code was only intended as a best effort solution to avoid wiping out all existing user data at once. Also, keep in mind that `ViewHistory` is already limited with regards to the number of documents it will simultaneous store data for.
120 lines
3.4 KiB
JavaScript
120 lines
3.4 KiB
JavaScript
/* Copyright 2012 Mozilla Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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const DEFAULT_VIEW_HISTORY_CACHE_SIZE = 20;
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/**
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* View History - This is a utility for saving various view parameters for
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* recently opened files.
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*
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* The way that the view parameters are stored depends on how PDF.js is built,
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* for 'gulp <flag>' the following cases exist:
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* - FIREFOX or MOZCENTRAL - uses sessionStorage.
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* - GENERIC or CHROME - uses localStorage, if it is available.
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*/
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class ViewHistory {
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constructor(fingerprint, cacheSize = DEFAULT_VIEW_HISTORY_CACHE_SIZE) {
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this.fingerprint = fingerprint;
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this.cacheSize = cacheSize;
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this._initializedPromise = this._readFromStorage().then((databaseStr) => {
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let database = JSON.parse(databaseStr || '{}');
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if (!('files' in database)) {
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database.files = [];
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}
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if (database.files.length >= this.cacheSize) {
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database.files.shift();
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}
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let index;
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for (let i = 0, length = database.files.length; i < length; i++) {
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let branch = database.files[i];
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if (branch.fingerprint === this.fingerprint) {
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index = i;
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break;
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}
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}
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if (typeof index !== 'number') {
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index = database.files.push({ fingerprint: this.fingerprint, }) - 1;
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}
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this.file = database.files[index];
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this.database = database;
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});
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}
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_writeToStorage() {
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return new Promise((resolve) => {
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let databaseStr = JSON.stringify(this.database);
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if (typeof PDFJSDev !== 'undefined' &&
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PDFJSDev.test('FIREFOX || MOZCENTRAL')) {
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sessionStorage.setItem('pdfjs.history', databaseStr);
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} else {
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localStorage.setItem('pdfjs.history', databaseStr);
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}
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resolve();
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});
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}
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_readFromStorage() {
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return new Promise(function(resolve) {
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if (typeof PDFJSDev !== 'undefined' &&
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PDFJSDev.test('FIREFOX || MOZCENTRAL')) {
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resolve(sessionStorage.getItem('pdfjs.history'));
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} else {
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resolve(localStorage.getItem('pdfjs.history'));
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}
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});
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}
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set(name, val) {
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return this._initializedPromise.then(() => {
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this.file[name] = val;
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return this._writeToStorage();
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});
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}
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setMultiple(properties) {
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return this._initializedPromise.then(() => {
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for (let name in properties) {
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this.file[name] = properties[name];
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}
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return this._writeToStorage();
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});
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}
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get(name, defaultValue) {
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return this._initializedPromise.then(() => {
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let val = this.file[name];
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return val !== undefined ? val : defaultValue;
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});
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}
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getMultiple(properties) {
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return this._initializedPromise.then(() => {
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let values = Object.create(null);
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for (let name in properties) {
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let val = this.file[name];
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values[name] = val !== undefined ? val : properties[name];
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}
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return values;
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});
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}
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}
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export {
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ViewHistory,
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};
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