383 lines
13 KiB
JavaScript
383 lines
13 KiB
JavaScript
/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set shiftwidth=2 tabstop=2 autoindent cindent expandtab: */
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/* 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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'use strict';
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var PDFHistory = {
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initialized: false,
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initialDestination: null,
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/**
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* @param {string} fingerprint
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* @param {IPDFLinkService} linkService
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*/
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initialize: function pdfHistoryInitialize(fingerprint, linkService) {
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this.initialized = true;
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this.reInitialized = false;
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this.allowHashChange = true;
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this.historyUnlocked = true;
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this.isViewerInPresentationMode = false;
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this.previousHash = window.location.hash.substring(1);
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this.currentBookmark = '';
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this.currentPage = 0;
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this.updatePreviousBookmark = false;
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this.previousBookmark = '';
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this.previousPage = 0;
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this.nextHashParam = '';
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this.fingerprint = fingerprint;
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this.linkService = linkService;
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this.currentUid = this.uid = 0;
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this.current = {};
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var state = window.history.state;
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if (this._isStateObjectDefined(state)) {
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// This corresponds to navigating back to the document
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// from another page in the browser history.
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if (state.target.dest) {
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this.initialDestination = state.target.dest;
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} else {
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linkService.setHash(state.target.hash);
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}
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this.currentUid = state.uid;
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this.uid = state.uid + 1;
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this.current = state.target;
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} else {
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// This corresponds to the loading of a new document.
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if (state && state.fingerprint &&
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this.fingerprint !== state.fingerprint) {
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// Reinitialize the browsing history when a new document
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// is opened in the web viewer.
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this.reInitialized = true;
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}
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this._pushOrReplaceState({ fingerprint: this.fingerprint }, true);
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}
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var self = this;
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window.addEventListener('popstate', function pdfHistoryPopstate(evt) {
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evt.preventDefault();
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evt.stopPropagation();
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if (!self.historyUnlocked) {
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return;
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}
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if (evt.state) {
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// Move back/forward in the history.
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self._goTo(evt.state);
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} else {
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// Handle the user modifying the hash of a loaded document.
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self.previousHash = window.location.hash.substring(1);
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// If the history is empty when the hash changes,
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// update the previous entry in the browser history.
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if (self.uid === 0) {
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var previousParams = (self.previousHash && self.currentBookmark &&
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self.previousHash !== self.currentBookmark) ?
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{ hash: self.currentBookmark, page: self.currentPage } :
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{ page: 1 };
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self.historyUnlocked = false;
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self.allowHashChange = false;
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window.history.back();
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self._pushToHistory(previousParams, false, true);
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window.history.forward();
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self.historyUnlocked = true;
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}
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self._pushToHistory({ hash: self.previousHash }, false, true);
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self._updatePreviousBookmark();
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}
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}, false);
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function pdfHistoryBeforeUnload() {
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var previousParams = self._getPreviousParams(null, true);
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if (previousParams) {
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var replacePrevious = (!self.current.dest &&
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self.current.hash !== self.previousHash);
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self._pushToHistory(previousParams, false, replacePrevious);
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self._updatePreviousBookmark();
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}
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// Remove the event listener when navigating away from the document,
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// since 'beforeunload' prevents Firefox from caching the document.
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window.removeEventListener('beforeunload', pdfHistoryBeforeUnload, false);
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}
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window.addEventListener('beforeunload', pdfHistoryBeforeUnload, false);
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window.addEventListener('pageshow', function pdfHistoryPageShow(evt) {
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// If the entire viewer (including the PDF file) is cached in the browser,
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// we need to reattach the 'beforeunload' event listener since
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// the 'DOMContentLoaded' event is not fired on 'pageshow'.
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window.addEventListener('beforeunload', pdfHistoryBeforeUnload, false);
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}, false);
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window.addEventListener('presentationmodechanged', function(e) {
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self.isViewerInPresentationMode = !!e.detail.active;
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});
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},
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_isStateObjectDefined: function pdfHistory_isStateObjectDefined(state) {
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return (state && state.uid >= 0 &&
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state.fingerprint && this.fingerprint === state.fingerprint &&
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state.target && state.target.hash) ? true : false;
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},
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_pushOrReplaceState: function pdfHistory_pushOrReplaceState(stateObj,
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replace) {
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if (replace) {
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//#if (GENERIC || CHROME)
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window.history.replaceState(stateObj, '', document.URL);
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//#else
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// window.history.replaceState(stateObj, '');
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//#endif
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} else {
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//#if (GENERIC || CHROME)
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window.history.pushState(stateObj, '', document.URL);
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//#else
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// window.history.pushState(stateObj, '');
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//#endif
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//#if CHROME
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// if (top === window) {
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// chrome.runtime.sendMessage('showPageAction');
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// }
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//#endif
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}
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},
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get isHashChangeUnlocked() {
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if (!this.initialized) {
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return true;
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}
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// If the current hash changes when moving back/forward in the history,
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// this will trigger a 'popstate' event *as well* as a 'hashchange' event.
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// Since the hash generally won't correspond to the exact the position
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// stored in the history's state object, triggering the 'hashchange' event
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// can thus corrupt the browser history.
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//
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// When the hash changes during a 'popstate' event, we *only* prevent the
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// first 'hashchange' event and immediately reset allowHashChange.
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// If it is not reset, the user would not be able to change the hash.
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var temp = this.allowHashChange;
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this.allowHashChange = true;
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return temp;
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},
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_updatePreviousBookmark: function pdfHistory_updatePreviousBookmark() {
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if (this.updatePreviousBookmark &&
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this.currentBookmark && this.currentPage) {
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this.previousBookmark = this.currentBookmark;
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this.previousPage = this.currentPage;
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this.updatePreviousBookmark = false;
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}
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},
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updateCurrentBookmark: function pdfHistoryUpdateCurrentBookmark(bookmark,
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pageNum) {
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if (this.initialized) {
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this.currentBookmark = bookmark.substring(1);
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this.currentPage = pageNum | 0;
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this._updatePreviousBookmark();
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}
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},
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updateNextHashParam: function pdfHistoryUpdateNextHashParam(param) {
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if (this.initialized) {
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this.nextHashParam = param;
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}
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},
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push: function pdfHistoryPush(params, isInitialBookmark) {
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if (!(this.initialized && this.historyUnlocked)) {
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return;
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}
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if (params.dest && !params.hash) {
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params.hash = (this.current.hash && this.current.dest &&
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this.current.dest === params.dest) ?
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this.current.hash :
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this.linkService.getDestinationHash(params.dest).split('#')[1];
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}
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if (params.page) {
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params.page |= 0;
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}
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if (isInitialBookmark) {
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var target = window.history.state.target;
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if (!target) {
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// Invoked when the user specifies an initial bookmark,
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// thus setting initialBookmark, when the document is loaded.
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this._pushToHistory(params, false);
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this.previousHash = window.location.hash.substring(1);
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}
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this.updatePreviousBookmark = this.nextHashParam ? false : true;
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if (target) {
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// If the current document is reloaded,
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// avoid creating duplicate entries in the history.
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this._updatePreviousBookmark();
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}
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return;
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}
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if (this.nextHashParam) {
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if (this.nextHashParam === params.hash) {
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this.nextHashParam = null;
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this.updatePreviousBookmark = true;
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return;
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} else {
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this.nextHashParam = null;
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}
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}
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if (params.hash) {
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if (this.current.hash) {
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if (this.current.hash !== params.hash) {
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this._pushToHistory(params, true);
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} else {
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if (!this.current.page && params.page) {
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this._pushToHistory(params, false, true);
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}
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this.updatePreviousBookmark = true;
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}
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} else {
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this._pushToHistory(params, true);
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}
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} else if (this.current.page && params.page &&
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this.current.page !== params.page) {
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this._pushToHistory(params, true);
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}
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},
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_getPreviousParams: function pdfHistory_getPreviousParams(onlyCheckPage,
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beforeUnload) {
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if (!(this.currentBookmark && this.currentPage)) {
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return null;
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} else if (this.updatePreviousBookmark) {
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this.updatePreviousBookmark = false;
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}
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if (this.uid > 0 && !(this.previousBookmark && this.previousPage)) {
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// Prevent the history from getting stuck in the current state,
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// effectively preventing the user from going back/forward in the history.
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//
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// This happens if the current position in the document didn't change when
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// the history was previously updated. The reasons for this are either:
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// 1. The current zoom value is such that the document does not need to,
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// or cannot, be scrolled to display the destination.
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// 2. The previous destination is broken, and doesn't actally point to a
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// position within the document.
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// (This is either due to a bad PDF generator, or the user making a
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// mistake when entering a destination in the hash parameters.)
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return null;
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}
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if ((!this.current.dest && !onlyCheckPage) || beforeUnload) {
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if (this.previousBookmark === this.currentBookmark) {
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return null;
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}
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} else if (this.current.page || onlyCheckPage) {
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if (this.previousPage === this.currentPage) {
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return null;
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}
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} else {
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return null;
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}
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var params = { hash: this.currentBookmark, page: this.currentPage };
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if (this.isViewerInPresentationMode) {
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params.hash = null;
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}
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return params;
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},
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_stateObj: function pdfHistory_stateObj(params) {
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return { fingerprint: this.fingerprint, uid: this.uid, target: params };
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},
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_pushToHistory: function pdfHistory_pushToHistory(params,
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addPrevious, overwrite) {
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if (!this.initialized) {
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return;
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}
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if (!params.hash && params.page) {
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params.hash = ('page=' + params.page);
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}
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if (addPrevious && !overwrite) {
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var previousParams = this._getPreviousParams();
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if (previousParams) {
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var replacePrevious = (!this.current.dest &&
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this.current.hash !== this.previousHash);
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this._pushToHistory(previousParams, false, replacePrevious);
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}
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}
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this._pushOrReplaceState(this._stateObj(params),
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(overwrite || this.uid === 0));
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this.currentUid = this.uid++;
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this.current = params;
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this.updatePreviousBookmark = true;
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},
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_goTo: function pdfHistory_goTo(state) {
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if (!(this.initialized && this.historyUnlocked &&
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this._isStateObjectDefined(state))) {
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return;
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}
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if (!this.reInitialized && state.uid < this.currentUid) {
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var previousParams = this._getPreviousParams(true);
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if (previousParams) {
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this._pushToHistory(this.current, false);
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this._pushToHistory(previousParams, false);
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this.currentUid = state.uid;
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window.history.back();
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return;
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}
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}
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this.historyUnlocked = false;
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if (state.target.dest) {
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this.linkService.navigateTo(state.target.dest);
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} else {
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this.linkService.setHash(state.target.hash);
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}
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this.currentUid = state.uid;
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if (state.uid > this.uid) {
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this.uid = state.uid;
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}
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this.current = state.target;
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this.updatePreviousBookmark = true;
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var currentHash = window.location.hash.substring(1);
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if (this.previousHash !== currentHash) {
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this.allowHashChange = false;
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}
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this.previousHash = currentHash;
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this.historyUnlocked = true;
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},
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back: function pdfHistoryBack() {
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this.go(-1);
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},
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forward: function pdfHistoryForward() {
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this.go(1);
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},
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go: function pdfHistoryGo(direction) {
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if (this.initialized && this.historyUnlocked) {
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var state = window.history.state;
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if (direction === -1 && state && state.uid > 0) {
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window.history.back();
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} else if (direction === 1 && state && state.uid < (this.uid - 1)) {
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window.history.forward();
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}
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}
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}
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};
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