356 lines
		
	
	
		
			10 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
			
		
		
	
	
			356 lines
		
	
	
		
			10 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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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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/* globals PDFFindBar, PDFJS, FindStates, FirefoxCom, Promise */
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'use strict';
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/**
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 * Provides a "search" or "find" functionality for the PDF.
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 * This object actually performs the search for a given string.
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 */
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var PDFFindController = {
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  startedTextExtraction: false,
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  extractTextPromises: [],
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  pendingFindMatches: {},
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  // If active, find results will be highlighted.
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  active: false,
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  // Stores the text for each page.
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  pageContents: [],
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  pageMatches: [],
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  // Currently selected match.
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  selected: {
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    pageIdx: -1,
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    matchIdx: -1
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  },
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  // Where find algorithm currently is in the document.
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  offset: {
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    pageIdx: null,
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    matchIdx: null
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  },
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  resumePageIdx: null,
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  state: null,
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  dirtyMatch: false,
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  findTimeout: null,
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  pdfPageSource: null,
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  integratedFind: false,
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  initialize: function(options) {
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    if(typeof PDFFindBar === 'undefined' || PDFFindBar === null) {
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      throw 'PDFFindController cannot be initialized ' +
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            'without a PDFFindBar instance';
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    }
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    this.pdfPageSource = options.pdfPageSource;
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    this.integratedFind = options.integratedFind;
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    var events = [
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      'find',
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      'findagain',
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      'findhighlightallchange',
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      'findcasesensitivitychange'
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    ];
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    this.firstPagePromise = new Promise(function (resolve) {
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      this.resolveFirstPage = resolve;
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    }.bind(this));
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    this.handleEvent = this.handleEvent.bind(this);
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    for (var i = 0; i < events.length; i++) {
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      window.addEventListener(events[i], this.handleEvent);
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    }
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  },
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  reset: function pdfFindControllerReset() {
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    this.startedTextExtraction = false;
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    this.extractTextPromises = [];
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    this.active = false;
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  },
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  calcFindMatch: function(pageIndex) {
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    var pageContent = this.pageContents[pageIndex];
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    var query = this.state.query;
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    var caseSensitive = this.state.caseSensitive;
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    var queryLen = query.length;
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    if (queryLen === 0) {
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      // Do nothing the matches should be wiped out already.
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      return;
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    }
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    if (!caseSensitive) {
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      pageContent = pageContent.toLowerCase();
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      query = query.toLowerCase();
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    }
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    var matches = [];
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    var matchIdx = -queryLen;
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    while (true) {
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      matchIdx = pageContent.indexOf(query, matchIdx + queryLen);
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      if (matchIdx === -1) {
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        break;
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      }
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      matches.push(matchIdx);
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    }
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    this.pageMatches[pageIndex] = matches;
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    this.updatePage(pageIndex);
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    if (this.resumePageIdx === pageIndex) {
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      this.resumePageIdx = null;
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      this.nextPageMatch();
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    }
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  },
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  extractText: function() {
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    if (this.startedTextExtraction) {
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      return;
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    }
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    this.startedTextExtraction = true;
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    this.pageContents = [];
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    var extractTextPromisesResolves = [];
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    for (var i = 0, ii = this.pdfPageSource.pdfDocument.numPages; i < ii; i++) {
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      this.extractTextPromises.push(new Promise(function (resolve) {
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        extractTextPromisesResolves.push(resolve);
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      }));
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    }
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    var self = this;
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    function extractPageText(pageIndex) {
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      self.pdfPageSource.pages[pageIndex].getTextContent().then(
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        function textContentResolved(bidiTexts) {
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          var str = '';
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          for (var i = 0; i < bidiTexts.length; i++) {
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            str += bidiTexts[i].str;
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          }
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          // Store the pageContent as a string.
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          self.pageContents.push(str);
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          extractTextPromisesResolves[pageIndex](pageIndex);
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          if ((pageIndex + 1) < self.pdfPageSource.pages.length) {
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            extractPageText(pageIndex + 1);
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          }
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        }
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      );
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    }
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    extractPageText(0);
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  },
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  handleEvent: function(e) {
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    if (this.state === null || e.type !== 'findagain') {
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      this.dirtyMatch = true;
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    }
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    this.state = e.detail;
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    this.updateUIState(FindStates.FIND_PENDING);
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    this.firstPagePromise.then(function() {
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      this.extractText();
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      clearTimeout(this.findTimeout);
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      if (e.type === 'find') {
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        // Only trigger the find action after 250ms of silence.
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        this.findTimeout = setTimeout(this.nextMatch.bind(this), 250);
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      } else {
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        this.nextMatch();
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      }
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    }.bind(this));
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  },
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  updatePage: function(idx) {
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    var page = this.pdfPageSource.pages[idx];
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    if (this.selected.pageIdx === idx) {
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      // If the page is selected, scroll the page into view, which triggers
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      // rendering the page, which adds the textLayer. Once the textLayer is
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      // build, it will scroll onto the selected match.
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      page.scrollIntoView();
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    }
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    if (page.textLayer) {
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      page.textLayer.updateMatches();
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    }
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  },
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  nextMatch: function() {
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    var previous = this.state.findPrevious;
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    var currentPageIndex = this.pdfPageSource.page - 1;
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    var numPages = this.pdfPageSource.pages.length;
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    this.active = true;
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    if (this.dirtyMatch) {
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      // Need to recalculate the matches, reset everything.
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      this.dirtyMatch = false;
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      this.selected.pageIdx = this.selected.matchIdx = -1;
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      this.offset.pageIdx = currentPageIndex;
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      this.offset.matchIdx = null;
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      this.hadMatch = false;
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      this.resumePageIdx = null;
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      this.pageMatches = [];
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      var self = this;
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      for (var i = 0; i < numPages; i++) {
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        // Wipe out any previous highlighted matches.
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        this.updatePage(i);
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        // As soon as the text is extracted start finding the matches.
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        if (!(i in this.pendingFindMatches)) {
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          this.pendingFindMatches[i] = true;
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          this.extractTextPromises[i].then(function(pageIdx) {
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            delete self.pendingFindMatches[pageIdx];
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            self.calcFindMatch(pageIdx);
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          });
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        }
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      }
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    }
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    // If there's no query there's no point in searching.
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    if (this.state.query === '') {
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      this.updateUIState(FindStates.FIND_FOUND);
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      return;
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    }
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    // If we're waiting on a page, we return since we can't do anything else.
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    if (this.resumePageIdx) {
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      return;
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    }
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    var offset = this.offset;
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    // If there's already a matchIdx that means we are iterating through a
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    // page's matches.
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    if (offset.matchIdx !== null) {
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      var numPageMatches = this.pageMatches[offset.pageIdx].length;
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      if ((!previous && offset.matchIdx + 1 < numPageMatches) ||
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          (previous && offset.matchIdx > 0)) {
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        // The simple case, we just have advance the matchIdx to select the next
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        // match on the page.
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        this.hadMatch = true;
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        offset.matchIdx = previous ? offset.matchIdx - 1 : offset.matchIdx + 1;
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        this.updateMatch(true);
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        return;
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      }
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      // We went beyond the current page's matches, so we advance to the next
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      // page.
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      this.advanceOffsetPage(previous);
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    }
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    // Start searching through the page.
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    this.nextPageMatch();
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  },
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  matchesReady: function(matches) {
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    var offset = this.offset;
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    var numMatches = matches.length;
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    var previous = this.state.findPrevious;
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    if (numMatches) {
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      // There were matches for the page, so initialize the matchIdx.
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      this.hadMatch = true;
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      offset.matchIdx = previous ? numMatches - 1 : 0;
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      this.updateMatch(true);
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      // matches were found
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      return true;
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    } else {
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      // No matches attempt to search the next page.
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      this.advanceOffsetPage(previous);
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      if (offset.wrapped) {
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        offset.matchIdx = null;
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        if (!this.hadMatch) {
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          // No point in wrapping there were no matches.
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          this.updateMatch(false);
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          // while matches were not found, searching for a page 
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          // with matches should nevertheless halt.
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          return true;
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        }
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      }
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      // matches were not found (and searching is not done)
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      return false;
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    }
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  },
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  nextPageMatch: function() {
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    if (this.resumePageIdx !== null) {
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      console.error('There can only be one pending page.');
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    }
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    do {
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      var pageIdx = this.offset.pageIdx;
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      var matches = this.pageMatches[pageIdx];
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      if (!matches) {
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        // The matches don't exist yet for processing by "matchesReady",
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        // so set a resume point for when they do exist.
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        this.resumePageIdx = pageIdx;
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        break;
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      }
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    } while (!this.matchesReady(matches));
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  },
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  advanceOffsetPage: function(previous) {
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    var offset = this.offset;
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    var numPages = this.extractTextPromises.length;
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    offset.pageIdx = previous ? offset.pageIdx - 1 : offset.pageIdx + 1;
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    offset.matchIdx = null;
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    if (offset.pageIdx >= numPages || offset.pageIdx < 0) {
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      offset.pageIdx = previous ? numPages - 1 : 0;
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      offset.wrapped = true;
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      return;
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    }
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  },
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  updateMatch: function(found) {
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    var state = FindStates.FIND_NOTFOUND;
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    var wrapped = this.offset.wrapped;
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    this.offset.wrapped = false;
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    if (found) {
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      var previousPage = this.selected.pageIdx;
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      this.selected.pageIdx = this.offset.pageIdx;
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      this.selected.matchIdx = this.offset.matchIdx;
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      state = wrapped ? FindStates.FIND_WRAPPED : FindStates.FIND_FOUND;
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      // Update the currently selected page to wipe out any selected matches.
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      if (previousPage !== -1 && previousPage !== this.selected.pageIdx) {
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        this.updatePage(previousPage);
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      }
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    }
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    this.updateUIState(state, this.state.findPrevious);
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    if (this.selected.pageIdx !== -1) {
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      this.updatePage(this.selected.pageIdx, true);
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    }
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  },
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  updateUIState: function(state, previous) {
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    if (this.integratedFind) {
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      FirefoxCom.request('updateFindControlState',
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                         {result: state, findPrevious: previous});
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      return;
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    }
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    PDFFindBar.updateUIState(state, previous);
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  }
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};
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