pdfjs-dist/lib/web/pdf_find_controller.js

/* Copyright 2017 Mozilla Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
'use strict';
var uiUtils = require('./ui_utils.js');
var scrollIntoView = uiUtils.scrollIntoView;
var FindStates = {
 FIND_FOUND: 0,
 FIND_NOTFOUND: 1,
 FIND_WRAPPED: 2,
 FIND_PENDING: 3
};
var FIND_SCROLL_OFFSET_TOP = -50;
var FIND_SCROLL_OFFSET_LEFT = -400;
var CHARACTERS_TO_NORMALIZE = {
 '\u2018': '\'',
 '\u2019': '\'',
 '\u201A': '\'',
 '\u201B': '\'',
 '\u201C': '"',
 '\u201D': '"',
 '\u201E': '"',
 '\u201F': '"',
 '\u00BC': '1/4',
 '\u00BD': '1/2',
 '\u00BE': '3/4'
};
var PDFFindController = function PDFFindControllerClosure() {
 function PDFFindController(options) {
  this.pdfViewer = options.pdfViewer || null;
  this.onUpdateResultsCount = null;
  this.onUpdateState = null;
  this.reset();
  var replace = Object.keys(CHARACTERS_TO_NORMALIZE).join('');
  this.normalizationRegex = new RegExp('[' + replace + ']', 'g');
 }
 PDFFindController.prototype = {
  reset: function PDFFindController_reset() {
   this.startedTextExtraction = false;
   this.extractTextPromises = [];
   this.pendingFindMatches = Object.create(null);
   this.active = false;
   this.pageContents = [];
   this.pageMatches = [];
   this.pageMatchesLength = null;
   this.matchCount = 0;
   this.selected = {
    pageIdx: -1,
    matchIdx: -1
   };
   this.offset = {
    pageIdx: null,
    matchIdx: null
   };
   this.pagesToSearch = null;
   this.resumePageIdx = null;
   this.state = null;
   this.dirtyMatch = false;
   this.findTimeout = null;
   this.firstPagePromise = new Promise(function (resolve) {
    this.resolveFirstPage = resolve;
   }.bind(this));
  },
  normalize: function PDFFindController_normalize(text) {
   return text.replace(this.normalizationRegex, function (ch) {
    return CHARACTERS_TO_NORMALIZE[ch];
   });
  },
  _prepareMatches: function PDFFindController_prepareMatches(matchesWithLength, matches, matchesLength) {
   function isSubTerm(matchesWithLength, currentIndex) {
    var currentElem, prevElem, nextElem;
    currentElem = matchesWithLength[currentIndex];
    nextElem = matchesWithLength[currentIndex + 1];
    if (currentIndex < matchesWithLength.length - 1 && currentElem.match === nextElem.match) {
     currentElem.skipped = true;
     return true;
    }
    for (var i = currentIndex - 1; i >= 0; i--) {
     prevElem = matchesWithLength[i];
     if (prevElem.skipped) {
      continue;
     }
     if (prevElem.match + prevElem.matchLength < currentElem.match) {
      break;
     }
     if (prevElem.match + prevElem.matchLength >= currentElem.match + currentElem.matchLength) {
      currentElem.skipped = true;
      return true;
     }
    }
    return false;
   }
   var i, len;
   matchesWithLength.sort(function (a, b) {
    return a.match === b.match ? a.matchLength - b.matchLength : a.match - b.match;
   });
   for (i = 0, len = matchesWithLength.length; i < len; i++) {
    if (isSubTerm(matchesWithLength, i)) {
     continue;
    }
    matches.push(matchesWithLength[i].match);
    matchesLength.push(matchesWithLength[i].matchLength);
   }
  },
  calcFindPhraseMatch: function PDFFindController_calcFindPhraseMatch(query, pageIndex, pageContent) {
   var matches = [];
   var queryLen = query.length;
   var matchIdx = -queryLen;
   while (true) {
    matchIdx = pageContent.indexOf(query, matchIdx + queryLen);
    if (matchIdx === -1) {
     break;
    }
    matches.push(matchIdx);
   }
   this.pageMatches[pageIndex] = matches;
  },
  calcFindWordMatch: function PDFFindController_calcFindWordMatch(query, pageIndex, pageContent) {
   var matchesWithLength = [];
   var queryArray = query.match(/\S+/g);
   var subquery, subqueryLen, matchIdx;
   for (var i = 0, len = queryArray.length; i < len; i++) {
    subquery = queryArray[i];
    subqueryLen = subquery.length;
    matchIdx = -subqueryLen;
    while (true) {
     matchIdx = pageContent.indexOf(subquery, matchIdx + subqueryLen);
     if (matchIdx === -1) {
      break;
     }
     matchesWithLength.push({
      match: matchIdx,
      matchLength: subqueryLen,
      skipped: false
     });
    }
   }
   if (!this.pageMatchesLength) {
    this.pageMatchesLength = [];
   }
   this.pageMatchesLength[pageIndex] = [];
   this.pageMatches[pageIndex] = [];
   this._prepareMatches(matchesWithLength, this.pageMatches[pageIndex], this.pageMatchesLength[pageIndex]);
  },
  calcFindMatch: function PDFFindController_calcFindMatch(pageIndex) {
   var pageContent = this.normalize(this.pageContents[pageIndex]);
   var query = this.normalize(this.state.query);
   var caseSensitive = this.state.caseSensitive;
   var phraseSearch = this.state.phraseSearch;
   var queryLen = query.length;
   if (queryLen === 0) {
    return;
   }
   if (!caseSensitive) {
    pageContent = pageContent.toLowerCase();
    query = query.toLowerCase();
   }
   if (phraseSearch) {
    this.calcFindPhraseMatch(query, pageIndex, pageContent);
   } else {
    this.calcFindWordMatch(query, pageIndex, pageContent);
   }
   this.updatePage(pageIndex);
   if (this.resumePageIdx === pageIndex) {
    this.resumePageIdx = null;
    this.nextPageMatch();
   }
   if (this.pageMatches[pageIndex].length > 0) {
    this.matchCount += this.pageMatches[pageIndex].length;
    this.updateUIResultsCount();
   }
  },
  extractText: function PDFFindController_extractText() {
   if (this.startedTextExtraction) {
    return;
   }
   this.startedTextExtraction = true;
   this.pageContents = [];
   var extractTextPromisesResolves = [];
   var numPages = this.pdfViewer.pagesCount;
   for (var i = 0; i < numPages; i++) {
    this.extractTextPromises.push(new Promise(function (resolve) {
     extractTextPromisesResolves.push(resolve);
    }));
   }
   var self = this;
   function extractPageText(pageIndex) {
    self.pdfViewer.getPageTextContent(pageIndex).then(function textContentResolved(textContent) {
     var textItems = textContent.items;
     var str = [];
     for (var i = 0, len = textItems.length; i < len; i++) {
      str.push(textItems[i].str);
     }
     self.pageContents.push(str.join(''));
     extractTextPromisesResolves[pageIndex](pageIndex);
     if (pageIndex + 1 < self.pdfViewer.pagesCount) {
      extractPageText(pageIndex + 1);
     }
    });
   }
   extractPageText(0);
  },
  executeCommand: function PDFFindController_executeCommand(cmd, state) {
   if (this.state === null || cmd !== 'findagain') {
    this.dirtyMatch = true;
   }
   this.state = state;
   this.updateUIState(FindStates.FIND_PENDING);
   this.firstPagePromise.then(function () {
    this.extractText();
    clearTimeout(this.findTimeout);
    if (cmd === 'find') {
     this.findTimeout = setTimeout(this.nextMatch.bind(this), 250);
    } else {
     this.nextMatch();
    }
   }.bind(this));
  },
  updatePage: function PDFFindController_updatePage(index) {
   if (this.selected.pageIdx === index) {
    this.pdfViewer.currentPageNumber = index + 1;
   }
   var page = this.pdfViewer.getPageView(index);
   if (page.textLayer) {
    page.textLayer.updateMatches();
   }
  },
  nextMatch: function PDFFindController_nextMatch() {
   var previous = this.state.findPrevious;
   var currentPageIndex = this.pdfViewer.currentPageNumber - 1;
   var numPages = this.pdfViewer.pagesCount;
   this.active = true;
   if (this.dirtyMatch) {
    this.dirtyMatch = false;
    this.selected.pageIdx = this.selected.matchIdx = -1;
    this.offset.pageIdx = currentPageIndex;
    this.offset.matchIdx = null;
    this.hadMatch = false;
    this.resumePageIdx = null;
    this.pageMatches = [];
    this.matchCount = 0;
    this.pageMatchesLength = null;
    var self = this;
    for (var i = 0; i < numPages; i++) {
     this.updatePage(i);
     if (!(i in this.pendingFindMatches)) {
      this.pendingFindMatches[i] = true;
      this.extractTextPromises[i].then(function (pageIdx) {
       delete self.pendingFindMatches[pageIdx];
       self.calcFindMatch(pageIdx);
      });
     }
    }
   }
   if (this.state.query === '') {
    this.updateUIState(FindStates.FIND_FOUND);
    return;
   }
   if (this.resumePageIdx) {
    return;
   }
   var offset = this.offset;
   this.pagesToSearch = numPages;
   if (offset.matchIdx !== null) {
    var numPageMatches = this.pageMatches[offset.pageIdx].length;
    if (!previous && offset.matchIdx + 1 < numPageMatches || previous && offset.matchIdx > 0) {
     this.hadMatch = true;
     offset.matchIdx = previous ? offset.matchIdx - 1 : offset.matchIdx + 1;
     this.updateMatch(true);
     return;
    }
    this.advanceOffsetPage(previous);
   }
   this.nextPageMatch();
  },
  matchesReady: function PDFFindController_matchesReady(matches) {
   var offset = this.offset;
   var numMatches = matches.length;
   var previous = this.state.findPrevious;
   if (numMatches) {
    this.hadMatch = true;
    offset.matchIdx = previous ? numMatches - 1 : 0;
    this.updateMatch(true);
    return true;
   }
   this.advanceOffsetPage(previous);
   if (offset.wrapped) {
    offset.matchIdx = null;
    if (this.pagesToSearch < 0) {
     this.updateMatch(false);
     return true;
    }
   }
   return false;
  },
  updateMatchPosition: function PDFFindController_updateMatchPosition(pageIndex, index, elements, beginIdx) {
   if (this.selected.matchIdx === index && this.selected.pageIdx === pageIndex) {
    var spot = {
     top: FIND_SCROLL_OFFSET_TOP,
     left: FIND_SCROLL_OFFSET_LEFT
    };
    scrollIntoView(elements[beginIdx], spot, true);
   }
  },
  nextPageMatch: function PDFFindController_nextPageMatch() {
   if (this.resumePageIdx !== null) {
    console.error('There can only be one pending page.');
   }
   do {
    var pageIdx = this.offset.pageIdx;
    var matches = this.pageMatches[pageIdx];
    if (!matches) {
     this.resumePageIdx = pageIdx;
     break;
    }
   } while (!this.matchesReady(matches));
  },
  advanceOffsetPage: function PDFFindController_advanceOffsetPage(previous) {
   var offset = this.offset;
   var numPages = this.extractTextPromises.length;
   offset.pageIdx = previous ? offset.pageIdx - 1 : offset.pageIdx + 1;
   offset.matchIdx = null;
   this.pagesToSearch--;
   if (offset.pageIdx >= numPages || offset.pageIdx < 0) {
    offset.pageIdx = previous ? numPages - 1 : 0;
    offset.wrapped = true;
   }
  },
  updateMatch: function PDFFindController_updateMatch(found) {
   var state = FindStates.FIND_NOTFOUND;
   var wrapped = this.offset.wrapped;
   this.offset.wrapped = false;
   if (found) {
    var previousPage = this.selected.pageIdx;
    this.selected.pageIdx = this.offset.pageIdx;
    this.selected.matchIdx = this.offset.matchIdx;
    state = wrapped ? FindStates.FIND_WRAPPED : FindStates.FIND_FOUND;
    if (previousPage !== -1 && previousPage !== this.selected.pageIdx) {
     this.updatePage(previousPage);
    }
   }
   this.updateUIState(state, this.state.findPrevious);
   if (this.selected.pageIdx !== -1) {
    this.updatePage(this.selected.pageIdx);
   }
  },
  updateUIResultsCount: function PDFFindController_updateUIResultsCount() {
   if (this.onUpdateResultsCount) {
    this.onUpdateResultsCount(this.matchCount);
   }
  },
  updateUIState: function PDFFindController_updateUIState(state, previous) {
   if (this.onUpdateState) {
    this.onUpdateState(state, previous, this.matchCount);
   }
  }
 };
 return PDFFindController;
}();
exports.FindStates = FindStates;
exports.PDFFindController = PDFFindController;