c750514903
Currently this method first uses a loop to build a temporary array to hold Promises, which are then resolved from a recursive helper function once the textContent is fetched for each page. To me, this is unncessarily complicated, since we can do everything within one loop by simply chaining the asynchronous calls to retrieve the textContent. (Note that this guarantees that the textContent of the pages is still fetched sequentially.)
489 lines
16 KiB
JavaScript
489 lines
16 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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import { createPromiseCapability } from './pdfjs';
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import { scrollIntoView } from './ui_utils';
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var FindStates = {
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FIND_FOUND: 0,
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FIND_NOTFOUND: 1,
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FIND_WRAPPED: 2,
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FIND_PENDING: 3
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};
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var FIND_SCROLL_OFFSET_TOP = -50;
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var FIND_SCROLL_OFFSET_LEFT = -400;
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var CHARACTERS_TO_NORMALIZE = {
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'\u2018': '\'', // Left single quotation mark
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'\u2019': '\'', // Right single quotation mark
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'\u201A': '\'', // Single low-9 quotation mark
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'\u201B': '\'', // Single high-reversed-9 quotation mark
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'\u201C': '"', // Left double quotation mark
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'\u201D': '"', // Right double quotation mark
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'\u201E': '"', // Double low-9 quotation mark
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'\u201F': '"', // Double high-reversed-9 quotation mark
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'\u00BC': '1/4', // Vulgar fraction one quarter
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'\u00BD': '1/2', // Vulgar fraction one half
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'\u00BE': '3/4', // Vulgar fraction three quarters
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};
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/**
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* Provides "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 = (function PDFFindControllerClosure() {
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function PDFFindController(options) {
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this.pdfViewer = options.pdfViewer || null;
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this.onUpdateResultsCount = null;
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this.onUpdateState = null;
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this.reset();
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// Compile the regular expression for text normalization once.
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var replace = Object.keys(CHARACTERS_TO_NORMALIZE).join('');
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this.normalizationRegex = new RegExp('[' + replace + ']', 'g');
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}
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PDFFindController.prototype = {
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reset: function PDFFindController_reset() {
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this.startedTextExtraction = false;
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this.extractTextPromises = [];
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this.pendingFindMatches = Object.create(null);
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this.active = false; // If active, find results will be highlighted.
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this.pageContents = []; // Stores the text for each page.
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this.pageMatches = [];
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this.pageMatchesLength = null;
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this.matchCount = 0;
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this.selected = { // Currently selected match.
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pageIdx: -1,
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matchIdx: -1
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};
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this.offset = { // Where the find algorithm currently is in the document.
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pageIdx: null,
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matchIdx: null
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};
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this.pagesToSearch = null;
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this.resumePageIdx = null;
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this.state = null;
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this.dirtyMatch = false;
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this.findTimeout = null;
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this._firstPagePromise = new Promise((resolve) => {
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this.resolveFirstPage = resolve;
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});
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},
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normalize: function PDFFindController_normalize(text) {
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return text.replace(this.normalizationRegex, function (ch) {
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return CHARACTERS_TO_NORMALIZE[ch];
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});
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},
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// Helper for multiple search - fills matchesWithLength array
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// and takes into account cases when one search term
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// include another search term (for example, "tamed tame" or "this is").
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// Looking for intersecting terms in the 'matches' and
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// leave elements with a longer match-length.
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_prepareMatches: function PDFFindController_prepareMatches(
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matchesWithLength, matches, matchesLength) {
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function isSubTerm(matchesWithLength, currentIndex) {
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var currentElem, prevElem, nextElem;
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currentElem = matchesWithLength[currentIndex];
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nextElem = matchesWithLength[currentIndex + 1];
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// checking for cases like "TAMEd TAME"
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if (currentIndex < matchesWithLength.length - 1 &&
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currentElem.match === nextElem.match) {
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currentElem.skipped = true;
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return true;
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}
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// checking for cases like "thIS IS"
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for (var i = currentIndex - 1; i >= 0; i--) {
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prevElem = matchesWithLength[i];
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if (prevElem.skipped) {
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continue;
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}
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if (prevElem.match + prevElem.matchLength < currentElem.match) {
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break;
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}
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if (prevElem.match + prevElem.matchLength >=
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currentElem.match + currentElem.matchLength) {
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currentElem.skipped = true;
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return true;
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}
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}
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return false;
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}
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var i, len;
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// Sorting array of objects { match: <match>, matchLength: <matchLength> }
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// in increasing index first and then the lengths.
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matchesWithLength.sort(function(a, b) {
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return a.match === b.match ?
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a.matchLength - b.matchLength : a.match - b.match;
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});
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for (i = 0, len = matchesWithLength.length; i < len; i++) {
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if (isSubTerm(matchesWithLength, i)) {
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continue;
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}
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matches.push(matchesWithLength[i].match);
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matchesLength.push(matchesWithLength[i].matchLength);
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}
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},
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calcFindPhraseMatch: function PDFFindController_calcFindPhraseMatch(
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query, pageIndex, pageContent) {
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var matches = [];
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var queryLen = query.length;
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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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},
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calcFindWordMatch: function PDFFindController_calcFindWordMatch(
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query, pageIndex, pageContent) {
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var matchesWithLength = [];
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// Divide the query into pieces and search for text on each piece.
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var queryArray = query.match(/\S+/g);
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var subquery, subqueryLen, matchIdx;
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for (var i = 0, len = queryArray.length; i < len; i++) {
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subquery = queryArray[i];
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subqueryLen = subquery.length;
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matchIdx = -subqueryLen;
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while (true) {
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matchIdx = pageContent.indexOf(subquery, matchIdx + subqueryLen);
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if (matchIdx === -1) {
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break;
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}
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// Other searches do not, so we store the length.
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matchesWithLength.push({
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match: matchIdx,
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matchLength: subqueryLen,
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skipped: false
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});
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}
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}
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// Prepare arrays for store the matches.
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if (!this.pageMatchesLength) {
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this.pageMatchesLength = [];
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}
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this.pageMatchesLength[pageIndex] = [];
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this.pageMatches[pageIndex] = [];
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// Sort matchesWithLength, clean up intersecting terms
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// and put the result into the two arrays.
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this._prepareMatches(matchesWithLength, this.pageMatches[pageIndex],
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this.pageMatchesLength[pageIndex]);
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},
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calcFindMatch: function PDFFindController_calcFindMatch(pageIndex) {
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var pageContent = this.normalize(this.pageContents[pageIndex]);
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var query = this.normalize(this.state.query);
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var caseSensitive = this.state.caseSensitive;
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var phraseSearch = this.state.phraseSearch;
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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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if (phraseSearch) {
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this.calcFindPhraseMatch(query, pageIndex, pageContent);
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} else {
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this.calcFindWordMatch(query, pageIndex, pageContent);
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}
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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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// Update the matches count
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if (this.pageMatches[pageIndex].length > 0) {
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this.matchCount += this.pageMatches[pageIndex].length;
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this.updateUIResultsCount();
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}
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},
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extractText() {
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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.length = 0;
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let promise = Promise.resolve();
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for (let i = 0, ii = this.pdfViewer.pagesCount; i < ii; i++) {
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let extractTextCapability = createPromiseCapability();
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this.extractTextPromises[i] = extractTextCapability.promise;
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promise = promise.then(() => {
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return this.pdfViewer.getPageTextContent(i).then((textContent) => {
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let textItems = textContent.items;
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let strBuf = [];
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for (let j = 0, jj = textItems.length; j < jj; j++) {
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strBuf.push(textItems[j].str);
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}
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// Store the pageContent as a string.
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this.pageContents[i] = strBuf.join('');
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extractTextCapability.resolve(i);
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});
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});
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}
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},
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executeCommand: function PDFFindController_executeCommand(cmd, state) {
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if (this.state === null || cmd !== 'findagain') {
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this.dirtyMatch = true;
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}
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this.state = state;
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this.updateUIState(FindStates.FIND_PENDING);
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this._firstPagePromise.then(() => {
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this.extractText();
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clearTimeout(this.findTimeout);
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if (cmd === '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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});
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},
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updatePage: function PDFFindController_updatePage(index) {
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if (this.selected.pageIdx === index) {
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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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this.pdfViewer.currentPageNumber = index + 1;
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}
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var page = this.pdfViewer.getPageView(index);
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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 PDFFindController_nextMatch() {
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var previous = this.state.findPrevious;
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var currentPageIndex = this.pdfViewer.currentPageNumber - 1;
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var numPages = this.pdfViewer.pagesCount;
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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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this.matchCount = 0;
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this.pageMatchesLength = null;
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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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// Keep track of how many pages we should maximally iterate through.
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this.pagesToSearch = numPages;
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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
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// the next match on the page.
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this.hadMatch = true;
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offset.matchIdx = (previous ? offset.matchIdx - 1 :
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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
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// the next 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 PDFFindController_matchesReady(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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return true;
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}
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// No matches, so 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.pagesToSearch < 0) {
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// No point in wrapping again, 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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* The method is called back from the text layer when match presentation
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* is updated.
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* @param {number} pageIndex - page index.
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* @param {number} index - match index.
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* @param {Array} elements - text layer div elements array.
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* @param {number} beginIdx - start index of the div array for the match.
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*/
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updateMatchPosition: function PDFFindController_updateMatchPosition(
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pageIndex, index, elements, beginIdx) {
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if (this.selected.matchIdx === index &&
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this.selected.pageIdx === pageIndex) {
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var spot = {
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top: FIND_SCROLL_OFFSET_TOP,
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left: FIND_SCROLL_OFFSET_LEFT
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};
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scrollIntoView(elements[beginIdx], spot,
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/* skipOverflowHiddenElements = */ true);
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}
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},
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nextPageMatch: function PDFFindController_nextPageMatch() {
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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 PDFFindController_advanceOffsetPage(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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this.pagesToSearch--;
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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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}
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},
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updateMatch: function PDFFindController_updateMatch(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);
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}
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},
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updateUIResultsCount:
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function PDFFindController_updateUIResultsCount() {
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if (this.onUpdateResultsCount) {
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this.onUpdateResultsCount(this.matchCount);
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}
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},
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updateUIState: function PDFFindController_updateUIState(state, previous) {
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if (this.onUpdateState) {
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this.onUpdateState(state, previous, this.matchCount);
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}
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}
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};
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return PDFFindController;
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})();
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export {
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FindStates,
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PDFFindController,
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};
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