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| /* Copyright 2012 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.
*/
import { createPromiseCapability } from 'pdfjs-lib';
import { scrollIntoView } from './ui_utils';
const FindState = {
FOUND: 0,
NOT_FOUND: 1,
WRAPPED: 2,
PENDING: 3,
};
const FIND_SCROLL_OFFSET_TOP = -50;
const FIND_SCROLL_OFFSET_LEFT = -400;
const FIND_TIMEOUT = 250; // ms
const CHARACTERS_TO_NORMALIZE = {
'\u2018': '\'', // Left single quotation mark
'\u2019': '\'', // Right single quotation mark
'\u201A': '\'', // Single low-9 quotation mark
'\u201B': '\'', // Single high-reversed-9 quotation mark
'\u201C': '"', // Left double quotation mark
'\u201D': '"', // Right double quotation mark
'\u201E': '"', // Double low-9 quotation mark
'\u201F': '"', // Double high-reversed-9 quotation mark
'\u00BC': '1/4', // Vulgar fraction one quarter
'\u00BD': '1/2', // Vulgar fraction one half
'\u00BE': '3/4', // Vulgar fraction three quarters
};
/**
* Provides search functionality to find a given string in a PDF document.
*/
class PDFFindController {
constructor({ pdfViewer, }) {
this.pdfViewer = pdfViewer;
this.onUpdateResultsCount = null;
this.onUpdateState = null;
this.reset();
// Compile the regular expression for text normalization once.
let replace = Object.keys(CHARACTERS_TO_NORMALIZE).join('');
this.normalizationRegex = new RegExp('[' + replace + ']', 'g');
}
reset() {
this.startedTextExtraction = false;
this.extractTextPromises = [];
this.pendingFindMatches = Object.create(null);
this.active = false; // If active, find results will be highlighted.
this.pageContents = []; // Stores the text for each page.
this.pageMatches = [];
this.pageMatchesLength = null;
this.matchCount = 0;
this.selected = { // Currently selected match.
pageIdx: -1,
matchIdx: -1,
};
this.offset = { // Where the find algorithm currently is in the document.
pageIdx: null,
matchIdx: null,
};
this.pagesToSearch = null;
this.resumePageIdx = null;
this.state = null;
this.dirtyMatch = false;
this.findTimeout = null;
this._firstPagePromise = new Promise((resolve) => {
this.resolveFirstPage = resolve;
});
}
normalize(text) {
return text.replace(this.normalizationRegex, function (ch) {
return CHARACTERS_TO_NORMALIZE[ch];
});
}
/**
* Helper for multi-term search that fills the `matchesWithLength` array
* and handles cases where one search term includes another search term (for
* example, "tamed tame" or "this is"). It looks for intersecting terms in
* the `matches` and keeps elements with a longer match length.
*/
_prepareMatches(matchesWithLength, matches, matchesLength) {
function isSubTerm(matchesWithLength, currentIndex) {
let currentElem = matchesWithLength[currentIndex];
let nextElem = matchesWithLength[currentIndex + 1];
// Check for cases like "TAMEd TAME".
if (currentIndex < matchesWithLength.length - 1 &&
currentElem.match === nextElem.match) {
currentElem.skipped = true;
return true;
}
// Check for cases like "thIS IS".
for (let i = currentIndex - 1; i >= 0; i--) {
let 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;
}
// Sort the array of `{ match: <match>, matchLength: <matchLength> }`
// objects on increasing index first and on the length otherwise.
matchesWithLength.sort(function(a, b) {
return a.match === b.match ? a.matchLength - b.matchLength :
a.match - b.match;
});
for (let i = 0, len = matchesWithLength.length; i < len; i++) {
if (isSubTerm(matchesWithLength, i)) {
continue;
}
matches.push(matchesWithLength[i].match);
matchesLength.push(matchesWithLength[i].matchLength);
}
}
calcFindPhraseMatch(query, pageIndex, pageContent) {
let matches = [];
let queryLen = query.length;
let matchIdx = -queryLen;
while (true) {
matchIdx = pageContent.indexOf(query, matchIdx + queryLen);
if (matchIdx === -1) {
break;
}
matches.push(matchIdx);
}
this.pageMatches[pageIndex] = matches;
}
calcFindWordMatch(query, pageIndex, pageContent) {
let matchesWithLength = [];
// Divide the query into pieces and search for text in each piece.
let queryArray = query.match(/\S+/g);
for (let i = 0, len = queryArray.length; i < len; i++) {
let subquery = queryArray[i];
let subqueryLen = subquery.length;
let matchIdx = -subqueryLen;
while (true) {
matchIdx = pageContent.indexOf(subquery, matchIdx + subqueryLen);
if (matchIdx === -1) {
break;
}
// Other searches do not, so we store the length.
matchesWithLength.push({
match: matchIdx,
matchLength: subqueryLen,
skipped: false,
});
}
}
// Prepare arrays for storing the matches.
if (!this.pageMatchesLength) {
this.pageMatchesLength = [];
}
this.pageMatchesLength[pageIndex] = [];
this.pageMatches[pageIndex] = [];
// Sort `matchesWithLength`, remove intersecting terms and put the result
// into the two arrays.
this._prepareMatches(matchesWithLength, this.pageMatches[pageIndex],
this.pageMatchesLength[pageIndex]);
}
calcFindMatch(pageIndex) {
let pageContent = this.normalize(this.pageContents[pageIndex]);
let query = this.normalize(this.state.query);
let caseSensitive = this.state.caseSensitive;
let phraseSearch = this.state.phraseSearch;
let queryLen = query.length;
if (queryLen === 0) {
// Do nothing: the matches should be wiped out already.
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();
}
// Update the match count.
if (this.pageMatches[pageIndex].length > 0) {
this.matchCount += this.pageMatches[pageIndex].length;
this.updateUIResultsCount();
}
}
extractText() {
if (this.startedTextExtraction) {
return;
}
this.startedTextExtraction = true;
this.pageContents.length = 0;
let promise = Promise.resolve();
for (let i = 0, ii = this.pdfViewer.pagesCount; i < ii; i++) {
let extractTextCapability = createPromiseCapability();
this.extractTextPromises[i] = extractTextCapability.promise;
promise = promise.then(() => {
return this.pdfViewer.getPageTextContent(i).then((textContent) => {
let textItems = textContent.items;
let strBuf = [];
for (let j = 0, jj = textItems.length; j < jj; j++) {
strBuf.push(textItems[j].str);
}
// Store the pageContent as a string.
this.pageContents[i] = strBuf.join('');
extractTextCapability.resolve(i);
}, (reason) => {
console.error(`Unable to get page ${i + 1} text content`, reason);
// Page error -- assuming no text content.
this.pageContents[i] = '';
extractTextCapability.resolve(i);
});
});
}
}
executeCommand(cmd, state) {
if (this.state === null || cmd !== 'findagain') {
this.dirtyMatch = true;
}
this.state = state;
this.updateUIState(FindState.PENDING);
this._firstPagePromise.then(() => {
this.extractText();
clearTimeout(this.findTimeout);
if (cmd === 'find') {
// Trigger the find action with a small delay to avoid starting the
// search when the user is still typing (saving resources).
this.findTimeout = setTimeout(this.nextMatch.bind(this), FIND_TIMEOUT);
} else {
this.nextMatch();
}
});
}
updatePage(index) {
if (this.selected.pageIdx === index) {
// If the page is selected, scroll the page into view, which triggers
// rendering the page, which adds the textLayer. Once the textLayer is
// build, it will scroll onto the selected match.
this.pdfViewer.currentPageNumber = index + 1;
}
let page = this.pdfViewer.getPageView(index);
if (page.textLayer) {
page.textLayer.updateMatches();
}
}
nextMatch() {
let previous = this.state.findPrevious;
let currentPageIndex = this.pdfViewer.currentPageNumber - 1;
let numPages = this.pdfViewer.pagesCount;
this.active = true;
if (this.dirtyMatch) {
// Need to recalculate the matches, reset everything.
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;
for (let i = 0; i < numPages; i++) {
// Wipe out any previously highlighted matches.
this.updatePage(i);
// Start finding the matches as soon as the text is extracted.
if (!(i in this.pendingFindMatches)) {
this.pendingFindMatches[i] = true;
this.extractTextPromises[i].then((pageIdx) => {
delete this.pendingFindMatches[pageIdx];
this.calcFindMatch(pageIdx);
});
}
}
}
// If there's no query there's no point in searching.
if (this.state.query === '') {
this.updateUIState(FindState.FOUND);
return;
}
// If we're waiting on a page, we return since we can't do anything else.
if (this.resumePageIdx) {
return;
}
let offset = this.offset;
// Keep track of how many pages we should maximally iterate through.
this.pagesToSearch = numPages;
// If there's already a `matchIdx` that means we are iterating through a
// page's matches.
if (offset.matchIdx !== null) {
let numPageMatches = this.pageMatches[offset.pageIdx].length;
if ((!previous && offset.matchIdx + 1 < numPageMatches) ||
(previous && offset.matchIdx > 0)) {
// The simple case; we just have advance the matchIdx to select
// the next match on the page.
this.hadMatch = true;
offset.matchIdx = (previous ? offset.matchIdx - 1 :
offset.matchIdx + 1);
this.updateMatch(true);
return;
}
// We went beyond the current page's matches, so we advance to
// the next page.
this.advanceOffsetPage(previous);
}
// Start searching through the page.
this.nextPageMatch();
}
matchesReady(matches) {
let offset = this.offset;
let numMatches = matches.length;
let previous = this.state.findPrevious;
if (numMatches) {
// There were matches for the page, so initialize `matchIdx`.
this.hadMatch = true;
offset.matchIdx = (previous ? numMatches - 1 : 0);
this.updateMatch(true);
return true;
}
// No matches, so attempt to search the next page.
this.advanceOffsetPage(previous);
if (offset.wrapped) {
offset.matchIdx = null;
if (this.pagesToSearch < 0) {
// No point in wrapping again, there were no matches.
this.updateMatch(false);
// While matches were not found, searching for a page
// with matches should nevertheless halt.
return true;
}
}
// Matches were not found (and searching is not done).
return false;
}
/**
* Called from the text layer when match presentation is updated.
*
* @param {number} pageIndex - The index of the page.
* @param {number} matchIndex - The index of the match.
* @param {Array} elements - Text layer `div` elements.
* @param {number} beginIdx - Start index of the `div` array for the match.
*/
updateMatchPosition(pageIndex, matchIndex, elements, beginIdx) {
if (this.selected.matchIdx === matchIndex &&
this.selected.pageIdx === pageIndex) {
let spot = {
top: FIND_SCROLL_OFFSET_TOP,
left: FIND_SCROLL_OFFSET_LEFT,
};
scrollIntoView(elements[beginIdx], spot,
/* skipOverflowHiddenElements = */ true);
}
}
nextPageMatch() {
if (this.resumePageIdx !== null) {
console.error('There can only be one pending page.');
}
let matches = null;
do {
let pageIdx = this.offset.pageIdx;
matches = this.pageMatches[pageIdx];
if (!matches) {
// The matches don't exist yet for processing by `matchesReady`,
// so set a resume point for when they do exist.
this.resumePageIdx = pageIdx;
break;
}
} while (!this.matchesReady(matches));
}
advanceOffsetPage(previous) {
let offset = this.offset;
let 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(found = false) {
let state = FindState.NOT_FOUND;
let wrapped = this.offset.wrapped;
this.offset.wrapped = false;
if (found) {
let previousPage = this.selected.pageIdx;
this.selected.pageIdx = this.offset.pageIdx;
this.selected.matchIdx = this.offset.matchIdx;
state = (wrapped ? FindState.WRAPPED : FindState.FOUND);
// Update the currently selected page to wipe out any selected matches.
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() {
if (this.onUpdateResultsCount) {
this.onUpdateResultsCount(this.matchCount);
}
}
updateUIState(state, previous) {
if (this.onUpdateState) {
this.onUpdateState(state, previous, this.matchCount);
}
}
}
export {
FindState,
PDFFindController,
};
// WEBPACK FOOTER //
// web/pdf_find_controller.js |