lib/web/pdf_find_controller.js

/**
 * @licstart The following is the entire license notice for the
 * Javascript code in this page
 *
 * Copyright 2020 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.
 *
 * @licend The above is the entire license notice for the
 * Javascript code in this page
 */
"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.PDFFindController = exports.FindState = void 0;

var _pdf = require("../pdf");

var _pdf_find_utils = require("./pdf_find_utils.js");

var _ui_utils = require("./ui_utils.js");

const FindState = {
  FOUND: 0,
  NOT_FOUND: 1,
  WRAPPED: 2,
  PENDING: 3
};
exports.FindState = FindState;
const FIND_TIMEOUT = 250;
const MATCH_SCROLL_OFFSET_TOP = -50;
const MATCH_SCROLL_OFFSET_LEFT = -400;
const CHARACTERS_TO_NORMALIZE = {
  "\u2018": "'",
  "\u2019": "'",
  "\u201A": "'",
  "\u201B": "'",
  "\u201C": '"',
  "\u201D": '"',
  "\u201E": '"',
  "\u201F": '"',
  "\u00BC": "1/4",
  "\u00BD": "1/2",
  "\u00BE": "3/4"
};
let normalizationRegex = null;

function normalize(text) {
  if (!normalizationRegex) {
    const replace = Object.keys(CHARACTERS_TO_NORMALIZE).join("");
    normalizationRegex = new RegExp(`[${replace}]`, "g");
  }

  return text.replace(normalizationRegex, function (ch) {
    return CHARACTERS_TO_NORMALIZE[ch];
  });
}

class PDFFindController {
  constructor({
    linkService,
    eventBus
  }) {
    this._linkService = linkService;
    this._eventBus = eventBus;

    this._reset();

    eventBus._on("findbarclose", this._onFindBarClose.bind(this));
  }

  get highlightMatches() {
    return this._highlightMatches;
  }

  get pageMatches() {
    return this._pageMatches;
  }

  get pageMatchesLength() {
    return this._pageMatchesLength;
  }

  get selected() {
    return this._selected;
  }

  get state() {
    return this._state;
  }

  setDocument(pdfDocument) {
    if (this._pdfDocument) {
      this._reset();
    }

    if (!pdfDocument) {
      return;
    }

    this._pdfDocument = pdfDocument;

    this._firstPageCapability.resolve();
  }

  executeCommand(cmd, state) {
    if (!state) {
      return;
    }

    const pdfDocument = this._pdfDocument;

    if (this._state === null || this._shouldDirtyMatch(cmd, state)) {
      this._dirtyMatch = true;
    }

    this._state = state;

    if (cmd !== "findhighlightallchange") {
      this._updateUIState(FindState.PENDING);
    }

    this._firstPageCapability.promise.then(() => {
      if (!this._pdfDocument || pdfDocument && this._pdfDocument !== pdfDocument) {
        return;
      }

      this._extractText();

      const findbarClosed = !this._highlightMatches;
      const pendingTimeout = !!this._findTimeout;

      if (this._findTimeout) {
        clearTimeout(this._findTimeout);
        this._findTimeout = null;
      }

      if (cmd === "find") {
        this._findTimeout = setTimeout(() => {
          this._nextMatch();

          this._findTimeout = null;
        }, FIND_TIMEOUT);
      } else if (this._dirtyMatch) {
        this._nextMatch();
      } else if (cmd === "findagain") {
        this._nextMatch();

        if (findbarClosed && this._state.highlightAll) {
          this._updateAllPages();
        }
      } else if (cmd === "findhighlightallchange") {
        if (pendingTimeout) {
          this._nextMatch();
        } else {
          this._highlightMatches = true;
        }

        this._updateAllPages();
      } else {
        this._nextMatch();
      }
    });
  }

  scrollMatchIntoView({
    element = null,
    pageIndex = -1,
    matchIndex = -1
  }) {
    if (!this._scrollMatches || !element) {
      return;
    } else if (matchIndex === -1 || matchIndex !== this._selected.matchIdx) {
      return;
    } else if (pageIndex === -1 || pageIndex !== this._selected.pageIdx) {
      return;
    }

    this._scrollMatches = false;
    const spot = {
      top: MATCH_SCROLL_OFFSET_TOP,
      left: MATCH_SCROLL_OFFSET_LEFT
    };
    (0, _ui_utils.scrollIntoView)(element, spot, true);
  }

  _reset() {
    this._highlightMatches = false;
    this._scrollMatches = false;
    this._pdfDocument = null;
    this._pageMatches = [];
    this._pageMatchesLength = [];
    this._state = null;
    this._selected = {
      pageIdx: -1,
      matchIdx: -1
    };
    this._offset = {
      pageIdx: null,
      matchIdx: null,
      wrapped: false
    };
    this._extractTextPromises = [];
    this._pageContents = [];
    this._matchesCountTotal = 0;
    this._pagesToSearch = null;
    this._pendingFindMatches = Object.create(null);
    this._resumePageIdx = null;
    this._dirtyMatch = false;
    clearTimeout(this._findTimeout);
    this._findTimeout = null;
    this._firstPageCapability = (0, _pdf.createPromiseCapability)();
  }

  get _query() {
    if (this._state.query !== this._rawQuery) {
      this._rawQuery = this._state.query;
      this._normalizedQuery = normalize(this._state.query);
    }

    return this._normalizedQuery;
  }

  _shouldDirtyMatch(cmd, state) {
    if (state.query !== this._state.query) {
      return true;
    }

    switch (cmd) {
      case "findagain":
        const pageNumber = this._selected.pageIdx + 1;
        const linkService = this._linkService;

        if (pageNumber >= 1 && pageNumber <= linkService.pagesCount && pageNumber !== linkService.page && !linkService.isPageVisible(pageNumber)) {
          return true;
        }

        return false;

      case "findhighlightallchange":
        return false;
    }

    return true;
  }

  _prepareMatches(matchesWithLength, matches, matchesLength) {
    function isSubTerm(currentIndex) {
      const currentElem = matchesWithLength[currentIndex];
      const nextElem = matchesWithLength[currentIndex + 1];

      if (currentIndex < matchesWithLength.length - 1 && currentElem.match === nextElem.match) {
        currentElem.skipped = true;
        return true;
      }

      for (let i = currentIndex - 1; i >= 0; i--) {
        const 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;
    }

    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(i)) {
        continue;
      }

      matches.push(matchesWithLength[i].match);
      matchesLength.push(matchesWithLength[i].matchLength);
    }
  }

  _isEntireWord(content, startIdx, length) {
    if (startIdx > 0) {
      const first = content.charCodeAt(startIdx);
      const limit = content.charCodeAt(startIdx - 1);

      if ((0, _pdf_find_utils.getCharacterType)(first) === (0, _pdf_find_utils.getCharacterType)(limit)) {
        return false;
      }
    }

    const endIdx = startIdx + length - 1;

    if (endIdx < content.length - 1) {
      const last = content.charCodeAt(endIdx);
      const limit = content.charCodeAt(endIdx + 1);

      if ((0, _pdf_find_utils.getCharacterType)(last) === (0, _pdf_find_utils.getCharacterType)(limit)) {
        return false;
      }
    }

    return true;
  }

  _calculatePhraseMatch(query, pageIndex, pageContent, entireWord) {
    const matches = [];
    const queryLen = query.length;
    let matchIdx = -queryLen;

    while (true) {
      matchIdx = pageContent.indexOf(query, matchIdx + queryLen);

      if (matchIdx === -1) {
        break;
      }

      if (entireWord && !this._isEntireWord(pageContent, matchIdx, queryLen)) {
        continue;
      }

      matches.push(matchIdx);
    }

    this._pageMatches[pageIndex] = matches;
  }

  _calculateWordMatch(query, pageIndex, pageContent, entireWord) {
    const matchesWithLength = [];
    const queryArray = query.match(/\S+/g);

    for (let i = 0, len = queryArray.length; i < len; i++) {
      const subquery = queryArray[i];
      const subqueryLen = subquery.length;
      let matchIdx = -subqueryLen;

      while (true) {
        matchIdx = pageContent.indexOf(subquery, matchIdx + subqueryLen);

        if (matchIdx === -1) {
          break;
        }

        if (entireWord && !this._isEntireWord(pageContent, matchIdx, subqueryLen)) {
          continue;
        }

        matchesWithLength.push({
          match: matchIdx,
          matchLength: subqueryLen,
          skipped: false
        });
      }
    }

    this._pageMatchesLength[pageIndex] = [];
    this._pageMatches[pageIndex] = [];

    this._prepareMatches(matchesWithLength, this._pageMatches[pageIndex], this._pageMatchesLength[pageIndex]);
  }

  _calculateMatch(pageIndex) {
    let pageContent = this._pageContents[pageIndex];
    let query = this._query;
    const {
      caseSensitive,
      entireWord,
      phraseSearch
    } = this._state;

    if (query.length === 0) {
      return;
    }

    if (!caseSensitive) {
      pageContent = pageContent.toLowerCase();
      query = query.toLowerCase();
    }

    if (phraseSearch) {
      this._calculatePhraseMatch(query, pageIndex, pageContent, entireWord);
    } else {
      this._calculateWordMatch(query, pageIndex, pageContent, entireWord);
    }

    if (this._state.highlightAll) {
      this._updatePage(pageIndex);
    }

    if (this._resumePageIdx === pageIndex) {
      this._resumePageIdx = null;

      this._nextPageMatch();
    }

    const pageMatchesCount = this._pageMatches[pageIndex].length;

    if (pageMatchesCount > 0) {
      this._matchesCountTotal += pageMatchesCount;

      this._updateUIResultsCount();
    }
  }

  _extractText() {
    if (this._extractTextPromises.length > 0) {
      return;
    }

    let promise = Promise.resolve();

    for (let i = 0, ii = this._linkService.pagesCount; i < ii; i++) {
      const extractTextCapability = (0, _pdf.createPromiseCapability)();
      this._extractTextPromises[i] = extractTextCapability.promise;
      promise = promise.then(() => {
        return this._pdfDocument.getPage(i + 1).then(pdfPage => {
          return pdfPage.getTextContent({
            normalizeWhitespace: true
          });
        }).then(textContent => {
          const textItems = textContent.items;
          const strBuf = [];

          for (let j = 0, jj = textItems.length; j < jj; j++) {
            strBuf.push(textItems[j].str);
          }

          this._pageContents[i] = normalize(strBuf.join(""));
          extractTextCapability.resolve(i);
        }, reason => {
          console.error(`Unable to get text content for page ${i + 1}`, reason);
          this._pageContents[i] = "";
          extractTextCapability.resolve(i);
        });
      });
    }
  }

  _updatePage(index) {
    if (this._scrollMatches && this._selected.pageIdx === index) {
      this._linkService.page = index + 1;
    }

    this._eventBus.dispatch("updatetextlayermatches", {
      source: this,
      pageIndex: index
    });
  }

  _updateAllPages() {
    this._eventBus.dispatch("updatetextlayermatches", {
      source: this,
      pageIndex: -1
    });
  }

  _nextMatch() {
    const previous = this._state.findPrevious;
    const currentPageIndex = this._linkService.page - 1;
    const numPages = this._linkService.pagesCount;
    this._highlightMatches = true;

    if (this._dirtyMatch) {
      this._dirtyMatch = false;
      this._selected.pageIdx = this._selected.matchIdx = -1;
      this._offset.pageIdx = currentPageIndex;
      this._offset.matchIdx = null;
      this._offset.wrapped = false;
      this._resumePageIdx = null;
      this._pageMatches.length = 0;
      this._pageMatchesLength.length = 0;
      this._matchesCountTotal = 0;

      this._updateAllPages();

      for (let i = 0; i < numPages; i++) {
        if (this._pendingFindMatches[i] === true) {
          continue;
        }

        this._pendingFindMatches[i] = true;

        this._extractTextPromises[i].then(pageIdx => {
          delete this._pendingFindMatches[pageIdx];

          this._calculateMatch(pageIdx);
        });
      }
    }

    if (this._query === "") {
      this._updateUIState(FindState.FOUND);

      return;
    }

    if (this._resumePageIdx) {
      return;
    }

    const offset = this._offset;
    this._pagesToSearch = numPages;

    if (offset.matchIdx !== null) {
      const numPageMatches = this._pageMatches[offset.pageIdx].length;

      if (!previous && offset.matchIdx + 1 < numPageMatches || previous && offset.matchIdx > 0) {
        offset.matchIdx = previous ? offset.matchIdx - 1 : offset.matchIdx + 1;

        this._updateMatch(true);

        return;
      }

      this._advanceOffsetPage(previous);
    }

    this._nextPageMatch();
  }

  _matchesReady(matches) {
    const offset = this._offset;
    const numMatches = matches.length;
    const previous = this._state.findPrevious;

    if (numMatches) {
      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;
  }

  _nextPageMatch() {
    if (this._resumePageIdx !== null) {
      console.error("There can only be one pending page.");
    }

    let matches = null;

    do {
      const pageIdx = this._offset.pageIdx;
      matches = this._pageMatches[pageIdx];

      if (!matches) {
        this._resumePageIdx = pageIdx;
        break;
      }
    } while (!this._matchesReady(matches));
  }

  _advanceOffsetPage(previous) {
    const offset = this._offset;
    const numPages = this._linkService.pagesCount;
    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;
    const wrapped = this._offset.wrapped;
    this._offset.wrapped = false;

    if (found) {
      const previousPage = this._selected.pageIdx;
      this._selected.pageIdx = this._offset.pageIdx;
      this._selected.matchIdx = this._offset.matchIdx;
      state = wrapped ? FindState.WRAPPED : FindState.FOUND;

      if (previousPage !== -1 && previousPage !== this._selected.pageIdx) {
        this._updatePage(previousPage);
      }
    }

    this._updateUIState(state, this._state.findPrevious);

    if (this._selected.pageIdx !== -1) {
      this._scrollMatches = true;

      this._updatePage(this._selected.pageIdx);
    }
  }

  _onFindBarClose(evt) {
    const pdfDocument = this._pdfDocument;

    this._firstPageCapability.promise.then(() => {
      if (!this._pdfDocument || pdfDocument && this._pdfDocument !== pdfDocument) {
        return;
      }

      if (this._findTimeout) {
        clearTimeout(this._findTimeout);
        this._findTimeout = null;
      }

      if (this._resumePageIdx) {
        this._resumePageIdx = null;
        this._dirtyMatch = true;
      }

      this._updateUIState(FindState.FOUND);

      this._highlightMatches = false;

      this._updateAllPages();
    });
  }

  _requestMatchesCount() {
    const {
      pageIdx,
      matchIdx
    } = this._selected;
    let current = 0,
        total = this._matchesCountTotal;

    if (matchIdx !== -1) {
      for (let i = 0; i < pageIdx; i++) {
        current += this._pageMatches[i] && this._pageMatches[i].length || 0;
      }

      current += matchIdx + 1;
    }

    if (current < 1 || current > total) {
      current = total = 0;
    }

    return {
      current,
      total
    };
  }

  _updateUIResultsCount() {
    this._eventBus.dispatch("updatefindmatchescount", {
      source: this,
      matchesCount: this._requestMatchesCount()
    });
  }

  _updateUIState(state, previous) {
    this._eventBus.dispatch("updatefindcontrolstate", {
      source: this,
      state,
      previous,
      matchesCount: this._requestMatchesCount(),
      rawQuery: this._state ? this._state.query : null
    });
  }

}

exports.PDFFindController = PDFFindController;