pdf.js/web/pdf_document_properties.js

/* 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, PDFDateString } from "pdfjs-lib";
import {
  getPageSizeInches,
  getPDFFileNameFromURL,
  isPortraitOrientation,
  NullL10n,
} from "./ui_utils.js";

const DEFAULT_FIELD_CONTENT = "-";

// See https://en.wikibooks.org/wiki/Lentis/Conversion_to_the_Metric_Standard_in_the_United_States
const NON_METRIC_LOCALES = ["en-us", "en-lr", "my"];

// Should use the format: `width x height`, in portrait orientation.
// See https://en.wikipedia.org/wiki/Paper_size
const US_PAGE_NAMES = {
  "8.5x11": "Letter",
  "8.5x14": "Legal",
};
const METRIC_PAGE_NAMES = {
  "297x420": "A3",
  "210x297": "A4",
};

function getPageName(size, isPortrait, pageNames) {
  const width = isPortrait ? size.width : size.height;
  const height = isPortrait ? size.height : size.width;

  return pageNames[`${width}x${height}`];
}

/**
 * @typedef {Object} PDFDocumentPropertiesOptions
 * @property {string} overlayName - Name/identifier for the overlay.
 * @property {Object} fields - Names and elements of the overlay's fields.
 * @property {HTMLDivElement} container - Div container for the overlay.
 * @property {HTMLButtonElement} closeButton - Button for closing the overlay.
 */

class PDFDocumentProperties {
  /**
   * @param {PDFDocumentPropertiesOptions} options
   * @param {OverlayManager} overlayManager - Manager for the viewer overlays.
   * @param {EventBus} eventBus - The application event bus.
   * @param {IL10n} l10n - Localization service.
   */
  constructor(
    { overlayName, fields, container, closeButton },
    overlayManager,
    eventBus,
    l10n = NullL10n
  ) {
    this.overlayName = overlayName;
    this.fields = fields;
    this.container = container;
    this.overlayManager = overlayManager;
    this.l10n = l10n;

    this._reset();

    if (closeButton) {
      // Bind the event listener for the Close button.
      closeButton.addEventListener("click", this.close.bind(this));
    }
    this.overlayManager.register(
      this.overlayName,
      this.container,
      this.close.bind(this)
    );

    if (eventBus) {
      eventBus._on("pagechanging", evt => {
        this._currentPageNumber = evt.pageNumber;
      });
      eventBus._on("rotationchanging", evt => {
        this._pagesRotation = evt.pagesRotation;
      });
    }

    this._isNonMetricLocale = true; // The default viewer locale is 'en-us'.
    l10n.getLanguage().then(locale => {
      this._isNonMetricLocale = NON_METRIC_LOCALES.includes(locale);
    });
  }

  /**
   * Open the document properties overlay.
   */
  open() {
    const freezeFieldData = data => {
      Object.defineProperty(this, "fieldData", {
        value: Object.freeze(data),
        writable: false,
        enumerable: true,
        configurable: true,
      });
    };

    Promise.all([
      this.overlayManager.open(this.overlayName),
      this._dataAvailableCapability.promise,
    ]).then(() => {
      const currentPageNumber = this._currentPageNumber;
      const pagesRotation = this._pagesRotation;

      // If the document properties were previously fetched (for this PDF file),
      // just update the dialog immediately to avoid redundant lookups.
      if (
        this.fieldData &&
        currentPageNumber === this.fieldData["_currentPageNumber"] &&
        pagesRotation === this.fieldData["_pagesRotation"]
      ) {
        this._updateUI();
        return;
      }

      // Get the document properties.
      this.pdfDocument
        .getMetadata()
        .then(({ info, metadata, contentDispositionFilename }) => {
          return Promise.all([
            info,
            metadata,
            contentDispositionFilename || getPDFFileNameFromURL(this.url || ""),
            this._parseFileSize(this.maybeFileSize),
            this._parseDate(info.CreationDate),
            this._parseDate(info.ModDate),
            this.pdfDocument.getPage(currentPageNumber).then(pdfPage => {
              return this._parsePageSize(
                getPageSizeInches(pdfPage),
                pagesRotation
              );
            }),
            this._parseLinearization(info.IsLinearized),
          ]);
        })
        .then(
          ([
            info,
            metadata,
            fileName,
            fileSize,
            creationDate,
            modDate,
            pageSize,
            isLinearized,
          ]) => {
            freezeFieldData({
              fileName,
              fileSize,
              title: info.Title,
              author: info.Author,
              subject: info.Subject,
              keywords: info.Keywords,
              creationDate,
              modificationDate: modDate,
              creator: info.Creator,
              producer: info.Producer,
              version: info.PDFFormatVersion,
              pageCount: this.pdfDocument.numPages,
              pageSize,
              linearized: isLinearized,
              _currentPageNumber: currentPageNumber,
              _pagesRotation: pagesRotation,
            });
            this._updateUI();

            // Get the correct fileSize, since it may not have been set (if
            // `this.setFileSize` wasn't called) or may be incorrectly set.
            return this.pdfDocument.getDownloadInfo();
          }
        )
        .then(({ length }) => {
          this.maybeFileSize = length;
          return this._parseFileSize(length);
        })
        .then(fileSize => {
          if (fileSize === this.fieldData["fileSize"]) {
            return; // The fileSize has already been correctly set.
          }
          const data = Object.assign(Object.create(null), this.fieldData);
          data["fileSize"] = fileSize;

          freezeFieldData(data);
          this._updateUI();
        });
    });
  }

  /**
   * Close the document properties overlay.
   */
  close() {
    this.overlayManager.close(this.overlayName);
  }

  /**
   * Set a reference to the PDF document and the URL in order
   * to populate the overlay fields with the document properties.
   * Note that the overlay will contain no information if this method
   * is not called.
   *
   * @param {PDFDocumentProxy} pdfDocument - A reference to the PDF document.
   * @param {string} url - The URL of the document.
   */
  setDocument(pdfDocument, url = null) {
    if (this.pdfDocument) {
      this._reset();
      this._updateUI(true);
    }
    if (!pdfDocument) {
      return;
    }
    this.pdfDocument = pdfDocument;
    this.url = url;

    this._dataAvailableCapability.resolve();
  }

  /**
   * Set the file size of the PDF document. This method is used to
   * update the file size in the document properties overlay once it
   * is known so we do not have to wait until the entire file is loaded.
   *
   * @param {number} fileSize - The file size of the PDF document.
   */
  setFileSize(fileSize) {
    if (Number.isInteger(fileSize) && fileSize > 0) {
      this.maybeFileSize = fileSize;
    }
  }

  /**
   * @private
   */
  _reset() {
    this.pdfDocument = null;
    this.url = null;

    this.maybeFileSize = 0;
    delete this.fieldData;
    this._dataAvailableCapability = createPromiseCapability();
    this._currentPageNumber = 1;
    this._pagesRotation = 0;
  }

  /**
   * Always updates all of the dialog fields, to prevent inconsistent UI state.
   * NOTE: If the contents of a particular field is neither a non-empty string,
   *       nor a number, it will fall back to `DEFAULT_FIELD_CONTENT`.
   * @private
   */
  _updateUI(reset = false) {
    if (reset || !this.fieldData) {
      for (const id in this.fields) {
        this.fields[id].textContent = DEFAULT_FIELD_CONTENT;
      }
      return;
    }
    if (this.overlayManager.active !== this.overlayName) {
      // Don't bother updating the dialog if has already been closed,
      // since it will be updated the next time `this.open` is called.
      return;
    }
    for (const id in this.fields) {
      const content = this.fieldData[id];
      this.fields[id].textContent =
        content || content === 0 ? content : DEFAULT_FIELD_CONTENT;
    }
  }

  /**
   * @private
   */
  async _parseFileSize(fileSize = 0) {
    const kb = fileSize / 1024;
    if (!kb) {
      return undefined;
    } else if (kb < 1024) {
      return this.l10n.get(
        "document_properties_kb",
        {
          size_kb: (+kb.toPrecision(3)).toLocaleString(),
          size_b: fileSize.toLocaleString(),
        },
        "{{size_kb}} KB ({{size_b}} bytes)"
      );
    }
    return this.l10n.get(
      "document_properties_mb",
      {
        size_mb: (+(kb / 1024).toPrecision(3)).toLocaleString(),
        size_b: fileSize.toLocaleString(),
      },
      "{{size_mb}} MB ({{size_b}} bytes)"
    );
  }

  /**
   * @private
   */
  async _parsePageSize(pageSizeInches, pagesRotation) {
    if (!pageSizeInches) {
      return undefined;
    }
    // Take the viewer rotation into account as well; compare with Adobe Reader.
    if (pagesRotation % 180 !== 0) {
      pageSizeInches = {
        width: pageSizeInches.height,
        height: pageSizeInches.width,
      };
    }
    const isPortrait = isPortraitOrientation(pageSizeInches);

    let sizeInches = {
      width: Math.round(pageSizeInches.width * 100) / 100,
      height: Math.round(pageSizeInches.height * 100) / 100,
    };
    // 1in == 25.4mm; no need to round to 2 decimals for millimeters.
    let sizeMillimeters = {
      width: Math.round(pageSizeInches.width * 25.4 * 10) / 10,
      height: Math.round(pageSizeInches.height * 25.4 * 10) / 10,
    };

    let pageName = null;
    let name =
      getPageName(sizeInches, isPortrait, US_PAGE_NAMES) ||
      getPageName(sizeMillimeters, isPortrait, METRIC_PAGE_NAMES);

    if (
      !name &&
      !(
        Number.isInteger(sizeMillimeters.width) &&
        Number.isInteger(sizeMillimeters.height)
      )
    ) {
      // Attempt to improve the page name detection by falling back to fuzzy
      // matching of the metric dimensions, to account for e.g. rounding errors
      // and/or PDF files that define the page sizes in an imprecise manner.
      const exactMillimeters = {
        width: pageSizeInches.width * 25.4,
        height: pageSizeInches.height * 25.4,
      };
      const intMillimeters = {
        width: Math.round(sizeMillimeters.width),
        height: Math.round(sizeMillimeters.height),
      };

      // Try to avoid false positives, by only considering "small" differences.
      if (
        Math.abs(exactMillimeters.width - intMillimeters.width) < 0.1 &&
        Math.abs(exactMillimeters.height - intMillimeters.height) < 0.1
      ) {
        name = getPageName(intMillimeters, isPortrait, METRIC_PAGE_NAMES);
        if (name) {
          // Update *both* sizes, computed above, to ensure that the displayed
          // dimensions always correspond to the detected page name.
          sizeInches = {
            width: Math.round((intMillimeters.width / 25.4) * 100) / 100,
            height: Math.round((intMillimeters.height / 25.4) * 100) / 100,
          };
          sizeMillimeters = intMillimeters;
        }
      }
    }
    if (name) {
      pageName = this.l10n.get(
        "document_properties_page_size_name_" + name.toLowerCase(),
        null,
        name
      );
    }

    return Promise.all([
      this._isNonMetricLocale ? sizeInches : sizeMillimeters,
      this.l10n.get(
        "document_properties_page_size_unit_" +
          (this._isNonMetricLocale ? "inches" : "millimeters"),
        null,
        this._isNonMetricLocale ? "in" : "mm"
      ),
      pageName,
      this.l10n.get(
        "document_properties_page_size_orientation_" +
          (isPortrait ? "portrait" : "landscape"),
        null,
        isPortrait ? "portrait" : "landscape"
      ),
    ]).then(([{ width, height }, unit, name, orientation]) => {
      return this.l10n.get(
        "document_properties_page_size_dimension_" +
          (name ? "name_" : "") +
          "string",
        {
          width: width.toLocaleString(),
          height: height.toLocaleString(),
          unit,
          name,
          orientation,
        },
        "{{width}} × {{height}} {{unit}} (" +
          (name ? "{{name}}, " : "") +
          "{{orientation}})"
      );
    });
  }

  /**
   * @private
   */
  async _parseDate(inputDate) {
    const dateObject = PDFDateString.toDateObject(inputDate);
    if (!dateObject) {
      return undefined;
    }
    return this.l10n.get(
      "document_properties_date_string",
      {
        date: dateObject.toLocaleDateString(),
        time: dateObject.toLocaleTimeString(),
      },
      "{{date}}, {{time}}"
    );
  }

  /**
   * @private
   */
  _parseLinearization(isLinearized) {
    return this.l10n.get(
      "document_properties_linearized_" + (isLinearized ? "yes" : "no"),
      null,
      isLinearized ? "Yes" : "No"
    );
  }
}

export { PDFDocumentProperties };