pdf.js/src/core/xfa/factory.js

/* Copyright 2021 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 {
  $appendChild,
  $globalData,
  $nodeName,
  $text,
  $toHTML,
  $toPages,
} from "./xfa_object.js";
import { Binder } from "./bind.js";
import { DataHandler } from "./data.js";
import { FontFinder } from "./fonts.js";
import { stripQuotes } from "./utils.js";
import { warn } from "../../shared/util.js";
import { XFAParser } from "./parser.js";
import { XhtmlNamespace } from "./xhtml.js";

class XFAFactory {
  constructor(data) {
    try {
      this.root = new XFAParser().parse(XFAFactory._createDocument(data));
      const binder = new Binder(this.root);
      this.form = binder.bind();
      this.dataHandler = new DataHandler(this.root, binder.getData());
      this.form[$globalData].template = this.form;
    } catch (e) {
      warn(`XFA - an error occurred during parsing and binding: ${e}`);
    }
  }

  isValid() {
    return this.root && this.form;
  }

  /**
   * In order to avoid to block the event loop, the conversion
   * into pages is made asynchronously.
   */
  _createPagesHelper() {
    const iterator = this.form[$toPages]();
    return new Promise((resolve, reject) => {
      const nextIteration = () => {
        try {
          const value = iterator.next();
          if (value.done) {
            resolve(value.value);
          } else {
            setTimeout(nextIteration, 0);
          }
        } catch (e) {
          reject(e);
        }
      };
      setTimeout(nextIteration, 0);
    });
  }

  async _createPages() {
    try {
      this.pages = await this._createPagesHelper();
      this.dims = this.pages.children.map(c => {
        const { width, height } = c.attributes.style;
        return [0, 0, parseInt(width), parseInt(height)];
      });
    } catch (e) {
      warn(`XFA - an error occurred during layout: ${e}`);
    }
  }

  getBoundingBox(pageIndex) {
    return this.dims[pageIndex];
  }

  async getNumPages() {
    if (!this.pages) {
      await this._createPages();
    }
    return this.dims.length;
  }

  setImages(images) {
    this.form[$globalData].images = images;
  }

  setFonts(fonts) {
    this.form[$globalData].fontFinder = new FontFinder(fonts);
    const missingFonts = [];
    for (let typeface of this.form[$globalData].usedTypefaces) {
      typeface = stripQuotes(typeface);
      const font = this.form[$globalData].fontFinder.find(typeface);
      if (!font) {
        missingFonts.push(typeface);
      }
    }

    if (missingFonts.length > 0) {
      return missingFonts;
    }

    return null;
  }

  appendFonts(fonts, reallyMissingFonts) {
    this.form[$globalData].fontFinder.add(fonts, reallyMissingFonts);
  }

  async getPages() {
    if (!this.pages) {
      await this._createPages();
    }
    const pages = this.pages;
    this.pages = null;
    return pages;
  }

  serializeData(storage) {
    return this.dataHandler.serialize(storage);
  }

  static _createDocument(data) {
    if (!data["/xdp:xdp"]) {
      return data["xdp:xdp"];
    }
    return Object.values(data).join("");
  }

  static getRichTextAsHtml(rc) {
    if (!rc || typeof rc !== "string") {
      return null;
    }

    try {
      let root = new XFAParser(XhtmlNamespace, /* richText */ true).parse(rc);
      if (!["body", "xhtml"].includes(root[$nodeName])) {
        // No body, so create one.
        const newRoot = XhtmlNamespace.body({});
        newRoot[$appendChild](root);
        root = newRoot;
      }

      const result = root[$toHTML]();
      if (!result.success) {
        return null;
      }

      const { html } = result;
      const { attributes } = html;
      if (attributes) {
        if (attributes.class) {
          attributes.class = attributes.class.filter(
            attr => !attr.startsWith("xfa")
          );
        }
        attributes.dir = "auto";
      }

      return { html, str: root[$text]() };
    } catch (e) {
      warn(`XFA - an error occurred during parsing of rich text: ${e}`);
    }
    return null;
  }
}

export { XFAFactory };