front_end/ui/SyntaxHighlighter.js

/*
 * Copyright (C) 2010 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

import * as Root from '../root/root.js';  // eslint-disable-line no-unused-vars
import * as TextUtils from '../text_utils/text_utils.js';

import {createTextChild} from './UIUtils.js';

export class SyntaxHighlighter {
  /**
   * @param {string} mimeType
   * @param {boolean} stripExtraWhitespace
   */
  constructor(mimeType, stripExtraWhitespace) {
    this._mimeType = mimeType;
    this._stripExtraWhitespace = stripExtraWhitespace;
  }

  /**
   * @param {string} content
   * @param {string} className
   * @return {!Element}
   */
  createSpan(content, className) {
    const span = document.createElement('span');
    span.className = className.replace(/\S+/g, 'cm-$&');
    if (this._stripExtraWhitespace && className !== 'whitespace') {
      content = content.replace(/^[\n\r]*/, '').replace(/\s*$/, '');
    }
    createTextChild(span, content);
    return span;
  }

  /**
   * @param {!Element} node
   * @return {!Promise.<void>}
   */
  syntaxHighlightNode(node) {
    const lines = node.textContent ? node.textContent.split('\n') : [];
    /** @type {number} */
    let plainTextStart;
    /** @type {string} */
    let line;

    const extension = Root.Runtime.Runtime.instance().extension(TextUtils.TextUtils.TokenizerFactory);
    if (extension) {
      return extension.instance().then(
          factory => processTokens.call(this, /** @type {!TextUtils.TextUtils.TokenizerFactory} */ (factory)));
    }
    return Promise.resolve();

    /**
     * @param {!TextUtils.TextUtils.TokenizerFactory} tokenizerFactory
     * @this {SyntaxHighlighter}
     */
    function processTokens(tokenizerFactory) {
      node.removeChildren();
      const tokenize = tokenizerFactory.createTokenizer(this._mimeType);
      for (let i = 0; i < lines.length; ++i) {
        line = lines[i];
        plainTextStart = 0;
        tokenize(line, processToken.bind(this));
        if (plainTextStart < line.length) {
          const plainText = line.substring(plainTextStart, line.length);
          createTextChild(node, plainText);
        }
        if (i < lines.length - 1) {
          createTextChild(node, '\n');
        }
      }
    }

    /**
     * @param {string} token
     * @param {?string} tokenType
     * @param {number} column
     * @param {number} newColumn
     * @this {SyntaxHighlighter}
     */
    function processToken(token, tokenType, column, newColumn) {
      if (!tokenType) {
        return;
      }

      if (column > plainTextStart) {
        const plainText = line.substring(plainTextStart, column);
        createTextChild(node, plainText);
      }
      node.appendChild(this.createSpan(token, tokenType));
      plainTextStart = newColumn;
    }
  }
}