react-native-devtools-frontend/front_end/formatter_worker/CSSFormatter.js

/*
 * Copyright (C) 2013 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 Platform from '../platform/platform.js';

import {FormattedContentBuilder} from './FormattedContentBuilder.js';  // eslint-disable-line no-unused-vars
import {createTokenizer} from './FormatterWorker.js';

export class CSSFormatter {
  /**
   * @param {!FormattedContentBuilder} builder
   */
  constructor(builder) {
    this._builder = builder;

    /** @type {number} */
    this._toOffset;
    /** @type {number} */
    this._fromOffset;
    /** @type {!Array.<number>} */
    this._lineEndings;
    /** @type {number} */
    this._lastLine = -1;
    /** @type {{ eatWhitespace: (boolean|undefined), seenProperty: (boolean|undefined), inPropertyValue: (boolean|undefined), afterClosingBrace: (boolean|undefined)}} */
    this._state = {
      eatWhitespace: undefined,
      seenProperty: undefined,
      inPropertyValue: undefined,
      afterClosingBrace: undefined,
    };
  }

  /**
   * @param {string} text
   * @param {!Array.<number>} lineEndings
   * @param {number} fromOffset
   * @param {number} toOffset
   */
  format(text, lineEndings, fromOffset, toOffset) {
    this._lineEndings = lineEndings;
    this._fromOffset = fromOffset;
    this._toOffset = toOffset;
    this._state = {
      eatWhitespace: undefined,
      seenProperty: undefined,
      inPropertyValue: undefined,
      afterClosingBrace: undefined,
    };
    this._lastLine = -1;
    const tokenize = createTokenizer('text/css');
    const oldEnforce = this._builder.setEnforceSpaceBetweenWords(false);
    tokenize(text.substring(this._fromOffset, this._toOffset), this._tokenCallback.bind(this));
    this._builder.setEnforceSpaceBetweenWords(oldEnforce);
  }

  /**
   * @param {string} token
   * @param {?string} type
   * @param {number} startPosition
   */
  _tokenCallback(token, type, startPosition) {
    startPosition += this._fromOffset;
    const startLine = Platform.ArrayUtilities.lowerBound(
        this._lineEndings, startPosition, Platform.ArrayUtilities.DEFAULT_COMPARATOR);
    if (startLine !== this._lastLine) {
      this._state.eatWhitespace = true;
    }
    // The css- prefix is optional, as we override that in the tokenizer defined
    // in CodeMirrorTextEditor.js. In a worker context, we don't use the prefix.
    if (type && (/^(css-)?property/.test(type) || /^(css-)?variable-2/.test(type)) && !this._state.inPropertyValue) {
      this._state.seenProperty = true;
    }
    this._lastLine = startLine;
    const isWhitespace = /^\s+$/.test(token);
    if (isWhitespace) {
      if (!this._state.eatWhitespace) {
        this._builder.addSoftSpace();
      }
      return;
    }
    this._state.eatWhitespace = false;
    if (token === '\n') {
      return;
    }

    if (token !== '}') {
      if (this._state.afterClosingBrace) {
        this._builder.addNewLine(true);
      }
      this._state.afterClosingBrace = false;
    }
    if (token === '}') {
      if (this._state.inPropertyValue) {
        this._builder.addNewLine();
      }
      this._builder.decreaseNestingLevel();
      this._state.afterClosingBrace = true;
      this._state.inPropertyValue = false;
    } else if (token === ':' && !this._state.inPropertyValue && this._state.seenProperty) {
      this._builder.addToken(token, startPosition);
      this._builder.addSoftSpace();
      this._state.eatWhitespace = true;
      this._state.inPropertyValue = true;
      this._state.seenProperty = false;
      return;
    } else if (token === '{') {
      this._builder.addSoftSpace();
      this._builder.addToken(token, startPosition);
      this._builder.addNewLine();
      this._builder.increaseNestingLevel();
      return;
    }

    this._builder.addToken(token, startPosition);

    if (type === 'comment' && !this._state.inPropertyValue && !this._state.seenProperty) {
      this._builder.addNewLine();
    }
    if (token === ';' && this._state.inPropertyValue) {
      this._state.inPropertyValue = false;
      this._builder.addNewLine();
    } else if (token === '}') {
      this._builder.addNewLine();
    }
  }
}