core/templates/services/code-normalizer.service.ts - develop - githubmirror/oppia

core/templates/services/code-normalizer.service.ts
118 строк4 KB
Hardik Goyal
Fix #7092: Remove downgradeComponent (#21903)
18 фев 2025, 21:22
18 фев 2025, 21:224dbd84c
// Copyright 2014 The Oppia Authors. All Rights Reserved.
//
// 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.

/**
 * @fileoverview Service for code normalization. Used by the code REPL
 * and pencil code interactions.
 */

import {Injectable} from '@angular/core';

@Injectable({
  providedIn: 'root',
})
export class CodeNormalizerService {
  removeLeadingWhitespace(str: string): string {
    return str.replace(/^\s+/g, '');
  }

  removeTrailingWhitespace(str: string): string {
    return str.replace(/\s+$/g, '');
  }

  removeIntermediateWhitespace(str: string): string {
    return str.replace(/\s+/g, ' ');
  }

  getNormalizedCode(codeString: string): string {
    /*
     * Normalizes a code string (which is assumed not to contain tab
     * characters). In particular:
     *
     * - Strips out lines that start with '#' (comments), possibly preceded by
     *     whitespace.
     * - Trims trailing whitespace on each line, and normalizes multiple
     *     whitespace characters within a single line into one space
     *     character.
     * - Removes blank newlines.
     * - Make the indentation level four spaces.
     */
    // TODO(sll): Augment this function to strip out comments that occur at
    // the end of a line. However, be careful with lines where '#' is
    // contained in quotes or the character is escaped.
    var FOUR_SPACES = '    ';
    // Maps the number of spaces at the beginning of a line to an int
    // specifying the desired indentation level.
    var numSpacesToDesiredIndentLevel: {[key: number]: number} = {
      0: 0,
    };

    var codeLines = this.removeTrailingWhitespace(codeString).split('\n');
    var normalizedCodeLines: string[] = [];
    codeLines.forEach((line: string) => {
      if (this.removeLeadingWhitespace(line).indexOf('#') === 0) {
        return;
      }
      line = this.removeTrailingWhitespace(line);
      if (!line) {
        return;
      }

      var numSpaces = line.length - this.removeLeadingWhitespace(line).length;

      var existingNumSpaces = Object.keys(numSpacesToDesiredIndentLevel).map(
        Number
      );
      var maxNumSpaces = Math.max.apply(null, existingNumSpaces);
      if (numSpaces > maxNumSpaces) {
        // Add a new indentation level.
        numSpacesToDesiredIndentLevel[numSpaces] = existingNumSpaces.length;
      }

      // This is set when the indentation level of the current line does not
      // start a new scope, and also does not match any previous indentation
      // level. This case is actually invalid, but for now, we take the
      // largest indentation level that is less than this one.
      // TODO(sll): Bad indentation should result in an error nearer the
      // source.
      var isShortfallLine =
        !numSpacesToDesiredIndentLevel.hasOwnProperty(numSpaces) &&
        numSpaces < maxNumSpaces;

      // Clear all existing indentation levels to the right of this one.
      for (var indentLength in numSpacesToDesiredIndentLevel) {
        if (Number(indentLength) > numSpaces) {
          delete numSpacesToDesiredIndentLevel[indentLength];
        }
      }

      if (isShortfallLine) {
        existingNumSpaces = Object.keys(numSpacesToDesiredIndentLevel).map(
          Number
        );
        numSpaces = Math.max.apply(null, existingNumSpaces);
      }

      var normalizedLine = '';
      for (var i = 0; i < numSpacesToDesiredIndentLevel[numSpaces]; i++) {
        normalizedLine += FOUR_SPACES;
      }
      normalizedLine += this.removeIntermediateWhitespace(
        this.removeLeadingWhitespace(line)
      );
      normalizedCodeLines.push(normalizedLine);
    });
    return normalizedCodeLines.join('\n');
  }
}