src/plugins/front-matter/yaml.js

/**
 * Forked from https://github.com/egoist/docute/blob/master/src/utils/yaml.js
 */
/* eslint-disable */
/*
YAML parser for Javascript
Author: Diogo Costa
This program is released under the MIT License as follows:
Copyright (c) 2011 Diogo Costa (costa.h4evr@gmail.com)
Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is
 furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
 all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.
*/

/**
 * @name YAML
 * @namespace
 */

var errors = [],
  reference_blocks = [],
  processing_time = 0,
  regex = {
    regLevel: new RegExp('^([\\s\\-]+)'),
    invalidLine: new RegExp('^\\-\\-\\-|^\\.\\.\\.|^\\s*#.*|^\\s*$'),
    dashesString: new RegExp('^\\s*\\"([^\\"]*)\\"\\s*$'),
    quotesString: new RegExp("^\\s*\\'([^\\']*)\\'\\s*$"),
    float: new RegExp('^[+-]?[0-9]+\\.[0-9]+(e[+-]?[0-9]+(\\.[0-9]+)?)?$'),
    integer: new RegExp('^[+-]?[0-9]+$'),
    array: new RegExp('\\[\\s*(.*)\\s*\\]'),
    map: new RegExp('\\{\\s*(.*)\\s*\\}'),
    key_value: new RegExp('([a-z0-9_-][ a-z0-9_-]*):( .+)', 'i'),
    single_key_value: new RegExp('^([a-z0-9_-][ a-z0-9_-]*):( .+?)$', 'i'),
    key: new RegExp('([a-z0-9_-][ a-z0-9_-]+):( .+)?', 'i'),
    item: new RegExp('^-\\s+'),
    trim: new RegExp('^\\s+|\\s+$'),
    comment: new RegExp(
      '([^\\\'\\"#]+([\\\'\\"][^\\\'\\"]*[\\\'\\"])*)*(#.*)?'
    ),
  };

/**
 * @class A block of lines of a given level.
 * @param {int} lvl The block's level.
 * @private
 */
function Block(lvl) {
  return {
    /* The block's parent */
    parent: null,
    /* Number of children */
    length: 0,
    /* Block's level */
    level: lvl,
    /* Lines of code to process */
    lines: [],
    /* Blocks with greater level */
    children: [],
    /* Add a block to the children collection */
    addChild: function (obj) {
      this.children.push(obj);
      obj.parent = this;
      ++this.length;
    },
  };
}

function parser(str) {
  var regLevel = regex['regLevel'];
  var invalidLine = regex['invalidLine'];
  var lines = str.split('\n');
  var m;
  var level = 0,
    curLevel = 0;

  var blocks = [];

  var result = new Block(-1);
  var currentBlock = new Block(0);
  result.addChild(currentBlock);
  var levels = [];
  var line = '';

  blocks.push(currentBlock);
  levels.push(level);

  for (var i = 0, len = lines.length; i < len; ++i) {
    line = lines[i];

    if (line.match(invalidLine)) {
      continue;
    }

    if ((m = regLevel.exec(line))) {
      level = m[1].length;
    } else level = 0;

    if (level > curLevel) {
      var oldBlock = currentBlock;
      currentBlock = new Block(level);
      oldBlock.addChild(currentBlock);
      blocks.push(currentBlock);
      levels.push(level);
    } else if (level < curLevel) {
      var added = false;

      var k = levels.length - 1;
      for (; k >= 0; --k) {
        if (levels[k] == level) {
          currentBlock = new Block(level);
          blocks.push(currentBlock);
          levels.push(level);
          if (blocks[k].parent != null) blocks[k].parent.addChild(currentBlock);
          added = true;
          break;
        }
      }

      if (!added) {
        errors.push('Error: Invalid indentation at line ' + i + ': ' + line);
        return;
      }
    }

    currentBlock.lines.push(line.replace(regex['trim'], ''));
    curLevel = level;
  }

  return result;
}

function processValue(val) {
  val = val.replace(regex['trim'], '');
  var m = null;

  if (val == 'true') {
    return true;
  } else if (val == 'false') {
    return false;
  } else if (val == '.NaN') {
    return Number.NaN;
  } else if (val == 'null') {
    return null;
  } else if (val == '.inf') {
    return Number.POSITIVE_INFINITY;
  } else if (val == '-.inf') {
    return Number.NEGATIVE_INFINITY;
  } else if ((m = val.match(regex['dashesString']))) {
    return m[1];
  } else if ((m = val.match(regex['quotesString']))) {
    return m[1];
  } else if ((m = val.match(regex['float']))) {
    return parseFloat(m[0]);
  } else if ((m = val.match(regex['integer']))) {
    return parseInt(m[0]);
  } else if (!isNaN((m = Date.parse(val)))) {
    return new Date(m);
  } else if ((m = val.match(regex['single_key_value']))) {
    var res = {};
    res[m[1]] = processValue(m[2]);
    return res;
  } else if ((m = val.match(regex['array']))) {
    var count = 0,
      c = ' ';
    var res = [];
    var content = '';
    var str = false;
    for (var j = 0, lenJ = m[1].length; j < lenJ; ++j) {
      c = m[1][j];
      if (c == "'" || c == '"') {
        if (str === false) {
          str = c;
          content += c;
          continue;
        } else if ((c == "'" && str == "'") || (c == '"' && str == '"')) {
          str = false;
          content += c;
          continue;
        }
      } else if (str === false && (c == '[' || c == '{')) {
        ++count;
      } else if (str === false && (c == ']' || c == '}')) {
        --count;
      } else if (str === false && count == 0 && c == ',') {
        res.push(processValue(content));
        content = '';
        continue;
      }

      content += c;
    }

    if (content.length > 0) res.push(processValue(content));
    return res;
  } else if ((m = val.match(regex['map']))) {
    var count = 0,
      c = ' ';
    var res = [];
    var content = '';
    var str = false;
    for (var j = 0, lenJ = m[1].length; j < lenJ; ++j) {
      c = m[1][j];
      if (c == "'" || c == '"') {
        if (str === false) {
          str = c;
          content += c;
          continue;
        } else if ((c == "'" && str == "'") || (c == '"' && str == '"')) {
          str = false;
          content += c;
          continue;
        }
      } else if (str === false && (c == '[' || c == '{')) {
        ++count;
      } else if (str === false && (c == ']' || c == '}')) {
        --count;
      } else if (str === false && count == 0 && c == ',') {
        res.push(content);
        content = '';
        continue;
      }

      content += c;
    }

    if (content.length > 0) res.push(content);

    var newRes = {};
    for (var j = 0, lenJ = res.length; j < lenJ; ++j) {
      if ((m = res[j].match(regex['key_value']))) {
        newRes[m[1]] = processValue(m[2]);
      }
    }

    return newRes;
  } else return val;
}

function processFoldedBlock(block) {
  var lines = block.lines;
  var children = block.children;
  var str = lines.join(' ');
  var chunks = [str];
  for (var i = 0, len = children.length; i < len; ++i) {
    chunks.push(processFoldedBlock(children[i]));
  }
  return chunks.join('\n');
}

function processLiteralBlock(block) {
  var lines = block.lines;
  var children = block.children;
  var str = lines.join('\n');
  for (var i = 0, len = children.length; i < len; ++i) {
    str += processLiteralBlock(children[i]);
  }
  return str;
}

function processBlock(blocks) {
  var m = null;
  var res = {};
  var lines = null;
  var children = null;
  var currentObj = null;

  var level = -1;

  var processedBlocks = [];

  var isMap = true;

  for (var j = 0, lenJ = blocks.length; j < lenJ; ++j) {
    if (level != -1 && level != blocks[j].level) continue;

    processedBlocks.push(j);

    level = blocks[j].level;
    lines = blocks[j].lines;
    children = blocks[j].children;
    currentObj = null;

    for (var i = 0, len = lines.length; i < len; ++i) {
      var line = lines[i];

      if ((m = line.match(regex['key']))) {
        var key = m[1];

        if (key[0] == '-') {
          key = key.replace(regex['item'], '');
          if (isMap) {
            isMap = false;
            if (typeof res.length === 'undefined') {
              res = [];
            }
          }
          if (currentObj != null) res.push(currentObj);
          currentObj = {};
          isMap = true;
        }

        if (typeof m[2] != 'undefined') {
          var value = m[2].replace(regex['trim'], '');
          if (value[0] == '&') {
            var nb = processBlock(children);
            if (currentObj != null) currentObj[key] = nb;
            else res[key] = nb;
            reference_blocks[value.substr(1)] = nb;
          } else if (value[0] == '|') {
            if (currentObj != null)
              currentObj[key] = processLiteralBlock(children.shift());
            else res[key] = processLiteralBlock(children.shift());
          } else if (value[0] == '*') {
            var v = value.substr(1);
            var no = {};

            if (typeof reference_blocks[v] == 'undefined') {
              errors.push("Reference '" + v + "' not found!");
            } else {
              for (var k in reference_blocks[v]) {
                no[k] = reference_blocks[v][k];
              }

              if (currentObj != null) currentObj[key] = no;
              else res[key] = no;
            }
          } else if (value[0] == '>') {
            if (currentObj != null)
              currentObj[key] = processFoldedBlock(children.shift());
            else res[key] = processFoldedBlock(children.shift());
          } else {
            if (currentObj != null) currentObj[key] = processValue(value);
            else res[key] = processValue(value);
          }
        } else {
          if (currentObj != null) currentObj[key] = processBlock(children);
          else res[key] = processBlock(children);
        }
      } else if (line.match(/^-\s*$/)) {
        if (isMap) {
          isMap = false;
          if (typeof res.length === 'undefined') {
            res = [];
          }
        }
        if (currentObj != null) res.push(currentObj);
        currentObj = {};
        isMap = true;
        continue;
      } else if ((m = line.match(/^-\s*(.*)/))) {
        if (currentObj != null) currentObj.push(processValue(m[1]));
        else {
          if (isMap) {
            isMap = false;
            if (typeof res.length === 'undefined') {
              res = [];
            }
          }
          res.push(processValue(m[1]));
        }
        continue;
      }
    }

    if (currentObj != null) {
      if (isMap) {
        isMap = false;
        if (typeof res.length === 'undefined') {
          res = [];
        }
      }
      res.push(currentObj);
    }
  }

  for (var j = processedBlocks.length - 1; j >= 0; --j) {
    blocks.splice.call(blocks, processedBlocks[j], 1);
  }

  return res;
}

function semanticAnalysis(blocks) {
  var res = processBlock(blocks.children);
  return res;
}

function preProcess(src) {
  var m;
  var lines = src.split('\n');

  var r = regex['comment'];

  for (var i in lines) {
    if ((m = lines[i].match(r))) {
      /*                var cmt = "";
            if(typeof m[3] != "undefined")
                lines[i] = m[1];
            else if(typeof m[3] != "undefined")
                lines[i] = m[3];
            else
                lines[i] = "";
                */
      if (typeof m[3] !== 'undefined') {
        lines[i] = m[0].substr(0, m[0].length - m[3].length);
      }
    }
  }

  return lines.join('\n');
}

function load(str) {
  errors = [];
  reference_blocks = [];
  processing_time = new Date().getTime();
  var pre = preProcess(str);
  var doc = parser(pre);
  var res = semanticAnalysis(doc);
  processing_time = new Date().getTime() - processing_time;

  return res;
}

export default load;