decode.js

// NOTE: This is mostly cribbed from https://github.com/isaacs/ini/blob/master/ini.js
// the difference is we don't have the [] suffix.

module.exports = function decode (str) {
  var out = {}
    , p = out
    , section = null
    , state = "START"
           // section     |key = value
    , re = /^\[([^\]]*)\]$|^([^=]+)(=(.*))?$/i
    , lines = str.split(/[\r\n]+/g)
    , section = null

  lines.forEach(function (line, _, __) {
    if (!line || line.match(/^\s*;/)) return
    var match = line.match(re)
    if (!match) return
    if (match[1] !== undefined) {
      section = unsafe(match[1])
      p = out[section] = out[section] || {}
      return
    }
    var key = unsafe(match[2])
      , value = match[3] ? unsafe((match[4] || "")) : true
    switch (value) {
      case 'true':
      case 'false':
      case 'null': value = JSON.parse(value)
    }

    // NOTE: I haven't found any evidence that systemd supports this syntax.
    //
    // Convert keys with '[]' suffix to an array
    // if (key.length > 2 && key.slice(-2) === "[]") {
    //     key = key.substring(0, key.length - 2)
    //     if (!p[key]) {
    //       p[key] = []
    //     }
    //     else if (!Array.isArray(p[key])) {
    //       p[key] = [p[key]]
    //     }
    // }

    // safeguard against resetting a previously defined
    // array by accidentally forgetting the brackets
    if (Array.isArray(p[key])) {
      p[key].push(value)
    }
    // systemd unit files can simply repeat keys, so we cover that case here.
    else if (p[key]) {
      p[key] = [p[key], value]
    }
    else {
      p[key] = value
    }
  })

  // {a:{y:1},"a.b":{x:2}} --> {a:{y:1,b:{x:2}}}
  // use a filter to return the keys that have to be deleted.
  Object.keys(out).filter(function (k, _, __) {
    if (!out[k] || typeof out[k] !== "object" || Array.isArray(out[k])) return false
    // see if the parent section is also an object.
    // if so, add it to that, and mark this one for deletion
    var parts = dotSplit(k)
      , p = out
      , l = parts.pop()
      , nl = l.replace(/\\\./g, '.')
    parts.forEach(function (part, _, __) {
      if (!p[part] || typeof p[part] !== "object") p[part] = {}
      p = p[part]
    })
    if (p === out && nl === l) return false
    p[nl] = out[k]
    return true
  }).forEach(function (del, _, __) {
    delete out[del]
  })

  return out
}

var dotSplit = function dotSplit (str) {
  return str.replace(/\1/g, '\2LITERAL\\1LITERAL\2')
         .replace(/\\\./g, '\1')
         .split(/\./).map(function (part) {
           return part.replace(/\1/g, '\\.')
                  .replace(/\2LITERAL\\1LITERAL\2/g, '\1')
         })
}

var safe = function safe (val) {
  return ( typeof val !== "string"
         || val.match(/[\r\n]/)
         || val.match(/^\[/)
         || (val.length > 1
             && val.charAt(0) === "\""
             && val.slice(-1) === "\"")
         || val !== val.trim() )
         ? JSON.stringify(val)
         : val.replace(/;/g, '\\;')
}

var unsafe = function unsafe (val, doUnesc) {
  val = (val || "").trim()
  if (val.charAt(0) === "\"" && val.slice(-1) === "\"") {
    try { val = JSON.parse(val) } catch (_) {}
  } else {
    // walk the val to find the first not-escaped ; character
    var esc = false
    var unesc = "";
    for (var i = 0, l = val.length; i < l; i++) {
      var c = val.charAt(i)
      if (esc) {
        if (c === "\\" || c === ";")
          unesc += c
        else
          unesc += "\\" + c
        esc = false
      } else if (c === ";") {
        break
      } else if (c === "\\") {
        esc = true
      } else {
        unesc += c
      }
    }
    if (esc)
      unesc += "\\"
    return unesc
  }
  return val
}