XMLFragment.coffee

# Represents a fragment of an XMl document
class XMLFragment


  # Initializes a new instance of `XMLFragment`
  #
  # `parent` the parent node
  # `name` element name
  # `attributes` an object containing name/value pairs of attributes
  # `text` element text
  constructor: (parent, name, attributes, text) ->
    @parent = parent
    @name = name
    @attributes = attributes
    @value = text
    @children = []


  # Creates a child element node
  #
  # `name` name of the node
  # `attributes` an object containing name/value pairs of attributes
  element: (name, attributes) ->
    if not name?
      throw new Error "Missing element name"

    name = '' + name or ''
    attributes ?= {}
    for own key, val of attributes
      attributes[key] = @escape val

    if not name.match "^" + @val.Name + "$"
      throw new Error "Invalid element name: " + name

    child = new XMLFragment @, name, attributes
    @children.push child
    return child


  # Creates a text node
  #
  # `value` element text
  text: (value) ->
    if not value?
      throw new Error "Missing element text"

    value = '' + value or ''
    value = @escape value

    if not value.match @val.CharData
      throw new Error "Invalid element text: " + value

    child = new XMLFragment @, '', {}, value
    @children.push child
    return @


  # Creates a CDATA node
  #
  # `value` element text without CDATA delimiters
  cdata: (value) ->
    if not value?
      throw new Error "Missing CDATA text"

    value = '' + value or ''

    if not value.match @val.CDATA
      throw new Error "Invalid CDATA text: " + value

    child = new XMLFragment @, '', {}, '<![CDATA[' + value + ']]>'
    @children.push child
    return @


  # Creates a comment node
  #
  # `value` comment text
  comment: (value) ->
    if not value?
      throw new Error "Missing comment text"

    value = '' + value or ''
    value = @escape value

    if not value.match("^" + @val.CommentContent + "$")
      throw new Error "Invalid comment text: " + value

    child = new XMLFragment @, '', {}, '<!-- ' + value + ' -->'
    @children.push child
    return @


  # Gets the parent node
  up: () ->
    if not @parent?
      throw new Error "This node has no parent"
    return @parent


  # Adds or modifies an attribute
  #
  # `name` attribute name
  # `value` attribute value
  attribute: (name, value) ->
    if not name?
      throw new Error "Missing attribute name"
    if not value?
      throw new Error "Missing attribute value"

    name = '' + name or ''
    value = '' + value or ''
    value = @escape value

    if not name.match "^" + @val.Name + "$"
      throw new Error "Invalid attribute name: " + name
    if not value.match "^" + @val.AttValue + "$"
      throw new Error "Invalid attribute value: " + value

    @attributes[name] = value

    return @


  # Converts the XML fragment to string
  #
  # `options.pretty` pretty prints the result
  # `options.indent` indentation for pretty print
  # `options.newline` newline sequence for pretty print
  toString: (options, level) ->
    pretty = options? and options.pretty or false
    indent = options? and options.indent or '  '
    newline = options? and options.newline or '\n'
    level or= 0

    space = new Array(level + 1).join(indent)

    r = ''
    # open tag
    if pretty
      r += space
    if not @value
      r += '<' + @name
    else
      r += '' + @value

    # attributes
    for attName, attValue of @attributes
      if @name == '!DOCTYPE'
        r += ' ' + attValue
      else
        r += ' ' + attName + '="' + attValue + '"'

    if @children.length == 0
      # empty element
      if not @value
        r += if @name == '?xml' then '?>' else if @name == '!DOCTYPE' then '>' else '/>'
      if pretty
        r += newline
    else
      r += '>'
      if pretty
        r += newline
      # inner tags
      for child in @children
        r += child.toString options, level + 1
      # close tag
      if pretty
        r += space
      r += '</' + @name + '>'
      if pretty
        r += newline

    return r


  # Escapes special characters <, >, ', ", &
  #
  # `str` the string to escape
  escape: (str) ->
    return str.replace(/&/g, '&amp;')
              .replace(/</g,'&lt;').replace(/>/g,'&gt;')
              .replace(/'/g, '&apos;').replace(/"/g, '&quot;')


  # Aliases
  ele: (name, attributes) -> @element name, attributes
  txt: (value) -> @text value
  dat: (value) -> @cdata value
  att: (name, value) -> @attribute name, value
  com: (name, value) -> @comment name, value
  e: (name, attributes) -> @element name, attributes
  t: (value) -> @text value
  d: (value) -> @cdata value
  a: (name, value) -> @attribute name, value
  c: (name, value) -> @comment name, value
  u: () -> @up


# Regular expressions to validate tokens
# See: http://www.w3.org/TR/xml/ 
# Supplementary Unicode code points not supported
XMLFragment::val = {}
XMLFragment::val.Space = "(?:\u0020|\u0009|\u000D|\u000A)+"
XMLFragment::val.Char = "\u0009|\u000A|\u000D|[\u0020-\uD7FF]|[\uE000-\uFFFD]"
XMLFragment::val.NameStartChar =
  ":|[A-Z]|_|[a-z]|[\u00C0-\u00D6]|[\u00D8-\u00F6]|[\u00F8-\u02FF]|" +
  "[\u0370-\u037D]|[\u037F-\u1FFF]|[\u200C-\u200D]|[\u2070-\u218F]|" +
  "[\u2C00-\u2FEF]|[\u3001-\uD7FF]|[\uF900-\uFDCF]|[\uFDF0-\uFFFD]"
XMLFragment::val.NameChar =
  XMLFragment::val.NameStartChar + '|' +
  "-|\.|[0-9]|\u00B7|[\u0300-\u036F]|[\u203F-\u2040]"
XMLFragment::val.CharRef = "&#[0-9]+;|&#x[0-9a-fA-F]+;"
XMLFragment::val.Name = 
  '(?:' + XMLFragment::val.NameStartChar + ')' +
  '(?:' + XMLFragment::val.NameChar + ')*'
XMLFragment::val.NMToken = '(?:' + XMLFragment::val.NameChar + ')+'
XMLFragment::val.EntityRef = '&' + XMLFragment::val.Name + ';'
XMLFragment::val.Reference = 
  '&' + XMLFragment::val.Name + ';' + '|' + XMLFragment::val.CharRef
XMLFragment::val.PEReference = '%' + XMLFragment::val.Name + ';'
XMLFragment::val.EntityValue =
  '(?:[^%&"]|%' + XMLFragment::val.Name + ';|&' + XMLFragment::val.Name + ';)*'
XMLFragment::val.AttValue =
  '(?:[^<&"]|' + XMLFragment::val.Reference + ')*'
XMLFragment::val.SystemLiteral = '[^"]*'
XMLFragment::val.PubIDChar = "\u0020|\u000D|\u000A|[a-zA-Z0-9]|[-'()+,./:=?;!*#@$_%]"
XMLFragment::val.PubIDLiteral = '(?:' + XMLFragment::val.PubIDChar + ')*'
XMLFragment::val.CommentChar = '(?!-)' + '(?:' + XMLFragment::val.Char + ')'
XMLFragment::val.CommentContent =
  '(?:' + XMLFragment::val.CommentChar + '|' +
  '-' + XMLFragment::val.CommentChar + ')*'
XMLFragment::val.Comment = '<!--' + XMLFragment::val.CommentContent + '-->'
XMLFragment::val.ExternalID =
  '(?:' + 'SYSTEM' + XMLFragment::val.Space + XMLFragment::val.SystemLiteral + ')|'
  '(?:' + 'PUBLIC' + XMLFragment::val.Space + XMLFragment::val.PubIDLateral +
  XMLFragment::val.Space + XMLFragment::val.SystemLiteral + ')'


XMLFragment::val.CharData = /^(?![^<&]*]]>[^<&]*)[^<&]*$/
XMLFragment::val.CDATA = /^(?:(?!]]>).)*$/


XMLFragment::val.VersionNum = /^1\.[0-9]+$/
XMLFragment::val.EncName = /^[A-Za-z](?:[A-Za-z0-9\._]|-)*$/


module.exports = XMLFragment