lib/rbyaml/serializer.rb

   1 require 'rbyaml/error'
   2 require 'rbyaml/events'
   3 require 'rbyaml/nodes'
   4
   5 module RbYAML
   6   class SerializerError < YAMLError
   7   end
   8
   9   class Serializer
  10     def initialize(emitter, resolver, opts={})
  11       @emitter = emitter
  12       @resolver = resolver
  13       @options = opts
  14       @use_explicit_start = opts[:ExplicitStart]
  15       @use_explicit_end = opts[:ExplicitEnd]
  16       @use_version = opts[:UseVersion] && opts[:Version]
  17       @use_tags = opts[:UseHeader]
  18       @anchor_template = opts[:AnchorFormat] || "id%03d"
  19       @serialized_nodes = {}
  20       @anchors = {}
  21       @last_anchor_id = 0
  22       @closed = nil
  23     end
  24
  25     def open
  26       if @closed.nil?
  27         @emitter.emit(StreamStartEvent.new)
  28         @closed = false
  29       elsif @closed
  30         raise SerializerError.new("serializer is closed")
  31       else
  32         raise SerializerError.new("serializer is already opened")
  33       end
  34     end
  35
  36     def close
  37       if @closed.nil?
  38         raise SerializerError.new("serializer is not opened")
  39       elsif !@closed
  40         @emitter.emit(StreamEndEvent.new)
  41         @closed = true
  42       end
  43     end
  44
  45     def serialize(node)
  46       if @closed.nil?
  47         raise SerializerError.new("serializer is not opened")
  48       elsif @closed
  49         raise SerializerError.new("serializer is closed")
  50       end
  51       @emitter.emit(DocumentStartEvent.new(@use_explicit_start,@use_version,@use_tags))
  52       anchor_node(node)
  53       serialize_node(node,nil,nil)
  54       @emitter.emit(DocumentEndEvent.new(@use_explicit_end))
  55       @serialized_nodes = {}
  56       @anchors = {}
  57       @last_alias_id = 0
  58     end
  59
  60     def anchor_node(node)
  61       if @anchors.include?(node)
  62         @anchors[node] ||= generate_anchor(node)
  63       else
  64         @anchors[node] = nil
  65         if SequenceNode === node
  66           for item in node.value
  67             anchor_node(item)
  68           end
  69         elsif MappingNode === node
  70           for key,val in node.value
  71             anchor_node(key)
  72             anchor_node(val)
  73           end
  74         end
  75       end
  76     end
  77
  78     def generate_anchor(node)
  79       @last_anchor_id += 1
  80       @anchor_template % @last_anchor_id
  81     end
  82
  83     def serialize_node(node,parent,index)
  84       talias = @anchors[node]
  85       if @serialized_nodes.include?(node)
  86         @emitter.emit(AliasEvent.new(talias))
  87       else
  88         @serialized_nodes[node] = true
  89         @resolver.descend_resolver(parent, index)
  90         if ScalarNode === node
  91           detected_tag = @resolver.resolve(ScalarNode, node.value, [true,false])
  92           default_tag = @resolver.resolve(ScalarNode, node.value, [false,true])
  93           implicit = (node.tag == detected_tag), (node.tag == default_tag)
  94           @emitter.emit(ScalarEvent.new(talias, node.tag, implicit, node.value,node.style))
  95         elsif SequenceNode === node
  96           implicit = (node.tag == @resolver.resolve(SequenceNode, node.value, true))
  97           @emitter.emit(SequenceStartEvent.new(talias, node.tag, implicit,node.flow_style))
  98           index = 0
  99           for item in node.value
 100             serialize_node(item,node,index)
 101             index += 1
 102           end
 103           @emitter.emit(SequenceEndEvent.new)
 104         elsif MappingNode === node
 105           implicit = (node.tag == @resolver.resolve(MappingNode, node.value, true))
 106           @emitter.emit(MappingStartEvent.new(talias, node.tag, implicit,node.flow_style))
 107           for key, value in node.value
 108             serialize_node(key,node,nil)
 109             serialize_node(value,node,key)
 110           end
 111           @emitter.emit(MappingEndEvent.new)
 112         end
 113       end
 114     end
 115   end
 116 end
 117