name : attribute_manager.rb # frozen_string_literal: true ## # Manages changes of attributes in a block of text class RDoc::Markup::AttributeManager ## # The NUL character NULL = "\000".freeze #-- # We work by substituting non-printing characters in to the text. For now # I'm assuming that I can substitute a character in the range 0..8 for a 7 # bit character without damaging the encoded string, but this might be # optimistic #++ A_PROTECT = 004 # :nodoc: ## # Special mask character to prevent inline markup handling PROTECT_ATTR = A_PROTECT.chr # :nodoc: ## # The attributes enabled for this markup object. attr_reader :attributes ## # This maps delimiters that occur around words (such as *bold* or +tt+) # where the start and end delimiters and the same. This lets us optimize # the regexp attr_reader :matching_word_pairs ## # And this is used when the delimiters aren't the same. In this case the # hash maps a pattern to the attribute character attr_reader :word_pair_map ## # This maps HTML tags to the corresponding attribute char attr_reader :html_tags ## # A \ in front of a character that would normally be processed turns off # processing. We do this by turning \< into <#{PROTECT} attr_reader :protectable ## # And this maps _regexp handling_ sequences to a name. A regexp handling # sequence is something like a WikiWord attr_reader :regexp_handlings ## # Creates a new attribute manager that understands bold, emphasized and # teletype text. def initialize @html_tags = {} @matching_word_pairs = {} @protectable = %w[<] @regexp_handlings = [] @word_pair_map = {} @attributes = RDoc::Markup::Attributes.new add_word_pair "*", "*", :BOLD add_word_pair "_", "_", :EM add_word_pair "+", "+", :TT add_html "em", :EM add_html "i", :EM add_html "b", :BOLD add_html "tt", :TT add_html "code", :TT end ## # Return an attribute object with the given turn_on and turn_off bits set def attribute(turn_on, turn_off) RDoc::Markup::AttrChanger.new turn_on, turn_off end ## # Changes the current attribute from +current+ to +new+ def change_attribute current, new diff = current ^ new attribute(new & diff, current & diff) end ## # Used by the tests to change attributes by name from +current_set+ to # +new_set+ def changed_attribute_by_name current_set, new_set current = new = 0 current_set.each do |name| current |= @attributes.bitmap_for(name) end new_set.each do |name| new |= @attributes.bitmap_for(name) end change_attribute(current, new) end ## # Copies +start_pos+ to +end_pos+ from the current string def copy_string(start_pos, end_pos) res = @str[start_pos...end_pos] res.gsub!(/\000/, '') res end ## # Map attributes like <b>text</b>to the sequence # \001\002<char>\001\003<char>, where <char> is a per-attribute specific # character def convert_attrs(str, attrs) # first do matching ones tags = @matching_word_pairs.keys.join("") re = /(^|\W)([#{tags}])([#\\]?[\w:.\/-]+?\S?)\2(\W|$)/ 1 while str.gsub!(re) do attr = @matching_word_pairs[$2] attrs.set_attrs($`.length + $1.length + $2.length, $3.length, attr) $1 + NULL * $2.length + $3 + NULL * $2.length + $4 end # then non-matching unless @word_pair_map.empty? then @word_pair_map.each do |regexp, attr| str.gsub!(regexp) { attrs.set_attrs($`.length + $1.length, $2.length, attr) NULL * $1.length + $2 + NULL * $3.length } end end end ## # Converts HTML tags to RDoc attributes def convert_html(str, attrs) tags = @html_tags.keys.join '|' 1 while str.gsub!(/<(#{tags})>(.*?)<\/\1>/i) { attr = @html_tags[$1.downcase] html_length = $1.length + 2 seq = NULL * html_length attrs.set_attrs($`.length + html_length, $2.length, attr) seq + $2 + seq + NULL } end ## # Converts regexp handling sequences to RDoc attributes def convert_regexp_handlings str, attrs @regexp_handlings.each do |regexp, attribute| str.scan(regexp) do capture = $~.size == 1 ? 0 : 1 s, e = $~.offset capture attrs.set_attrs s, e - s, attribute | @attributes.regexp_handling end end end ## # Escapes regexp handling sequences of text to prevent conversion to RDoc def mask_protected_sequences # protect __send__, __FILE__, etc. @str.gsub!(/__([a-z]+)__/i, "_#{PROTECT_ATTR}_#{PROTECT_ATTR}\\1_#{PROTECT_ATTR}_#{PROTECT_ATTR}") @str.gsub!(/(\A|[^\\])\\([#{Regexp.escape @protectable.join}])/m, "\\1\\2#{PROTECT_ATTR}") @str.gsub!(/\\(\\[#{Regexp.escape @protectable.join}])/m, "\\1") end ## # Unescapes regexp handling sequences of text def unmask_protected_sequences @str.gsub!(/(.)#{PROTECT_ATTR}/, "\\1\000") end ## # Adds a markup class with +name+ for words wrapped in the +start+ and # +stop+ character. To make words wrapped with "*" bold: # # am.add_word_pair '*', '*', :BOLD def add_word_pair(start, stop, name) raise ArgumentError, "Word flags may not start with '<'" if start[0,1] == '<' bitmap = @attributes.bitmap_for name if start == stop then @matching_word_pairs[start] = bitmap else pattern = /(#{Regexp.escape start})(\S+)(#{Regexp.escape stop})/ @word_pair_map[pattern] = bitmap end @protectable << start[0,1] @protectable.uniq! end ## # Adds a markup class with +name+ for words surrounded by HTML tag +tag+. # To process emphasis tags: # # am.add_html 'em', :EM def add_html(tag, name) @html_tags[tag.downcase] = @attributes.bitmap_for name end ## # Adds a regexp handling for +pattern+ with +name+. A simple URL handler # would be: # # @am.add_regexp_handling(/((https?:)\S+\w)/, :HYPERLINK) def add_regexp_handling pattern, name @regexp_handlings << [pattern, @attributes.bitmap_for(name)] end ## # Processes +str+ converting attributes, HTML and regexp handlings def flow str @str = str.dup mask_protected_sequences @attrs = RDoc::Markup::AttrSpan.new @str.length convert_attrs @str, @attrs convert_html @str, @attrs convert_regexp_handlings @str, @attrs unmask_protected_sequences split_into_flow end ## # Debug method that prints a string along with its attributes def display_attributes puts puts @str.tr(NULL, "!") bit = 1 16.times do |bno| line = "" @str.length.times do |i| if (@attrs[i] & bit) == 0 line << " " else if bno.zero? line << "S" else line << ("%d" % (bno+1)) end end end puts(line) unless line =~ /^ *$/ bit <<= 1 end end ## # Splits the string into chunks by attribute change def split_into_flow res = [] current_attr = 0 str_len = @str.length # skip leading invisible text i = 0 i += 1 while i < str_len and @str[i].chr == "\0" start_pos = i # then scan the string, chunking it on attribute changes while i < str_len new_attr = @attrs[i] if new_attr != current_attr if i > start_pos res << copy_string(start_pos, i) start_pos = i end res << change_attribute(current_attr, new_attr) current_attr = new_attr if (current_attr & @attributes.regexp_handling) != 0 then i += 1 while i < str_len and (@attrs[i] & @attributes.regexp_handling) != 0 res << RDoc::Markup::RegexpHandling.new(current_attr, copy_string(start_pos, i)) start_pos = i next end end # move on, skipping any invisible characters begin i += 1 end while i < str_len and @str[i].chr == "\0" end # tidy up trailing text if start_pos < str_len res << copy_string(start_pos, str_len) end # and reset to all attributes off res << change_attribute(current_attr, 0) if current_attr != 0 res end end