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Diffstat (limited to 'activesupport/vendor/builder/xmlbase.rb')
-rw-r--r-- | activesupport/vendor/builder/xmlbase.rb | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/activesupport/vendor/builder/xmlbase.rb b/activesupport/vendor/builder/xmlbase.rb new file mode 100644 index 0000000000..7202bb2ead --- /dev/null +++ b/activesupport/vendor/builder/xmlbase.rb @@ -0,0 +1,143 @@ +#!/usr/bin/env ruby + +require 'builder/blankslate' + +module Builder #:nodoc: + + # Generic error for builder + class IllegalBlockError < RuntimeError #:nodoc: + end + + # XmlBase is a base class for building XML builders. See + # Builder::XmlMarkup and Builder::XmlEvents for examples. + class XmlBase < BlankSlate #:nodoc: + + # Create an XML markup builder. + # + # out:: Object receiving the markup.1 +out+ must respond to + # <tt><<</tt>. + # indent:: Number of spaces used for indentation (0 implies no + # indentation and no line breaks). + # initial:: Level of initial indentation. + # + def initialize(indent=0, initial=0) + @indent = indent + @level = initial + end + + # Create a tag named +sym+. Other than the first argument which + # is the tag name, the arguements are the same as the tags + # implemented via <tt>method_missing</tt>. + def tag!(sym, *args, &block) + self.__send__(sym, *args, &block) + end + + # Create XML markup based on the name of the method. This method + # is never invoked directly, but is called for each markup method + # in the markup block. + def method_missing(sym, *args, &block) + text = nil + attrs = nil + sym = "#{sym}:#{args.shift}" if args.first.kind_of?(Symbol) + args.each do |arg| + case arg + when Hash + attrs ||= {} + attrs.merge!(arg) + else + text ||= '' + text << arg.to_s + end + end + if block + unless text.nil? + raise ArgumentError, "XmlMarkup cannot mix a text argument with a block" + end + _capture_outer_self(block) if @self.nil? + _indent + _start_tag(sym, attrs) + _newline + _nested_structures(block) + _indent + _end_tag(sym) + _newline + elsif text.nil? + _indent + _start_tag(sym, attrs, true) + _newline + else + _indent + _start_tag(sym, attrs) + text! text + _end_tag(sym) + _newline + end + @target + end + + # Append text to the output target. Escape any markup. May be + # used within the markup brackets as: + # + # builder.p { br; text! "HI" } #=> <p><br/>HI</p> + def text!(text) + _text(_escape(text)) + end + + # Append text to the output target without escaping any markup. + # May be used within the markup brackets as: + # + # builder.p { |x| x << "<br/>HI" } #=> <p><br/>HI</p> + # + # This is useful when using non-builder enabled software that + # generates strings. Just insert the string directly into the + # builder without changing the inserted markup. + # + # It is also useful for stacking builder objects. Builders only + # use <tt><<</tt> to append to the target, so by supporting this + # method/operation builders can use other builders as their + # targets. + def <<(text) + _text(text) + end + + # For some reason, nil? is sent to the XmlMarkup object. If nil? + # is not defined and method_missing is invoked, some strange kind + # of recursion happens. Since nil? won't ever be an XML tag, it + # is pretty safe to define it here. (Note: this is an example of + # cargo cult programming, + # cf. http://fishbowl.pastiche.org/2004/10/13/cargo_cult_programming). + def nil? + false + end + + private + + def _escape(text) + text. + gsub(%r{&}, '&'). + gsub(%r{<}, '<'). + gsub(%r{>}, '>') + end + + def _capture_outer_self(block) + @self = eval("self", block) + end + + def _newline + return if @indent == 0 + text! "\n" + end + + def _indent + return if @indent == 0 || @level == 0 + text!(" " * (@level * @indent)) + end + + def _nested_structures(block) + @level += 1 + block.call(self) + ensure + @level -= 1 + end + end +end |