Checkout of Instiki Trunk 1/21/2007.

vendor/rails/actionpack/lib/action_controller/code_generation.rb

@@ -0,0 +1,235 @@
+module ActionController
+  module CodeGeneration #:nodoc:
+    class GenerationError < StandardError #:nodoc:
+    end
+  
+    class Source #:nodoc:
+      attr_reader :lines, :indentation_level
+      IndentationString = '  '
+      def initialize
+        @lines, @indentation_level = [], 0
+      end
+      def line(line)
+        @lines << (IndentationString * @indentation_level + line)
+      end
+      alias :<< :line
+    
+      def indent
+        @indentation_level += 1
+        yield
+        ensure
+        @indentation_level -= 1
+      end
+    
+      def to_s() lines.join("\n") end
+    end
+
+    class CodeGenerator #:nodoc:
+      attr_accessor :source, :locals
+      def initialize(source = nil)
+        @locals = []
+        @source = source || Source.new
+      end
+    
+      BeginKeywords = %w(if unless begin until while def).collect {|kw| kw.to_sym}
+      ResumeKeywords = %w(elsif else rescue).collect {|kw| kw.to_sym}
+      Keywords = BeginKeywords + ResumeKeywords
+    
+      def method_missing(keyword, *text)
+        if Keywords.include? keyword
+          if ResumeKeywords.include? keyword
+            raise GenerationError, "Can only resume with #{keyword} immediately after an end" unless source.lines.last =~ /^\s*end\s*$/ 
+            source.lines.pop # Remove the 'end'
+          end
+      
+          line "#{keyword} #{text.join ' '}"
+          begin source.indent { yield(self.dup) }
+          ensure line 'end'
+          end
+        else
+          super(keyword, *text)
+        end
+      end
+    
+      def line(*args) self.source.line(*args) end
+      alias :<< :line
+      def indent(*args, &block) source(*args, &block) end
+      def to_s() source.to_s end
+    
+      def share_locals_with(other)
+        other.locals = self.locals = (other.locals | locals) 
+      end
+    
+      FieldsToDuplicate = [:locals]
+      def dup
+        copy = self.class.new(source)
+        self.class::FieldsToDuplicate.each do |sym|
+          value = self.send(sym)
+          value = value.dup unless value.nil? || value.is_a?(Numeric)
+          copy.send("#{sym}=", value)
+        end
+        return copy
+      end
+    end
+
+    class RecognitionGenerator < CodeGenerator #:nodoc:
+      Attributes = [:after, :before, :current, :results, :constants, :depth, :move_ahead, :finish_statement]
+      attr_accessor(*Attributes)
+      FieldsToDuplicate = CodeGenerator::FieldsToDuplicate + Attributes
+    
+      def initialize(*args)
+        super(*args)
+        @after, @before = [], []
+        @current = nil
+        @results, @constants = {}, {}
+        @depth = 0
+        @move_ahead = nil
+        @finish_statement = Proc.new {|hash_expr| hash_expr}
+      end
+    
+      def if_next_matches(string, &block)
+        test = Routing.test_condition(next_segment(true), string)
+        self.if(test, &block)
+      end
+    
+      def move_forward(places = 1)
+        dup = self.dup
+        dup.depth += 1
+        dup.move_ahead = places
+        yield dup
+      end
+    
+      def next_segment(assign_inline = false, default = nil)
+        if locals.include?(segment_name)
+          code = segment_name
+        else
+          code = "#{segment_name} = #{path_name}[#{index_name}]"
+          if assign_inline
+            code = "(#{code})"
+          else
+            line(code)
+            code = segment_name
+          end
+        
+          locals << segment_name
+        end
+        code = "(#{code} || #{default.inspect})" if default 
+      
+        return code.to_s
+      end
+    
+      def segment_name() "segment#{depth}".to_sym end
+      def path_name() :path end
+      def index_name
+        move_ahead, @move_ahead = @move_ahead, nil
+        move_ahead ? "index += #{move_ahead}" : 'index'
+      end
+    
+      def continue
+        dup = self.dup
+        dup.before << dup.current
+        dup.current = dup.after.shift
+        dup.go
+      end
+    
+      def go
+        if current then current.write_recognition(self)
+        else self.finish
+        end
+      end 
+    
+      def result(key, expression, delay = false)
+        unless delay
+          line "#{key}_value = #{expression}"
+          expression = "#{key}_value"
+        end
+        results[key] = expression
+      end
+      def constant_result(key, object)
+        constants[key] = object
+      end
+  
+      def finish(ensure_traversal_finished = true)
+        pairs = [] 
+        (results.keys + constants.keys).uniq.each do |key|
+          pairs << "#{key.to_s.inspect} => #{results[key] ? results[key] : constants[key].inspect}"
+        end
+        hash_expr = "{#{pairs.join(', ')}}"
+      
+        statement = finish_statement.call(hash_expr)
+        if ensure_traversal_finished then self.if("! #{next_segment(true)}") {|gp| gp << statement}
+        else self << statement
+        end
+      end
+    end
+  
+    class GenerationGenerator < CodeGenerator #:nodoc:
+      Attributes = [:after, :before, :current, :segments]
+      attr_accessor(*Attributes)
+      FieldsToDuplicate = CodeGenerator::FieldsToDuplicate + Attributes
+    
+      def initialize(*args)
+        super(*args)
+        @after, @before = [], []
+        @current = nil
+        @segments = []
+      end
+    
+      def hash_name() 'hash' end
+      def local_name(key) "#{key}_value" end
+    
+      def hash_value(key, assign = true, default = nil)
+        if locals.include?(local_name(key)) then code = local_name(key)
+        else
+          code = "hash[#{key.to_sym.inspect}]"
+          if assign
+            code = "(#{local_name(key)} = #{code})"
+            locals << local_name(key)
+          end
+        end
+        code = "(#{code} || (#{default.inspect}))" if default
+        return code
+      end 
+    
+      def expire_for_keys(*keys)
+        return if keys.empty?
+        conds = keys.collect {|key| "expire_on[#{key.to_sym.inspect}]"}
+        line "not_expired, #{hash_name} = false, options if not_expired && #{conds.join(' && ')}"
+      end
+    
+      def add_segment(*segments)
+        d = dup
+        d.segments.concat segments
+        yield d
+      end
+    
+      def go
+        if current then current.write_generation(self)
+        else self.finish
+        end
+      end
+    
+      def continue
+        d = dup
+        d.before << d.current
+        d.current = d.after.shift
+        d.go
+      end
+    
+      def finish
+        line %("/#{segments.join('/')}")
+      end
+
+      def check_conditions(conditions)
+        tests = []
+        generator = nil
+        conditions.each do |key, condition|
+          tests << (generator || self).hash_value(key, true) if condition.is_a? Regexp
+          tests << Routing.test_condition((generator || self).hash_value(key, false), condition)
+          generator = self.dup unless generator
+        end
+        return tests.join(' && ')
+      end
+    end
+  end
+end