Bundle tilt

lib/tilt.rb

@@ -0,0 +1,297 @@
+module Tilt
+  @template_mappings = {}
+
+  # Register a template implementation by file extension.
+  def self.register(ext, template_class)
+    ext = ext.sub(/^\./, '')
+    @template_mappings[ext.downcase] = template_class
+  end
+
+  # Create a new template for the given file using the file's extension
+  # to determine the the template mapping.
+  def self.new(file, line=nil, options={}, &block)
+    if template_class = self[File.basename(file)]
+      template_class.new(file, line, options, &block)
+    else
+      fail "No template engine registered for #{File.basename(file)}"
+    end
+  end
+
+  # Lookup a template class given for the given filename or file
+  # extension. Return nil when no implementation is found.
+  def self.[](filename)
+    ext = filename.to_s.downcase
+    until ext.empty?
+      return @template_mappings[ext]  if @template_mappings.key?(ext)
+      ext = ext.sub(/^[^.]*\.?/, '')
+    end
+    nil
+  end
+
+  # Base class for template implementations. Subclasses must implement
+  # the #compile! method and one of the #evaluate or #template_source
+  # methods.
+  class Template
+    # Template source; loaded from a file or given directly.
+    attr_reader :data
+
+    # The name of the file where the template data was loaded from.
+    attr_reader :file
+
+    # The line number in #file where template data was loaded from.
+    attr_reader :line
+
+    # A Hash of template engine specific options. This is passed directly
+    # to the underlying engine and is not used by the generic template
+    # interface.
+    attr_reader :options
+
+    # Create a new template with the file, line, and options specified. By
+    # default, template data is read from the file specified. When a block
+    # is given, it should read template data and return as a String. When
+    # file is nil, a block is required.
+    def initialize(file=nil, line=1, options={}, &block)
+      raise ArgumentError, "file or block required" if file.nil? && block.nil?
+      @file = file
+      @line = line || 1
+      @options = options || {}
+      @reader = block || lambda { |t| File.read(file) }
+    end
+
+    # Render the template in the given scope with the locals specified. If a
+    # block is given, it is typically available within the template via
+    # +yield+.
+    def render(scope=Object.new, locals={}, &block)
+      if @data.nil?
+        @data = @reader.call(self)
+        compile!
+      end
+      evaluate scope, locals || {}, &block
+    end
+
+    # The filename used in backtraces to describe the template.
+    def eval_file
+      @file || '(__TEMPLATE__)'
+    end
+
+  protected
+    # Do whatever preparation is necessary to "compile" the template.
+    # Called immediately after template #data is loaded. Instance variables
+    # set in this method are available when #evaluate is called.
+    #
+    # Subclasses must provide an implementation of this method.
+    def compile!
+      raise NotImplementedError
+    end
+
+    # Process the template and return the result. Subclasses should override
+    # this method unless they implement the #template_source.
+    def evaluate(scope, locals, &block)
+      source, offset = local_assignment_code(locals)
+      source = [source, template_source].join("\n")
+      scope.instance_eval source, eval_file, line - offset
+    end
+
+    # Return a string containing the (Ruby) source code for the template. The
+    # default Template#evaluate implementation requires this method be
+    # defined.
+    def template_source
+      raise NotImplementedError
+    end
+
+  private
+    def local_assignment_code(locals)
+      return ['', 1] if locals.empty?
+      source = locals.collect { |k,v| "#{k} = locals[:#{k}]" }
+      [source.join("\n"), source.length]
+    end
+
+    def require_template_library(name)
+      warn "WARN: loading '#{name}' library in a non thread-safe way; " +
+           "explicit require '#{name}' suggested."
+      require name
+    end
+  end
+
+  # Extremely simple template cache implementation.
+  class Cache
+    def initialize
+      @cache = {}
+    end
+
+    def fetch(*key)
+      key = key.map { |part| part.to_s }.join(":")
+      @cache[key] ||= yield
+    end
+
+    def clear
+      @cache = {}
+    end
+  end
+
+  # Template Implementations ================================================
+
+  # The template source is evaluated as a Ruby string. The #{} interpolation
+  # syntax can be used to generated dynamic output.
+  class StringTemplate < Template
+    def compile!
+      @code = "%Q{#{data}}"
+    end
+
+    def template_source
+      @code
+    end
+  end
+  register 'str', StringTemplate
+
+  # ERB template implementation. See:
+  # http://www.ruby-doc.org/stdlib/libdoc/erb/rdoc/classes/ERB.html
+  #
+  # It's suggested that your program require 'erb' at load
+  # time when using this template engine.
+  class ERBTemplate < Template
+    def compile!
+      require_template_library 'erb' unless defined?(::ERB)
+      @engine = ::ERB.new(data, nil, nil, '@_out_buf')
+    end
+
+    def template_source
+      @engine.src
+    end
+
+    def evaluate(scope, locals, &block)
+      source, offset = local_assignment_code(locals)
+      source = [source, template_source].join("\n")
+
+      original_out_buf =
+        scope.instance_variables.any? { |var| var.to_sym == :@_out_buf } &&
+        scope.instance_variable_get(:@_out_buf)
+
+      scope.instance_eval source, eval_file, line - offset
+
+      output = scope.instance_variable_get(:@_out_buf)
+      scope.instance_variable_set(:@_out_buf, original_out_buf)
+
+      output
+    end
+
+  private
+
+    # ERB generates a line to specify the character coding of the generated
+    # source in 1.9. Account for this in the line offset.
+    if RUBY_VERSION >= '1.9.0'
+      def local_assignment_code(locals)
+        source, offset = super
+        [source, offset + 1]
+      end
+    end
+  end
+  %w[erb rhtml].each { |ext| register ext, ERBTemplate }
+
+  # Haml template implementation. See:
+  # http://haml.hamptoncatlin.com/
+  #
+  # It's suggested that your program require 'haml' at load
+  # time when using this template engine.
+  class HamlTemplate < Template
+    def compile!
+      require_template_library 'haml' unless defined?(::Haml::Engine)
+      @engine = ::Haml::Engine.new(data, haml_options)
+    end
+
+    def evaluate(scope, locals, &block)
+      @engine.render(scope, locals, &block)
+    end
+
+  private
+    def haml_options
+      options.merge(:filename => eval_file, :line => line)
+    end
+  end
+  register 'haml', HamlTemplate
+
+  # Sass template implementation. See:
+  # http://haml.hamptoncatlin.com/
+  #
+  # Sass templates do not support object scopes, locals, or yield.
+  #
+  # It's suggested that your program require 'sass' at load
+  # time when using this template engine.
+  class SassTemplate < Template
+    def compile!
+      require_template_library 'sass' unless defined?(::Sass::Engine)
+      @engine = ::Sass::Engine.new(data, sass_options)
+    end
+
+    def evaluate(scope, locals, &block)
+      @engine.render
+    end
+
+  private
+    def sass_options
+      options.merge(:filename => eval_file, :line => line)
+    end
+  end
+  register 'sass', SassTemplate
+
+  # Builder template implementation. See:
+  # http://builder.rubyforge.org/
+  #
+  # It's suggested that your program require 'builder' at load
+  # time when using this template engine.
+  class BuilderTemplate < Template
+    def compile!
+      require_template_library 'builder' unless defined?(::Builder)
+    end
+
+    def evaluate(scope, locals, &block)
+      xml = ::Builder::XmlMarkup.new(:indent => 2)
+      if data.respond_to?(:to_str)
+        locals[:xml] = xml
+        super(scope, locals, &block)
+      elsif data.kind_of?(Proc)
+        data.call(xml)
+      end
+      xml.target!
+    end
+
+    def template_source
+      data.to_str
+    end
+  end
+  register 'builder', BuilderTemplate
+
+  # Liquid template implementation. See:
+  # http://liquid.rubyforge.org/
+  #
+  # LiquidTemplate does not support scopes or yield blocks.
+  #
+  # It's suggested that your program require 'liquid' at load
+  # time when using this template engine.
+  class LiquidTemplate < Template
+    def compile!
+      require_template_library 'liquid' unless defined?(::Liquid::Template)
+      @engine = ::Liquid::Template.parse(data)
+    end
+
+    def evaluate(scope, locals, &block)
+      locals = locals.inject({}) { |hash,(k,v)| hash[k.to_s] = v ; hash }
+      @engine.render(locals)
+    end
+  end
+  register 'liquid', LiquidTemplate
+
+  # Discount Markdown implementation.
+  class RDiscountTemplate < Template
+    def compile!
+      require_template_library 'rdiscount' unless defined?(::RDiscount)
+      @engine = RDiscount.new(data)
+    end
+
+    def evaluate(scope, locals, &block)
+      @engine.to_html
+    end
+  end
+  register 'markdown', RDiscountTemplate
+
+end