From 01e18dd460ac11d1771090a36fbb4965c3d8b561 Mon Sep 17 00:00:00 2001
From: Ben Hollis <ben@benhollis.net>
Date: Sat, 7 Apr 2012 11:14:55 -0700
Subject: [PATCH] Add a method to all Template classes that states whether the
 template sllows running arbitrary Ruby script. This is useful for users of
 Tilt who want to disallow templates that support script or who want to treat
 them differently.

---
 lib/tilt/coffee.rb   |  4 ++++
 lib/tilt/css.rb      |  8 ++++++++
 lib/tilt/liquid.rb   |  4 ++++
 lib/tilt/markdown.rb | 24 ++++++++++++++++++++++++
 lib/tilt/radius.rb   |  4 ++++
 lib/tilt/rdoc.rb     |  4 ++++
 lib/tilt/template.rb |  9 +++++++++
 lib/tilt/textile.rb  |  4 ++++
 lib/tilt/wiki.rb     |  8 ++++++++
 9 files changed, 69 insertions(+)

diff --git a/lib/tilt/coffee.rb b/lib/tilt/coffee.rb
index ac6d6dc2..fafaac8a 100644
--- a/lib/tilt/coffee.rb
+++ b/lib/tilt/coffee.rb
@@ -45,6 +45,10 @@ def prepare
     def evaluate(scope, locals, &block)
       @output ||= CoffeeScript.compile(data, options)
     end
+
+    def allows_script?
+      false
+    end
   end
 end
 
diff --git a/lib/tilt/css.rb b/lib/tilt/css.rb
index 021bb8b9..8626db17 100644
--- a/lib/tilt/css.rb
+++ b/lib/tilt/css.rb
@@ -24,6 +24,10 @@ def evaluate(scope, locals, &block)
       @output ||= @engine.render
     end
 
+    def allows_script?
+      false
+    end
+
   private
     def sass_options
       options.merge(:filename => eval_file, :line => line, :syntax => :sass)
@@ -67,6 +71,10 @@ def prepare
     def evaluate(scope, locals, &block)
       @output ||= @engine.to_css
     end
+
+    def allows_script?
+      false
+    end
   end
 end
 
diff --git a/lib/tilt/liquid.rb b/lib/tilt/liquid.rb
index 74a63afc..33649111 100644
--- a/lib/tilt/liquid.rb
+++ b/lib/tilt/liquid.rb
@@ -37,5 +37,9 @@ def evaluate(scope, locals, &block)
       locals['content'] = locals['yield']
       @engine.render(locals)
     end
+
+    def allows_script?
+      false
+    end
   end
 end
diff --git a/lib/tilt/markdown.rb b/lib/tilt/markdown.rb
index 396fb126..e549ad53 100644
--- a/lib/tilt/markdown.rb
+++ b/lib/tilt/markdown.rb
@@ -37,6 +37,10 @@ def prepare
     def evaluate(scope, locals, &block)
       @output ||= @engine.to_html
     end
+
+    def allows_script?
+      false
+    end
   end
 
   # Upskirt Markdown implementation. See:
@@ -61,6 +65,10 @@ def evaluate(scope, locals, &block)
       @engine.evaluate(scope, locals, &block)
     end
 
+    def allows_script?
+      false
+    end
+
     # Compatibility mode for Redcarpet 1.x
     class Redcarpet1 < RDiscountTemplate
       self.default_mime_type = 'text/html'
@@ -116,6 +124,10 @@ def prepare
       def evaluate(scope, locals, &block)
         @output ||= @engine.render(data)
       end
+
+      def allows_script?
+        false
+      end
     end
   end
 
@@ -140,6 +152,10 @@ def prepare
     def evaluate(scope, locals, &block)
       @output ||= @engine.to_html
     end
+
+    def allows_script?
+      false
+    end
   end
 
   # Maruku markdown implementation. See:
@@ -161,6 +177,10 @@ def prepare
     def evaluate(scope, locals, &block)
       @output ||= @engine.to_html
     end
+
+    def allows_script?
+      false
+    end
   end
 
   # Kramdown Markdown implementation. See:
@@ -185,6 +205,10 @@ def prepare
     def evaluate(scope, locals, &block)
       @output ||= @engine.to_html
     end
+
+    def allows_script?
+      false
+    end
   end
 end
 
diff --git a/lib/tilt/radius.rb b/lib/tilt/radius.rb
index 88e1a194..64ec9085 100644
--- a/lib/tilt/radius.rb
+++ b/lib/tilt/radius.rb
@@ -47,5 +47,9 @@ def evaluate(scope, locals, &block)
       parser = Radius::Parser.new(context, options)
       parser.parse(data)
     end
+
+    def allows_script?
+      false
+    end
   end
 end
diff --git a/lib/tilt/rdoc.rb b/lib/tilt/rdoc.rb
index 33450e59..60906002 100644
--- a/lib/tilt/rdoc.rb
+++ b/lib/tilt/rdoc.rb
@@ -29,5 +29,9 @@ def prepare
     def evaluate(scope, locals, &block)
       @output ||= @engine.to_s
     end
+
+    def allows_script?
+      false
+    end
   end
 end
diff --git a/lib/tilt/template.rb b/lib/tilt/template.rb
index 227c24f5..3db4a92a 100644
--- a/lib/tilt/template.rb
+++ b/lib/tilt/template.rb
@@ -92,6 +92,15 @@ def eval_file
       file || '(__TEMPLATE__)'
     end
 
+    # Whether or not this template engine allows executing Ruby script
+    # within the template. If this is false, +scope+ and +locals+ will
+    # generally not be used, nor will the provided block be avaiable 
+    # via +yield+.
+    # This should be overridden by template subclasses.
+    def allows_script?
+      true
+    end
+
   protected
     # Called once and only once for each template subclass the first time
     # the template class is initialized. This should be used to require the
diff --git a/lib/tilt/textile.rb b/lib/tilt/textile.rb
index fd4f4c13..c5e89c3d 100644
--- a/lib/tilt/textile.rb
+++ b/lib/tilt/textile.rb
@@ -20,6 +20,10 @@ def prepare
     def evaluate(scope, locals, &block)
       @output ||= @engine.to_html
     end
+
+    def allows_script?
+      false
+    end
   end
 end
 
diff --git a/lib/tilt/wiki.rb b/lib/tilt/wiki.rb
index dd1f2852..1349eb2f 100644
--- a/lib/tilt/wiki.rb
+++ b/lib/tilt/wiki.rb
@@ -24,6 +24,10 @@ def prepare
     def evaluate(scope, locals, &block)
       @output ||= @engine.to_html
     end
+
+    def allows_script?
+      false
+    end
   end
 
   # WikiCloth implementation. See:
@@ -46,5 +50,9 @@ def prepare
     def evaluate(scope, locals, &block)
       @output ||= @engine.to_html
     end
+
+    def allows_script?
+      false
+    end
   end
 end