introduce a `tree` factory method for creating the dep tree

also add an EMPTY sentinel node

2 files changed, 62 insertions, 0 deletions

diff --git a/actionview/lib/action_view/digestor.rb b/actionview/lib/action_view/digestor.rb
index 657026fa14..d31154061c 100644
--- a/actionview/lib/action_view/digestor.rb
+++ b/actionview/lib/action_view/digestor.rb
@@ -55,6 +55,55 @@ module ActionView
         end
     end
 
+    EMPTY = Class.new {
+      def name; 'missing'; end
+      def digest; ''; end
+    }.new
+
+    def self.tree(name, finder, partial = false, seen = {})
+      if obj = seen[name]
+        obj
+      else
+        logical_name = name.gsub(%r|/_|, "/")
+        template = finder.disable_cache { finder.find(logical_name, [], partial) }
+        node = seen[name] = Node.new(name, logical_name, template, partial, [])
+        deps = DependencyTracker.find_dependencies(name, template, finder.view_paths)
+        deps.each do |dep_file|
+          l_name = dep_file.gsub(%r|/_|, "/")
+          if finder.disable_cache { finder.exists?(l_name, [], true) }
+            node.children << tree(dep_file, finder, true, seen)
+          else
+            node.children << Missing.new(dep_file, l_name, nil, true, [])
+          end
+        end
+        node
+      end
+    end
+
+    class Node < Struct.new(:name, :logical_name, :template, :partial, :children)
+      def to_dep(finder)
+        if partial
+          PartialDigestor.new(name, finder, partial: partial)
+        else
+          Digestor.new(name, finder, partial: partial)
+        end
+      end
+
+      def digest
+        Digest::MD5.hexdigest("#{template.source}-#{dependency_digest}")
+      end
+
+      def dependency_digest
+        children.map(&:digest).join("-")
+      end
+    end
+
+    class Missing < Node
+      def digest
+        ''
+      end
+    end
+
     attr_reader :name, :finder, :options
 
     def initialize(name, finder, options = {})
@@ -78,6 +127,12 @@ module ActionView
       []
     end
 
+    def children
+      dependencies.collect do |dependency|
+        PartialDigestor.new(dependency, finder)
+      end
+    end
+
     def nested_dependencies
       dependencies.collect do |dependency|
         dependencies = PartialDigestor.new(dependency, finder).nested_dependencies
diff --git a/actionview/test/template/digestor_test.rb b/actionview/test/template/digestor_test.rb
index bfab97cf1e..5e553859f0 100644
--- a/actionview/test/template/digestor_test.rb
+++ b/actionview/test/template/digestor_test.rb
@@ -36,6 +36,13 @@ class TemplateDigestorTest < ActionView::TestCase
     ActionView::Digestor.cache.clear
   end
 
+  def test_amaze
+    node = ActionView::Digestor.tree "messages/show", finder
+    x = ActionView::Digestor.new("messages/show", finder)
+    #assert_equal digest("messages/show"), node.to_dep(finder).digest
+    assert_equal digest("messages/show"), node.digest
+  end
+
   def test_top_level_change_reflected
     assert_digest_difference("messages/show") do
       change_template("messages/show")