Merge pull request #8530 from dasch/dependency-trackers

Custom dependency trackers for the template digestor

4 files changed, 146 insertions, 45 deletions

diff --git a/actionpack/lib/action_view/dependency_tracker.rb b/actionpack/lib/action_view/dependency_tracker.rb
new file mode 100644
index 0000000000..3de5cd150b
--- /dev/null
+++ b/actionpack/lib/action_view/dependency_tracker.rb
@@ -0,0 +1,91 @@
+require 'thread_safe'
+
+module ActionView
+  class DependencyTracker
+    @trackers = ThreadSafe::Cache.new
+
+    def self.find_dependencies(name, template)
+      tracker = @trackers[template.handler]
+
+      if tracker.present?
+        tracker.call(name, template)
+      else
+        []
+      end
+    end
+
+    def self.register_tracker(extension, tracker)
+      handler = Template.handler_for_extension(extension)
+      @trackers[handler] = tracker
+    end
+
+    def self.remove_tracker(handler)
+      @trackers.delete(handler)
+    end
+
+    class ERBTracker
+      EXPLICIT_DEPENDENCY = /# Template Dependency: (\S+)/
+
+      # Matches:
+      #   render partial: "comments/comment", collection: commentable.comments
+      #   render "comments/comments"
+      #   render 'comments/comments'
+      #   render('comments/comments')
+      #
+      #   render(@topic)         => render("topics/topic")
+      #   render(topics)         => render("topics/topic")
+      #   render(message.topics) => render("topics/topic")
+      RENDER_DEPENDENCY = /
+        render\s*                     # render, followed by optional whitespace
+        \(?                           # start an optional parenthesis for the render call
+        (partial:|:partial\s+=>)?\s*  # naming the partial, used with collection -- 1st capture
+        ([@a-z"'][@a-z_\/\."']+)      # the template name itself -- 2nd capture
+      /x
+
+      def self.call(name, template)
+        new(name, template).dependencies
+      end
+
+      def initialize(name, template)
+        @name, @template = name, template
+      end
+
+      def dependencies
+        render_dependencies + explicit_dependencies
+      end
+
+      private
+        attr_reader :name, :template
+
+        def source
+          template.source
+        end
+
+        def directory
+          name.split("/")[0..-2].join("/")
+        end
+
+        def render_dependencies
+          source.scan(RENDER_DEPENDENCY).
+            collect(&:second).uniq.
+
+            # render(@topic)         => render("topics/topic")
+            # render(topics)         => render("topics/topic")
+            # render(message.topics) => render("topics/topic")
+            collect { |name| name.sub(/\A@?([a-z]+\.)*([a-z_]+)\z/) { "#{$2.pluralize}/#{$2.singularize}" } }.
+
+            # render("headline") => render("message/headline")
+            collect { |name| name.include?("/") ? name : "#{directory}/#{name}" }.
+
+            # replace quotes from string renders
+            collect { |name| name.gsub(/["']/, "") }
+        end
+
+        def explicit_dependencies
+          source.scan(EXPLICIT_DEPENDENCY).flatten.uniq
+        end
+    end
+
+    register_tracker :erb, ERBTracker
+  end
+end
diff --git a/actionpack/lib/action_view/digestor.rb b/actionpack/lib/action_view/digestor.rb
index 4507861dcc..9324a1ac50 100644
--- a/actionpack/lib/action_view/digestor.rb
+++ b/actionpack/lib/action_view/digestor.rb
@@ -1,25 +1,8 @@
 require 'thread_safe'
+require 'action_view/dependency_tracker'
 
 module ActionView
   class Digestor
-    EXPLICIT_DEPENDENCY = /# Template Dependency: (\S+)/
-
-    # Matches:
-    #   render partial: "comments/comment", collection: commentable.comments
-    #   render "comments/comments"
-    #   render 'comments/comments'
-    #   render('comments/comments')
-    #
-    #   render(@topic)         => render("topics/topic")
-    #   render(topics)         => render("topics/topic")
-    #   render(message.topics) => render("topics/topic")
-    RENDER_DEPENDENCY = /
-      render\s*                     # render, followed by optional whitespace
-      \(?                           # start an optional parenthesis for the render call
-      (partial:|:partial\s+=>)?\s*  # naming the partial, used with collection -- 1st capture
-      ([@a-z"'][@a-z_\/\."']+)      # the template name itself -- 2nd capture
-    /x
-
     cattr_reader(:cache)
     @@cache = ThreadSafe::Cache.new
 
@@ -47,7 +30,7 @@ module ActionView
     end
 
     def dependencies
-      render_dependencies + explicit_dependencies
+      DependencyTracker.find_dependencies(name, template)
     rescue ActionView::MissingTemplate
       [] # File doesn't exist, so no dependencies
     end
@@ -69,16 +52,16 @@ module ActionView
         name.gsub(%r|/_|, "/")
       end
 
-      def directory
-        name.split("/")[0..-2].join("/")
-      end
-
       def partial?
         false
       end
 
+      def template
+        @template ||= finder.find(logical_name, [], partial?, formats: [ format ])
+      end
+
       def source
-        @source ||= finder.find(logical_name, [], partial?, formats: [ format ]).source
+        template.source
       end
 
       def dependency_digest
@@ -89,26 +72,6 @@ module ActionView
         (template_digests + injected_dependencies).join("-")
       end
 
-      def render_dependencies
-        source.scan(RENDER_DEPENDENCY).
-          collect(&:second).uniq.
-
-          # render(@topic)         => render("topics/topic")
-          # render(topics)         => render("topics/topic")
-          # render(message.topics) => render("topics/topic")
-          collect { |name| name.sub(/\A@?([a-z]+\.)*([a-z_]+)\z/) { "#{$2.pluralize}/#{$2.singularize}" } }.
-
-          # render("headline") => render("message/headline")
-          collect { |name| name.include?("/") ? name : "#{directory}/#{name}" }.
-
-          # replace quotes from string renders
-          collect { |name| name.gsub(/["']/, "") }
-      end
-
-      def explicit_dependencies
-        source.scan(EXPLICIT_DEPENDENCY).flatten.uniq
-      end
-
       def injected_dependencies
         Array.wrap(options[:dependencies])
       end
diff --git a/actionpack/test/template/dependency_tracker_test.rb b/actionpack/test/template/dependency_tracker_test.rb
new file mode 100644
index 0000000000..9c68afbdbd
--- /dev/null
+++ b/actionpack/test/template/dependency_tracker_test.rb
@@ -0,0 +1,46 @@
+require 'abstract_unit'
+require 'action_view/dependency_tracker'
+
+class DependencyTrackerTest < ActionView::TestCase
+  Neckbeard = lambda {|template| template.source }
+  Bowtie = lambda {|template| template.source }
+
+  class NeckbeardTracker
+    def self.call(name, template)
+      ["foo/#{name}"]
+    end
+  end
+
+  class FakeTemplate
+    attr_reader :source, :handler
+
+    def initialize(source, handler = Neckbeard)
+      @source, @handler = source, handler
+    end
+  end
+
+  def tracker
+    ActionView::DependencyTracker
+  end
+
+  def setup
+    ActionView::Template.register_template_handler :neckbeard, Neckbeard
+    tracker.register_tracker(:neckbeard, NeckbeardTracker)
+  end
+
+  def teardown
+    tracker.remove_tracker(:neckbeard)
+  end
+
+  def test_finds_tracker_by_template_handler
+    template = FakeTemplate.new("boo/hoo")
+    dependencies = tracker.find_dependencies("boo/hoo", template)
+    assert_equal ["foo/boo/hoo"], dependencies
+  end
+
+  def test_returns_empty_array_if_no_tracker_is_found
+    template = FakeTemplate.new("boo/hoo", Bowtie)
+    dependencies = tracker.find_dependencies("boo/hoo", template)
+    assert_equal [], dependencies
+  end
+end
diff --git a/actionpack/test/template/digestor_test.rb b/actionpack/test/template/digestor_test.rb
index 849e2981a6..e29cecabc0 100644
--- a/actionpack/test/template/digestor_test.rb
+++ b/actionpack/test/template/digestor_test.rb
@@ -2,10 +2,11 @@ require 'abstract_unit'
 require 'fileutils'
 
 class FixtureTemplate
-  attr_reader :source
+  attr_reader :source, :handler
 
   def initialize(template_path)
     @source = File.read(template_path)
+    @handler = ActionView::Template.handler_for_extension(:erb)
   rescue Errno::ENOENT
     raise ActionView::MissingTemplate.new([], "", [], true, [])
   end