Rename Template::Lookup to LookupContext.

1 files changed, 80 insertions, 0 deletions

diff --git a/actionpack/lib/action_view/lookup_context.rb b/actionpack/lib/action_view/lookup_context.rb
new file mode 100644
index 0000000000..82aebe1678
--- /dev/null
+++ b/actionpack/lib/action_view/lookup_context.rb
@@ -0,0 +1,80 @@
+module ActionView
+  # LookupContext is the object responsible to hold all information required to lookup
+  # templates, i.e. view paths and details. The LookupContext is also responsible to
+  # generate a key, given to view paths, used in the resolver cache lookup. Since
+  # this key is generated just once during the request, it speeds up all cache accesses.
+  class LookupContext #:nodoc:
+    attr_reader :details, :view_paths
+
+    class DetailsKey #:nodoc:
+      attr_reader :details
+      alias :eql? :equal?
+
+      @details_keys = Hash.new
+
+      def self.get(details)
+        @details_keys[details] ||= new(details)
+      end
+
+      def initialize(details)
+        @details, @hash = details, details.hash
+      end
+    end
+
+    def initialize(view_paths, details = {})
+      @details, @details_key = details, nil
+      self.view_paths = view_paths
+    end
+
+    # Shortcut to read formats from details.
+    def formats
+      @details[:formats]
+    end
+
+    # Shortcut to set formats in details.
+    def formats=(value)
+      self.details = @details.merge(:formats => Array(value))
+    end
+
+    # Whenever setting view paths, makes a copy so we can manipulate then in
+    # instance objects as we wish.
+    def view_paths=(paths)
+      @view_paths = ActionView::Base.process_view_paths(paths)
+    end
+
+    # Setter for details. Everything this method is invoked, we need to nullify
+    # the details key if it changed.
+    def details=(details)
+      @details = details
+      @details_key = nil if @details_key && @details_key.details != details
+    end
+
+    def details_key
+      @details_key ||= DetailsKey.get(details) unless details.empty?
+    end
+
+    # Update the details keys by merging the given hash into the current
+    # details hash. If a block is given, the details are modified just during
+    # the execution of the block and reverted to the previous value after.
+    def update_details(new_details)
+      old_details  = self.details
+      self.details = old_details.merge(new_details)
+
+      if block_given?
+        begin
+          yield
+        ensure
+          self.details = old_details
+        end
+      end
+    end
+
+    def find_template(name, prefix = nil, partial = false)
+      @view_paths.find(name, details, prefix, partial || false, details_key)
+    end
+
+    def template_exists?(name, prefix = nil, partial = false)
+      @view_paths.exists?(name, details, prefix, partial || false, details_key)
+    end
+  end
+end
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