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-rw-r--r--actionpack/lib/action_view/flows.rb79
1 files changed, 79 insertions, 0 deletions
diff --git a/actionpack/lib/action_view/flows.rb b/actionpack/lib/action_view/flows.rb
new file mode 100644
index 0000000000..386a06511f
--- /dev/null
+++ b/actionpack/lib/action_view/flows.rb
@@ -0,0 +1,79 @@
+require 'active_support/core_ext/string/output_safety'
+
+module ActionView
+ class OutputFlow #:nodoc:
+ attr_reader :content
+
+ def initialize
+ @content = Hash.new { |h,k| h[k] = ActiveSupport::SafeBuffer.new }
+ end
+
+ # Called by _layout_for to read stored values.
+ def get(key)
+ @content[key]
+ end
+
+ # Called by each renderer object to set the layout contents.
+ def set(key, value)
+ @content[key] = value
+ end
+
+ # Called by content_for
+ def append(key, value)
+ @content[key] << value
+ end
+
+ # Called by provide
+ def append!(key, value)
+ @content[key] << value
+ end
+ end
+
+ class StreamingFlow < OutputFlow #:nodoc:
+ def initialize(view, fiber)
+ @view = view
+ @parent = nil
+ @child = view.output_buffer
+ @content = view._view_flow.content
+ @fiber = fiber
+ @root = Fiber.current.object_id
+ end
+
+ # Try to get an stored content. If the content
+ # is not available and we are inside the layout
+ # fiber, we set that we are waiting for the given
+ # key and yield.
+ def get(key)
+ return super if @content.key?(key)
+
+ if inside_fiber?
+ view = @view
+
+ begin
+ @waiting_for = key
+ view.output_buffer, @parent = @child, view.output_buffer
+ Fiber.yield
+ ensure
+ @waiting_for = nil
+ view.output_buffer, @child = @parent, view.output_buffer
+ end
+ end
+
+ super
+ end
+
+ # Appends the contents for the given key. This is called
+ # by provides and resumes back to the fiber if it is
+ # the key it is waiting for.
+ def append!(key, value)
+ super
+ @fiber.resume if @waiting_for == key
+ end
+
+ private
+
+ def inside_fiber?
+ Fiber.current.object_id != @root
+ end
+ end
+end \ No newline at end of file