Yo dawg, I heard you like streaming. So I put a fiber, inside a block, inside a body, so you can stream.

1 files changed, 64 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..1ac62961d1
--- /dev/null
+++ b/actionpack/lib/action_view/flows.rb
@@ -0,0 +1,64 @@
+require 'active_support/core_ext/string/output_safety'
+
+module ActionView
+  class OutputFlow
+    attr_reader :content
+
+    def initialize
+      @content = Hash.new { |h,k| h[k] = ActiveSupport::SafeBuffer.new }
+    end
+
+    def get(key)
+      @content[key]
+    end
+
+    def set(key, value)
+      @content[key] = value
+    end
+
+    def append(key, value)
+      @content[key] << value
+    end
+  end
+
+  class StreamingFlow < OutputFlow
+    def initialize(flow, fiber)
+      @content = 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?
+        begin
+          @waiting_for = key
+          Fiber.yield
+        ensure
+          @waiting_for = nil
+        end
+      end
+
+      super
+    end
+
+    # Set 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 set(key, value)
+      super
+      @fiber.resume if @waiting_for == key
+    end
+
+    private
+
+    def inside_fiber?
+      Fiber.current.object_id != @root
+    end
+  end
+end
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