Merge pull request #23152 from matthewd/actioncable-concurrent

Eliminate the EventMachine dependency

1 files changed, 68 insertions, 0 deletions

diff --git a/actioncable/lib/action_cable/connection/stream_event_loop.rb b/actioncable/lib/action_cable/connection/stream_event_loop.rb
new file mode 100644
index 0000000000..f773814973
--- /dev/null
+++ b/actioncable/lib/action_cable/connection/stream_event_loop.rb
@@ -0,0 +1,68 @@
+require 'nio'
+
+module ActionCable
+  module Connection
+    class StreamEventLoop
+      def initialize
+        @nio = NIO::Selector.new
+        @map = {}
+        @stopping = false
+        @todo = Queue.new
+
+        Thread.new do
+          Thread.current.abort_on_exception = true
+          run
+        end
+      end
+
+      def attach(io, stream)
+        @todo << lambda do
+          @map[io] = stream
+          @nio.register(io, :r)
+        end
+        @nio.wakeup
+      end
+
+      def detach(io, stream)
+        @todo << lambda do
+          @nio.deregister(io)
+          @map.delete io
+        end
+        @nio.wakeup
+      end
+
+      def stop
+        @stopping = true
+        @nio.wakeup
+      end
+
+      def run
+        loop do
+          if @stopping
+            @nio.close
+            break
+          end
+
+          until @todo.empty?
+            @todo.pop(true).call
+          end
+
+          if monitors = @nio.select
+            monitors.each do |monitor|
+              io = monitor.io
+              stream = @map[io]
+
+              begin
+                stream.receive io.read_nonblock(4096)
+              rescue IO::WaitReadable
+                next
+              rescue EOFError
+                stream.close
+              end
+            end
+          end
+        end
+      end
+    end
+  end
+end