From 7da8f7696fafc22a50dbcded6ca44cad7ae32ab6 Mon Sep 17 00:00:00 2001
From: Eric Wong <normalperson@yhbt.net>
Date: Wed, 25 Nov 2009 10:18:02 -0800
Subject: add FiberPool concurrency model

This is another Fiber-based concurrency model that can exploit
a streaming "rack.input" for clients.  Spawning Fibers seems
pretty fast, but maybe there are apps that will benefit from
this.
---
 lib/rainbows.rb                 |  1 +
 lib/rainbows/dev_fd_response.rb |  4 ++-
 lib/rainbows/fiber_pool.rb      | 61 +++++++++++++++++++++++++++++++++++++++++
 t/GNUmakefile                   |  1 +
 t/simple-http_FiberPool.ru      |  9 ++++++
 5 files changed, 75 insertions(+), 1 deletion(-)
 create mode 100644 lib/rainbows/fiber_pool.rb
 create mode 100644 t/simple-http_FiberPool.ru

diff --git a/lib/rainbows.rb b/lib/rainbows.rb
index 20f6ea8..27f2df2 100644
--- a/lib/rainbows.rb
+++ b/lib/rainbows.rb
@@ -77,6 +77,7 @@ module Rainbows
     :RevThreadSpawn => 50,
     :EventMachine => 50,
     :FiberSpawn => 50,
+    :FiberPool => 50,
   }.each do |model, _|
     u = model.to_s.gsub(/([a-z0-9])([A-Z0-9])/) { "#{$1}_#{$2.downcase!}" }
     autoload model, "rainbows/#{u.downcase!}"
diff --git a/lib/rainbows/dev_fd_response.rb b/lib/rainbows/dev_fd_response.rb
index 5b90d24..9ad326c 100644
--- a/lib/rainbows/dev_fd_response.rb
+++ b/lib/rainbows/dev_fd_response.rb
@@ -38,8 +38,10 @@ module Rainbows
         end
 
         # we need to make sure our pipe output is Fiber-compatible
-        env["rainbows.model"] == :FiberSpawn and
+        case env["rainbows.model"]
+        when :FiberSpawn, :FiberPool
           return [ status, headers.to_hash, Fiber::IO.new(io,::Fiber.current) ]
+        end
       else # unlikely, char/block device file, directory, ...
         return response
       end
diff --git a/lib/rainbows/fiber_pool.rb b/lib/rainbows/fiber_pool.rb
new file mode 100644
index 0000000..8c408b9
--- /dev/null
+++ b/lib/rainbows/fiber_pool.rb
@@ -0,0 +1,61 @@
+# -*- encoding: binary -*-
+require 'rainbows/fiber'
+require 'pp'
+
+module Rainbows
+
+  # A Fiber-based concurrency model for Ruby 1.9.  This uses a pool of
+  # Fibers to handle client IO to run the application and the root Fiber
+  # for scheduling and connection acceptance.  The pool size is equal to
+  # the number of +worker_connections+.  This model supports a streaming
+  # "rack.input" with lightweight concurrency.  Applications are
+  # strongly advised to wrap slow all IO objects (sockets, pipes) using
+  # the Rainbows::Fiber::IO class whenever possible.
+
+  module FiberPool
+    include Fiber::Base
+
+    def worker_loop(worker)
+      init_worker_process(worker)
+      pool = []
+      worker_connections.times {
+        ::Fiber.new {
+          process_client(::Fiber.yield) while pool << ::Fiber.current
+        }.resume # resume to hit ::Fiber.yield so it waits on a client
+      }
+      Fiber::Base.const_set(:APP, app)
+      rd = Fiber::RD
+      wr = Fiber::WR
+
+      begin
+        ret = begin
+          G.tick
+          IO.select(rd.keys.concat(LISTENERS), wr.keys, nil, 1) or next
+        rescue Errno::EINTR
+          retry
+        rescue Errno::EBADF, TypeError
+          LISTENERS.compact!
+          G.cur > 0 ? retry : break
+        end
+
+        # active writers first, then _all_ readers for keepalive timeout
+        ret[1].concat(rd.keys).each { |c| c.f.resume }
+
+        # accept() is an expensive syscall
+        (ret.first & LISTENERS).each do |l|
+          fib = pool.shift or break
+          io = begin
+            l.accept_nonblock
+          rescue Errno::EAGAIN, Errno::ECONNABORTED
+            pool << fib
+            next
+          end
+          fib.resume(Fiber::IO.new(io, fib))
+        end
+      rescue => e
+        listen_loop_error(e)
+      end while G.alive || G.cur > 0
+    end
+
+  end
+end
diff --git a/t/GNUmakefile b/t/GNUmakefile
index 359f300..934ce47 100644
--- a/t/GNUmakefile
+++ b/t/GNUmakefile
@@ -22,6 +22,7 @@ models := ThreadPool ThreadSpawn Rev EventMachine
 ifeq ($(RUBY_VERSION),1.9.1) # 1.9.2-preview1 was broken
   models += Revactor
   models += FiberSpawn
+  models += FiberPool
 
   # technically this works under 1.8, too, it's just slow
   models += RevThreadSpawn
diff --git a/t/simple-http_FiberPool.ru b/t/simple-http_FiberPool.ru
new file mode 100644
index 0000000..ae5b649
--- /dev/null
+++ b/t/simple-http_FiberPool.ru
@@ -0,0 +1,9 @@
+use Rack::ContentLength
+use Rack::ContentType
+run lambda { |env|
+  if env['rack.multithread'] == false && env['rainbows.model'] == :FiberPool
+    [ 200, {}, [ Thread.current.inspect << "\n" ] ]
+  else
+    raise "rack.multithread is not true"
+  end
+}
-- 
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