quitter: save one syscall and implement for non-eventfd

pipes and eventfd are always writable after creation, thus
there's no need to trigger it and watch for readability.
This saves us some code in the Linux case (and we currently
only support GNU/Linux).

1 files changed, 24 insertions, 0 deletions

diff --git a/lib/yahns/queue_quitter_pipe.rb b/lib/yahns/queue_quitter_pipe.rb
new file mode 100644
index 0000000..1aa0643
--- /dev/null
+++ b/lib/yahns/queue_quitter_pipe.rb
@@ -0,0 +1,24 @@
+# Copyright (C) 2013, Eric Wong <normalperson@yhbt.net> and all contributors
+# License: GPLv3 or later (https://www.gnu.org/licenses/gpl-3.0.txt)
+#
+# POSIX pipe version, see queue_quitter.rb for the (preferred) eventfd one
+class Yahns::QueueQuitter # :nodoc:
+  attr_reader :to_io
+  def initialize
+    reader, @to_io = IO.pipe
+    @to_io.close_on_exec = true
+    reader.close
+  end
+
+  def yahns_step
+    Thread.current.exit
+  end
+
+  def fileno
+    @to_io.fileno
+  end
+
+  def close
+    @to_io.close
+  end
+end