From 940c0b3cffa7f691620e7890ada15c7519817307 Mon Sep 17 00:00:00 2001
From: Eric Wong <e@80x24.org>
Date: Fri, 20 Dec 2019 01:39:14 +0000
Subject: provide fiddle-based eventfd implementation

sleepy_penguin requires a compiler and development headers to
install, so it could be a PITA to install for users on
distro-provided Ruby.  Allow fiddle since it's part of the Ruby
standard library since 1.9.2 and users won't have to install
anything else.
---
 lib/dtas/sigevent/efd.rb        |  2 ++
 lib/dtas/sigevent/fiddle_efd.rb | 38 ++++++++++++++++++++++++++++++++++++++
 lib/dtas/sigevent/pipe.rb       |  2 +-
 3 files changed, 41 insertions(+), 1 deletion(-)
 create mode 100644 lib/dtas/sigevent/fiddle_efd.rb

(limited to 'lib/dtas/sigevent')

diff --git a/lib/dtas/sigevent/efd.rb b/lib/dtas/sigevent/efd.rb
index 4be2c84..22772ee 100644
--- a/lib/dtas/sigevent/efd.rb
+++ b/lib/dtas/sigevent/efd.rb
@@ -3,6 +3,8 @@
 
 # used in various places for safe wakeups from IO.select via signals
 # This requires a modern Linux system and the "sleepy_penguin" RubyGem
+require 'sleepy_penguin'
+
 class DTAS::Sigevent < SleepyPenguin::EventFD # :nodoc:
   def self.new
     super(0, :CLOEXEC)
diff --git a/lib/dtas/sigevent/fiddle_efd.rb b/lib/dtas/sigevent/fiddle_efd.rb
new file mode 100644
index 0000000..e29f6ca
--- /dev/null
+++ b/lib/dtas/sigevent/fiddle_efd.rb
@@ -0,0 +1,38 @@
+# Copyright (C) 2013-2019 all contributors <dtas-all@nongnu.org>
+# License: GPL-3.0+ <https://www.gnu.org/licenses/gpl-3.0.txt>
+# frozen_string_literal: true
+
+# used in various places for safe wakeups from IO.select via signals
+# This requires a modern GNU/Linux system with eventfd(2) support
+require_relative '../nonblock'
+require 'fiddle'
+class DTAS::Sigevent # :nodoc:
+
+  EventFD = Fiddle::Function.new(DTAS.libc['eventfd'],
+    [ Fiddle::TYPE_INT, Fiddle::TYPE_INT ], # initval, flags
+    Fiddle::TYPE_INT) # fd
+
+  attr_reader :to_io
+  ONE = [ 1 ].pack('Q').freeze
+
+  def initialize
+    fd = EventFD.call(0, 02000000|00004000) # EFD_CLOEXEC|EFD_NONBLOCK
+    raise "eventfd failed: #{Fiddle.last_error}" if fd < 0
+    @to_io = DTAS::Nonblock.for_fd(fd)
+    @buf = ''.b
+  end
+
+  def signal
+    @to_io.syswrite(ONE)
+  end
+
+  def readable_iter
+    @to_io.read_nonblock(8, @buf, exception: false)
+    yield self, nil # calls DTAS::Process.reaper
+    :wait_readable
+  end
+
+  def close
+    @to_io.close
+  end
+end
diff --git a/lib/dtas/sigevent/pipe.rb b/lib/dtas/sigevent/pipe.rb
index 921a5b3..0ea9d31 100644
--- a/lib/dtas/sigevent/pipe.rb
+++ b/lib/dtas/sigevent/pipe.rb
@@ -3,7 +3,7 @@
 # frozen_string_literal: true
 
 # used in various places for safe wakeups from IO.select via signals
-# A fallback for non-Linux systems lacking the "sleepy_penguin" RubyGem
+# A fallback for non-Linux systems lacking the "splice" syscall
 require_relative '../nonblock'
 class DTAS::Sigevent # :nodoc:
   attr_reader :to_io
-- 
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