[PATCH 1/2] use a common /dev/null

[Eric Wong <e@80x24.org>]

This allows us to avoid wasting time reopening the same
device over and over again.
---
 lib/dtas.rb               | 5 +++++
 lib/dtas/buffer/splice.rb | 3 +--
 lib/dtas/format.rb        | 4 ++--
 lib/dtas/player.rb        | 2 +-
 lib/dtas/sink.rb          | 2 +-
 5 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/lib/dtas.rb b/lib/dtas.rb
index f11d549..0b704ca 100644
--- a/lib/dtas.rb
+++ b/lib/dtas.rb
@@ -13,6 +13,11 @@ module DTAS # :nodoc:
       Time.now.to_f
     end
   end
+
+  @null = nil
+  def self.null
+    @null ||= File.open('/dev/null', 'r+')
+  end
 end
 
 require_relative 'dtas/compat_onenine'
diff --git a/lib/dtas/buffer/splice.rb b/lib/dtas/buffer/splice.rb
index 02ce877..be40881 100644
--- a/lib/dtas/buffer/splice.rb
+++ b/lib/dtas/buffer/splice.rb
@@ -10,7 +10,6 @@ module DTAS::Buffer::Splice # :nodoc:
   MAX_AT_ONCE = 4096 # page size in Linux
   MAX_AT_ONCE_1 = 65536
   MAX_SIZE = File.read("/proc/sys/fs/pipe-max-size").to_i
-  DEVNULL = File.open("/dev/null", "r+")
   F_MOVE = IO::Splice::F_MOVE
 
   def buffer_size
@@ -25,7 +24,7 @@ module DTAS::Buffer::Splice # :nodoc:
 
   # be sure to only call this with nil when all writers to @wr are done
   def discard(bytes)
-    IO.splice(@to_io, nil, DEVNULL, nil, bytes)
+    IO.splice(@to_io, nil, DTAS.null, nil, bytes)
   end
 
   def broadcast_one(targets, limit = nil)
diff --git a/lib/dtas/format.rb b/lib/dtas/format.rb
index a6314bd..cfcec64 100644
--- a/lib/dtas/format.rb
+++ b/lib/dtas/format.rb
@@ -44,9 +44,9 @@ class DTAS::Format # :nodoc:
 
   def self.precision(env, infile)
     # sox.git f4562efd0aa3
-    qx(env, %W(soxi -p #{infile}), err: "/dev/null").to_i
+    qx(env, %W(soxi -p #{infile}), err: DTAS.null).to_i
   rescue # fallback to parsing the whole output
-    s = qx(env, %W(soxi #{infile}), err: "/dev/null")
+    s = qx(env, %W(soxi #{infile}), err: DTAS.null)
     s =~ /Precision\s+:\s*(\d+)-bit/n
     v = $1.to_i
     return v if v > 0
diff --git a/lib/dtas/player.rb b/lib/dtas/player.rb
index cdf1265..a102618 100644
--- a/lib/dtas/player.rb
+++ b/lib/dtas/player.rb
@@ -426,7 +426,7 @@ class DTAS::Player # :nodoc:
 
       dst = @sink_buf
       pending.dst_assoc(dst)
-      pending.src_spawn(@format, @rg, out: dst.wr, in: "/dev/null")
+      pending.src_spawn(@format, @rg, out: dst.wr, in: DTAS.null)
 
       # watch and restart on modifications
       pending.respond_to?(:watch_begin) and
diff --git a/lib/dtas/sink.rb b/lib/dtas/sink.rb
index 70d6861..0bf49f4 100644
--- a/lib/dtas/sink.rb
+++ b/lib/dtas/sink.rb
@@ -91,7 +91,7 @@ class DTAS::Sink # :nodoc:
         w.sink = self
         rv << w
       end
-      opts[:in] = "/dev/null"
+      opts[:in] = DTAS.null
 
       # map to real /dev/fd/* values and setup proper redirects
       cmd = cmd.gsub(DEVFD_RE) do
-- 
EW