Favor Struct members to instance variables

There's a small memory reduction to be had when forking
oodles of processes and the Perl hacker in me still
gets confused into thinking those are arrays...

3 files changed, 62 insertions, 63 deletions

diff --git a/lib/unicorn/app/exec_cgi.rb b/lib/unicorn/app/exec_cgi.rb
index 4d8e701..147b279 100644
--- a/lib/unicorn/app/exec_cgi.rb
+++ b/lib/unicorn/app/exec_cgi.rb
@@ -5,7 +5,7 @@ module Unicorn::App
 
   # This class is highly experimental (even more so than the rest of Unicorn)
   # and has never run anything other than cgit.
-  class ExecCgi
+  class ExecCgi < Struct.new(:args)
 
     CHUNK_SIZE = 16384
     PASS_VARS = %w(
@@ -32,12 +32,12 @@ module Unicorn::App
     #     run Unicorn::App::ExecCgi.new("/path/to/cgit.cgi")
     #   end
     def initialize(*args)
-      @args = args.dup
-      first = @args[0] or
+      self.args = args
+      first = args[0] or
         raise ArgumentError, "need path to executable"
-      first[0..0] == "/" or @args[0] = ::File.expand_path(first)
-      File.executable?(@args[0]) or
-        raise ArgumentError, "#{@args[0]} is not executable"
+      first[0..0] == "/" or args[0] = ::File.expand_path(first)
+      File.executable?(args[0]) or
+        raise ArgumentError, "#{args[0]} is not executable"
     end
 
     # Calls the app
@@ -65,14 +65,14 @@ module Unicorn::App
         val = env[key] or next
         ENV[key] = val
       end
-      ENV['SCRIPT_NAME'] = @args[0]
+      ENV['SCRIPT_NAME'] = args[0]
       ENV['GATEWAY_INTERFACE'] = 'CGI/1.1'
       env.keys.grep(/^HTTP_/) { |key| ENV[key] = env[key] }
 
       a = IO.new(0).reopen(inp)
       b = IO.new(1).reopen(out)
       c = IO.new(2).reopen(err)
-      exec(*@args)
+      exec(*args)
     end
 
     # Extracts headers from CGI out, will change the offset of out.
@@ -89,23 +89,24 @@ module Unicorn::App
         offset = 4
       end
       offset += head.length
-      out.instance_variable_set('@unicorn_app_exec_cgi_offset', offset)
-      size -= offset
 
       # Allows +out+ to be used as a Rack body.
-      def out.each
-        sysseek(@unicorn_app_exec_cgi_offset)
-
-        # don't use a preallocated buffer for sysread since we can't
-        # guarantee an actual socket is consuming the yielded string
-        # (or if somebody is pushing to an array for eventual concatenation
-        begin
-          yield(sysread(CHUNK_SIZE))
-        rescue EOFError
-          return
-        end while true
-      end
+      out.instance_eval { class << self; self; end }.instance_eval {
+        define_method(:each) { |&blk|
+          sysseek(offset)
+
+          # don't use a preallocated buffer for sysread since we can't
+          # guarantee an actual socket is consuming the yielded string
+          # (or if somebody is pushing to an array for eventual concatenation
+          begin
+            blk.call(sysread(CHUNK_SIZE))
+          rescue EOFError
+            break
+          end while true
+        }
+      }
 
+      size -= offset
       prev = nil
       headers = Rack::Utils::HeaderHash.new
       head.split(/\r?\n/).each do |line|
@@ -144,7 +145,7 @@ module Unicorn::App
       err.seek(0)
       dst = env['rack.errors']
       pid = status.pid
-      dst.write("#{pid}: #{@args.inspect} status=#{status} stderr:\n")
+      dst.write("#{pid}: #{args.inspect} status=#{status} stderr:\n")
       err.each_line { |line| dst.write("#{pid}: #{line}") }
       dst.flush
     end
diff --git a/lib/unicorn/app/inetd.rb b/lib/unicorn/app/inetd.rb
index e22b308..580b456 100644
--- a/lib/unicorn/app/inetd.rb
+++ b/lib/unicorn/app/inetd.rb
@@ -4,65 +4,66 @@
 # this class *must* be used with Rack::Chunked
 
 module Unicorn::App
-  class Inetd
+  class Inetd < Struct.new(:cmd)
 
-    class CatBody
+    class CatBody < Struct.new(:errors, :err_rd, :out_rd, :pid_map)
       def initialize(env, cmd)
-        @cmd = cmd
-        @input, @errors = env['rack.input'], env['rack.errors']
+        self.errors = env['rack.errors']
         in_rd, in_wr = IO.pipe
-        @err_rd, err_wr = IO.pipe
-        @out_rd, out_wr = IO.pipe
+        self.err_rd, err_wr = IO.pipe
+        self.out_rd, out_wr = IO.pipe
 
-        @cmd_pid = fork {
+        cmd_pid = fork {
           inp, out, err = (0..2).map { |i| IO.new(i) }
           inp.reopen(in_rd)
           out.reopen(out_wr)
           err.reopen(err_wr)
-          [ in_rd, in_wr, @err_rd, err_wr, @out_rd, out_wr ].each { |io|
-            io.close
-          }
+          [ in_rd, in_wr, err_rd, err_wr, out_rd, out_wr ].each { |i| i.close }
           exec(*cmd)
         }
         [ in_rd, err_wr, out_wr ].each { |io| io.close }
-        [ in_wr, @err_rd, @out_rd ].each { |io| io.binmode }
+        [ in_wr, err_rd, out_rd ].each { |io| io.binmode }
         in_wr.sync = true
 
         # Unfortunately, input here must be processed inside a seperate
         # thread/process using blocking I/O since env['rack.input'] is not
         # IO.select-able and attempting to make it so would trip Rack::Lint
-        @inp_pid = fork {
-          [ @err_rd, @out_rd ].each { |io| io.close }
+        inp_pid = fork {
+          input = env['rack.input']
+          [ err_rd, out_rd ].each { |io| io.close }
           buf = Unicorn::Z.dup
 
-          # this is dependent on @input.read having readpartial semantics:
-          while @input.read(16384, buf)
+          # this is dependent on input.read having readpartial semantics:
+          while input.read(16384, buf)
             in_wr.write(buf)
           end
           in_wr.close
         }
         in_wr.close
+        self.pid_map = {
+          inp_pid => 'input streamer',
+          cmd_pid => cmd.inspect,
+        }
       end
 
       def each(&block)
-        buf = Unicorn::Z.dup
         begin
-          rd, = IO.select([@err_rd, @out_rd])
+          rd, = IO.select([err_rd, out_rd])
           rd && rd.first or next
 
-          if rd.include?(@err_rd)
+          if rd.include?(err_rd)
             begin
-              @errors.write(@err_rd.read_nonblock(16384, buf))
+              errors.write(err_rd.read_nonblock(16384))
             rescue Errno::EINTR
             rescue Errno::EAGAIN
               break
             end while true
           end
 
-          rd.include?(@out_rd) or next
+          rd.include?(out_rd) or next
 
           begin
-            yield @out_rd.read_nonblock(16384, buf)
+            yield out_rd.read_nonblock(16384)
           rescue Errno::EINTR
           rescue Errno::EAGAIN
             break
@@ -75,15 +76,13 @@ module Unicorn::App
       end
 
       def close
-        @input = nil
-        [ [ @cmd.inspect, @cmd_pid ], [ 'input streamer', @inp_pid ]
-        ].each { |str, pid|
+        pid_map.each { |pid, str|
           begin
             pid, status = Process.waitpid2(pid)
             status.success? or
-              @errors.write("#{str}: #{status.inspect} (PID:#{pid})\n")
+              errors.write("#{str}: #{status.inspect} (PID:#{pid})\n")
           rescue Errno::ECHILD
-            @errors.write("Failed to reap #{str} (PID:#{pid})\n")
+            errors.write("Failed to reap #{str} (PID:#{pid})\n")
           end
         }
       end
@@ -91,16 +90,15 @@ module Unicorn::App
     end
 
     def initialize(*cmd)
-      @cmd = cmd
+      self.cmd = cmd
     end
 
     def call(env)
-      expect = env[Unicorn::Const::HTTP_EXPECT] and
-        /\A100-continue\z/i =~ expect and
+      /\A100-continue\z/i =~ env[Unicorn::Const::HTTP_EXPECT] and
           return [ 100, {} , [] ]
 
       [ 200, { 'Content-Type' => 'application/octet-stream' },
-       CatBody.new(env, @cmd) ]
+       CatBody.new(env, cmd) ]
     end
 
   end
diff --git a/lib/unicorn/app/old_rails/static.rb b/lib/unicorn/app/old_rails/static.rb
index 17c007c..51a0017 100644
--- a/lib/unicorn/app/old_rails/static.rb
+++ b/lib/unicorn/app/old_rails/static.rb
@@ -19,28 +19,28 @@ require 'rack/file'
 # This means that if you are using page caching it will actually work
 # with Unicorn and you should see a decent speed boost (but not as
 # fast as if you use a static server like nginx).
-class Unicorn::App::OldRails::Static
+class Unicorn::App::OldRails::Static < Struct.new(:app, :root, :file_server)
   FILE_METHODS = { 'GET' => true, 'HEAD' => true }.freeze
   REQUEST_METHOD = 'REQUEST_METHOD'.freeze
   REQUEST_URI = 'REQUEST_URI'.freeze
   PATH_INFO = 'PATH_INFO'.freeze
 
   def initialize(app)
-    @app = app
-    @root = "#{::RAILS_ROOT}/public"
-    @file_server = ::Rack::File.new(@root)
+    self.app = app
+    self.root = "#{::RAILS_ROOT}/public"
+    self.file_server = ::Rack::File.new(root)
   end
 
   def call(env)
     # short circuit this ASAP if serving non-file methods
-    FILE_METHODS.include?(env[REQUEST_METHOD]) or return @app.call(env)
+    FILE_METHODS.include?(env[REQUEST_METHOD]) or return app.call(env)
 
     # first try the path as-is
     path_info = env[PATH_INFO].chomp("/")
-    if File.file?("#@root/#{::Rack::Utils.unescape(path_info)}")
+    if File.file?("#{root}/#{::Rack::Utils.unescape(path_info)}")
       # File exists as-is so serve it up
       env[PATH_INFO] = path_info
-      return @file_server.call(env)
+      return file_server.call(env)
     end
 
     # then try the cached version:
@@ -50,11 +50,11 @@ class Unicorn::App::OldRails::Static
     env[REQUEST_URI] =~ /^#{Regexp.escape(path_info)}(;[^\?]+)/
     path_info << "#$1#{ActionController::Base.page_cache_extension}"
 
-    if File.file?("#@root/#{::Rack::Utils.unescape(path_info)}")
+    if File.file?("#{root}/#{::Rack::Utils.unescape(path_info)}")
       env[PATH_INFO] = path_info
-      return @file_server.call(env)
+      return file_server.call(env)
     end
 
-    @app.call(env) # call OldRails
+    app.call(env) # call OldRails
   end
 end if defined?(Unicorn::App::OldRails)