server.rb in tork-19.0.1

- old
+ new

@@ -1,9 +1,9 @@
 require 'socket'
-require 'thread'
 require 'json'
 require 'shellwords'
+require 'set'
 
 module Tork
 class Server
 
   def self.address program=$0
@@ -14,24 +14,24 @@
     # only JSON messages are supposed to be emitted on STDOUT
     # so make puts() in the user code write to STDERR instead
     @stdout = STDOUT.dup
     STDOUT.reopen STDERR
 
-    @clients = [STDIN]
-    @servers = []
+    @clients = Set.new.add(STDIN)
+    @servers = Set.new
   end
 
   def loop
     server = UNIXServer.open(Server.address)
-    @servers << server
+    @servers.add server
     catch :quit do
       while @clients.include? STDIN
-        IO.select(@servers + @clients).first.each do |stream|
+        IO.select((@servers + @clients).to_a).first.each do |stream|
           @client = stream
 
           if stream == server
-            @clients << stream.accept
+            @clients.add stream.accept
 
           elsif (stream.eof? rescue true)
             @clients.delete stream
 
           elsif @command = hear(stream, stream.gets)
@@ -49,36 +49,28 @@
     throw :quit
   end
 
 protected
 
-  JSON_REGEXP = /\A\s*[\[\{]/.freeze
-
-  # On failure to decode the message, warns the sender and returns nil.
+  # Returns nil if the message received was not meant for processing.
   def hear sender, message
-    if message =~ JSON_REGEXP
-      JSON.load message
-
-    # accept non-JSON "command lines" from clients
-    elsif @clients.include? sender
+    JSON.load message
+  rescue JSON::ParserError => error
+    if @clients.include? sender
+      # accept non-JSON "command lines" from clients
       Shellwords.split message
-
-    # forward tell() output from children to clients
-    elsif @servers.include? sender
+    else
+      # forward tell() output from servers to clients
       tell @clients, message, false
       nil
     end
-  rescue JSON::ParserError => error
-    tell sender, error
-    nil
   end
 
   def recv client, command
     __send__(*command)
   rescue => error
     tell client, error
-    nil
   end
 
   def send one_or_more_clients, message
     tell one_or_more_clients, JSON.dump(message), false
   end
@@ -106,22 +98,22 @@
     end
   end
 
   def popen command
     child = IO.popen(command, 'r+')
-    @servers << child
+    @servers.add child
     child
   end
 
   def pclose child
-    return unless @servers.delete child
+    return unless @servers.delete? child
 
     # this should be enough to stop programs that use Tork::Server#loop
     # because their IO.select() loop terminates on the closing of STDIN
     child.close_write
 
     # but some programs like tork-herald(1) need to be killed explicitly
-    # because they do not follow this convention of exiting on STDIN close
+    # because they do not follow our convention of exiting on STDIN close
     Process.kill :SIGTERM, child.pid
     Process.waitpid child.pid
 
     # this will block until the child process has exited so we must kill it
     # explicitly (as above) to ensure that this program does not hang here