Merge branch 'peppe/ct_remove_nodelay/OTP-13462' into maint-18

* peppe/ct_remove_nodelay/OTP-13462:
  Update the reference manual
  Make the nodelay setting configurable and false per default

5 files changed, 61 insertions, 26 deletions

diff --git a/lib/common_test/doc/src/ct_telnet.xml b/lib/common_test/doc/src/ct_telnet.xml
index b7ba352104..1de278d30c 100644
--- a/lib/common_test/doc/src/ct_telnet.xml
+++ b/lib/common_test/doc/src/ct_telnet.xml
@@ -64,6 +64,8 @@
         remaining string terminated) = 0</p></item>
       <item><p>Polling interval (sleep time between polls) = 1 second</p>
       </item>
+      <item><p>The TCP_NODELAY option for the telnet socket
+        is disabled (set to <c>false</c>) per default</p></item>
     </list>
 
     <p>These parameters can be modified by the user with the following
@@ -76,7 +78,8 @@
                     {reconnection_interval,Millisec},
                     {keep_alive,Bool},
                     {poll_limit,N},
-                    {poll_interval,Millisec}]}.</pre>
+                    {poll_interval,Millisec},
+                    {tcp_nodelay,Bool}]}.</pre>
 
     <p><c>Millisec = integer(), N = integer()</c></p>
 
diff --git a/lib/common_test/doc/src/unix_telnet.xml b/lib/common_test/doc/src/unix_telnet.xml
index 189379c39a..a064a222d6 100644
--- a/lib/common_test/doc/src/unix_telnet.xml
+++ b/lib/common_test/doc/src/unix_telnet.xml
@@ -80,7 +80,7 @@
 
   <funcs>
     <func>
-      <name>connect(ConnName, Ip, Port, Timeout, KeepAlive, Extra) -&gt; {ok, Handle} | {error, Reason}</name>
+      <name>connect(ConnName, Ip, Port, Timeout, KeepAlive, TCPNoDelay, Extra) -&gt; {ok, Handle} | {error, Reason}</name>
       <fsummary>Callback for ct_telnet.erl.</fsummary>
         <type>
           <v>ConnName = target_name()</v>
@@ -88,6 +88,7 @@
           <v>Port = integer()</v>
           <v>Timeout = integer()</v>
           <v>KeepAlive = bool()</v>
+	  <v>TCPNoDelay = bool()</v>
           <v>Extra = target_name() | {Username, Password}</v>
           <v>Username = string()</v>
           <v>Password = string()</v>
diff --git a/lib/common_test/src/ct_telnet.erl b/lib/common_test/src/ct_telnet.erl
index 4d3fd2d094..f5f4f648f4 100644
--- a/lib/common_test/src/ct_telnet.erl
+++ b/lib/common_test/src/ct_telnet.erl
@@ -42,7 +42,8 @@
 %%                    {reconnection_interval,Millisec},
 %%                    {keep_alive,Bool},
 %%                    {poll_limit,N},
-%%                    {poll_interval,Millisec}]}.</pre>
+%%                    {poll_interval,Millisec},
+%%                    {tcp_nodelay,Bool}]}.</pre>
 %% <p><code>Millisec = integer(), N = integer()</code></p>
 %% <p>Enter the <code>telnet_settings</code> term in a configuration 
 %% file included in the test and ct_telnet will retrieve the information
@@ -182,7 +183,8 @@
 	       conn_to=?DEFAULT_TIMEOUT, 
 	       com_to=?DEFAULT_TIMEOUT, 
 	       reconns=?RECONNS,
-	       reconn_int=?RECONN_TIMEOUT}).
+	       reconn_int=?RECONN_TIMEOUT,
+	       tcp_nodelay=false}).
 
 %%%-----------------------------------------------------------------
 %%% @spec open(Name) -> {ok,Handle} | {error,Reason}
@@ -602,8 +604,18 @@ init(Name,{Ip,Port,Type},{TargetMod,KeepAlive,Extra}) ->
 	     Settings ->
 		 set_telnet_defaults(Settings,#state{})				    
 	 end,
-    case catch TargetMod:connect(Name,Ip,Port,S0#state.conn_to,
-				 KeepAlive,Extra) of
+    %% Handle old user versions of TargetMod
+    code:ensure_loaded(TargetMod),
+    try
+	case erlang:function_exported(TargetMod,connect,7) of
+	    true ->
+		TargetMod:connect(Name,Ip,Port,S0#state.conn_to,
+				  KeepAlive,S0#state.tcp_nodelay,Extra);
+	    false ->
+		TargetMod:connect(Name,Ip,Port,S0#state.conn_to,
+				  KeepAlive,Extra)
+	end
+    of
 	{ok,TelnPid} ->
 	    put({ct_telnet_pid2name,TelnPid},Name),
 	    S1 = S0#state{host=Ip,
@@ -625,15 +637,18 @@ init(Name,{Ip,Port,Type},{TargetMod,KeepAlive,Extra}) ->
 		"Connection timeout: ~p\n"
 		"Keep alive: ~w\n"
 		"Poll limit: ~w\n"
-		"Poll interval: ~w",
+		"Poll interval: ~w\n"
+		"TCP nodelay: ~w",
 		[Ip,Port,S1#state.com_to,S1#state.reconns,
 		 S1#state.reconn_int,S1#state.conn_to,KeepAlive,
-		 S1#state.poll_limit,S1#state.poll_interval]),
+		 S1#state.poll_limit,S1#state.poll_interval,
+		 S1#state.tcp_nodelay]),
 	    {ok,TelnPid,S1};
-	{'EXIT',Reason} ->
-	    {error,Reason};
 	Error ->
 	    Error
+    catch
+	_:Reason ->
+	    {error,Reason}
     end.
 
 type(telnet) -> ip;
@@ -653,6 +668,8 @@ set_telnet_defaults([{poll_limit,PL}|Ss],S) ->
     set_telnet_defaults(Ss,S#state{poll_limit=PL});
 set_telnet_defaults([{poll_interval,PI}|Ss],S) ->
     set_telnet_defaults(Ss,S#state{poll_interval=PI});
+set_telnet_defaults([{tcp_nodelay,NoDelay}|Ss],S) ->
+    set_telnet_defaults(Ss,S#state{tcp_nodelay=NoDelay});
 set_telnet_defaults([Unknown|Ss],S) ->
     force_log(S,error,
 	      "Bad element in telnet_settings: ~p",[Unknown]),
@@ -794,8 +811,17 @@ reconnect(Ip,Port,N,State=#state{name=Name,
 				 keep_alive=KeepAlive,
 				 extra=Extra,
 				 conn_to=ConnTo,
-				 reconn_int=ReconnInt}) ->
-    case TargetMod:connect(Name,Ip,Port,ConnTo,KeepAlive,Extra) of
+				 reconn_int=ReconnInt,
+				 tcp_nodelay=NoDelay}) ->
+    %% Handle old user versions of TargetMod
+    ConnResult =
+	case erlang:function_exported(TargetMod,connect,7) of
+	    true ->
+		TargetMod:connect(Name,Ip,Port,ConnTo,KeepAlive,NoDelay,Extra);
+	    false ->
+		TargetMod:connect(Name,Ip,Port,ConnTo,KeepAlive,Extra)
+	end,
+    case ConnResult of
 	{ok,NewPid} ->
 	    put({ct_telnet_pid2name,NewPid},Name),
 	    {ok, NewPid, State#state{teln_pid=NewPid}};
diff --git a/lib/common_test/src/ct_telnet_client.erl b/lib/common_test/src/ct_telnet_client.erl
index 99d683244c..bdab456cfa 100644
--- a/lib/common_test/src/ct_telnet_client.erl
+++ b/lib/common_test/src/ct_telnet_client.erl
@@ -35,7 +35,7 @@
 
 %%-define(debug, true).
 
--export([open/2, open/3, open/4, open/5, close/1]).
+-export([open/2, open/3, open/4, open/5, open/6, close/1]).
 -export([send_data/2, send_data/3, get_data/1]).
 
 -define(TELNET_PORT, 23).
@@ -70,19 +70,22 @@
 -record(state,{conn_name, get_data, keep_alive=true, log_pos=1}).
 
 open(Server, ConnName) ->
-    open(Server, ?TELNET_PORT, ?OPEN_TIMEOUT, true, ConnName).
+    open(Server, ?TELNET_PORT, ?OPEN_TIMEOUT, true, false, ConnName).
 
 open(Server, Port, ConnName) ->
-    open(Server, Port, ?OPEN_TIMEOUT, true, ConnName).
+    open(Server, Port, ?OPEN_TIMEOUT, true, false, ConnName).
 
 open(Server, Port, Timeout, ConnName) ->
-    open(Server, Port, Timeout, true, ConnName).
+    open(Server, Port, Timeout, true, false, ConnName).
 
 open(Server, Port, Timeout, KeepAlive, ConnName) ->
+    open(Server, Port, Timeout, KeepAlive, false, ConnName).
+
+open(Server, Port, Timeout, KeepAlive, NoDelay, ConnName) ->
     Self = self(),
     Pid = spawn(fun() ->
 			init(Self, Server, Port, Timeout,
-			     KeepAlive, ConnName)
+			     KeepAlive, NoDelay, ConnName)
 		end),
     receive 
 	{open,Pid} ->
@@ -114,8 +117,8 @@ get_data(Pid) ->
 
 %%%-----------------------------------------------------------------
 %%% Internal functions
-init(Parent, Server, Port, Timeout, KeepAlive, ConnName) ->
-    case gen_tcp:connect(Server, Port, [list,{packet,0},{nodelay,true}], Timeout) of
+init(Parent, Server, Port, Timeout, KeepAlive, NoDelay, ConnName) ->
+    case gen_tcp:connect(Server, Port, [list,{packet,0},{nodelay,NoDelay}], Timeout) of
 	{ok,Sock} ->
 	    dbg("~p connected to: ~p (port: ~w, keep_alive: ~w)\n",
 		[ConnName,Server,Port,KeepAlive]),
diff --git a/lib/common_test/src/unix_telnet.erl b/lib/common_test/src/unix_telnet.erl
index e5b3058999..2fc585735d 100644
--- a/lib/common_test/src/unix_telnet.erl
+++ b/lib/common_test/src/unix_telnet.erl
@@ -27,7 +27,8 @@
 %%%        {port,PortNum},                 % optional
 %%%        {username,UserName},
 %%%        {password,Password},
-%%%        {keep_alive,Bool}]}.            % optional</pre>
+%%%        {keep_alive,Bool},              % optional
+%%%        {tcp_nodely,Bool}]}             % optional</pre>
 %%%
 %%% <p>To communicate via telnet to the host specified by
 %%% <code>HostNameOrIpAddress</code>, use the interface functions in
@@ -55,7 +56,7 @@
 -compile(export_all).
 
 %% Callbacks for ct_telnet.erl
--export([connect/6,get_prompt_regexp/0]).
+-export([connect/7,get_prompt_regexp/0]).
 -import(ct_telnet,[start_gen_log/1,log/4,end_gen_log/0]).
 
 -define(username,"login: ").
@@ -82,6 +83,7 @@ get_prompt_regexp() ->
 %%%      Port = integer()
 %%%      Timeout = integer()
 %%%      KeepAlive = bool()
+%%%      TCPNoDelay = bool()
 %%%      Extra = ct:target_name() | {Username,Password}
 %%%      Username = string()
 %%%      Password = string()
@@ -91,25 +93,25 @@ get_prompt_regexp() ->
 %%% @doc Callback for ct_telnet.erl.
 %%%
 %%% <p>Setup telnet connection to a unix host.</p>
-connect(ConnName,Ip,Port,Timeout,KeepAlive,Extra) ->
+connect(ConnName,Ip,Port,Timeout,KeepAlive,TCPNoDelay,Extra) ->
     case Extra of
 	{Username,Password} -> 
-	    connect1(ConnName,Ip,Port,Timeout,KeepAlive,
+	    connect1(ConnName,Ip,Port,Timeout,KeepAlive,TCPNoDelay,
 		     Username,Password);
 	KeyOrName ->
 	    case get_username_and_password(KeyOrName) of
 		{ok,{Username,Password}} ->
-		    connect1(ConnName,Ip,Port,Timeout,KeepAlive,
+		    connect1(ConnName,Ip,Port,Timeout,KeepAlive,TCPNoDelay,
 			     Username,Password);
 		Error ->
 		    Error
 	    end
     end.
 
-connect1(Name,Ip,Port,Timeout,KeepAlive,Username,Password) ->
+connect1(Name,Ip,Port,Timeout,KeepAlive,TCPNoDelay,Username,Password) ->
     start_gen_log("unix_telnet connect"),
     Result = 
-	case ct_telnet_client:open(Ip,Port,Timeout,KeepAlive,Name) of
+	case ct_telnet_client:open(Ip,Port,Timeout,KeepAlive,TCPNoDelay,Name) of
 	    {ok,Pid} ->
 		case ct_telnet:silent_teln_expect(Name,Pid,[],
 						  [prompt],?prx,[]) of