[inets/httpc] Fix the selection of session for keep-alive mode

When selecting a session, the "state" of the session (specifically if
the server has responded) was not taken into account. Attempting to
fix this, a "state" field (actually available) has been added to the
session record.

OTP-9847

3 files changed, 73 insertions, 16 deletions

diff --git a/lib/inets/src/http_client/httpc_handler.erl b/lib/inets/src/http_client/httpc_handler.erl
index 587e24cc8d..8874304bd6 100644
--- a/lib/inets/src/http_client/httpc_handler.erl
+++ b/lib/inets/src/http_client/httpc_handler.erl
@@ -1403,7 +1403,9 @@ try_to_enable_pipeline_or_keep_alive(
     end.
 
 answer_request(#request{id = RequestId, from = From} = Request, Msg, 
-	       #state{timers = Timers, profile_name = ProfileName} = State) -> 
+	       #state{session      = Session, 
+		      timers       = Timers, 
+		      profile_name = ProfileName} = State) -> 
     ?hcrt("answer request", [{request, Request}, {msg, Msg}]),
     httpc_response:send(From, Msg),
     RequestTimers = Timers#timers.request_timers,
@@ -1412,12 +1414,22 @@ answer_request(#request{id = RequestId, from = From} = Request, Msg,
     Timer = {RequestId, TimerRef},
     cancel_timer(TimerRef, {timeout, Request#request.id}),
     httpc_manager:request_done(RequestId, ProfileName),
-
+    NewSession = maybe_make_session_available(ProfileName, Session), 
+    Timers2 = Timers#timers{request_timers = lists:delete(Timer, 
+							  RequestTimers)}, 
     State#state{request = Request#request{from = answer_sent},
-		timers = 
-		Timers#timers{request_timers =
-			      lists:delete(Timer, RequestTimers)}}.
-
+		session = NewSession, 
+		timers  = Timers2}.
+
+maybe_make_session_available(ProfileName, 
+			     #session{id        = SessionId, 
+				      available = false} = Session) ->
+    httpc_manager:update_session(ProfileName, SessionId, 
+				 #session.available, true),
+    Session#session{available = true};
+maybe_make_session_available(_ProfileName, Session) ->
+    Session.
+    
 cancel_timers(#timers{request_timers = ReqTmrs, queue_timer = QTmr}) ->
     cancel_timer(QTmr, timeout_queue),
     CancelTimer = fun({_, Timer}) -> cancel_timer(Timer, timeout) end, 
diff --git a/lib/inets/src/http_client/httpc_internal.hrl b/lib/inets/src/http_client/httpc_internal.hrl
index 1d8a5b6a92..3261061d61 100644
--- a/lib/inets/src/http_client/httpc_internal.hrl
+++ b/lib/inets/src/http_client/httpc_internal.hrl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 2005-2010. All Rights Reserved.
+%% Copyright Ericsson AB 2005-2012. All Rights Reserved.
 %%
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
@@ -112,17 +112,37 @@
 	}
        ).               
 
+
 -record(session,
 	{
-	  id,           % {{Host, Port}, HandlerPid}
-	  client_close, % true | false
-	  scheme,       % http (HTTP/TCP) | https (HTTP/SSL/TCP)
-	  socket,       % Open socket, used by connection
-	  socket_type,  % socket-type, used by connection
-	  queue_length = 1, % Current length of pipeline or keep-alive queue  
-	  type          % pipeline | keep_alive (wait for response before sending new request) 
+	  %% {{Host, Port}, HandlerPid}
+	  id, 
+
+	  %% true | false
+	  client_close, 
+
+	  %% http (HTTP/TCP) | https (HTTP/SSL/TCP)
+	  scheme, 
+
+	  %% Open socket, used by connection
+	  socket, 
+	  
+	  %% socket-type, used by connection
+	  socket_type,
+
+	  %% Current length of pipeline or keep-alive queue  
+	  queue_length = 1, 
+
+	  %% pipeline | keep_alive (wait for response before sending new request) 
+	  type, 
+
+	  %% true | false
+	  %% This will be true, when a response has been received for 
+	  %% the first request. See type above.
+	  available = false
 	 }).
 
+
 -record(http_cookie,
 	{
 	  domain,
diff --git a/lib/inets/src/http_client/httpc_manager.erl b/lib/inets/src/http_client/httpc_manager.erl
index 9015bf1ce2..d699f1e7d8 100644
--- a/lib/inets/src/http_client/httpc_manager.erl
+++ b/lib/inets/src/http_client/httpc_manager.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %% 
-%% Copyright Ericsson AB 2002-2011. All Rights Reserved.
+%% Copyright Ericsson AB 2002-2012. All Rights Reserved.
 %% 
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
@@ -34,6 +34,7 @@
 	 retry_request/2, 
 	 redirect_request/2,
 	 insert_session/2, 
+	 update_session/4, 
 	 delete_session/2, 
 	 set_options/2, 
 	 store_cookies/3,
@@ -193,6 +194,29 @@ insert_session(Session, ProfileName) ->
 
 
 %%--------------------------------------------------------------------
+%% Function: update_session(ProfileName, SessionId, Pos, Value) -> _
+%%	Session - #session{}
+%%      ProfileName - atom()
+%%
+%% Description: Update, only one field (Pos) of the session record
+%%              identified by the SessionId, the session information 
+%%              of the httpc manager table <ProfileName>_session_db. 
+%%              Intended to be called by the httpc request handler process.
+%%--------------------------------------------------------------------
+
+update_session(ProfileName, SessionId, Pos, Value) ->
+    SessionDbName = session_db_name(ProfileName), 
+    ?hcrt("insert session", 
+	  [{id,      SessionId}, 
+	   {pos,     Pos}, 
+	   {value,   Value}, 
+	   {profile, ProfileName}]),
+    ets:update_element(SessionDbName, SessionId, {Pos, Value}).
+
+
+
+
+%%--------------------------------------------------------------------
 %% Function: delete_session(SessionId, ProfileName) -> _
 %%	SessionId -  {{Host, Port}, HandlerPid}
 %%      ProfileName - atom()
@@ -679,6 +703,7 @@ select_session(Method, HostPort, Scheme, SessionType,
 			       scheme       = Scheme,
 			       queue_length = '$2',
 			       type         = SessionType,
+			       available    = true, 
 			       _            = '_'},
 	    %% {'_', {HostPort, '$1'}, false, Scheme, '_', '$2', SessionTyp}, 
 	    Candidates = ets:match(SessionDb, Pattern), 
@@ -716,7 +741,7 @@ pipeline_or_keep_alive(Request, HandlerPid, State) ->
 	    ets:insert(State#state.handler_db, {Request#request.id,
 						HandlerPid,
 						Request#request.from});
-	_  -> %timeout pipelining failed
+	_  -> % timeout pipelining failed
 	    start_handler(Request, State)
     end.