Le 25/10/2012 13:07, Bernd a ?crit :
very nice indeed and readable even on pseudo-code, but ...
Show quoted text 13 lines
Here is an alternative way to implement it (this one can even reply
and have a conversation of multiple commands going forth an back
between the client and server):
pocedure OnEverythingGetsStarted;
begin
if State = WAITING then exit;
State := WAITING
maybe also disable some buttons that might interfere
open the connection
send the request
start the timeout timer
// return from that event
this is exactly what I have to avoid: user gains control on screen. A workaround is to disable the window itself. But then another timer is needed to ensure that whatever happens or NOTHING happens, control will return back to the starting point.
Furthermore, all requests coded until now have to be moved outside of the procedures or events holding them: a lot of work What if:
pocedure OnEverythingGetsStarted;
*var
AHandles: PWOHandleArray;*
* **Res: DWORD;*
begin
if State = WAITING then exit;
State := WAITING
maybe also disable some buttons that might interfere
open the connection
Event.ResetEvent; // not signaled
send the request
start the timeout timer
AHandles[0] := Timer.Handle;
AHandles[1] := Event.Handle; // posted by the OnReceive
event
Res:=WaitForMultipleObjects(2, @AHandles, False, Timeout);
// wait for first reset, not interested for all
case Res of
... continue processing depending of the answer or no answer
end;
end;
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end;
procedure OnTimer;
begin
if State = WAITING then begin
Disconnect
State := IDLE
Timer.enabled := False;
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enable the disabled buttons
end;
end;
procedure OnReceive(S: TLSocket);
begin
Answer := S.GetMessage()
forget about the rest of the procedure and do instead:
DoWhatEverBeforeProcessData(Answer);
Event.SetEvent; // event signaled
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case Answer of
'foo': begin
DoThis();
SendAnotherCommand();
end
'bar': begin
DoThat();
SendSomeThingDifferent();
end
.. I have dozens of messages to process in the internal protocol
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else begin
DoWhateverNeedsToBeDone();
S.Disconnect;
State := IDLE;
enable the disabled buttons
end;
end;
This will never block and never freeze and never eat any unneeded CPU
cycles and it is les code than messing around with the eventers and
CallAction directly and also less code than low level programming
against sockets and/or winsock2 directly.
Anyway, I can agree with this above.
But the application has to be re-engineered.
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