r-zakarya
d41dbfbb3a
Lancee, fermee par la croix (tray), puis relancee : la fenetre revenait derriere les autres, seule son icone dans la barre des taches. Mesure : visible, non minimisee, pas au premier plan. La 2e instance, qui recoit le double-clic, reveille la 1re par un message ; mais la 1re n'a recu aucune entree, et Windows lui refuse SetForegroundWindow. La 2e cede maintenant son droit (AllowSetForegroundWindow) avant d'envoyer le message. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
86 lines
2.8 KiB
ObjectPascal
86 lines
2.8 KiB
ObjectPascal
unit PM.SingleInstance;
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{
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Single-instance guard.
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AcquireOrSignal:
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- First instance: creates a named mutex and returns True. Caller proceeds.
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- Subsequent instance: detects the mutex, broadcasts WM_PMSHOW so the
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running instance restores from tray, returns False. Caller exits.
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WM_PMSHOW is a RegisterWindowMessage('PMServer_ShowExisting') — system-
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unique, all processes that register the same string get the same ID.
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PM.Bridge listens for it on its message-only window.
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}
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interface
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uses
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Winapi.Windows, Winapi.Messages;
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const
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// Mutex name lives in the Local\ namespace → per-user-session, so a
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// second user on the same machine (RDP, Switch User) can still launch
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// their own instance. The Global\ namespace would block them.
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PMSERVER_MUTEX_NAME = 'Local\PMServer.SingleInstance.Mutex';
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// System-wide unique message ID, computed once. Bridge + .dpr both call
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// this to get the same UINT.
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function WM_PMShowMessage: UINT;
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// Try to become the single instance. True = we are first; False = another
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// instance was already running (we have signalled it and the caller must
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// exit immediately).
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function AcquireOrSignal: Boolean;
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implementation
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var
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_Mutex: THandle = 0;
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_WmShow: UINT = 0;
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function WM_PMShowMessage: UINT;
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begin
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if _WmShow = 0 then
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_WmShow := RegisterWindowMessage('PMServer_ShowExisting');
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Result := _WmShow;
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end;
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function AcquireOrSignal: Boolean;
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var
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LErr: DWORD;
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begin
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_Mutex := CreateMutex(nil, True, PMSERVER_MUTEX_NAME);
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LErr := GetLastError;
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if (_Mutex <> 0) and (LErr <> ERROR_ALREADY_EXISTS) then
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begin
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// We are the first instance. Keep the mutex alive for the process
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// lifetime — Windows releases it automatically on exit.
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Result := True;
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Exit;
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end;
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// Another instance is already running. Close our handle (it isn't ours)
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// and broadcast the show-message to all top-level windows. The running
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// bridge picks it up on its message-only window.
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if _Mutex <> 0 then
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begin
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CloseHandle(_Mutex);
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_Mutex := 0;
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end;
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// CEDER LE PREMIER PLAN AVANT DE REVEILLER L'AUTRE. C'est NOUS qui venons de
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// recevoir le double-clic de l'utilisateur, donc nous seuls avons le droit de
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// passer devant. Sans cette cession, l'instance deja lancee — qui n'a recu
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// aucune entree — se voit refuser SetForegroundWindow par Windows : sa
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// fenetre se montre DERRIERE les autres, avec seulement son icone dans la
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// barre des taches. Mesure avant correctif : visible, non minimisee, pas au
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// premier plan. Tous processus parce que le PID de l'autre instance n'est pas connu
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// ici ; le droit cede expire a la prochaine entree utilisateur.
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AllowSetForegroundWindow(DWORD(-1)); // ASFW_ANY, absent de Winapi.Windows
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PostMessage(HWND_BROADCAST, WM_PMShowMessage, 0, 0);
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Result := False;
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end;
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end.
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