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root/public/ibx/trunk/runtime/IBEvents.pas

Comparing ibx/trunk/runtime/IBEvents.pas (file contents):
Revision 7 by tony, Sun Aug 5 18:28:19 2012 UTC vs.
Revision 47 by tony, Mon Jan 9 15:31:51 2017 UTC

#	Line 44 | Line 44
44
45		unit IBEvents;
46
47	<	{$Mode Delphi}
47	>	{$mode objfpc}{$H+}
48
49		interface
50
#	Line 54 | Line 54 | uses
54		{$ELSE}
55		unix,
56		{$ENDIF}
57	<	Classes, Graphics, Controls,
58	<	Forms, Dialogs, IBHeader, IBExternals, IB, IBDatabase;
57	>	Classes, IBExternals, IB, IBDatabase;
58
59		const
60		MaxEvents = 15;
#	Line 69 | Line 68 | type
68
69		TIBEvents = class(TComponent)
70		private
72	–	FIBLoaded: Boolean;
71		FBase: TIBBase;
72	+	FEventIntf: IEvents;
73		FEvents: TStrings;
74		FOnEventAlert: TEventAlert;
76	–	FEventHandler: TObject;
75		FRegistered: boolean;
76		FDeferredRegister: boolean;
77	+	FStartEvent: boolean;
78	+	procedure EventHandler(Sender: IEvents);
79	+	procedure ProcessEvents;
80		procedure EventChange(sender: TObject);
81		function GetDatabase: TIBDatabase;
81	–	function GetDatabaseHandle: TISC_DB_HANDLE;
82		procedure SetDatabase( value: TIBDatabase);
83		procedure ValidateDatabase( Database: TIBDatabase);
84		procedure DoBeforeDatabaseDisconnect(Sender: TObject);
#	Line 93 | Line 93 | type
93		destructor Destroy; override;
94		procedure RegisterEvents;
95		procedure UnRegisterEvents;
96	–	property DatabaseHandle: TISC_DB_HANDLE read GetDatabaseHandle;
96		property DeferredRegister: boolean read FDeferredRegister write FDeferredRegister;
97	+	property EventIntf: IEvents read FEventIntf;
98		published
99		property Database: TIBDatabase read GetDatabase write SetDatabase;
100		property Events: TStrings read FEvents write SetEvents;
#	Line 105 | Line 105 | type
105
106		implementation
107
108	<	uses
109	<	IBIntf, syncobjs;
110	<
111	<	type
112	<
113	<	TEventHandlerStates = (
114	<	stIdle,           {Events not monitored}
115	<	stHasEvb,         {Event Block Allocated but not queued}
116	<	stQueued,         {Waiting for Event}
117	<	stSignalled       {Event Callback signalled Event}
118	<	);
119	<
120	<	{ TEventHandler }
121	<
122	<	TEventHandler = class(TThread)
123	<	private
124	<	FOwner: TIBEvents;
125	<	FCriticalSection: TCriticalSection;   {protects race conditions in stQueued state}
126	<	{$IFDEF WINDOWS}
127	<	{Make direct use of Windows API as TEventObject don't seem to work under
128	<	Windows!}
129	<	FEventHandler: THandle;
130	<	{$ELSE}
131	<	FEventWaiting: TEventObject;
132	<	{$ENDIF}
133	<	FState: TEventHandlerStates;
134	<	FEventBuffer: PChar;
135	<	FEventBufferLen: integer;
136	<	FEventID: ISC_LONG;
137	<	FRegisteredState: Boolean;
138	<	FResultBuffer: PChar;
139	<	FEvents: TStringList;
140	<	FSignalFired: boolean;
141	<	procedure QueueEvents;
142	<	procedure CancelEvents;
143	<	procedure HandleEventSignalled(length: short; updated: PChar);
144	<	procedure DoEventSignalled;
145	<	protected
146	<	procedure Execute; override;
147	<	public
148	<	constructor Create(Owner: TIBEvents);
149	<	destructor Destroy; override;
150	<	procedure Terminate;
151	<	procedure RegisterEvents(Events: TStrings);
152	<	procedure UnregisterEvents;
153	<	end;
154	<
155	<	{This procedure is used for the event call back - note the cdecl }
156	<
157	<	procedure IBEventCallback( ptr: pointer; length: short; updated: PChar); cdecl;
158	<	begin
159	<	if (ptr = nil) or (length = 0) or (updated = nil) then
160	<	Exit;
161	<	{ Handle events asynchronously in second thread }
162	<	TEventHandler(ptr).HandleEventSignalled(length,updated);
163	<	end;
164	<
165	<
166	<
167	<	{ TEventHandler }
168	<
169	<	procedure TEventHandler.QueueEvents;
170	<	var
171	<	callback: pointer;
172	<	DBH: TISC_DB_HANDLE;
173	<	begin
174	<	if FState <> stHasEvb then
175	<	Exit;
176	<	FCriticalSection.Enter;
177	<	try
178	<	callback := @IBEventCallback;
179	<	DBH := FOwner.DatabaseHandle;
180	<	if (isc_que_events( StatusVector, @DBH, @FEventID, FEventBufferLen,
181	<	FEventBuffer, TISC_CALLBACK(callback), PVoid(Self)) <> 0) then
182	<	IBDatabaseError;
183	<	FState := stQueued
184	<	finally
185	<	FCriticalSection.Leave
186	<	end;
187	<	end;
188	<
189	<	procedure TEventHandler.CancelEvents;
190	<	var
191	<	DBH: TISC_DB_HANDLE;
192	<	begin
193	<	if FState in [stQueued,stSignalled] then
194	<	begin
195	<	FCriticalSection.Enter;
196	<	try
197	<	DBH := FOwner.DatabaseHandle;
198	<	if (isc_Cancel_events( StatusVector, @DBH, @FEventID) <> 0) then
199	<	IBDatabaseError;
200	<	FState := stHasEvb;
201	<	finally
202	<	FCriticalSection.Leave
203	<	end;
204	<	end;
205	<
206	<	if FState = stHasEvb then
207	<	begin
208	<	isc_free( FEventBuffer);
209	<	FEventBuffer := nil;
210	<	isc_free( FResultBuffer);
211	<	FResultBuffer := nil;
212	<	FState := stIdle
213	<	end;
214	<	FSignalFired := false
215	<	end;
216	<
217	<	procedure TEventHandler.HandleEventSignalled(length: short; updated: PChar);
218	<	begin
219	<	FCriticalSection.Enter;
220	<	try
221	<	if FState <> stQueued then
222	<	Exit;
223	<	Move(Updated[0], FResultBuffer[0], Length);
224	<	FState := stSignalled;
225	<	{$IFDEF WINDOWS}
226	<	SetEVent(FEventHandler);
227	<	{$ELSE}
228	<	FEventWaiting.SetEvent;
229	<	{$ENDIF}
230	<	finally
231	<	FCriticalSection.Leave
232	<	end;
233	<	end;
234	<
235	<	procedure TEventHandler.DoEventSignalled;
236	<	var
237	<	i: integer;
238	<	CancelAlerts: boolean;
239	<	Status: array[0..19] of ISC_LONG; {Note in 64 implementation the ibase.h implementation
240	<	is different from Interbase 6.0 API documentatoin}
241	<	begin
242	<	if FState <> stSignalled then
243	<	Exit;
244	<	isc_event_counts( @Status, FEventBufferLen, FEventBuffer, FResultBuffer);
245	<	CancelAlerts := false;
246	<	if not FSignalFired then
247	<	FSignalFired := true   {Ignore first time}
248	<	else
249	<	if assigned(FOwner.FOnEventAlert)  then
250	<	begin
251	<	for i := 0 to FEvents.Count - 1 do
252	<	begin
253	<	try
254	<	if (Status[i] <> 0) and not CancelAlerts then
255	<	FOwner.FOnEventAlert( self, FEvents[i], Status[i], CancelAlerts);
256	<	except
257	<	Application.HandleException( nil);
258	<	end;
259	<	end;
260	<	end;
261	<	FState := stHasEvb;
262	<	if  CancelAlerts then
263	<	CancelEvents
264	<	else
265	<	QueueEvents
266	<	end;
267	<
268	<	procedure TEventHandler.Execute;
269	<	begin
270	<	while not Terminated do
271	<	begin
272	<	{$IFDEF WINDOWS}
273	<	WaitForSingleObject(FEventHandler,INFINITE);
274	<	{$ELSE}
275	<	FEventWaiting.WaitFor(INFINITE);
276	<	{$ENDIF}
277	<
278	<	if not Terminated and (FState = stSignalled) then
279	<	Synchronize(DoEventSignalled)
280	<	end;
281	<	end;
282	<
283	<
284	<
285	<	constructor TEventHandler.Create(Owner: TIBEvents);
286	<	var
287	<	PSa : PSecurityAttributes;
288	<	{$IFDEF WINDOWS}
289	<	Sd : TSecurityDescriptor;
290	<	Sa : TSecurityAttributes;
291	<	begin
292	<	InitializeSecurityDescriptor(@Sd,SECURITY_DESCRIPTOR_REVISION);
293	<	SetSecurityDescriptorDacl(@Sd,true,nil,false);
294	<	Sa.nLength := SizeOf(Sa);
295	<	Sa.lpSecurityDescriptor := @Sd;
296	<	Sa.bInheritHandle := true;
297	<	PSa := @Sa;
298	<	{$ELSE}
299	<	begin
300	<	PSa:= nil;
301	<	{$ENDIF}
302	<	inherited Create(true);
303	<	FOwner := Owner;
304	<	FState := stIdle;
305	<	FCriticalSection := TCriticalSection.Create;
306	<	{$IFDEF WINDOWS}
307	<	FEventHandler := CreateEvent(PSa,false,true,nil);
308	<	{$ELSE}
309	<	FEventWaiting := TEventObject.Create(PSa,false,true,FOwner.Name+'.Events');
310	<	{$ENDIF}
311	<	FEvents := TStringList.Create;
312	<	FreeOnTerminate := true;
313	<	Resume
314	<	end;
315	<
316	<	destructor TEventHandler.Destroy;
317	<	begin
318	<	if assigned(FCriticalSection) then FCriticalSection.Free;
319	<	{$IFDEF WINDOWS}
320	<	CloseHandle(FEventHandler);
321	<	{$ELSE}
322	<	if assigned(FEventWaiting) then FEventWaiting.Free;
323	<	{$ENDIF}
324	<	if assigned(FEvents) then FEvents.Free;
325	<	inherited Destroy;
326	<	end;
327	<
328	<	procedure TEventHandler.Terminate;
329	<	begin
330	<	inherited Terminate;
331	<	{$IFDEF WINDOWS}
332	<	SetEvent(FEventHandler);
333	<	{$ELSE}
334	<	FEventWaiting.SetEvent;
335	<	{$ENDIF}
336	<	CancelEvents;
337	<	end;
338	<
339	<	procedure TEventHandler.RegisterEvents(Events: TStrings);
340	<	var
341	<	i: integer;
342	<	EventNames: array of PChar;
343	<	begin
344	<	UnregisterEvents;
345	<
346	<	if Events.Count = 0 then
347	<	exit;
348	<
349	<	setlength(EventNames,MaxEvents);
350	<	try
351	<	for i := 0 to Events.Count-1 do
352	<	EventNames[i] := PChar(Events[i]);
353	<	FEvents.Assign(Events);
354	<	FEventBufferlen := isc_event_block(@FEventBuffer,@FResultBuffer,
355	<	Events.Count,
356	<	EventNames[0],EventNames[1],EventNames[2],
357	<	EventNames[3],EventNames[4],EventNames[5],
358	<	EventNames[6],EventNames[7],EventNames[8],
359	<	EventNames[9],EventNames[10],EventNames[11],
360	<	EventNames[12],EventNames[13],EventNames[14]
361	<	);
362	<	FState := stHasEvb;
363	<	FRegisteredState := true;
364	<	QueueEvents
365	<	finally
366	<	SetLength(EventNames,0)
367	<	end;
368	<	end;
369	<
370	<	procedure TEventHandler.UnregisterEvents;
371	<	begin
372	<	if FRegisteredState then
373	<	begin
374	<	CancelEvents;
375	<	FRegisteredState := false;
376	<	end;
377	<	end;
108	>	uses SysUtils, FBMessages;
109
110		{ TIBEvents }
111
#	Line 389 | Line 120 | end;
120		constructor TIBEvents.Create( AOwner: TComponent);
121		begin
122		inherited Create( AOwner);
392	–	FIBLoaded := False;
393	–	CheckIBLoaded;
394	–	FIBLoaded := True;
123		FBase := TIBBase.Create(Self);
124	<	FBase.BeforeDatabaseDisconnect := DoBeforeDatabaseDisconnect;
125	<	FBase.AfterDatabaseConnect := DoAfterDatabaseConnect;
124	>	FBase.BeforeDatabaseDisconnect := @DoBeforeDatabaseDisconnect;
125	>	FBase.AfterDatabaseConnect := @DoAfterDatabaseConnect;
126		FEvents := TStringList.Create;
127	+	FStartEvent := true;
128		with TStringList( FEvents) do
129		begin
130	<	OnChange := EventChange;
130	>	OnChange := @EventChange;
131		Duplicates := dupIgnore;
132		end;
404	–	FEventHandler := TEventHandler.Create(self)
133		end;
134
135		destructor TIBEvents.Destroy;
136		begin
137	<	if FIBLoaded then
138	<	begin
139	<	UnregisterEvents;
140	<	SetDatabase(nil);
141	<	TStringList(FEvents).OnChange := nil;
414	<	FBase.Free;
415	<	FEvents.Free;
416	<	end;
417	<	if assigned(FEventHandler) then
418	<	TEventHandler(FEventHandler).Terminate;
419	<	FEventHandler := nil;
420	<	inherited Destroy;
137	>	UnregisterEvents;
138	>	SetDatabase(nil);
139	>	TStringList(FEvents).OnChange := nil;
140	>	FBase.Free;
141	>	FEvents.Free;
142		end;
143
144	+	procedure TIBEvents.EventHandler(Sender: IEvents);
145	+	begin
146	+	TThread.Synchronize(nil,@ProcessEvents);
147	+	end;
148
149	+	procedure TIBEvents.ProcessEvents;
150	+	var EventCounts: TEventCounts;
151	+	CancelAlerts: Boolean;
152	+	i: integer;
153	+	begin
154	+	if (csDestroying in ComponentState) or (FEventIntf = nil) then Exit;
155	+	CancelAlerts := false;
156	+	EventCounts := FEventIntf.ExtractEventCounts;
157	+	if FStartEvent then
158	+	FStartEvent := false {ignore the first one}
159	+	else
160	+	if assigned(FOnEventAlert) then
161	+	begin
162	+	CancelAlerts := false;
163	+	for i := 0 to Length(EventCounts) -1 do
164	+	begin
165	+	OnEventAlert(self,EventCounts[i].EventName,EventCounts[i].Count,CancelAlerts);
166	+	if CancelAlerts then break;
167	+	end;
168	+	end;
169	+	if CancelAlerts then
170	+	UnRegisterEvents
171	+	else
172	+	FEventIntf.AsyncWaitForEvent(@EventHandler);
173	+	end;
174
175		procedure TIBEvents.EventChange( sender: TObject);
176		begin
#	Line 432 | Line 182 | begin
182		begin
183		TStringList(Events).OnChange := nil;
184		Events.Delete( MaxEvents);
185	<	TStringList(Events).OnChange := EventChange;
185	>	TStringList(Events).OnChange := @EventChange;
186		IBError(ibxeMaximumEvents, [nil]);
187		end;
188	<	if Registered then
189	<	TEventHandler(FEventHandler).RegisterEvents(Events);
188	>	if Registered  and (FEventIntf <> nil) then
189	>	begin
190	>	FEventIntf.SetEvents(Events);
191	>	FEventIntf.AsyncWaitForEvent(@EventHandler);
192	>	end;
193		end;
194
195		procedure TIBEvents.Notification( AComponent: TComponent;
#	Line 452 | Line 205 | end;
205
206		procedure TIBEvents.RegisterEvents;
207		begin
208	+	if FRegistered then Exit;
209		ValidateDatabase( Database);
210		if csDesigning in ComponentState then FRegistered := true
211		else
#	Line 460 | Line 214 | begin
214		FDeferredRegister := true
215		else
216		begin
217	<	TEventHandler(FEventHandler).RegisterEvents(Events);
217	>	FEventIntf := Database.Attachment.GetEventHandler(Events);
218	>	FEventIntf.AsyncWaitForEvent(@EventHandler);
219		FRegistered := true;
220		end;
221		end;
#	Line 488 | Line 243 | begin
243		Result := FBase.Database
244		end;
245
246	<	procedure TIBEvents.SetRegistered( value: Boolean);
246	>	procedure TIBEvents.SetRegistered(value: boolean);
247		begin
248		FDeferredRegister := false;
249		if not assigned(FBase) or (FBase.Database = nil) then
#	Line 500 | Line 255 | begin
255		if value then RegisterEvents else UnregisterEvents;
256		end;
257
258	<	procedure TIBEvents.UnregisterEvents;
258	>	procedure TIBEvents.UnRegisterEvents;
259		begin
260		FDeferredRegister := false;
261		if not FRegistered then
#	Line 509 | Line 264 | begin
264		FRegistered := false
265		else
266		begin
267	<	TEventHandler(FEventHandler).UnRegisterEvents;
267	>	FEventIntf := nil;
268		FRegistered := false;
269		end;
270		end;
#	Line 525 | Line 280 | begin
280		Registered := true
281		end;
282
528	–	function TIBEvents.GetDatabaseHandle: TISC_DB_HANDLE;
529	–	begin
530	–	ValidateDatabase(FBase.Database);
531	–	Result := FBase.Database.Handle;
532	–	end;
533	–
283
284		end.

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