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

Comparing ibx/trunk/runtime/IBEvents.pas (file contents):
Revision 33 by tony, Sat Jul 18 12:30:52 2015 UTC vs.
Revision 143 by tony, Fri Feb 23 12:11:21 2018 UTC

#	Line 27 | Line 27
27		{    IBX For Lazarus (Firebird Express)                                  }
28		{    Contributor: Tony Whyman, MWA Software http://www.mwasoftware.co.uk }
29		{    Portions created by MWA Software are copyright McCallum Whyman      }
30	<	{    Associates Ltd 2011                                                 }
30	>	{    Associates Ltd 2011 - 2018                                               }
31		{                                                                        }
32		{************************************************************************}
33
#	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		{$ENDIF}
57	<	Classes, IBHeader, IBExternals, IB, IBDatabase;
57	>	Classes, IBExternals, IB, IBDatabase;
58
59		const
60		MaxEvents = 15;
#	Line 68 | Line 68 | type
68
69		TIBEvents = class(TComponent)
70		private
71	–	FIBLoaded: Boolean;
71		FBase: TIBBase;
72	+	FEventIntf: IEvents;
73		FEvents: TStrings;
74		FOnEventAlert: TEventAlert;
75	–	FEventHandler: TObject;
75		FRegistered: boolean;
76		FDeferredRegister: boolean;
77	+	FStartEvent: boolean;
78	+	procedure EventHandler(Sender: IEvents);
79	+	procedure ProcessEvents;
80		procedure EventChange(sender: TObject);
81		function GetDatabase: TIBDatabase;
80	–	function GetDatabaseHandle: TISC_DB_HANDLE;
82		procedure SetDatabase( value: TIBDatabase);
83		procedure ValidateDatabase( Database: TIBDatabase);
84		procedure DoBeforeDatabaseDisconnect(Sender: TObject);
#	Line 92 | Line 93 | type
93		destructor Destroy; override;
94		procedure RegisterEvents;
95		procedure UnRegisterEvents;
95	–	property DatabaseHandle: TISC_DB_HANDLE read GetDatabaseHandle;
96		property DeferredRegister: boolean read FDeferredRegister write FDeferredRegister;
97	+	property EventIntf: IEvents read FEventIntf;
98		published
99		property Database: TIBDatabase read GetDatabase write SetDatabase;
100		property Events: TStrings read FEvents write SetEvents;
#	Line 104 | Line 105 | type
105
106		implementation
107
108	<	uses
108	<	IBIntf, syncobjs, SysUtils;
109	<
110	<	type
111	<
112	<	TEventHandlerStates = (
113	<	stIdle,           {Events not monitored}
114	<	stHasEvb,         {Event Block Allocated but not queued}
115	<	stQueued,         {Waiting for Event}
116	<	stSignalled       {Event Callback signalled Event}
117	<	);
118	<
119	<	{ TEventHandler }
120	<
121	<	TEventHandler = class(TThread)
122	<	private
123	<	FOwner: TIBEvents;
124	<	FCriticalSection: TCriticalSection;   {protects race conditions in stQueued state}
125	<	{$IFDEF WINDOWS}
126	<	{Make direct use of Windows API as TEventObject don't seem to work under
127	<	Windows!}
128	<	FEventHandler: THandle;
129	<	{$ELSE}
130	<	FEventWaiting: TEventObject;
131	<	{$ENDIF}
132	<	FState: TEventHandlerStates;
133	<	FEventBuffer: PChar;
134	<	FEventBufferLen: integer;
135	<	FEventID: ISC_LONG;
136	<	FRegisteredState: Boolean;
137	<	FResultBuffer: PChar;
138	<	FEvents: TStringList;
139	<	FSignalFired: boolean;
140	<	procedure QueueEvents;
141	<	procedure CancelEvents;
142	<	procedure HandleEventSignalled(length: short; updated: PChar);
143	<	procedure DoEventSignalled;
144	<	protected
145	<	procedure Execute; override;
146	<	public
147	<	constructor Create(Owner: TIBEvents);
148	<	destructor Destroy; override;
149	<	procedure Terminate;
150	<	procedure RegisterEvents(Events: TStrings);
151	<	procedure UnregisterEvents;
152	<	end;
153	<
154	<	{This procedure is used for the event call back - note the cdecl }
155	<
156	<	procedure IBEventCallback( ptr: pointer; length: short; updated: PChar); cdecl;
157	<	begin
158	<	if (ptr = nil) or (length = 0) or (updated = nil) then
159	<	Exit;
160	<	{ Handle events asynchronously in second thread }
161	<	TEventHandler(ptr).HandleEventSignalled(length,updated);
162	<	end;
163	<
164	<
165	<
166	<	{ TEventHandler }
167	<
168	<	procedure TEventHandler.QueueEvents;
169	<	var
170	<	callback: pointer;
171	<	DBH: TISC_DB_HANDLE;
172	<	begin
173	<	if FState <> stHasEvb then
174	<	Exit;
175	<	FCriticalSection.Enter;
176	<	try
177	<	callback := @IBEventCallback;
178	<	DBH := FOwner.DatabaseHandle;
179	<	if (isc_que_events( StatusVector, @DBH, @FEventID, FEventBufferLen,
180	<	FEventBuffer, TISC_CALLBACK(callback), PVoid(Self)) <> 0) then
181	<	IBDatabaseError;
182	<	FState := stQueued
183	<	finally
184	<	FCriticalSection.Leave
185	<	end;
186	<	end;
187	<
188	<	procedure TEventHandler.CancelEvents;
189	<	var
190	<	DBH: TISC_DB_HANDLE;
191	<	begin
192	<	if FState in [stQueued,stSignalled] then
193	<	begin
194	<	FCriticalSection.Enter;
195	<	try
196	<	DBH := FOwner.DatabaseHandle;
197	<	if (isc_Cancel_events( StatusVector, @DBH, @FEventID) <> 0) then
198	<	IBDatabaseError;
199	<	FState := stHasEvb;
200	<	finally
201	<	FCriticalSection.Leave
202	<	end;
203	<	end;
204	<
205	<	if FState = stHasEvb then
206	<	begin
207	<	isc_free( FEventBuffer);
208	<	FEventBuffer := nil;
209	<	isc_free( FResultBuffer);
210	<	FResultBuffer := nil;
211	<	FState := stIdle
212	<	end;
213	<	FSignalFired := false
214	<	end;
215	<
216	<	procedure TEventHandler.HandleEventSignalled(length: short; updated: PChar);
217	<	begin
218	<	FCriticalSection.Enter;
219	<	try
220	<	if FState <> stQueued then
221	<	Exit;
222	<	Move(Updated[0], FResultBuffer[0], Length);
223	<	FState := stSignalled;
224	<	{$IFDEF WINDOWS}
225	<	SetEVent(FEventHandler);
226	<	{$ELSE}
227	<	FEventWaiting.SetEvent;
228	<	{$ENDIF}
229	<	finally
230	<	FCriticalSection.Leave
231	<	end;
232	<	end;
233	<
234	<	procedure TEventHandler.DoEventSignalled;
235	<	var
236	<	i: integer;
237	<	CancelAlerts: boolean;
238	<	Status: array[0..19] of ISC_LONG; {Note in 64 implementation the ibase.h implementation
239	<	is different from Interbase 6.0 API documentatoin}
240	<	begin
241	<	if FState <> stSignalled then
242	<	Exit;
243	<	isc_event_counts( @Status, FEventBufferLen, FEventBuffer, FResultBuffer);
244	<	CancelAlerts := false;
245	<	if not FSignalFired then
246	<	FSignalFired := true   {Ignore first time}
247	<	else
248	<	if assigned(FOwner.FOnEventAlert)  then
249	<	begin
250	<	for i := 0 to FEvents.Count - 1 do
251	<	begin
252	<	try
253	<	if (Status[i] <> 0) and not CancelAlerts then
254	<	FOwner.FOnEventAlert( self, FEvents[i], Status[i], CancelAlerts);
255	<	except
256	<	FOwner.FBase.HandleException(Self)
257	<	end;
258	<	end;
259	<	end;
260	<	FState := stHasEvb;
261	<	if  CancelAlerts then
262	<	CancelEvents
263	<	else
264	<	QueueEvents
265	<	end;
266	<
267	<	procedure TEventHandler.Execute;
268	<	begin
269	<	while not Terminated do
270	<	begin
271	<	{$IFDEF WINDOWS}
272	<	WaitForSingleObject(FEventHandler,INFINITE);
273	<	{$ELSE}
274	<	FEventWaiting.WaitFor(INFINITE);
275	<	{$ENDIF}
276	<
277	<	if not Terminated and (FState = stSignalled) then
278	<	Synchronize(DoEventSignalled)
279	<	end;
280	<	end;
281	<
282	<
283	<
284	<	constructor TEventHandler.Create(Owner: TIBEvents);
285	<	var
286	<	PSa : PSecurityAttributes;
287	<	{$IFDEF WINDOWS}
288	<	Sd : TSecurityDescriptor;
289	<	Sa : TSecurityAttributes;
290	<	begin
291	<	InitializeSecurityDescriptor(@Sd,SECURITY_DESCRIPTOR_REVISION);
292	<	SetSecurityDescriptorDacl(@Sd,true,nil,false);
293	<	Sa.nLength := SizeOf(Sa);
294	<	Sa.lpSecurityDescriptor := @Sd;
295	<	Sa.bInheritHandle := true;
296	<	PSa := @Sa;
297	<	{$ELSE}
298	<	begin
299	<	PSa:= nil;
300	<	{$ENDIF}
301	<	inherited Create(true);
302	<	FOwner := Owner;
303	<	FState := stIdle;
304	<	FCriticalSection := TCriticalSection.Create;
305	<	{$IFDEF WINDOWS}
306	<	FEventHandler := CreateEvent(PSa,false,true,nil);
307	<	{$ELSE}
308	<	FEventWaiting := TEventObject.Create(PSa,false,true,FOwner.Name+'.Events');
309	<	{$ENDIF}
310	<	FEvents := TStringList.Create;
311	<	FreeOnTerminate := true;
312	<	Resume
313	<	end;
314	<
315	<	destructor TEventHandler.Destroy;
316	<	begin
317	<	if assigned(FCriticalSection) then FCriticalSection.Free;
318	<	{$IFDEF WINDOWS}
319	<	CloseHandle(FEventHandler);
320	<	{$ELSE}
321	<	if assigned(FEventWaiting) then FEventWaiting.Free;
322	<	{$ENDIF}
323	<	if assigned(FEvents) then FEvents.Free;
324	<	inherited Destroy;
325	<	end;
326	<
327	<	procedure TEventHandler.Terminate;
328	<	begin
329	<	inherited Terminate;
330	<	{$IFDEF WINDOWS}
331	<	SetEvent(FEventHandler);
332	<	{$ELSE}
333	<	FEventWaiting.SetEvent;
334	<	{$ENDIF}
335	<	CancelEvents;
336	<	end;
337	<
338	<	procedure TEventHandler.RegisterEvents(Events: TStrings);
339	<	var
340	<	i: integer;
341	<	EventNames: array of PChar;
342	<	begin
343	<	UnregisterEvents;
344	<
345	<	if Events.Count = 0 then
346	<	exit;
347	<
348	<	setlength(EventNames,MaxEvents);
349	<	try
350	<	for i := 0 to Events.Count-1 do
351	<	EventNames[i] := PChar(Events[i]);
352	<	FEvents.Assign(Events);
353	<	FEventBufferlen := isc_event_block(@FEventBuffer,@FResultBuffer,
354	<	Events.Count,
355	<	EventNames[0],EventNames[1],EventNames[2],
356	<	EventNames[3],EventNames[4],EventNames[5],
357	<	EventNames[6],EventNames[7],EventNames[8],
358	<	EventNames[9],EventNames[10],EventNames[11],
359	<	EventNames[12],EventNames[13],EventNames[14]
360	<	);
361	<	FState := stHasEvb;
362	<	FRegisteredState := true;
363	<	QueueEvents
364	<	finally
365	<	SetLength(EventNames,0)
366	<	end;
367	<	end;
368	<
369	<	procedure TEventHandler.UnregisterEvents;
370	<	begin
371	<	if FRegisteredState then
372	<	begin
373	<	CancelEvents;
374	<	FRegisteredState := false;
375	<	end;
376	<	end;
108	>	uses SysUtils, FBMessages;
109
110		{ TIBEvents }
111
#	Line 388 | Line 120 | end;
120		constructor TIBEvents.Create( AOwner: TComponent);
121		begin
122		inherited Create( AOwner);
391	–	FIBLoaded := False;
392	–	CheckIBLoaded;
393	–	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;
403	–	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;
413	<	FBase.Free;
414	<	FEvents.Free;
415	<	end;
416	<	if assigned(FEventHandler) then
417	<	TEventHandler(FEventHandler).Terminate;
418	<	FEventHandler := nil;
419	<	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 431 | 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 451 | 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 459 | 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 487 | 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 499 | 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 508 | 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 524 | Line 280 | begin
280		Registered := true
281		end;
282
527	–	function TIBEvents.GetDatabaseHandle: TISC_DB_HANDLE;
528	–	begin
529	–	ValidateDatabase(FBase.Database);
530	–	Result := FBase.Database.Handle;
531	–	end;
532	–
283
284		end.

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