client/2.5/FB25Events.pas

(*
 *  Firebird Interface (fbintf). The fbintf components provide a set of
 *  Pascal language bindings for the Firebird API. Although predominantly
 *  a new development they include source code taken from IBX and may be
 *  considered a derived product. This software thus also includes the copyright
 *  notice and license conditions from IBX.
 *
 *  Except for those parts dervied from IBX, contents of this file are subject
 *  to the Initial Developer's Public License Version 1.0 (the "License"); you
 *  may not use this file except in compliance with the License. You may obtain a
 *  copy of the License here:
 *
 *    http://www.firebirdsql.org/index.php?op=doc&id=idpl
 *
 *  Software distributed under the License is distributed on an "AS
 *  IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 *  implied. See the License for the specific language governing rights
 *  and limitations under the License.
 *
 *  The Initial Developer of the Original Code is Tony Whyman.
 *
 *  The Original Code is (C) 2016 Tony Whyman, MWA Software
 *  (http://www.mwasoftware.co.uk).
 *
 *  All Rights Reserved.
 *
 *  Contributor(s): ______________________________________.
 *
*)
{************************************************************************}
{                                                                        }
{       Borland Delphi Visual Component Library                          }
{       InterBase Express core components                                }
{                                                                        }
{       Copyright (c) 1998-2000 Inprise Corporation                      }
{                                                                        }
{    InterBase Express is based in part on the product                   }
{    Free IB Components, written by Gregory H. Deatz for                 }
{    Hoagland, Longo, Moran, Dunst & Doukas Company.                     }
{    Free IB Components is used under license.                           }
{                                                                        }
{    The contents of this file are subject to the InterBase              }
{    Public License Version 1.0 (the "License"); you may not             }
{    use this file except in compliance with the License. You            }
{    may obtain a copy of the License at http://www.Inprise.com/IPL.html }
{    Software distributed under the License is distributed on            }
{    an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either              }
{    express or implied. See the License for the specific language       }
{    governing rights and limitations under the License.                 }
{    The Original Code was created by InterBase Software Corporation     }
{       and its successors.                                              }
{    Portions created by Inprise Corporation are Copyright (C) Inprise   }
{       Corporation. All Rights Reserved.                                }
{    Contributor(s): Jeff Overcash                                       }
{                                                                        }
{    IBX For Lazarus (Firebird Express)                                  }
{    Contributor: Tony Whyman, MWA Software http://www.mwasoftware.co.uk }
{    Portions created by MWA Software are copyright McCallum Whyman      }
{    Associates Ltd 2011 - 2015                                                }
{                                                                        }
{************************************************************************}
unit FB25Events;
{$IFDEF MSWINDOWS} 
{$DEFINE WINDOWS} 
{$ENDIF}

{$IFDEF FPC}
{$mode delphi}
{$interfaces COM}
{$ENDIF}

interface

uses
  {$IFDEF WINDOWS}Windows, {$ENDIF}Classes, SysUtils, IB, FB25ClientAPI, FB25Attachment,
  IBExternals, IBHeader, syncobjs, FBEvents;

type
  TFB25Events = class;

  { TEventhandlerInterface }

  TEventhandlerInterface = class
  private
    FOwner: TFB25Events;
    {$IFDEF WINDOWS}
    {Make direct use of Windows API as TEventObject don't seem to work under
     Windows!}
    FEventHandler: THandle;
    {$ELSE}
    FEventWaiting: TEventObject;
    {$ENDIF}
  public
    constructor Create(aOwner: TFB25Events);
    destructor Destroy; override;
    procedure eventCallbackFunction(length: short; updated: PAnsiChar);
    procedure WaitForEvent;
    procedure CancelWait;
 end;

  { TFB25Events }

  TFB25Events = class(TFBEvents,IEvents)
  private
    FEventID: ISC_LONG;
    FDBHandle: TISC_DB_HANDLE;
    FEventHandlerThread: TObject;
    FAsyncEventCallback: TEventhandlerInterface;
    FFirebird25ClientAPI: TFB25ClientAPI;
  protected
    procedure CancelEvents(Force: boolean = false); override;
    function GetIEvents: IEvents; override;
  public
    constructor Create(DBAttachment: TFB25Attachment; Events: TStrings);
    destructor Destroy; override;

    {IEvents}
    procedure WaitForEvent;
    procedure AsyncWaitForEvent(EventHandler: TEventHandler); override;
  end;

implementation

uses  FBMessages;

type

  { TEventHandlerThread }

  TEventHandlerThread = class(TThread)
  private
    FOwner: TFB25Events;
    FEventHandler: TEventhandlerInterface;
  protected
    procedure Execute; override;
  public
    constructor Create(Owner: TFB25Events; EventHandler: TEventhandlerInterface);
    procedure Terminate;
  end;

  { TEventHandlerThread }

 procedure TEventHandlerThread.Execute;
 begin
   while not Terminated do
   begin
     FEventHandler.WaitForEvent;

     if not Terminated  then
       FOwner.EventSignaled;
   end;
 end;

 constructor TEventHandlerThread.Create(Owner: TFB25Events;
   EventHandler: TEventhandlerInterface);
 begin
   inherited Create(false);
   FOwner := Owner;
   FEventHandler := EventHandler;
   FreeOnTerminate := true;
 end;

 procedure TEventHandlerThread.Terminate;
 begin
   inherited Terminate;
   FEventHandler.CancelWait;
 end;

  {This procedure is used for the event call back - note the cdecl }

 procedure IBEventCallback( ptr: pointer; length: short; updated: PAnsiChar); cdecl;
 begin
   if (ptr = nil) or (length = 0) or (updated = nil) then
     Exit;
   { Handle events asynchronously in second thread }
   TEventhandlerInterface(ptr).eventCallbackFunction(length,updated);
 end;

{ TEventhandlerInterface }

constructor TEventhandlerInterface.Create(aOwner: TFB25Events);
var
  PSa : PSecurityAttributes;
{$IFDEF WINDOWS}
  Sd : TSecurityDescriptor;
  Sa : TSecurityAttributes;
begin
  InitializeSecurityDescriptor(@Sd,SECURITY_DESCRIPTOR_REVISION);
  SetSecurityDescriptorDacl(@Sd,true,nil,false);
  Sa.nLength := SizeOf(Sa);
  Sa.lpSecurityDescriptor := @Sd;
  Sa.bInheritHandle := true;
  PSa := @Sa;
{$ELSE}
  GUID : TGUID;
begin
  PSa:= nil;
{$ENDIF}
  inherited Create;
{$IFDEF WINDOWS}
  FEventHandler := CreateEvent(PSa,false,false,nil);
{$ELSE}
  CreateGuid(GUID);
  FEventWaiting := TEventObject.Create(PSa,false,false,GUIDToString(GUID));
{$ENDIF}
  FOWner := aOwner;
end;

destructor TEventhandlerInterface.Destroy;
begin
{$IFDEF WINDOWS}
  CloseHandle(FEventHandler);
{$ELSE}
  if assigned(FEventWaiting) then FEventWaiting.Free;
{$ENDIF}
  inherited Destroy;
end;

procedure TEventhandlerInterface.eventCallbackFunction(length: short;
  updated: PAnsiChar);
begin
  FOwner.FCriticalSection.Enter;
  try
    if FOwner.FResultBuffer <> nil then
      Move(updated[0], FOwner.FResultBuffer[0], length);
  finally
    FOwner.FCriticalSection.Leave
  end;
//  writeln('Set Event');
  {$IFDEF WINDOWS}
  SetEvent(FEventHandler);
  {$ELSE}
  FEventWaiting.SetEvent;
  {$ENDIF}
end;

procedure TEventhandlerInterface.WaitForEvent;
begin
  {$IFDEF WINDOWS}
  WaitForSingleObject(FEventHandler,INFINITE);
  {$ELSE}
  FEventWaiting.WaitFor(INFINITE);
  {$ENDIF}
//  writeln('Event Wait Ends');
end;

procedure TEventhandlerInterface.CancelWait;
begin
  {$IFDEF WINDOWS}
  SetEvent(FEventHandler);
  {$ELSE}
  FEventWaiting.SetEvent;
  {$ENDIF}
end;


  { TFB25Events }

procedure TFB25Events.CancelEvents(Force: boolean);
begin
  FCriticalSection.Enter;
  try
    if not FInWaitState then Exit;
    with FFirebird25ClientAPI do
      if (Call(isc_Cancel_events( StatusVector, @FDBHandle, @FEventID),false) > 0) and not Force then
        IBDatabaseError;

    FInWaitState := false;
    inherited CancelEvents(Force);
  finally
    FCriticalSection.Leave
  end;
end;

function TFB25Events.GetIEvents: IEvents;
begin
  Result := self;
end;

constructor TFB25Events.Create(DBAttachment: TFB25Attachment; Events: TStrings);
begin
  inherited Create(DBAttachment,DBAttachment,Events);
  FDBHandle := DBAttachment.Handle;
  FFirebird25ClientAPI := DBAttachment.Firebird25ClientAPI;
  OnDatabaseError := FFirebird25ClientAPI.IBDataBaseError;
  FAsyncEventCallback := TEventhandlerInterface.Create(self);
  FEventHandlerThread := TEventHandlerThread.Create(self,FAsyncEventCallback);
end;

destructor TFB25Events.Destroy;
begin
  CancelEvents(true);
  if assigned(FEventHandlerThread) then
    TEventHandlerThread(FEventHandlerThread).Terminate;
  if assigned(FAsyncEventCallback) then
    TEventhandlerInterface(FAsyncEventCallback).Free;
  inherited Destroy;
end;

procedure TFB25Events.AsyncWaitForEvent(EventHandler: TEventHandler);
var callback: pointer;
begin
  FCriticalSection.Enter;
  try
    if FInWaitState then
      IBError(ibxeInEventWait,[nil]);

    FEventHandler := EventHandler;
    callback := @IBEventCallback;
    with FFirebird25ClientAPI do
      Call(isc_que_events( StatusVector, @FDBHandle, @FEventID, FEventBufferLen,
                     FEventBuffer, TISC_CALLBACK(callback), PVoid(FAsyncEventCallback)));
    FInWaitState := true;
  finally
    FCriticalSection.Leave
  end;
end;

procedure TFB25Events.WaitForEvent;
begin
  if FInWaitState then
    IBError(ibxeInEventWait,[nil]);

  FInWaitState := true;
  try
    with FFirebird25ClientAPI do
       Call(isc_wait_for_event(StatusVector,@FDBHandle, FEventBufferlen,FEventBuffer,FResultBuffer));
  finally
    FInWaitState := false;
  end;
end;

end.

Revision:	362
Committed:	Tue Dec 7 13:27:39 2021 UTC (2 years, 4 months ago) by tony
Content type:	text/x-pascal
Original Path:	*ibx/branches/journaling/fbintf/client/2.5/FB25Events.pas*
File size:	10038 byte(s)
Log Message:	initiate test release
#	User	Rev	Content
1	tony	45	(*
2			* Firebird Interface (fbintf). The fbintf components provide a set of
3			* Pascal language bindings for the Firebird API. Although predominantly
4			* a new development they include source code taken from IBX and may be
5			* considered a derived product. This software thus also includes the copyright
6			* notice and license conditions from IBX.
7			*
8			* Except for those parts dervied from IBX, contents of this file are subject
9			* to the Initial Developer's Public License Version 1.0 (the "License"); you
10			* may not use this file except in compliance with the License. You may obtain a
11			* copy of the License here:
12			*
13			* http://www.firebirdsql.org/index.php?op=doc&id=idpl
14			*
15			* Software distributed under the License is distributed on an "AS
16			* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
17			* implied. See the License for the specific language governing rights
18			* and limitations under the License.
19			*
20			* The Initial Developer of the Original Code is Tony Whyman.
21			*
22			* The Original Code is (C) 2016 Tony Whyman, MWA Software
23			* (http://www.mwasoftware.co.uk).
24			*
25			* All Rights Reserved.
26			*
27			* Contributor(s): ______________________________________.
28			*
29			*)
30			{************************************************************************}
31			{ }
32			{ Borland Delphi Visual Component Library }
33			{ InterBase Express core components }
34			{ }
35			{ Copyright (c) 1998-2000 Inprise Corporation }
36			{ }
37			{ InterBase Express is based in part on the product }
38			{ Free IB Components, written by Gregory H. Deatz for }
39			{ Hoagland, Longo, Moran, Dunst & Doukas Company. }
40			{ Free IB Components is used under license. }
41			{ }
42			{ The contents of this file are subject to the InterBase }
43			{ Public License Version 1.0 (the "License"); you may not }
44			{ use this file except in compliance with the License. You }
45			{ may obtain a copy of the License at http://www.Inprise.com/IPL.html }
46			{ Software distributed under the License is distributed on }
47			{ an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either }
48			{ express or implied. See the License for the specific language }
49			{ governing rights and limitations under the License. }
50			{ The Original Code was created by InterBase Software Corporation }
51			{ and its successors. }
52			{ Portions created by Inprise Corporation are Copyright (C) Inprise }
53			{ Corporation. All Rights Reserved. }
54			{ Contributor(s): Jeff Overcash }
55			{ }
56			{ IBX For Lazarus (Firebird Express) }
57			{ Contributor: Tony Whyman, MWA Software http://www.mwasoftware.co.uk }
58			{ Portions created by MWA Software are copyright McCallum Whyman }
59			{ Associates Ltd 2011 - 2015 }
60			{ }
61			{************************************************************************}
62			unit FB25Events;
63	tony	56	{$IFDEF MSWINDOWS}
64			{$DEFINE WINDOWS}
65			{$ENDIF}
66	tony	45
67			{$IFDEF FPC}
68	tony	56	{$mode delphi}
69	tony	45	{$interfaces COM}
70			{$ENDIF}
71
72			interface
73
74			uses
75			{$IFDEF WINDOWS}Windows, {$ENDIF}Classes, SysUtils, IB, FB25ClientAPI, FB25Attachment,
76	tony	216	IBExternals, IBHeader, syncobjs, FBEvents;
77	tony	45
78			type
79			TFB25Events = class;
80
81			{ TEventhandlerInterface }
82
83			TEventhandlerInterface = class
84			private
85			FOwner: TFB25Events;
86			{$IFDEF WINDOWS}
87			{Make direct use of Windows API as TEventObject don't seem to work under
88			Windows!}
89			FEventHandler: THandle;
90			{$ELSE}
91			FEventWaiting: TEventObject;
92			{$ENDIF}
93			public
94			constructor Create(aOwner: TFB25Events);
95			destructor Destroy; override;
96	tony	56	procedure eventCallbackFunction(length: short; updated: PAnsiChar);
97	tony	45	procedure WaitForEvent;
98			procedure CancelWait;
99			end;
100
101			{ TFB25Events }
102
103			TFB25Events = class(TFBEvents,IEvents)
104			private
105			FEventID: ISC_LONG;
106			FDBHandle: TISC_DB_HANDLE;
107			FEventHandlerThread: TObject;
108			FAsyncEventCallback: TEventhandlerInterface;
109	tony	263	FFirebird25ClientAPI: TFB25ClientAPI;
110	tony	45	protected
111			procedure CancelEvents(Force: boolean = false); override;
112			function GetIEvents: IEvents; override;
113			public
114			constructor Create(DBAttachment: TFB25Attachment; Events: TStrings);
115			destructor Destroy; override;
116
117			{IEvents}
118			procedure WaitForEvent;
119	tony	47	procedure AsyncWaitForEvent(EventHandler: TEventHandler); override;
120	tony	45	end;
121
122			implementation
123
124			uses FBMessages;
125
126			type
127
128			{ TEventHandlerThread }
129
130			TEventHandlerThread = class(TThread)
131			private
132			FOwner: TFB25Events;
133			FEventHandler: TEventhandlerInterface;
134			protected
135			procedure Execute; override;
136			public
137			constructor Create(Owner: TFB25Events; EventHandler: TEventhandlerInterface);
138			procedure Terminate;
139			end;
140
141			{ TEventHandlerThread }
142
143			procedure TEventHandlerThread.Execute;
144			begin
145			while not Terminated do
146			begin
147			FEventHandler.WaitForEvent;
148
149			if not Terminated then
150			FOwner.EventSignaled;
151			end;
152			end;
153
154			constructor TEventHandlerThread.Create(Owner: TFB25Events;
155			EventHandler: TEventhandlerInterface);
156			begin
157	tony	56	inherited Create(false);
158	tony	45	FOwner := Owner;
159			FEventHandler := EventHandler;
160			FreeOnTerminate := true;
161			end;
162
163			procedure TEventHandlerThread.Terminate;
164			begin
165			inherited Terminate;
166			FEventHandler.CancelWait;
167			end;
168
169			{This procedure is used for the event call back - note the cdecl }
170
171	tony	56	procedure IBEventCallback( ptr: pointer; length: short; updated: PAnsiChar); cdecl;
172	tony	45	begin
173			if (ptr = nil) or (length = 0) or (updated = nil) then
174			Exit;
175			{ Handle events asynchronously in second thread }
176			TEventhandlerInterface(ptr).eventCallbackFunction(length,updated);
177			end;
178
179			{ TEventhandlerInterface }
180
181			constructor TEventhandlerInterface.Create(aOwner: TFB25Events);
182			var
183			PSa : PSecurityAttributes;
184			{$IFDEF WINDOWS}
185			Sd : TSecurityDescriptor;
186			Sa : TSecurityAttributes;
187			begin
188			InitializeSecurityDescriptor(@Sd,SECURITY_DESCRIPTOR_REVISION);
189			SetSecurityDescriptorDacl(@Sd,true,nil,false);
190			Sa.nLength := SizeOf(Sa);
191			Sa.lpSecurityDescriptor := @Sd;
192			Sa.bInheritHandle := true;
193			PSa := @Sa;
194			{$ELSE}
195			GUID : TGUID;
196			begin
197			PSa:= nil;
198			{$ENDIF}
199			inherited Create;
200			{$IFDEF WINDOWS}
201	tony	47	FEventHandler := CreateEvent(PSa,false,false,nil);
202	tony	45	{$ELSE}
203			CreateGuid(GUID);
204			FEventWaiting := TEventObject.Create(PSa,false,false,GUIDToString(GUID));
205			{$ENDIF}
206			FOWner := aOwner;
207			end;
208
209			destructor TEventhandlerInterface.Destroy;
210			begin
211			{$IFDEF WINDOWS}
212			CloseHandle(FEventHandler);
213			{$ELSE}
214			if assigned(FEventWaiting) then FEventWaiting.Free;
215			{$ENDIF}
216			inherited Destroy;
217			end;
218
219			procedure TEventhandlerInterface.eventCallbackFunction(length: short;
220	tony	56	updated: PAnsiChar);
221	tony	45	begin
222			FOwner.FCriticalSection.Enter;
223			try
224			if FOwner.FResultBuffer <> nil then
225			Move(updated[0], FOwner.FResultBuffer[0], length);
226			finally
227			FOwner.FCriticalSection.Leave
228			end;
229	tony	47	// writeln('Set Event');
230			{$IFDEF WINDOWS}
231			SetEvent(FEventHandler);
232			{$ELSE}
233			FEventWaiting.SetEvent;
234			{$ENDIF}
235	tony	45	end;
236
237			procedure TEventhandlerInterface.WaitForEvent;
238			begin
239			{$IFDEF WINDOWS}
240			WaitForSingleObject(FEventHandler,INFINITE);
241			{$ELSE}
242			FEventWaiting.WaitFor(INFINITE);
243			{$ENDIF}
244	tony	47	// writeln('Event Wait Ends');
245	tony	45	end;
246
247			procedure TEventhandlerInterface.CancelWait;
248			begin
249			{$IFDEF WINDOWS}
250			SetEvent(FEventHandler);
251			{$ELSE}
252			FEventWaiting.SetEvent;
253			{$ENDIF}
254			end;
255
256
257			{ TFB25Events }
258
259			procedure TFB25Events.CancelEvents(Force: boolean);
260			begin
261			FCriticalSection.Enter;
262			try
263			if not FInWaitState then Exit;
264	tony	263	with FFirebird25ClientAPI do
265	tony	45	if (Call(isc_Cancel_events( StatusVector, @FDBHandle, @FEventID),false) > 0) and not Force then
266			IBDatabaseError;
267
268			FInWaitState := false;
269			inherited CancelEvents(Force);
270			finally
271			FCriticalSection.Leave
272			end;
273			end;
274
275			function TFB25Events.GetIEvents: IEvents;
276			begin
277			Result := self;
278			end;
279
280			constructor TFB25Events.Create(DBAttachment: TFB25Attachment; Events: TStrings);
281			begin
282			inherited Create(DBAttachment,DBAttachment,Events);
283			FDBHandle := DBAttachment.Handle;
284	tony	263	FFirebird25ClientAPI := DBAttachment.Firebird25ClientAPI;
285			OnDatabaseError := FFirebird25ClientAPI.IBDataBaseError;
286	tony	45	FAsyncEventCallback := TEventhandlerInterface.Create(self);
287			FEventHandlerThread := TEventHandlerThread.Create(self,FAsyncEventCallback);
288			end;
289
290			destructor TFB25Events.Destroy;
291			begin
292			CancelEvents(true);
293			if assigned(FEventHandlerThread) then
294			TEventHandlerThread(FEventHandlerThread).Terminate;
295			if assigned(FAsyncEventCallback) then
296			TEventhandlerInterface(FAsyncEventCallback).Free;
297			inherited Destroy;
298			end;
299
300			procedure TFB25Events.AsyncWaitForEvent(EventHandler: TEventHandler);
301			var callback: pointer;
302			begin
303			FCriticalSection.Enter;
304			try
305			if FInWaitState then
306			IBError(ibxeInEventWait,[nil]);
307
308			FEventHandler := EventHandler;
309			callback := @IBEventCallback;
310	tony	263	with FFirebird25ClientAPI do
311	tony	45	Call(isc_que_events( StatusVector, @FDBHandle, @FEventID, FEventBufferLen,
312			FEventBuffer, TISC_CALLBACK(callback), PVoid(FAsyncEventCallback)));
313			FInWaitState := true;
314			finally
315			FCriticalSection.Leave
316			end;
317			end;
318
319			procedure TFB25Events.WaitForEvent;
320			begin
321			if FInWaitState then
322			IBError(ibxeInEventWait,[nil]);
323
324			FInWaitState := true;
325			try
326	tony	263	with FFirebird25ClientAPI do
327	tony	45	Call(isc_wait_for_event(StatusVector,@FDBHandle, FEventBufferlen,FEventBuffer,FResultBuffer));
328			finally
329			FInWaitState := false;
330			end;
331			end;
332
333			end.
334