udr/client/FBEvents.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 FBEvents;
{$IFDEF MSWINDOWS} 
{$DEFINE WINDOWS} 
{$ENDIF}

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

interface

uses
  Classes, SysUtils, IB, FBClientAPI, syncobjs, FBActivityMonitor;

type

  { TFBEvents }

  {Firebird Event and Result buffer syntax is:

    record
      version: byte;
      event: array of packed record
        strlen: byte;
        strchars: array of AnsiChar; //no of chars given by strlen
        EventCounts: long;
      end;
    end;

  }

  TFBEvents = class(TActivityReporter)
  private
    FEvents: TStringList;
    FAttachment: IAttachment;
    FEventCounts: TEventCounts;
    FFirebirdClientAPI: TFBClientAPI;
  protected
    FEventBuffer: PByte;
    FEventBufferLen: integer;
    FResultBuffer: PByte;
    FEventHandler: TEventHandler;
    FCriticalSection: TCriticalSection;
    FInWaitState: boolean;
    procedure CreateEventBlock;
    procedure CancelEvents(Force: boolean = false); virtual;
    procedure EventSignaled;
    function GetIEvents: IEvents; virtual; abstract;
    procedure ProcessEventCounts;
  public
    const EPB_version1 = 1;
  public
    constructor Create(DBAttachment: IAttachment; aMonitor: IActivityMonitor; Events: TStrings);
    destructor Destroy; override;

    {IEvents}
    procedure GetEvents(EventNames: TStrings);
    procedure SetEvents(EventNames: TStrings); overload;
    procedure SetEvents(Event: AnsiString); overload;
    procedure Cancel;
    function ExtractEventCounts: TEventCounts;
    function GetAttachment: IAttachment;
    procedure AsyncWaitForEvent(EventHandler: TEventHandler); virtual; abstract;
  end;


implementation

uses FBMessages, IBExternals;

const
  MaxEvents = 15;

{ TFBEvents }

(* Original Firebird 'C' code

SLONG API_ROUTINE_VARARG isc_event_block(UCHAR** event_buffer,
  UCHAR** result_buffer,
  USHORT count, ...)
{
/**************************************
 *
 *      i s c _ e v e n t _ b l o c k
 *
 **************************************
 *
 * Functional description
 *      Create an initialized event parameter block from a
 *      variable number of input arguments.
 *      Return the size of the block.
 *
 *      Return 0 if any error occurs.
 *
 **************************************/
        va_list ptr;

        va_start(ptr, count);

        // calculate length of event parameter block, setting initial length to include version
        // and counts for each argument

        SLONG length = 1;
        USHORT i = count;
        while (i--)
        {
                const char* q = va_arg(ptr, SCHAR * );
                length += static_cast<SLONG>(strlen(q)) + 5;
        }
        va_end(ptr);

        UCHAR* p = *event_buffer = (UCHAR * ) gds__alloc((SLONG) length);
        // FREE: apparently never freed
        if (!*event_buffer)                     // NOMEM:
                return 0;
        if ((*result_buffer = (UCHAR * ) gds__alloc((SLONG) length)) == NULL)
        {
                // NOMEM:
                // FREE: apparently never freed
                gds__free(*event_buffer);
                *event_buffer = NULL;
                return 0;
        }

        // initialize the block with event names and counts

        *p++ = EPB_version1;

        va_start(ptr, count);

        i = count;
        while (i--)
        {
                const char* q = va_arg(ptr, SCHAR * );

                // Strip the blanks from the ends
                const char* end = q + strlen(q);
                while (--end >= q && *end == ' ')
                        ;
                *p++ = end - q + 1;
                while (q <= end)
                        *p++ = *q++;
                *p++ = 0;
                *p++ = 0;
                *p++ = 0;
                *p++ = 0;
        }
        va_end(ptr);

        return static_cast<SLONG>(p - *event_buffer);
}
*)

{CreateEventBlock effectively replaces isc_event_block}

procedure TFBEvents.CreateEventBlock;
var i: integer;
    P: PByte;
begin
  {calculate length of event parameter block, setting initial length to include version
   and counts for each argument}

  FEventBufferLen := 1;
  for i := 0 to FEvents.Count - 1 do
    FEventBufferLen := FEventBufferLen + length(FEvents[i]) + 1 + sizeof(Long);

  with FFirebirdClientAPI do
  begin
    IBAlloc(FEventBuffer,0,FEventBufferLen);
    if FEventBuffer = nil then Exit;
    {$if declared(FillByte)}
    FillByte(FEventBuffer^,FEventBufferLen,0);
    {$else}
    FillChar(FEventBuffer^,FEventBufferLen,0);
    {$ifend}
    IBAlloc(FResultBuffer,0,FEventBufferLen);
    if FResultBuffer = nil then
    begin
      FreeMem(FEventBuffer);
      Exit;
    end;

    P := FEventBuffer;
    P^ := EPB_version1;
    Inc(P);
    SetLength(FEventCounts,FEvents.Count);

    for i := 0 to FEvents.Count - 1 do
    begin
      P^ := Length(FEvents[i]);
      Inc(P);
      Move(FEvents[i][1],P^,Length(FEvents[i]));
      Inc(P,Length(FEvents[i])+sizeof(Long));
      FEventCounts[i].EventName := FEvents[i];
    end;
  end;

{  for i := 0 to FEventBufferLen - 1 do
  write(Format('%x ', [FEventBuffer[i]]));
   writeln;}
end;

procedure TFBEvents.CancelEvents(Force: boolean);
begin
  FEventHandler := nil;
end;

procedure TFBEvents.EventSignaled;
var Handler: TEventHandler;
begin
  Handler := nil;
  FCriticalSection.Enter;
  try
    if not FInWaitState then Exit;
    FInWaitState := false;
    ProcessEventCounts;
    if assigned(FEventHandler)  then
    begin
      Handler := FEventHandler;
      FEventHandler := nil;
    end;
  finally
    FCriticalSection.Leave;
  end;
  if assigned(Handler) then
    Handler(GetIEvents);
end;

(*
  Original Firebird 'C' code for isc_event_counts

void API_ROUTINE isc_event_counts(ULONG* result_vector,
                                                                  SSHORT buffer_length,
                                                                  UCHAR* event_buffer,
                                                                  const UCHAR* result_buffer)
{
/**************************************
 *
 *      g d s _ $ e v e n t _ c o u n t s
 *
 **************************************
 *
 * Functional description
 *      Get the delta between two events in an event
 *      parameter block.  Used to update gds_events
 *      for GPRE support of events.
 *
 **************************************/
        ULONG* vec = result_vector;
        const UCHAR* p = event_buffer;
        const UCHAR* q = result_buffer;
        USHORT length = buffer_length;
        const UCHAR* const end = p + length;

        // analyze the event blocks, getting the delta for each event

        p++;
        q++;
        while (p < end)
        {
                // skip over the event name

                const USHORT i = (USHORT)* p++;
                p += i;
                q += i + 1;

                // get the change in count

                const ULONG initial_count = gds__vax_integer(p, sizeof(SLONG));
                p += sizeof(SLONG);
                const ULONG new_count = gds__vax_integer(q, sizeof(SLONG));
                q += sizeof(SLONG);
                *vec++ = new_count - initial_count;
        }

        // copy over the result to the initial block to prepare
        // for the next call to gds__event_wait

        memcpy(event_buffer, result_buffer, length);
}
*)

{ProcessEventCounts effectively replaces isc_event_counts}

procedure TFBEvents.ProcessEventCounts;

var i: integer;
    P, Q: PByte;
    initial_count: Long;
    new_count: Long;
    len: byte;
begin
  P := FEventBuffer;
  Q := FResultBuffer;
  Inc(P); {skip past version byte}
  Inc(Q);
  for i := 0 to Length(FEventCounts) - 1 do
  with FFirebirdClientAPI do
  begin
    {skip over the event name}
    len := P^;
    P := P + len + 1;
    Q := Q + len + 1; {event name length in P^}
    initial_count := DecodeInteger(P,sizeof(Long));
    Inc(P,sizeof(Long));
    new_count := DecodeInteger(Q,sizeof(Long));
    Inc(Q,sizeof(Long));
    FEventCounts[i].Count := new_count - initial_count;
  end;
  Move(FResultBuffer^,FEventBuffer^,FEventBufferLen);
end;

constructor TFBEvents.Create(DBAttachment: IAttachment;
  aMonitor: IActivityMonitor; Events: TStrings);
begin
  inherited Create(aMonitor);
  FAttachment := DBAttachment;
  FFirebirdClientAPI := DBAttachment.getFirebirdAPI as TFBClientAPI;
  if Events.Count > MaxEvents then
    IBError(ibxeMaximumEvents, [nil]);

  FCriticalSection := TCriticalSection.Create;
  FEvents := TStringList.Create;
  FEvents.Assign(Events);
  CreateEventBlock;
end;

destructor TFBEvents.Destroy;
begin
  if assigned(FCriticalSection) then FCriticalSection.Free;
  if assigned(FEvents) then FEvents.Free;
  with FFirebirdClientAPI do
  begin
    if FEventBuffer <> nil then
      FreeMem( FEventBuffer);
    if FResultBuffer <> nil then
      FreeMem( FResultBuffer);
  end;
  inherited Destroy;
end;

procedure TFBEvents.GetEvents(EventNames: TStrings);
begin
  EventNames.Assign(FEvents)
end;

procedure TFBEvents.SetEvents(EventNames: TStrings);
var i: integer;
begin
  {$ifdef Unix}
  if (EventNames.Count > 0) and not IsMultiThread then
    IBError(ibxeMultiThreadRequired,['Firebird Events Handling']);
  {$endif}
  if EventNames.Text <> FEvents.Text then
  begin
    Cancel;
    for i := 0 to EventNames.Count - 1 do
      FEvents[i] := Trim(EventNames[i]);
    CreateEventBlock;
  end;
end;

procedure TFBEvents.SetEvents(Event: AnsiString);
var S: TStringList;
begin
  S := TStringList.Create;
  try
    S.Add(Event);
    SetEvents(S);
  finally
    S.Free;
  end;
end;

procedure TFBEvents.Cancel;
begin
  if assigned(FEventHandler) then
    CancelEvents;
end;

function TFBEvents.ExtractEventCounts: TEventCounts;
begin
  Result := FEventCounts;
end;

function TFBEvents.GetAttachment: IAttachment;
begin
  Result := FAttachment;
end;

end.

Revision:	371
Committed:	Wed Jan 5 15:21:22 2022 UTC (2 years, 10 months ago) by tony
Content type:	text/x-pascal
File size:	12469 byte(s)
Log Message:	Beta Release 0.1
#	Content
1	(*
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 FBEvents;
63	{$IFDEF MSWINDOWS}
64	{$DEFINE WINDOWS}
65	{$ENDIF}
66
67	{$IFDEF FPC}
68	{$mode delphi}
69	{$interfaces COM}
70	{$ENDIF}
71
72	interface
73
74	uses
75	Classes, SysUtils, IB, FBClientAPI, syncobjs, FBActivityMonitor;
76
77	type
78
79	{ TFBEvents }
80
81	{Firebird Event and Result buffer syntax is:
82
83	record
84	version: byte;
85	event: array of packed record
86	strlen: byte;
87	strchars: array of AnsiChar; //no of chars given by strlen
88	EventCounts: long;
89	end;
90	end;
91
92	}
93
94	TFBEvents = class(TActivityReporter)
95	private
96	FEvents: TStringList;
97	FAttachment: IAttachment;
98	FEventCounts: TEventCounts;
99	FFirebirdClientAPI: TFBClientAPI;
100	protected
101	FEventBuffer: PByte;
102	FEventBufferLen: integer;
103	FResultBuffer: PByte;
104	FEventHandler: TEventHandler;
105	FCriticalSection: TCriticalSection;
106	FInWaitState: boolean;
107	procedure CreateEventBlock;
108	procedure CancelEvents(Force: boolean = false); virtual;
109	procedure EventSignaled;
110	function GetIEvents: IEvents; virtual; abstract;
111	procedure ProcessEventCounts;
112	public
113	const EPB_version1 = 1;
114	public
115	constructor Create(DBAttachment: IAttachment; aMonitor: IActivityMonitor; Events: TStrings);
116	destructor Destroy; override;
117
118	{IEvents}
119	procedure GetEvents(EventNames: TStrings);
120	procedure SetEvents(EventNames: TStrings); overload;
121	procedure SetEvents(Event: AnsiString); overload;
122	procedure Cancel;
123	function ExtractEventCounts: TEventCounts;
124	function GetAttachment: IAttachment;
125	procedure AsyncWaitForEvent(EventHandler: TEventHandler); virtual; abstract;
126	end;
127
128
129	implementation
130
131	uses FBMessages, IBExternals;
132
133	const
134	MaxEvents = 15;
135
136	{ TFBEvents }
137
138	(* Original Firebird 'C' code
139
140	SLONG API_ROUTINE_VARARG isc_event_block(UCHAR** event_buffer,
141	UCHAR** result_buffer,
142	USHORT count, ...)
143	{
144	/**************************************
145	*
146	* i s c _ e v e n t _ b l o c k
147	*
148	**************************************
149	*
150	* Functional description
151	* Create an initialized event parameter block from a
152	* variable number of input arguments.
153	* Return the size of the block.
154	*
155	* Return 0 if any error occurs.
156	*
157	**************************************/
158	va_list ptr;
159
160	va_start(ptr, count);
161
162	// calculate length of event parameter block, setting initial length to include version
163	// and counts for each argument
164
165	SLONG length = 1;
166	USHORT i = count;
167	while (i--)
168	{
169	const char* q = va_arg(ptr, SCHAR * );
170	length += static_cast<SLONG>(strlen(q)) + 5;
171	}
172	va_end(ptr);
173
174	UCHAR* p = event_buffer = (UCHAR ) gds__alloc((SLONG) length);
175	// FREE: apparently never freed
176	if (!*event_buffer) // NOMEM:
177	return 0;
178	if ((result_buffer = (UCHAR ) gds__alloc((SLONG) length)) == NULL)
179	{
180	// NOMEM:
181	// FREE: apparently never freed
182	gds__free(*event_buffer);
183	*event_buffer = NULL;
184	return 0;
185	}
186
187	// initialize the block with event names and counts
188
189	*p++ = EPB_version1;
190
191	va_start(ptr, count);
192
193	i = count;
194	while (i--)
195	{
196	const char* q = va_arg(ptr, SCHAR * );
197
198	// Strip the blanks from the ends
199	const char* end = q + strlen(q);
200	while (--end >= q && *end == ' ')
201	;
202	*p++ = end - q + 1;
203	while (q <= end)
204	p++ = q++;
205	*p++ = 0;
206	*p++ = 0;
207	*p++ = 0;
208	*p++ = 0;
209	}
210	va_end(ptr);
211
212	return static_cast<SLONG>(p - *event_buffer);
213	}
214	*)
215
216	{CreateEventBlock effectively replaces isc_event_block}
217
218	procedure TFBEvents.CreateEventBlock;
219	var i: integer;
220	P: PByte;
221	begin
222	{calculate length of event parameter block, setting initial length to include version
223	and counts for each argument}
224
225	FEventBufferLen := 1;
226	for i := 0 to FEvents.Count - 1 do
227	FEventBufferLen := FEventBufferLen + length(FEvents[i]) + 1 + sizeof(Long);
228
229	with FFirebirdClientAPI do
230	begin
231	IBAlloc(FEventBuffer,0,FEventBufferLen);
232	if FEventBuffer = nil then Exit;
233	{$if declared(FillByte)}
234	FillByte(FEventBuffer^,FEventBufferLen,0);
235	{$else}
236	FillChar(FEventBuffer^,FEventBufferLen,0);
237	{$ifend}
238	IBAlloc(FResultBuffer,0,FEventBufferLen);
239	if FResultBuffer = nil then
240	begin
241	FreeMem(FEventBuffer);
242	Exit;
243	end;
244
245	P := FEventBuffer;
246	P^ := EPB_version1;
247	Inc(P);
248	SetLength(FEventCounts,FEvents.Count);
249
250	for i := 0 to FEvents.Count - 1 do
251	begin
252	P^ := Length(FEvents[i]);
253	Inc(P);
254	Move(FEvents[i][1],P^,Length(FEvents[i]));
255	Inc(P,Length(FEvents[i])+sizeof(Long));
256	FEventCounts[i].EventName := FEvents[i];
257	end;
258	end;
259
260	{ for i := 0 to FEventBufferLen - 1 do
261	write(Format('%x ', [FEventBuffer[i]]));
262	writeln;}
263	end;
264
265	procedure TFBEvents.CancelEvents(Force: boolean);
266	begin
267	FEventHandler := nil;
268	end;
269
270	procedure TFBEvents.EventSignaled;
271	var Handler: TEventHandler;
272	begin
273	Handler := nil;
274	FCriticalSection.Enter;
275	try
276	if not FInWaitState then Exit;
277	FInWaitState := false;
278	ProcessEventCounts;
279	if assigned(FEventHandler) then
280	begin
281	Handler := FEventHandler;
282	FEventHandler := nil;
283	end;
284	finally
285	FCriticalSection.Leave;
286	end;
287	if assigned(Handler) then
288	Handler(GetIEvents);
289	end;
290
291	(*
292	Original Firebird 'C' code for isc_event_counts
293
294	void API_ROUTINE isc_event_counts(ULONG* result_vector,
295	SSHORT buffer_length,
296	UCHAR* event_buffer,
297	const UCHAR* result_buffer)
298	{
299	/**************************************
300	*
301	* g d s _ $ e v e n t _ c o u n t s
302	*
303	**************************************
304	*
305	* Functional description
306	* Get the delta between two events in an event
307	* parameter block. Used to update gds_events
308	* for GPRE support of events.
309	*
310	**************************************/
311	ULONG* vec = result_vector;
312	const UCHAR* p = event_buffer;
313	const UCHAR* q = result_buffer;
314	USHORT length = buffer_length;
315	const UCHAR* const end = p + length;
316
317	// analyze the event blocks, getting the delta for each event
318
319	p++;
320	q++;
321	while (p < end)
322	{
323	// skip over the event name
324
325	const USHORT i = (USHORT)* p++;
326	p += i;
327	q += i + 1;
328
329	// get the change in count
330
331	const ULONG initial_count = gds__vax_integer(p, sizeof(SLONG));
332	p += sizeof(SLONG);
333	const ULONG new_count = gds__vax_integer(q, sizeof(SLONG));
334	q += sizeof(SLONG);
335	*vec++ = new_count - initial_count;
336	}
337
338	// copy over the result to the initial block to prepare
339	// for the next call to gds__event_wait
340
341	memcpy(event_buffer, result_buffer, length);
342	}
343	*)
344
345	{ProcessEventCounts effectively replaces isc_event_counts}
346
347	procedure TFBEvents.ProcessEventCounts;
348
349	var i: integer;
350	P, Q: PByte;
351	initial_count: Long;
352	new_count: Long;
353	len: byte;
354	begin
355	P := FEventBuffer;
356	Q := FResultBuffer;
357	Inc(P); {skip past version byte}
358	Inc(Q);
359	for i := 0 to Length(FEventCounts) - 1 do
360	with FFirebirdClientAPI do
361	begin
362	{skip over the event name}
363	len := P^;
364	P := P + len + 1;
365	Q := Q + len + 1; {event name length in P^}
366	initial_count := DecodeInteger(P,sizeof(Long));
367	Inc(P,sizeof(Long));
368	new_count := DecodeInteger(Q,sizeof(Long));
369	Inc(Q,sizeof(Long));
370	FEventCounts[i].Count := new_count - initial_count;
371	end;
372	Move(FResultBuffer^,FEventBuffer^,FEventBufferLen);
373	end;
374
375	constructor TFBEvents.Create(DBAttachment: IAttachment;
376	aMonitor: IActivityMonitor; Events: TStrings);
377	begin
378	inherited Create(aMonitor);
379	FAttachment := DBAttachment;
380	FFirebirdClientAPI := DBAttachment.getFirebirdAPI as TFBClientAPI;
381	if Events.Count > MaxEvents then
382	IBError(ibxeMaximumEvents, [nil]);
383
384	FCriticalSection := TCriticalSection.Create;
385	FEvents := TStringList.Create;
386	FEvents.Assign(Events);
387	CreateEventBlock;
388	end;
389
390	destructor TFBEvents.Destroy;
391	begin
392	if assigned(FCriticalSection) then FCriticalSection.Free;
393	if assigned(FEvents) then FEvents.Free;
394	with FFirebirdClientAPI do
395	begin
396	if FEventBuffer <> nil then
397	FreeMem( FEventBuffer);
398	if FResultBuffer <> nil then
399	FreeMem( FResultBuffer);
400	end;
401	inherited Destroy;
402	end;
403
404	procedure TFBEvents.GetEvents(EventNames: TStrings);
405	begin
406	EventNames.Assign(FEvents)
407	end;
408
409	procedure TFBEvents.SetEvents(EventNames: TStrings);
410	var i: integer;
411	begin
412	{$ifdef Unix}
413	if (EventNames.Count > 0) and not IsMultiThread then
414	IBError(ibxeMultiThreadRequired,['Firebird Events Handling']);
415	{$endif}
416	if EventNames.Text <> FEvents.Text then
417	begin
418	Cancel;
419	for i := 0 to EventNames.Count - 1 do
420	FEvents[i] := Trim(EventNames[i]);
421	CreateEventBlock;
422	end;
423	end;
424
425	procedure TFBEvents.SetEvents(Event: AnsiString);
426	var S: TStringList;
427	begin
428	S := TStringList.Create;
429	try
430	S.Add(Event);
431	SetEvents(S);
432	finally
433	S.Free;
434	end;
435	end;
436
437	procedure TFBEvents.Cancel;
438	begin
439	if assigned(FEventHandler) then
440	CancelEvents;
441	end;
442
443	function TFBEvents.ExtractEventCounts: TEventCounts;
444	begin
445	Result := FEventCounts;
446	end;
447
448	function TFBEvents.GetAttachment: IAttachment;
449	begin
450	Result := FAttachment;
451	end;
452
453	end.
454