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;
    function ProcessEventCounts: boolean;
  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: string); overload;
    procedure Cancel;
    function ExtractEventCounts: TEventCounts;
    function GetAttachment: IAttachment;
    procedure AsyncWaitForEvent(EventHandler: TEventHandler); virtual; abstract;
    procedure WaitForEvent; 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;
    var s: Ansistring;
begin
  {calculate length of event parameter block, setting initial length to include version
   and counts for each argument}

   if FEventBuffer <> nil then FreeAndNil(FEventBuffer);
   if FResultBuffer <> nil then FreeAndNil(FResultBuffer);

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

  with FFirebirdClientAPI do
  begin
    IBAlloc(FEventBuffer,0,FEventBufferLen);
    if FEventBuffer = nil then Exit;
    FillChar(FEventBuffer^,FEventBufferLen,0);
    IBAlloc(FResultBuffer,0,FEventBufferLen);
    if FResultBuffer = nil then
    begin
      FreeAndNil(FEventBuffer);
      Exit;
    end;
    FillChar(FResultBuffer^,FEventBufferLen,0);

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

    for i := 0 to FEvents.Count - 1 do
    begin
      s := FEvents[i];
      P^ := Length(s);
      Inc(P);
      Move(s[1],P^,Length(s));
      Inc(P,Length(s)+sizeof(Long));
      FEventCounts[i].EventName := s;
    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;
    if ProcessEventCounts and assigned(FEventHandler)  then
    begin
      Handler := FEventHandler;
      FEventHandler := nil;
      FInWaitState := false;
    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}

function TFBEvents.ProcessEventCounts: boolean;

var i: integer;
    P, Q: PByte;
    initial_count: Long;
    new_count: Long;
    len: byte;
begin
  Result := false;
  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;
    if FEventCounts[i].Count > 0 then
      Result := true;
  //  writeln('Event Count[',i,'] = ',FEventCounts[i].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: string);
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:	381
Committed:	Sat Jan 15 00:06:22 2022 UTC (2 years, 3 months ago) by tony
Content type:	text/x-pascal
File size:	12760 byte(s)
Log Message:	Release Candidate 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	function ProcessEventCounts: boolean;
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: string); overload;
122	procedure Cancel;
123	function ExtractEventCounts: TEventCounts;
124	function GetAttachment: IAttachment;
125	procedure AsyncWaitForEvent(EventHandler: TEventHandler); virtual; abstract;
126	procedure WaitForEvent; virtual; abstract;
127	end;
128
129
130	implementation
131
132	uses FBMessages, IBExternals;
133
134	const
135	MaxEvents = 15;
136
137	{ TFBEvents }
138
139	(* Original Firebird 'C' code
140
141	SLONG API_ROUTINE_VARARG isc_event_block(UCHAR** event_buffer,
142	UCHAR** result_buffer,
143	USHORT count, ...)
144	{
145	/**************************************
146	*
147	* i s c _ e v e n t _ b l o c k
148	*
149	**************************************
150	*
151	* Functional description
152	* Create an initialized event parameter block from a
153	* variable number of input arguments.
154	* Return the size of the block.
155	*
156	* Return 0 if any error occurs.
157	*
158	**************************************/
159	va_list ptr;
160
161	va_start(ptr, count);
162
163	// calculate length of event parameter block, setting initial length to include version
164	// and counts for each argument
165
166	SLONG length = 1;
167	USHORT i = count;
168	while (i--)
169	{
170	const char* q = va_arg(ptr, SCHAR * );
171	length += static_cast<SLONG>(strlen(q)) + 5;
172	}
173	va_end(ptr);
174
175	UCHAR* p = event_buffer = (UCHAR ) gds__alloc((SLONG) length);
176	// FREE: apparently never freed
177	if (!*event_buffer) // NOMEM:
178	return 0;
179	if ((result_buffer = (UCHAR ) gds__alloc((SLONG) length)) == NULL)
180	{
181	// NOMEM:
182	// FREE: apparently never freed
183	gds__free(*event_buffer);
184	*event_buffer = NULL;
185	return 0;
186	}
187
188	// initialize the block with event names and counts
189
190	*p++ = EPB_version1;
191
192	va_start(ptr, count);
193
194	i = count;
195	while (i--)
196	{
197	const char* q = va_arg(ptr, SCHAR * );
198
199	// Strip the blanks from the ends
200	const char* end = q + strlen(q);
201	while (--end >= q && *end == ' ')
202	;
203	*p++ = end - q + 1;
204	while (q <= end)
205	p++ = q++;
206	*p++ = 0;
207	*p++ = 0;
208	*p++ = 0;
209	*p++ = 0;
210	}
211	va_end(ptr);
212
213	return static_cast<SLONG>(p - *event_buffer);
214	}
215	*)
216
217	{CreateEventBlock effectively replaces isc_event_block}
218
219	procedure TFBEvents.CreateEventBlock;
220	var i: integer;
221	P: PByte;
222	var s: Ansistring;
223	begin
224	{calculate length of event parameter block, setting initial length to include version
225	and counts for each argument}
226
227	if FEventBuffer <> nil then FreeAndNil(FEventBuffer);
228	if FResultBuffer <> nil then FreeAndNil(FResultBuffer);
229
230	FEventBufferLen := 1;
231	for i := 0 to FEvents.Count - 1 do
232	begin
233	s := FEvents[i];
234	FEventBufferLen := FEventBufferLen + length(s) + 1 + sizeof(Long);
235	end;
236
237	with FFirebirdClientAPI do
238	begin
239	IBAlloc(FEventBuffer,0,FEventBufferLen);
240	if FEventBuffer = nil then Exit;
241	FillChar(FEventBuffer^,FEventBufferLen,0);
242	IBAlloc(FResultBuffer,0,FEventBufferLen);
243	if FResultBuffer = nil then
244	begin
245	FreeAndNil(FEventBuffer);
246	Exit;
247	end;
248	FillChar(FResultBuffer^,FEventBufferLen,0);
249
250	P := FEventBuffer;
251	P^ := EPB_version1;
252	Inc(P);
253	SetLength(FEventCounts,FEvents.Count);
254
255	for i := 0 to FEvents.Count - 1 do
256	begin
257	s := FEvents[i];
258	P^ := Length(s);
259	Inc(P);
260	Move(s[1],P^,Length(s));
261	Inc(P,Length(s)+sizeof(Long));
262	FEventCounts[i].EventName := s;
263	end;
264	end;
265
266	{ for i := 0 to FEventBufferLen - 1 do
267	write(Format('%x ', [FEventBuffer[i]]));
268	writeln; }
269	end;
270
271	procedure TFBEvents.CancelEvents(Force: boolean);
272	begin
273	FEventHandler := nil;
274	end;
275
276	procedure TFBEvents.EventSignaled;
277	var Handler: TEventHandler;
278	begin
279	Handler := nil;
280	FCriticalSection.Enter;
281	try
282	if not FInWaitState then Exit;
283	if ProcessEventCounts and assigned(FEventHandler) then
284	begin
285	Handler := FEventHandler;
286	FEventHandler := nil;
287	FInWaitState := false;
288	end;
289	finally
290	FCriticalSection.Leave;
291	end;
292	if assigned(Handler) then
293	Handler(GetIEvents);
294	end;
295
296	(*
297	Original Firebird 'C' code for isc_event_counts
298
299	void API_ROUTINE isc_event_counts(ULONG* result_vector,
300	SSHORT buffer_length,
301	UCHAR* event_buffer,
302	const UCHAR* result_buffer)
303	{
304	/**************************************
305	*
306	* g d s _ $ e v e n t _ c o u n t s
307	*
308	**************************************
309	*
310	* Functional description
311	* Get the delta between two events in an event
312	* parameter block. Used to update gds_events
313	* for GPRE support of events.
314	*
315	**************************************/
316	ULONG* vec = result_vector;
317	const UCHAR* p = event_buffer;
318	const UCHAR* q = result_buffer;
319	USHORT length = buffer_length;
320	const UCHAR* const end = p + length;
321
322	// analyze the event blocks, getting the delta for each event
323
324	p++;
325	q++;
326	while (p < end)
327	{
328	// skip over the event name
329
330	const USHORT i = (USHORT)* p++;
331	p += i;
332	q += i + 1;
333
334	// get the change in count
335
336	const ULONG initial_count = gds__vax_integer(p, sizeof(SLONG));
337	p += sizeof(SLONG);
338	const ULONG new_count = gds__vax_integer(q, sizeof(SLONG));
339	q += sizeof(SLONG);
340	*vec++ = new_count - initial_count;
341	}
342
343	// copy over the result to the initial block to prepare
344	// for the next call to gds__event_wait
345
346	memcpy(event_buffer, result_buffer, length);
347	}
348	*)
349
350	{ProcessEventCounts effectively replaces isc_event_counts}
351
352	function TFBEvents.ProcessEventCounts: boolean;
353
354	var i: integer;
355	P, Q: PByte;
356	initial_count: Long;
357	new_count: Long;
358	len: byte;
359	begin
360	Result := false;
361	P := FEventBuffer;
362	Q := FResultBuffer;
363	Inc(P); {skip past version byte}
364	Inc(Q);
365	for i := 0 to Length(FEventCounts) - 1 do
366	with FFirebirdClientAPI do
367	begin
368	{skip over the event name}
369	len := P^;
370	P := P + len + 1;
371	Q := Q + len + 1; {event name length in P^}
372	initial_count := DecodeInteger(P,sizeof(Long));
373	Inc(P,sizeof(Long));
374	new_count := DecodeInteger(Q,sizeof(Long));
375	Inc(Q,sizeof(Long));
376	FEventCounts[i].Count := new_count - initial_count;
377	if FEventCounts[i].Count > 0 then
378	Result := true;
379	// writeln('Event Count[',i,'] = ',FEventCounts[i].Count);
380	end;
381	Move(FResultBuffer^,FEventBuffer^,FEventBufferLen);
382	end;
383
384	constructor TFBEvents.Create(DBAttachment: IAttachment;
385	aMonitor: IActivityMonitor; Events: TStrings);
386	begin
387	inherited Create(aMonitor);
388	FAttachment := DBAttachment;
389	FFirebirdClientAPI := DBAttachment.getFirebirdAPI as TFBClientAPI;
390	if Events.Count > MaxEvents then
391	IBError(ibxeMaximumEvents, [nil]);
392
393	FCriticalSection := TCriticalSection.Create;
394	FEvents := TStringList.Create;
395	FEvents.Assign(Events);
396	CreateEventBlock;
397	end;
398
399	destructor TFBEvents.Destroy;
400	begin
401	if assigned(FCriticalSection) then FCriticalSection.Free;
402	if assigned(FEvents) then FEvents.Free;
403	with FFirebirdClientAPI do
404	begin
405	if FEventBuffer <> nil then
406	FreeMem( FEventBuffer);
407	if FResultBuffer <> nil then
408	FreeMem( FResultBuffer);
409	end;
410	inherited Destroy;
411	end;
412
413	procedure TFBEvents.GetEvents(EventNames: TStrings);
414	begin
415	EventNames.Assign(FEvents)
416	end;
417
418	procedure TFBEvents.SetEvents(EventNames: TStrings);
419	var i: integer;
420	begin
421	{$ifdef Unix}
422	if (EventNames.Count > 0) and not IsMultiThread then
423	IBError(ibxeMultiThreadRequired,['Firebird Events Handling']);
424	{$endif}
425	if EventNames.Text <> FEvents.Text then
426	begin
427	Cancel;
428	for i := 0 to EventNames.Count - 1 do
429	FEvents[i] := Trim(EventNames[i]);
430	CreateEventBlock;
431	end;
432	end;
433
434	procedure TFBEvents.SetEvents(Event: string);
435	var S: TStringList;
436	begin
437	S := TStringList.Create;
438	try
439	S.Add(Event);
440	SetEvents(S);
441	finally
442	S.Free;
443	end;
444	end;
445
446	procedure TFBEvents.Cancel;
447	begin
448	if assigned(FEventHandler) then
449	CancelEvents;
450	end;
451
452	function TFBEvents.ExtractEventCounts: TEventCounts;
453	begin
454	Result := FEventCounts;
455	end;
456
457	function TFBEvents.GetAttachment: IAttachment;
458	begin
459	Result := FAttachment;
460	end;
461
462	end.
463