fbintf/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
    FConnectionCodePage: TSystemCodePage;
    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;
    property ConnectionCodePage: TSystemCodePage read FConnectionCodePage;

    {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
  begin
    FreeMem( FEventBuffer);
    FEventBuffer := nil;
  end;
  if FResultBuffer <> nil then
  begin
    FreeMem( FResultBuffer);
    FResultBuffer := nil;
  end;

  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
      FreeMem(FEventBuffer);
      FEventBuffer := nil;
      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;
  FConnectionCodePage := DBAttachment.GetCodePage;
  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:	421
Committed:	Sat Oct 21 14:22:28 2023 UTC (6 months, 1 week ago) by tony
Content type:	text/x-pascal
File size:	13035 byte(s)
Log Message:	Release 2.6.3 Merged
#	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	FConnectionCodePage: TSystemCodePage;
97	FEvents: TStringList;
98	FAttachment: IAttachment;
99	FEventCounts: TEventCounts;
100	FFirebirdClientAPI: TFBClientAPI;
101	protected
102	FEventBuffer: PByte;
103	FEventBufferLen: integer;
104	FResultBuffer: PByte;
105	FEventHandler: TEventHandler;
106	FCriticalSection: TCriticalSection;
107	FInWaitState: boolean;
108	procedure CreateEventBlock;
109	procedure CancelEvents(Force: boolean = false); virtual;
110	procedure EventSignaled;
111	function GetIEvents: IEvents; virtual; abstract;
112	function ProcessEventCounts: boolean;
113	public
114	const EPB_version1 = 1;
115	public
116	constructor Create(DBAttachment: IAttachment; aMonitor: IActivityMonitor; Events: TStrings);
117	destructor Destroy; override;
118	property ConnectionCodePage: TSystemCodePage read FConnectionCodePage;
119
120	{IEvents}
121	procedure GetEvents(EventNames: TStrings);
122	procedure SetEvents(EventNames: TStrings); overload;
123	procedure SetEvents(Event: string); overload;
124	procedure Cancel;
125	function ExtractEventCounts: TEventCounts;
126	function GetAttachment: IAttachment;
127	procedure AsyncWaitForEvent(EventHandler: TEventHandler); virtual; abstract;
128	procedure WaitForEvent; virtual; abstract;
129	end;
130
131
132	implementation
133
134	uses FBMessages, IBExternals;
135
136	const
137	MaxEvents = 15;
138
139	{ TFBEvents }
140
141	(* Original Firebird 'C' code
142
143	SLONG API_ROUTINE_VARARG isc_event_block(UCHAR** event_buffer,
144	UCHAR** result_buffer,
145	USHORT count, ...)
146	{
147	/**************************************
148	*
149	* i s c _ e v e n t _ b l o c k
150	*
151	**************************************
152	*
153	* Functional description
154	* Create an initialized event parameter block from a
155	* variable number of input arguments.
156	* Return the size of the block.
157	*
158	* Return 0 if any error occurs.
159	*
160	**************************************/
161	va_list ptr;
162
163	va_start(ptr, count);
164
165	// calculate length of event parameter block, setting initial length to include version
166	// and counts for each argument
167
168	SLONG length = 1;
169	USHORT i = count;
170	while (i--)
171	{
172	const char* q = va_arg(ptr, SCHAR * );
173	length += static_cast<SLONG>(strlen(q)) + 5;
174	}
175	va_end(ptr);
176
177	UCHAR* p = event_buffer = (UCHAR ) gds__alloc((SLONG) length);
178	// FREE: apparently never freed
179	if (!*event_buffer) // NOMEM:
180	return 0;
181	if ((result_buffer = (UCHAR ) gds__alloc((SLONG) length)) == NULL)
182	{
183	// NOMEM:
184	// FREE: apparently never freed
185	gds__free(*event_buffer);
186	*event_buffer = NULL;
187	return 0;
188	}
189
190	// initialize the block with event names and counts
191
192	*p++ = EPB_version1;
193
194	va_start(ptr, count);
195
196	i = count;
197	while (i--)
198	{
199	const char* q = va_arg(ptr, SCHAR * );
200
201	// Strip the blanks from the ends
202	const char* end = q + strlen(q);
203	while (--end >= q && *end == ' ')
204	;
205	*p++ = end - q + 1;
206	while (q <= end)
207	p++ = q++;
208	*p++ = 0;
209	*p++ = 0;
210	*p++ = 0;
211	*p++ = 0;
212	}
213	va_end(ptr);
214
215	return static_cast<SLONG>(p - *event_buffer);
216	}
217	*)
218
219	{CreateEventBlock effectively replaces isc_event_block}
220
221	procedure TFBEvents.CreateEventBlock;
222	var i: integer;
223	P: PByte;
224	var s: Ansistring;
225	begin
226	{calculate length of event parameter block, setting initial length to include version
227	and counts for each argument}
228
229	if FEventBuffer <> nil then
230	begin
231	FreeMem( FEventBuffer);
232	FEventBuffer := nil;
233	end;
234	if FResultBuffer <> nil then
235	begin
236	FreeMem( FResultBuffer);
237	FResultBuffer := nil;
238	end;
239
240	FEventBufferLen := 1;
241	for i := 0 to FEvents.Count - 1 do
242	begin
243	s := FEvents[i];
244	FEventBufferLen := FEventBufferLen + length(s) + 1 + sizeof(Long);
245	end;
246
247	with FFirebirdClientAPI do
248	begin
249	IBAlloc(FEventBuffer,0,FEventBufferLen);
250	if FEventBuffer = nil then Exit;
251	FillChar(FEventBuffer^,FEventBufferLen,0);
252	IBAlloc(FResultBuffer,0,FEventBufferLen);
253	if FResultBuffer = nil then
254	begin
255	FreeMem(FEventBuffer);
256	FEventBuffer := nil;
257	Exit;
258	end;
259	FillChar(FResultBuffer^,FEventBufferLen,0);
260
261	P := FEventBuffer;
262	P^ := EPB_version1;
263	Inc(P);
264	SetLength(FEventCounts,FEvents.Count);
265
266	for i := 0 to FEvents.Count - 1 do
267	begin
268	s := FEvents[i];
269	P^ := Length(s);
270	Inc(P);
271	Move(s[1],P^,Length(s));
272	Inc(P,Length(s)+sizeof(Long));
273	FEventCounts[i].EventName := s;
274	end;
275	end;
276
277	{ for i := 0 to FEventBufferLen - 1 do
278	write(Format('%x ', [FEventBuffer[i]]));
279	writeln; }
280	end;
281
282	procedure TFBEvents.CancelEvents(Force: boolean);
283	begin
284	FEventHandler := nil;
285	end;
286
287	procedure TFBEvents.EventSignaled;
288	var Handler: TEventHandler;
289	begin
290	Handler := nil;
291	FCriticalSection.Enter;
292	try
293	if not FInWaitState then Exit;
294	if ProcessEventCounts and assigned(FEventHandler) then
295	begin
296	Handler := FEventHandler;
297	FEventHandler := nil;
298	FInWaitState := false;
299	end;
300	finally
301	FCriticalSection.Leave;
302	end;
303	if assigned(Handler) then
304	Handler(GetIEvents);
305	end;
306
307	(*
308	Original Firebird 'C' code for isc_event_counts
309
310	void API_ROUTINE isc_event_counts(ULONG* result_vector,
311	SSHORT buffer_length,
312	UCHAR* event_buffer,
313	const UCHAR* result_buffer)
314	{
315	/**************************************
316	*
317	* g d s _ $ e v e n t _ c o u n t s
318	*
319	**************************************
320	*
321	* Functional description
322	* Get the delta between two events in an event
323	* parameter block. Used to update gds_events
324	* for GPRE support of events.
325	*
326	**************************************/
327	ULONG* vec = result_vector;
328	const UCHAR* p = event_buffer;
329	const UCHAR* q = result_buffer;
330	USHORT length = buffer_length;
331	const UCHAR* const end = p + length;
332
333	// analyze the event blocks, getting the delta for each event
334
335	p++;
336	q++;
337	while (p < end)
338	{
339	// skip over the event name
340
341	const USHORT i = (USHORT)* p++;
342	p += i;
343	q += i + 1;
344
345	// get the change in count
346
347	const ULONG initial_count = gds__vax_integer(p, sizeof(SLONG));
348	p += sizeof(SLONG);
349	const ULONG new_count = gds__vax_integer(q, sizeof(SLONG));
350	q += sizeof(SLONG);
351	*vec++ = new_count - initial_count;
352	}
353
354	// copy over the result to the initial block to prepare
355	// for the next call to gds__event_wait
356
357	memcpy(event_buffer, result_buffer, length);
358	}
359	*)
360
361	{ProcessEventCounts effectively replaces isc_event_counts}
362
363	function TFBEvents.ProcessEventCounts: boolean;
364
365	var i: integer;
366	P, Q: PByte;
367	initial_count: Long;
368	new_count: Long;
369	len: byte;
370	begin
371	Result := false;
372	P := FEventBuffer;
373	Q := FResultBuffer;
374	Inc(P); {skip past version byte}
375	Inc(Q);
376	for i := 0 to Length(FEventCounts) - 1 do
377	with FFirebirdClientAPI do
378	begin
379	{skip over the event name}
380	len := P^;
381	P := P + len + 1;
382	Q := Q + len + 1; {event name length in P^}
383	initial_count := DecodeInteger(P,sizeof(Long));
384	Inc(P,sizeof(Long));
385	new_count := DecodeInteger(Q,sizeof(Long));
386	Inc(Q,sizeof(Long));
387	FEventCounts[i].Count := new_count - initial_count;
388	if FEventCounts[i].Count > 0 then
389	Result := true;
390	// writeln('Event Count[',i,'] = ',FEventCounts[i].Count);
391	end;
392	Move(FResultBuffer^,FEventBuffer^,FEventBufferLen);
393	end;
394
395	constructor TFBEvents.Create(DBAttachment: IAttachment;
396	aMonitor: IActivityMonitor; Events: TStrings);
397	begin
398	inherited Create(aMonitor);
399	FAttachment := DBAttachment;
400	FFirebirdClientAPI := DBAttachment.getFirebirdAPI as TFBClientAPI;
401	FConnectionCodePage := DBAttachment.GetCodePage;
402	if Events.Count > MaxEvents then
403	IBError(ibxeMaximumEvents, [nil]);
404
405	FCriticalSection := TCriticalSection.Create;
406	FEvents := TStringList.Create;
407	FEvents.Assign(Events);
408	CreateEventBlock;
409	end;
410
411	destructor TFBEvents.Destroy;
412	begin
413	if assigned(FCriticalSection) then FCriticalSection.Free;
414	if assigned(FEvents) then FEvents.Free;
415	with FFirebirdClientAPI do
416	begin
417	if FEventBuffer <> nil then
418	FreeMem( FEventBuffer);
419	if FResultBuffer <> nil then
420	FreeMem( FResultBuffer);
421	end;
422	inherited Destroy;
423	end;
424
425	procedure TFBEvents.GetEvents(EventNames: TStrings);
426	begin
427	EventNames.Assign(FEvents)
428	end;
429
430	procedure TFBEvents.SetEvents(EventNames: TStrings);
431	var i: integer;
432	begin
433	{$ifdef Unix}
434	if (EventNames.Count > 0) and not IsMultiThread then
435	IBError(ibxeMultiThreadRequired,['Firebird Events Handling']);
436	{$endif}
437	if EventNames.Text <> FEvents.Text then
438	begin
439	Cancel;
440	for i := 0 to EventNames.Count - 1 do
441	FEvents[i] := Trim(EventNames[i]);
442	CreateEventBlock;
443	end;
444	end;
445
446	procedure TFBEvents.SetEvents(Event: string);
447	var S: TStringList;
448	begin
449	S := TStringList.Create;
450	try
451	S.Add(Event);
452	SetEvents(S);
453	finally
454	S.Free;
455	end;
456	end;
457
458	procedure TFBEvents.Cancel;
459	begin
460	if assigned(FEventHandler) then
461	CancelEvents;
462	end;
463
464	function TFBEvents.ExtractEventCounts: TEventCounts;
465	begin
466	Result := FEventCounts;
467	end;
468
469	function TFBEvents.GetAttachment: IAttachment;
470	begin
471	Result := FAttachment;
472	end;
473
474	end.
475