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(*
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* Firebird Interface (fbintf). The fbintf components provide a set of
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* Pascal language bindings for the Firebird API. Although predominantly
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* a new development they include source code taken from IBX and may be
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* considered a derived product. This software thus also includes the copyright
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* notice and license conditions from IBX.
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*
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* Except for those parts dervied from IBX, contents of this file are subject
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* to the Initial Developer's Public License Version 1.0 (the "License"); you
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* may not use this file except in compliance with the License. You may obtain a
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* copy of the License here:
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*
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* http://www.firebirdsql.org/index.php?op=doc&id=idpl
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*
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* Software distributed under the License is distributed on an "AS
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* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
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* implied. See the License for the specific language governing rights
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* and limitations under the License.
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*
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* The Initial Developer of the Original Code is Tony Whyman.
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*
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* The Original Code is (C) 2016 Tony Whyman, MWA Software
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* (http://www.mwasoftware.co.uk).
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*
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* All Rights Reserved.
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*
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* Contributor(s): ______________________________________.
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*
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*)
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{************************************************************************}
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{ }
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{ Borland Delphi Visual Component Library }
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{ InterBase Express core components }
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{ }
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{ Copyright (c) 1998-2000 Inprise Corporation }
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{ }
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{ InterBase Express is based in part on the product }
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{ Free IB Components, written by Gregory H. Deatz for }
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{ Hoagland, Longo, Moran, Dunst & Doukas Company. }
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{ Free IB Components is used under license. }
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{ }
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{ The contents of this file are subject to the InterBase }
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{ Public License Version 1.0 (the "License"); you may not }
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{ use this file except in compliance with the License. You }
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{ may obtain a copy of the License at http://www.Inprise.com/IPL.html }
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{ Software distributed under the License is distributed on }
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{ an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either }
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{ express or implied. See the License for the specific language }
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{ governing rights and limitations under the License. }
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{ The Original Code was created by InterBase Software Corporation }
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{ and its successors. }
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{ Portions created by Inprise Corporation are Copyright (C) Inprise }
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{ Corporation. All Rights Reserved. }
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{ Contributor(s): Jeff Overcash }
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{ }
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{ IBX For Lazarus (Firebird Express) }
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{ Contributor: Tony Whyman, MWA Software http://www.mwasoftware.co.uk }
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{ Portions created by MWA Software are copyright McCallum Whyman }
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{ Associates Ltd 2011 - 2015 }
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{ }
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{************************************************************************}
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unit FBEvents;
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{$IFDEF MSWINDOWS}
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{$DEFINE WINDOWS}
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{$ENDIF}
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{$IFDEF FPC}
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{$mode delphi}
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{$interfaces COM}
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{$ENDIF}
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interface
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uses
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Classes, SysUtils, IB, FBClientAPI, syncobjs, FBActivityMonitor;
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type
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{ TFBEvents }
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{Firebird Event and Result buffer syntax is:
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record
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version: byte;
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event: array of packed record
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strlen: byte;
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strchars: array of AnsiChar; //no of chars given by strlen
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EventCounts: long;
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end;
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end;
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}
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TFBEvents = class(TActivityReporter)
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private
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FEvents: TStringList;
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FAttachment: IAttachment;
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FEventCounts: TEventCounts;
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FFirebirdClientAPI: TFBClientAPI;
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protected
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FEventBuffer: PByte;
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FEventBufferLen: integer;
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FResultBuffer: PByte;
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FEventHandler: TEventHandler;
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FCriticalSection: TCriticalSection;
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FInWaitState: boolean;
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procedure CreateEventBlock;
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procedure CancelEvents(Force: boolean = false); virtual;
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procedure EventSignaled;
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function GetIEvents: IEvents; virtual; abstract;
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procedure ProcessEventCounts;
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public
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const EPB_version1 = 1;
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public
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constructor Create(DBAttachment: IAttachment; aMonitor: IActivityMonitor; Events: TStrings);
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destructor Destroy; override;
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{IEvents}
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procedure GetEvents(EventNames: TStrings);
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procedure SetEvents(EventNames: TStrings); overload;
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procedure SetEvents(Event: AnsiString); overload;
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procedure Cancel;
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function ExtractEventCounts: TEventCounts;
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function GetAttachment: IAttachment;
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procedure AsyncWaitForEvent(EventHandler: TEventHandler); virtual; abstract;
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end;
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implementation
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uses FBMessages, IBExternals;
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const
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MaxEvents = 15;
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{ TFBEvents }
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(* Original Firebird 'C' code
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SLONG API_ROUTINE_VARARG isc_event_block(UCHAR** event_buffer,
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UCHAR** result_buffer,
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USHORT count, ...)
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{
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/**************************************
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*
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* i s c _ e v e n t _ b l o c k
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*
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**************************************
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*
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* Functional description
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* Create an initialized event parameter block from a
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* variable number of input arguments.
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* Return the size of the block.
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*
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* Return 0 if any error occurs.
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*
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**************************************/
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va_list ptr;
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va_start(ptr, count);
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// calculate length of event parameter block, setting initial length to include version
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// and counts for each argument
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SLONG length = 1;
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USHORT i = count;
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while (i--)
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{
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const char* q = va_arg(ptr, SCHAR * );
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length += static_cast<SLONG>(strlen(q)) + 5;
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}
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va_end(ptr);
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UCHAR* p = *event_buffer = (UCHAR * ) gds__alloc((SLONG) length);
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// FREE: apparently never freed
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if (!*event_buffer) // NOMEM:
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return 0;
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if ((*result_buffer = (UCHAR * ) gds__alloc((SLONG) length)) == NULL)
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{
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// NOMEM:
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// FREE: apparently never freed
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gds__free(*event_buffer);
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*event_buffer = NULL;
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return 0;
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}
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// initialize the block with event names and counts
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*p++ = EPB_version1;
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va_start(ptr, count);
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i = count;
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while (i--)
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{
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const char* q = va_arg(ptr, SCHAR * );
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// Strip the blanks from the ends
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const char* end = q + strlen(q);
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while (--end >= q && *end == ' ')
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;
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*p++ = end - q + 1;
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while (q <= end)
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*p++ = *q++;
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*p++ = 0;
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*p++ = 0;
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*p++ = 0;
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*p++ = 0;
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}
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va_end(ptr);
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return static_cast<SLONG>(p - *event_buffer);
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}
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*)
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{CreateEventBlock effectively replaces isc_event_block}
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procedure TFBEvents.CreateEventBlock;
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var i: integer;
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P: PByte;
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begin
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{calculate length of event parameter block, setting initial length to include version
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and counts for each argument}
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FEventBufferLen := 1;
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for i := 0 to FEvents.Count - 1 do
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FEventBufferLen := FEventBufferLen + length(FEvents[i]) + 1 + sizeof(Long);
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with FFirebirdClientAPI do
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begin
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IBAlloc(FEventBuffer,0,FEventBufferLen);
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if FEventBuffer = nil then Exit;
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{$if declared(FillByte)}
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FillByte(FEventBuffer^,FEventBufferLen,0);
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{$else}
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FillChar(FEventBuffer^,FEventBufferLen,0);
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{$ifend}
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IBAlloc(FResultBuffer,0,FEventBufferLen);
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if FResultBuffer = nil then
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begin
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FreeMem(FEventBuffer);
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Exit;
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end;
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P := FEventBuffer;
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P^ := EPB_version1;
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Inc(P);
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SetLength(FEventCounts,FEvents.Count);
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for i := 0 to FEvents.Count - 1 do
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begin
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P^ := Length(FEvents[i]);
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Inc(P);
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Move(FEvents[i][1],P^,Length(FEvents[i]));
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Inc(P,Length(FEvents[i])+sizeof(Long));
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FEventCounts[i].EventName := FEvents[i];
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end;
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end;
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{ for i := 0 to FEventBufferLen - 1 do
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write(Format('%x ', [FEventBuffer[i]]));
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writeln;}
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end;
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procedure TFBEvents.CancelEvents(Force: boolean);
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begin
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FEventHandler := nil;
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end;
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procedure TFBEvents.EventSignaled;
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var Handler: TEventHandler;
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begin
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Handler := nil;
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FCriticalSection.Enter;
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try
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if not FInWaitState then Exit;
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FInWaitState := false;
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ProcessEventCounts;
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if assigned(FEventHandler) then
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begin
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Handler := FEventHandler;
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FEventHandler := nil;
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end;
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finally
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FCriticalSection.Leave;
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end;
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if assigned(Handler) then
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Handler(GetIEvents);
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end;
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(*
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Original Firebird 'C' code for isc_event_counts
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void API_ROUTINE isc_event_counts(ULONG* result_vector,
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SSHORT buffer_length,
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UCHAR* event_buffer,
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const UCHAR* result_buffer)
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{
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/**************************************
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*
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* g d s _ $ e v e n t _ c o u n t s
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*
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**************************************
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*
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* Functional description
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* Get the delta between two events in an event
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* parameter block. Used to update gds_events
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* for GPRE support of events.
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*
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**************************************/
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ULONG* vec = result_vector;
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const UCHAR* p = event_buffer;
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const UCHAR* q = result_buffer;
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USHORT length = buffer_length;
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const UCHAR* const end = p + length;
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// analyze the event blocks, getting the delta for each event
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p++;
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q++;
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while (p < end)
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{
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// skip over the event name
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const USHORT i = (USHORT)* p++;
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p += i;
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q += i + 1;
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// get the change in count
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const ULONG initial_count = gds__vax_integer(p, sizeof(SLONG));
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p += sizeof(SLONG);
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const ULONG new_count = gds__vax_integer(q, sizeof(SLONG));
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q += sizeof(SLONG);
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*vec++ = new_count - initial_count;
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}
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// copy over the result to the initial block to prepare
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// for the next call to gds__event_wait
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memcpy(event_buffer, result_buffer, length);
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}
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*)
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{ProcessEventCounts effectively replaces isc_event_counts}
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procedure TFBEvents.ProcessEventCounts;
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var i: integer;
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P, Q: PByte;
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initial_count: Long;
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new_count: Long;
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len: byte;
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begin
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P := FEventBuffer;
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Q := FResultBuffer;
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Inc(P); {skip past version byte}
|
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Inc(Q);
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for i := 0 to Length(FEventCounts) - 1 do
|
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with FFirebirdClientAPI do
|
| 361 |
begin
|
| 362 |
{skip over the event name}
|
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len := P^;
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P := P + len + 1;
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Q := Q + len + 1; {event name length in P^}
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initial_count := DecodeInteger(P,sizeof(Long));
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Inc(P,sizeof(Long));
|
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new_count := DecodeInteger(Q,sizeof(Long));
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Inc(Q,sizeof(Long));
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FEventCounts[i].Count := new_count - initial_count;
|
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end;
|
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Move(FResultBuffer^,FEventBuffer^,FEventBufferLen);
|
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end;
|
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|
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constructor TFBEvents.Create(DBAttachment: IAttachment;
|
| 376 |
aMonitor: IActivityMonitor; Events: TStrings);
|
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begin
|
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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 |
|
