Стартовый пул

RXLib/.svn/pristine/b9/b9a8536b44a0b5ca99a5707ee68e89271fcbeba2.svn-base

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+{ RxDBGrid sort engine module for FBDataSet
+
+  Copyright (C) 2011 BugMaker from freepascal.ru
+
+  This library is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Library General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or (at your
+  option) any later version with the following modification:
+
+  As a special exception, the copyright holders of this library give you
+  permission to link this library with independent modules to produce an
+  executable, regardless of the license terms of these independent modules,and
+  to copy and distribute the resulting executable under terms of your choice,
+  provided that you also meet, for each linked independent module, the terms
+  and conditions of the license of that module. An independent module is a
+  module which is not derived from or based on this library. If you modify
+  this library, you may extend this exception to your version of the library,
+  but you are not obligated to do so. If you do not wish to do so, delete this
+  exception statement from your version.
+
+  This program is distributed in the hope that it will be useful, but WITHOUT
+  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+  FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License
+  for more details.
+
+  You should have received a copy of the GNU Library General Public License
+  along with this library; if not, write to the Free Software Foundation,
+  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+}
+
+unit exsortsql;
+
+{$mode objfpc}{$H+}
+
+interface
+
+uses
+  Classes, SysUtils, DB, RxDBGrid;
+
+type
+
+  { TSQLQuerySortEngine }
+
+  TSQLQuerySortEngine = class(TRxDBGridSortEngine)
+  public
+    procedure Sort(FieldName: string; ADataSet:TDataSet; Asc:boolean; SortOptions:TRxSortEngineOptions);override;
+    procedure SortList(ListField: string; ADataSet: TDataSet; Asc: array of boolean; SortOptions: TRxSortEngineOptions); override;
+  end;
+
+implementation
+uses SQLDB, RegExpr, strUtils;
+
+
+procedure TSQLQuerySortEngine.Sort(FieldName: string; ADataSet: TDataSet;
+  Asc: boolean; SortOptions: TRxSortEngineOptions);
+begin
+  SortList(FieldName,ADataSet,Asc,SortOptions);
+end;
+
+procedure TSQLQuerySortEngine.SortList(ListField: string; ADataSet: TDataSet;
+  Asc: array of boolean; SortOptions: TRxSortEngineOptions);
+var
+  S:string;
+  i, C:integer;
+  cmd:string;
+  strLen:Integer;
+  RegExpr: TRegExpr;
+  Mask:String;
+  OldParams:TParams;
+begin
+    if not (Assigned(ADataSet) and ADataset.Active) then exit;
+
+    S:='';
+    C:=Pos(';', ListField);
+    i:=0;
+    while C>0 do
+    begin
+      if S<>'' then S:=S+',';
+      S:=S + Copy(ListField, 1, C-1);
+      Delete(ListField, 1, C);
+
+      if (i<=High(Asc)) and (not Asc[i]) then
+        S:=S + ' DESC';
+      C:=Pos(';', ListField);
+      inc(i);
+    end;
+
+    if ListField<>'' then
+    begin
+      if S<>'' then S:=S+',';
+      S:=S + ListField;
+      if (i<=High(Asc)) and (not Asc[i]) then
+        S:=S + ' DESC';
+    end;
+
+    OldParams:=TParams.Create;
+    OldParams.Assign((ADataSet as TSQLQuery).Params);
+    cmd:=(ADataSet as TSQLQuery).SQL.Text;
+    strlen:=length(cmd);
+    //Регулярное выражение позволяет найти уже имеющуюся конструкцию ORDER BY,
+    //если она написана одной строкой, и между словами не понапихали комментариев :)
+    //Работоспособные примеры:
+    //ORDER BY FIELD1, FIELD2 DESC, FIELD100500
+    //oRdeR bY    fielD1   ,   FiElD2,FieLD100500 DESC
+    //Неработоспособный:
+    //ORDER BY FIELD1,
+    //FIELD2,
+    //FIELD100500
+    mask:='(?i)(^|\s)\s*order\s+by\s+\S+\.?\S*(\s+desc)?\s*(,\s*\S+\.?\S*(\s+desc)?(^|s*))*';
+    with TRegExpr.Create do begin
+
+      Expression := mask;
+      if Exec(cmd) then begin
+        s:=LeftStr(cmd,MatchPos[0]-1)
+        +slinebreak+'order by '
+        +s+slineBreak
+        +RightStr(cmd, strlen-MatchPos[0]-MatchLen[0]+1);
+      end
+      else
+        s:=cmd+slinebreak+'order by '+s+slineBreak;
+
+      ADataSet.Active:=False;
+      (ADataSet as TSQLQuery).SQL.Text:=s;
+      (ADataSet as TSQLQuery).Params.Assign(OldParams);
+      OldParams.Free;
+      ADataSet.Active:=True;
+      Free;
+    end;
+
+end;
+
+initialization
+  RegisterRxDBGridSortEngine(TSQLQuerySortEngine, 'TSQLQuery');
+end.