Alexey_Gawrilow
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{ TObjectGuard }
type
// PPointer = ^pointer;
IObjectGuard = interface(IInterface)
['{7A8C03C6-924B-4652-8703-909ABE4BF8EA}']
{
Removes Obj from the guard, so it won't be automatically finalized.
Useful when e.g. returning created objects from a function.
If an exception is raised, Result can be automatically freed. Example:<br>
<code>
g := NewObjectGuard(TNewObject.Create, Result);
DoStuff; // This may raise an exception. Result will be freed by guard.
g.Remit; // OK to return Result from function. Result will not be freed by guard.
</code>
}
procedure Remit;
function Obj: TObject;
end;
TObjectGuard = class(TInterfacedObject, IObjectGuard)
protected
FObj: TObject;
FRef: PPointer;
procedure Remit;
function Obj: TObject;
public
constructor Create(aObj: TObject);
constructor CreateRef(aObj: TObject; aRef: PPointer = nil);
destructor Destroy; override;
end;
TObjectGuardClass = class of TObjectGuard;
function NewObjectGuard(Obj: TObject): IObjectGuard; overload;
function NewObjectGuard(Obj: TObject; const GuardClass: TObjectGuardClass): IObjectGuard; overload;
function NewObjectGuard(Obj: TObject; out Ref): IObjectGuard; overload;
function NewObjectGuardRef(Obj: TObject; var Ref): IObjectGuard;
/// <summary>Object Guard.</summary>
function _gO(Obj: TObject): IObjectGuard; overload;
/// <summary>Object Guard.</summary>
function _gO(Obj: TObject; out Ref): IObjectGuard; overload;
{/TObjectGuard }
{
Optimized object guard implementation.
deleted 
}
{ TObjectGuard }
procedure TObjectGuard.Remit;
begin
FObj := nil;
end;
function TObjectGuard.Obj: TObject;
begin
Result := FObj;
end;
constructor TObjectGuard.Create(aObj: TObject);
begin
inherited Create();
FObj := aObj;
FRef := nil;
end;
constructor TObjectGuard.CreateRef(aObj: TObject; aRef: PPointer = nil);
begin
inherited Create();
FObj := aObj;
FRef := aRef;
end;
destructor TObjectGuard.Destroy;
begin
FObj.Free();
if Assigned(FRef) then
FRef^ := nil;
inherited;
end;
function NewObjectGuard(Obj: TObject): IObjectGuard;
begin
Assert(Assigned(Obj), '{1C2EC9F8-C7EC-4570-BDAA-0CF565D7B0D9}');
Result := TObjectGuard.Create(Obj);
end;
function _gO(Obj: TObject): IObjectGuard;
begin
Assert(Assigned(Obj), '{2617F77F-1333-4285-8F99-F5AA3442CDCA}');
Result := TObjectGuard.Create(Obj);
end;
function NewObjectGuard(Obj: TObject; const GuardClass: TObjectGuardClass): IObjectGuard;
begin
Assert(Assigned(Obj), '{2504F1BF-31B5-4A6C-AABA-9E62D1655768}');
Assert(Assigned(GuardClass), '{D6C502A8-73DE-410E-A71E-13BD18992586}');
Result := GuardClass.Create(Obj);
end;
function NewObjectGuard(Obj: TObject; out Ref): IObjectGuard;
begin
Assert(Assigned(Obj), '{E14C6C2A-DFDE-48E8-B19C-16C084C8E812}');
Result := TObjectGuard.Create(Obj);
TObject(Ref) := Obj;
end;
function _gO(Obj: TObject; out Ref): IObjectGuard;
begin
Assert(Assigned(Obj), '{5162D39A-BF7C-4808-B275-625E0EE5E602}');
Result := TObjectGuard.Create(Obj);
TObject(Ref) := Obj;
end;
function NewObjectGuardRef(Obj: TObject; var Ref): IObjectGuard;
begin
Assert(Assigned(Obj), '{56C8F8EC-33BC-42CD-A029-DC3F22765087}');
Result := TObjectGuard.CreateRef(Obj, PPointer(Ref));
end;
{/TObjectGuard }
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