I have read these questions and answers
How to change the implementation (detour) of an externally declared function
but i can't figere out how patch a private method of a class located in anoher unit.
Check this sample I want to patch the Bar
procedure.
Unit ThidParty;
Interface
Type
TFoo =Class
private
procedure Bar;
end;
I think which the key is find a way to obtain the address of the private method.
So, How I can patch a private method of a delphi class?
The solution outlined below works for versions up to and including Delphi Seattle. You can use a class helper to crack the class:
Unit1
type
TTest = class
private
procedure Foo;
end;
Unit2
type
TMyTestHelper = class helper for TTest
function GetFooAddress: Pointer;
end;
function TMyTestHelper.GetFooAddress: Pointer;
var
MethodPtr: procedure of object;
begin
MethodPtr := Self.Foo;
Result := TMethod(MethodPtr).Code;
end;
function FooAddress: Pointer;
begin
Result := TTest(nil).GetFooAddress;//don't need to instantiate an object
end;
Pass the return value from FooAddress
to one of your patching functions and you are golden.
However, starting with Delphi 10.1 Berlin, this no longer works! Class helpers can no longer access strict protected, strict private or private members. This "feature" was actually a compiler bug that Embarcadero has now fixed in Berlin. You are out of luck.