Garbage collector in Delphi?

The short answer is no!

But...

Before talking about garbage collection we need to talk about another term in programming languages like C that is called a smart pointer, so what is a smart pointer?

SMART POINTER

In software programming languages like C or Delphi, a smart pointer is a programming construct or class that acts as a wrapper around a regular pointer. It provides additional functionality and automates memory management to help prevent common issues such as memory leaks, dangling pointers, and accessing deallocated memory.

The primary purpose of a smart pointer is to ensure proper memory deallocation and ownership semantics. When you allocate memory dynamically using functions like malloc() in C or New() in Delphi, it's important to release the memory when it's no longer needed to avoid memory leaks. Smart pointers handle this automatically by deallocating the memory when the smart pointer goes out of scope or is explicitly released.

Smart pointers typically use reference counting or garbage collection techniques to manage memory. Reference counting keeps track of how many references point to a particular memory location, and when the reference count reaches zero, the memory is deallocated. Garbage collection involves periodically identifying and reclaiming memory that is no longer accessible.

There are different types of smart pointers available, such as unique_ptr, shared_ptr, and weak_ptr (in C++), or interfaces like IInterface and records (in Delphi).

Each type has its own set of features and ownership semantics, allowing programmers to choose the appropriate smart pointer based on their specific requirements.

By using smart pointers, programmers can reduce manual memory management errors and make their code more robust, reliable, and less prone to memory-related bugs.

Smart pointer implementation Sample

In Delphi, the IInterface serves as the base for implementing smart pointers. You can define your own custom interface that extends IInterface and includes additional methods specific to your smart pointer implementation.

Here's a simple example of a custom smart pointer implementation using reference counting:

type
  TMySmartPtr = class(TInterfacedObject)
  private
    FData: TObject;
  public
    constructor Create(AData: TObject);
    destructor Destroy; override;
    function GetData: TObject;
  end;

constructor TMySmartPtr.Create(AData: TObject);
begin
  inherited Create;
  FData := AData;
end;

destructor TMySmartPtr.Destroy;
begin
  FData.Free; // Release the owned object
  FData := nil;
  inherited Destroy;
end;

function TMySmartPtr.GetData: TObject;
begin
  Result := FData;
end;

In this example, TMySmartPtr is a custom smart pointer class that manages the lifetime of an owned object (FData). The object is freed when the smart pointer goes out of scope or is explicitly destroyed.

You can use this smart pointer as follows:

var
  MyPtr: TMySmartPtr;
begin
  MyPtr := TMySmartPtr.Create(TObject.Create);
  // Use the smart pointer and its underlying object
  // ...
  // no need to free the created Object!
  // Smart pointer goes out of scope, object is automatically freed
end;

In this code snippet, an instance of TMySmartPtr is created and assigned a newly created TObject. When MyPtr goes out of scope or is set to nil, the smart pointer's destructor is called, which in turn frees the owned object.

Delphi also provides interfaces like IInterfaceList and TContainedObject that offer more advanced smart pointer capabilities, such as managing ownership hierarchies or implementing weak references.

Remember that this is a simplified example, and in real-world scenarios, you may need to consider additional factors like thread safety, circular references, and other edge cases. It's always recommended to thoroughly test and review your smart pointer implementation to ensure correctness and efficiency.

Is this sample the best approach in this regard?

Probably NO!😆

So what? 

Here is my smart pointer repository that collected 7 different versions of smart pointers implementations, please have a look and find the best approach based on your taste!

Please have a look at real-world samples here:

https://github.com/AliDehbansiahkarbon/SmartPointers