style: Use std::unique_ptr<std::istream> in InputStreamBase

[N-Dekker]

Simplified the class by removing its member variables m_DeleteIStream and m_WasmStringStream. Avoided manual memory management.

[Copilot]

Pull Request Overview

This PR modernizes the InputStreamBase class by replacing manual memory management with std::unique_ptr<std::istream>, eliminating the need for manual cleanup and simplifying the class design.

Key changes:

• Replaced raw pointer m_IStream with std::unique_ptr<std::istream>
• Removed manual memory management variables m_DeleteIStream and m_WasmStringStream
• Moved method implementations from header to source file

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
include/itkInputStreamBase.h	Replaced raw pointer with unique_ptr, removed manual memory management members, moved method declarations
src/itkInputStreamBase.cxx	Added method implementations using unique_ptr and modern C++ practices

[Copilot]

This line attempts to move-construct a stringstream from another stringstream, but the GetStringStream() method likely returns a reference, not a movable object. This could result in compilation errors or unintended copying. Consider using a different approach to transfer the stream data.

Suggested change

	m_IStream = std::make_unique<std::stringstream>(std::move(wasmStringStream->GetStringStream()));
	std::stringstream tempStream = wasmStringStream->GetStringStream();
	m_IStream = std::make_unique<std::stringstream>(tempStream.str());

[N-Dekker]

The change suggested by Copilot does not compile. Specifically:

    std::stringstream tempStream = wasmStringStream->GetStringStream();

This suggestion would try to copy-construct a std::stringstream, but std::stringstream is not copy-constructible!

std::stringstream is move-construcible, so the stringstream of a WasmStringStream object can be properly moved into another stringstream, as in the proposed PR. Especially because the WasmStringStream object itself is no longer used afterwards.

[thewtex]

@N-Dekker thanks!