Scope Guard

[joren-dev]

Overview

This pull request and code is written by both me and @Nerlant. Credits to him for helping and partly writing the code

Changes:

• adds scope guard base

Usage

#include <concepts>
#include <tuple>
#include <type_traits>
#include <utility>

#include <Windows.h>
#include <tlhelp32.h>

#include <pe_scope_guard/pe_scope_guard.hpp>

int main()
{
	const HANDLE a = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
	const HANDLE b = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
	{

		// lambda
		auto c = [a]() { CloseHandle(a); };

		// A combination of c and rvalue lambda's is completely fine
		peach::ScopeGuard test(
			[a]() { CloseHandle(a); },
			[b]() { CloseHandle(b); },
			c
		);

	}

	// Handles closed here
}

Any changes on files besides the ones directly connected to your feature/change (emtpy if none):

• none

Additional Notes:

With clang 11 in release the dissambly will look like:

  HANDLE v0; // rsi
  HANDLE v1; // rsi

  v0 = CreateToolhelp32Snapshot(2u, 0);
  v1 = CreateToolhelp32Snapshot(2u, 0);
  v0 = CreateToolhelp32Snapshot(2u, 0);
  CloseHandle(v0);
  CloseHandle(v1);
  JUMPOUT(func);

Quite optimal to say the least.

• One can pass lvalue lambda's, rvalue lambda's and plain c-style functions
• Amount of arguments and functors is unlimited
• The constructor is constexpr if the passed values passed through the capture list are compile time
• If the dtor throws std::terminate() is called
• The functor passed must have void as return type because the return value is neglected either way

Tests:

• Test feature thorougly
• Compiles w/ clang 11
• Formatted according to the .clang-format

Extra

• Add explanation/documentation on wiki/readme page