Add support for ^ in C++/CLI and C++/CX from Microsoft in clang-format

[llvmbot]

Bugzilla Link	26752
Version	unspecified
OS	All
Reporter	LLVM Bugzilla Contributor

Extended Description

C++/CLI and C++/CX by Microsoft is C++ with a few extension to allow interacting with the .NET runtime:

• https://en.wikipedia.org/wiki/C%2B%2B/CLI
• https://en.wikipedia.org/wiki/C%2B%2B/CX

clang-format works on such source files without any problem except for handling the "hat notation" which is used to indicate managed objects.

• Foo&: usual C++ reference
• Foo*: usual C++ pointer
• Foo^: Managed object (C++/CLI and C++/CX only)

As in:

Foo^ foo = ref new Foo();

Since clang-format doesn't know about this special syntax, it "incorrectly" reformats:

String^ StringToPlatformString(const std::string& in) {
return gcnew String(StringToWString(in).c_str());
}

std::string PlatformStringToString(String^ in) {
pin_ptr ptr = PtrToStringChars(in); // Must pin the pointer to avoid GC while in unmanaged code
return WStringToString(ptr);
}

as

String ^ StringToPlatformString(const std::string& in) {
return gcnew String(StringToWString(in).c_str());
}

std::string PlatformStringToString(String ^ in) {

pin_ptr ptr = PtrToStringChars(in); // Must pin the pointer to avoid GC while in unmanaged code
return WStringToString(ptr);
}

[calumr]

Just to clarify (as the formatting is a little screwy in the original desciption) this is what clang-format is currently doing to C++/CLI code:

#pragma once

class StringUtil
{
public:
    static inline System::String ^
        convert(BSTR aString) { return msclr::interop::marshal_as<System::String ^>(aString); }

        static inline System::String
        ^
        convert(const std::string & aString) { return convertFromUTF8(aString); }

        static inline System::String
        ^ convertFromUTF8(const std::string & aString) {
              return System::Text::Encoding::UTF8->GetString((unsigned char *)aString.data(),
                                                             aString.size());
          }
};