(feature) Implementing a userland interface

[kakserpom]

Problem

While waiting for #527 I tried this:

pub fn ce_my_userland_interface() -> &'static ClassEntry {
    ClassEntry::try_find("\\MyUserlandInterface").expect("\\MyUserlandInterface not found")
}

// ...

#[php(implements(ce = ce_my_userland_interface, stub = "\\MyUserlandInterface"))]

But then there doesn't seem to be an obvious way to run a script before loading the extension.
So the interface class is not defined at startup time and ce_my_userland_interface() panics.

Solution

pub fn adhoc_php_class_implements(class: &str, interface: &str) -> Option<()> {
    use ext_php_rs::ffi::zend_do_implement_interface;
    use ext_php_rs::types::ZendStr;
    use ext_php_rs::zend::ClassEntry;
    use ext_php_rs::zend::ExecutorGlobals;
    use std::ptr;
    ExecutorGlobals::get().class_table()?;
    let mut class = ZendStr::new(class, false);
    let interface = ClassEntry::try_find(interface)?;
    unsafe {
        zend_do_implement_interface(
            ext_php_rs::ffi::zend_lookup_class_ex(
                &raw mut *class,
                ptr::null_mut(),
                0,
            )
            .as_mut()?,
            ptr::from_ref(interface).cast_mut(),
        )
    };
    Some(())
}

Then in some place like __construct:

static INIT: Once = Once::new();
INIT.call_once(|| {
    adhoc_php_class_implements(
        "MyClass",
        "MyInterface",
    );
});

I think it would be useful to add this feature to ext-php-rs.

What do you guys think?