diplomat-runtime 0.15.1

Common runtime utilities used by diplomat codegen
Documentation 
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//! Wasm-specific glue code
//!
//! This is a private module
use alloc::format;

// https://blog.rust-lang.org/2026/04/04/changes-to-webassembly-targets-and-handling-undefined-symbols/#what-is-going-to-break-and-how-to-fix
#[link(wasm_import_module = "env")]
extern "C" {
    fn diplomat_throw_error_js(ptr: *const u8, len: usize);

    #[cfg(feature = "log")]
    fn diplomat_console_error_js(ptr: *const u8, len: usize);
    #[cfg(feature = "log")]
    fn diplomat_console_warn_js(ptr: *const u8, len: usize);
    #[cfg(feature = "log")]
    fn diplomat_console_info_js(ptr: *const u8, len: usize);
    #[cfg(feature = "log")]
    fn diplomat_console_log_js(ptr: *const u8, len: usize);
    #[cfg(feature = "log")]
    fn diplomat_console_debug_js(ptr: *const u8, len: usize);
}

/// In theory, this function may be useful for other backends eventually, but
/// currently it is only useful in WASM so it is in this module.
#[no_mangle]
unsafe extern "C" fn diplomat_init() {
    #[cfg(debug_assertions)]
    std::panic::set_hook(Box::new(panic_handler));
    #[cfg(feature = "log")]
    log::set_logger(&ConsoleLogger)
        .map(|()| log::set_max_level(log::LevelFilter::Debug))
        .unwrap();
}

fn panic_handler(info: &std::panic::PanicHookInfo) {
    let msg = match info.payload().downcast_ref::<&'static str>() {
        Some(&s) => s,
        None => match info.payload().downcast_ref::<String>() {
            Some(s) => s.as_str(),
            None => "Box<Any>",
        },
    };

    let msg = match info.location() {
        Some(l) => format!(
            "wasm panicked at {}:{}:{}:\n{msg}",
            l.file(),
            l.line(),
            l.column(),
        ),
        None => format!("wasm panicked at <unknown location>:\n{msg}"),
    };

    unsafe { diplomat_throw_error_js(msg.as_ptr(), msg.len()) }
}

#[cfg(feature = "log")]
struct ConsoleLogger;

#[cfg(feature = "log")]
impl log::Log for ConsoleLogger {
    #[inline]
    fn enabled(&self, metadata: &log::Metadata) -> bool {
        metadata.level() <= log::max_level()
    }

    fn log(&self, record: &log::Record) {
        if !self.enabled(record.metadata()) {
            return;
        }

        let out = match record.level() {
            log::Level::Error => diplomat_console_error_js,
            log::Level::Warn => diplomat_console_warn_js,
            log::Level::Info => diplomat_console_info_js,
            log::Level::Debug => diplomat_console_log_js,
            log::Level::Trace => diplomat_console_debug_js,
        };

        let msg = alloc::format!("{}", record.args());

        unsafe { out(msg.as_ptr(), msg.len()) };
    }

    fn flush(&self) {}
}