Struct hot_lib_reloader::LibReloadObserver

pub struct LibReloadObserver { /* private fields */ }

A LibReloadObserver allows to wait for library changes. See

• LibReloadObserver::wait_for_about_to_reload and
• LibReloadObserver::wait_for_reload for details.

You can use those methods individually or in combination. In particular, if you want to serialize state before a library change happens and then deserialize / migrate it when the library update is done, using both methods in combination is quite useful. Something along the lines of:

#[hot_module(dylib = "lib")]
mod hot_lib {
    #[lib_change_subscription]
    pub fn subscribe() -> hot_lib_reloader::LibReloadObserver { }
}

fn test() {
    let lib_observer = hot_lib::subscribe();

    /* ... */

    // wait for reload to begin (at this point the  old version is still loaded)
    let update_blocker = lib_observer.wait_for_about_to_reload();

    /* do update preparations here, e.g. serialize state */

    // drop the blocker to allow update
    drop(update_blocker);

    // wait for reload to be completed
    lib_observer.wait_for_reload();

    /* new lib version is loaded now so you can e.g. restore state */
}

Implementations

impl LibReloadObserver

pub fn wait_for_about_to_reload(&self) -> BlockReload

A call to this method will do a blocking wait until the watched library is about to change. It returns a BlockReload token. While this token is in scope you will prevent the pending update to proceed. This is useful for doing preparations for the update and while the old library version is still loaded. You can for example serialize state.

pub fn wait_for_about_to_reload_timeout( &self, timeout: Duration ) -> Option<BlockReload>

Like Self::wait_for_about_to_reload but for a limited time. In case of a timeout return None.

pub fn wait_for_reload(&self)

Will do blocking wait until a new library version is loaded.

pub fn wait_for_reload_timeout(&self, timeout: Duration) -> bool

Like Self::wait_for_reload but for a limited time. In case of a timeout return false.