Struct drying_paint::WatchContext

pub struct WatchContext { /* fields omitted */ }

Most of the functions in this crate require that they are executing in a context. The context keeps track of some "global" state which enables the functionality in this crate.

The following will panic if done outside of a WatchContext:

• Calling WatchContext::update_current() (you can use WatchContext::update() to concisely update a context from outside itself).
• Mutating a Watched value.
• Calling WatchedEvent::dispatch()
• Calling WatchedMeta::trigger() (the two above are actually just specific variations on this)
• Creating a Watcher

When a watched value changes, the code watching those values will be queued onto the WatchContext. WatchContext::update_current() will execute all pending operations. Note: Because Watcher makes use of a RefCell internally to execute the watching code, you should not keep references gotten from Watcher::data() or Watcher::data_mut() around during WatchContext::update_current() or WatchContext::update().

Methods

impl WatchContext

pub fn new() -> Self

Create a new WatchContext

pub fn with<F: FnOnce()>(&mut self, func: F)

Set this WatchContext as the current one for the duration of the passed function. Note that it is supported (although discouraged) to nest WatchContexts within each other.

pub fn update_current()

Execute all operations which are currently pending because a value they were watching changed. Note: Because Watcher makes use of a RefCell internally to execute the watching code, you should not keep references gotten from Watcher::data() or Watcher::data_mut() around during WatchContext::update_current() or WatchContext::update().

Panics

This function will panic if called outside of WatchContext::with, or if any function queued for update panics.

pub fn update(&mut self)

The same as doing context.with(|| WatchContext::update_current())