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This wasn't very Rust friendly by holding on to a callback that was used to add events whenever the low threshold was crossed. This was more or less a port of the C++ version of this component. With this change, the caller will be notified (by return value) if the threshold was crossed downwards, so that it can add events themselves. This removes the callback, the lifetime modifier, and having to clone events.
Just minor improvements to use Rust language features.
lndmrk
approved these changes
Mar 20, 2026
| impl AddAssign<usize> for ThresholdWatcher<'_> { | ||
| fn add_assign(&mut self, rhs: usize) { | ||
| self.value += rhs; | ||
| // Returns `true` if the threshold was crossed downwards. |
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/// To make it a doc comment (since it's pub)
| (self.low_cb)(); | ||
| } | ||
| self.low_threshold = low_threshold; | ||
| pub fn add(&mut self, amount: usize) { |
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Maybe add a comment here for consistency
| if old_value > self.low_threshold && self.value <= self.low_threshold { | ||
| (self.low_cb)(); | ||
| } | ||
| // Returns `true` if the new threshold is lower than the current value, which means that the |
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The large part of this PR is to change ThresholdWatcher to be a "simpler component" by not having it trigger callbacks itself. It was more or less ported from C++ and used a C++ way of doing things.
Now it is more explicit, and requires callers to perform actions when the threshold is crossed (which the mutators indicate). This removes the lifetime annotations and having to clone the events, and all that.
And then there are some very minor refactorings to use the Rust language better.