31 lines
685 B
Rust
31 lines
685 B
Rust
use once_cell::unsync::OnceCell;
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/// Wrapper around `OnceCell` implementing `Deref`, and thus also panicking
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/// when not set (or set twice).
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///
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/// To be used in place of `gtk::TemplateChild`, but without xml.
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pub struct DerefCell<T>(OnceCell<T>);
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impl<T> DerefCell<T> {
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#[track_caller]
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pub fn set(&self, value: T) {
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if self.0.set(value).is_err() {
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panic!("Initialized twice");
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}
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}
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}
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impl<T> Default for DerefCell<T> {
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fn default() -> Self {
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Self(OnceCell::default())
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}
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}
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impl<T> std::ops::Deref for DerefCell<T> {
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type Target = T;
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#[track_caller]
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fn deref(&self) -> &T {
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self.0.get().unwrap()
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}
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}
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