44 lines
782 B
Rust
44 lines
782 B
Rust
use std::ops::{Deref, DerefMut};
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pub struct Delta<T> {
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value: T,
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changed: bool,
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}
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#[allow(dead_code)]
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impl<T> Delta<T> {
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pub fn new(value: T) -> Self {
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Delta {
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value,
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changed: false,
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}
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}
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pub fn peek_delta(&self) -> Option<&T> {
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self.changed.then_some(&self.value)
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}
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pub fn delta(&mut self) -> Option<&mut T> {
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let delta = self.changed.then_some(&mut self.value);
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self.changed = false;
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delta
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}
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pub fn value(&self) -> &T {
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&self.value
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}
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pub fn value_mut(&mut self) -> &mut T {
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self.changed = true;
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&mut self.value
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}
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}
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impl<T> Deref for Delta<T> {
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type Target = T;
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fn deref(&self) -> &Self::Target {
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&self.value
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}
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}
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impl<T> DerefMut for Delta<T> {
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fn deref_mut(&mut self) -> &mut Self::Target {
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self.changed = true;
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&mut self.value
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}
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}
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