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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,175 @@ | ||
| pub use std::cell::Cell; | ||
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| use core::cmp::Ordering; | ||
| use core::fmt::{self, Debug}; | ||
| use std::fmt::Pointer; | ||
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| /// A mutable Wasm-memory location. | ||
| /// | ||
| /// # Examples | ||
| /// | ||
| /// In this example, you can see that `WasmCell<T>` enables mutation inside an | ||
| /// immutable struct. In other words, it enables "interior mutability". | ||
| /// | ||
| /// ``` | ||
| /// use wasmer::WasmCell; | ||
| /// | ||
| /// struct SomeStruct { | ||
| /// regular_field: u8, | ||
| /// special_field: WasmCell<u8>, | ||
| /// } | ||
| /// | ||
| /// let my_struct = SomeStruct { | ||
| /// regular_field: 0, | ||
| /// special_field: WasmCell::new(1), | ||
| /// }; | ||
| /// | ||
| /// let new_value = 100; | ||
| /// | ||
| /// // ERROR: `my_struct` is immutable | ||
| /// // my_struct.regular_field = new_value; | ||
| /// | ||
| /// // WORKS: although `my_struct` is immutable, `special_field` is a `WasmCell`, | ||
| /// // which can always be mutated | ||
| /// my_struct.special_field.set(new_value); | ||
| /// assert_eq!(my_struct.special_field.get(), new_value); | ||
| /// ``` | ||
| /// | ||
| /// See the [module-level documentation](self) for more. | ||
| #[repr(transparent)] | ||
| pub struct WasmCell<'a, T: ?Sized> { | ||
| inner: &'a Cell<T>, | ||
| } | ||
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| unsafe impl<T: ?Sized> Send for WasmCell<'_, T> where T: Send {} | ||
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| unsafe impl<T: ?Sized> Sync for WasmCell<'_, T> {} | ||
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| impl<'a, T: Copy> Clone for WasmCell<'a, T> { | ||
| #[inline] | ||
| fn clone(&self) -> WasmCell<'a, T> { | ||
| WasmCell { inner: self.inner } | ||
| } | ||
| } | ||
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| impl<T: PartialEq + Copy> PartialEq for WasmCell<'_, T> { | ||
| #[inline] | ||
| fn eq(&self, other: &WasmCell<T>) -> bool { | ||
| self.inner.eq(&other.inner) | ||
| } | ||
| } | ||
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| impl<T: Eq + Copy> Eq for WasmCell<'_, T> {} | ||
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| impl<T: PartialOrd + Copy> PartialOrd for WasmCell<'_, T> { | ||
| #[inline] | ||
| fn partial_cmp(&self, other: &WasmCell<T>) -> Option<Ordering> { | ||
| self.inner.partial_cmp(&other.inner) | ||
| } | ||
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| #[inline] | ||
| fn lt(&self, other: &WasmCell<T>) -> bool { | ||
| self.inner < other.inner | ||
| } | ||
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| #[inline] | ||
| fn le(&self, other: &WasmCell<T>) -> bool { | ||
| self.inner <= other.inner | ||
| } | ||
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| #[inline] | ||
| fn gt(&self, other: &WasmCell<T>) -> bool { | ||
| self.inner > other.inner | ||
| } | ||
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| #[inline] | ||
| fn ge(&self, other: &WasmCell<T>) -> bool { | ||
| self.inner >= other.inner | ||
| } | ||
| } | ||
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| impl<T: Ord + Copy> Ord for WasmCell<'_, T> { | ||
| #[inline] | ||
| fn cmp(&self, other: &WasmCell<T>) -> Ordering { | ||
| self.inner.cmp(&other.inner) | ||
| } | ||
| } | ||
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| impl<'a, T> WasmCell<'a, T> { | ||
| /// Creates a new `WasmCell` containing the given value. | ||
| /// | ||
| /// # Examples | ||
| /// | ||
| /// ``` | ||
| /// use wasmer::WasmCell; | ||
| /// | ||
| /// let c = WasmCell::new(5); | ||
| /// ``` | ||
| #[inline] | ||
| pub const fn new(cell: &'a Cell<T>) -> WasmCell<'a, T> { | ||
| WasmCell { inner: cell } | ||
| } | ||
| } | ||
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| impl<'a, T: Copy> WasmCell<'a, T> { | ||
| /// Returns a copy of the contained value. | ||
| /// | ||
| /// # Examples | ||
| /// | ||
| /// ``` | ||
| /// use wasmer::WasmCell; | ||
| /// | ||
| /// let c = WasmCell::new(5); | ||
| /// | ||
| /// let five = c.get(); | ||
| /// ``` | ||
| #[inline] | ||
| pub fn get(&self) -> T { | ||
| self.inner.get() | ||
| } | ||
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| /// Get an unsafe mutable pointer to the inner item | ||
| /// in the Cell. | ||
| /// | ||
| /// # Safety | ||
| /// | ||
| /// This method is highly discouraged to use. We have it for | ||
| /// compatibility reasons with Emscripten. | ||
| /// It is unsafe because changing an item inline will change | ||
| /// the underlying memory. | ||
| /// | ||
| /// It's highly encouraged to use the `set` method instead. | ||
| #[deprecated( | ||
| since = "2.0.0", | ||
| note = "Please use the memory-safe set method instead" | ||
| )] | ||
| #[doc(hidden)] | ||
| pub unsafe fn get_mut(&self) -> &'a mut T { | ||
| &mut *self.inner.as_ptr() | ||
| } | ||
| } | ||
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| impl<T: Debug> Debug for WasmCell<'_, T> { | ||
| #[inline] | ||
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | ||
| self.inner.fmt(f) | ||
| } | ||
| } | ||
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| impl<T: Sized> WasmCell<'_, T> { | ||
| /// Sets the contained value. | ||
| /// | ||
| /// # Examples | ||
| /// | ||
| /// ``` | ||
| /// use wasmer::WasmCell; | ||
| /// | ||
| /// let c = WasmCell::new(5); | ||
| /// | ||
| /// c.set(10); | ||
| /// ``` | ||
| #[inline] | ||
| pub fn set(&self, val: T) { | ||
| self.inner.set(val); | ||
| } | ||
| } |
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