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41 lines
1.3 KiB
Rust
41 lines
1.3 KiB
Rust
use crate::{MultitraitObject};
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pub trait TryClone: Sized {
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fn try_clone(&self) -> Option<Self>;
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}
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/// Returns a raw pointer to the cloned data.
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/// This will leak the memory of the underlying pointer.
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/// This trait is implemented for all types that implement clone
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/// so you can pass this trait to the object constructor. This
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/// way the given object can be cloned with [TryClone].
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pub unsafe trait RawClone {
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#[doc(hidden)]
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#[must_use]
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unsafe fn raw_clone(&self) -> *mut ();
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}
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/// A trait that tries cloning an object and returns an option
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/// with the variant depending on the result. For a multitrait object
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/// to be clonable it needs to have the [RawClone] trait registered.
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unsafe impl<T: Clone> RawClone for T {
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unsafe fn raw_clone(&self) -> *mut () {
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Box::into_raw(Box::new(self.clone())) as *mut ()
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}
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}
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impl TryClone for MultitraitObject {
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fn try_clone(&self) -> Option<Self> {
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let clone = self.downcast_trait::<dyn RawClone>()?;
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let data_ptr = unsafe {
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// SAFETY: We're using the pointer in the multitrait object so
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// it won't leak memory
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clone.raw_clone()
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};
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Some(MultitraitObject {
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data: data_ptr,
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original_typeid: self.original_typeid.clone(),
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traits: self.traits.clone(),
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})
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}
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} |