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use crate::ops::{Begin, BeginMut, End, EndMut, Increment, Indirection}; use crate::vector_ops::{Data, DataMut, Size}; use crate::{ cpp_iter, CppBox, CppDeletable, CppIterator, DynamicCast, Ptr, StaticDowncast, StaticUpcast, }; use std::ops::Deref; use std::{fmt, ptr, slice}; /// A non-null, mutable pointer to a C++ object (similar to a C++ reference). /// /// `Ref` never owns its content. /// /// Note that unlike Rust references, `Ref` can be freely copied, /// producing multiple mutable pointers to the same object, which is usually necessary /// to do when working with C++ libraries. /// /// `Ref` implements operator traits and delegates them /// to the corresponding C++ operators. /// This means that you can use `&ptr + value` to access the object's `operator+`. /// /// `Ref` implements `Deref` allowing to call the object's methods /// directly. In addition, methods of the object's first base class are also directly available /// thanks to nested `Deref` implementations. /// /// If the object provides an iterator interface through `begin()` and `end()` functions, /// `Ref` will implement `IntoIterator`, so you can iterate on it directly. /// /// ### Safety /// /// It's not possible to automatically track the ownership of objects possibly managed by C++ /// libraries. The user must ensure that the object is alive while `Ref` exists. Note that /// with `Ref`, it's possible to call unsafe C++ code without using any more unsafe Rust code, /// for example, by using operator traits, so care should be taken when exposing /// `Ref` in a safe interface. pub struct Ref<T>(ptr::NonNull<T>); /// Creates another pointer to the same object. impl<T> Clone for Ref<T> { fn clone(&self) -> Self { Ref(self.0) } } /// Creates another pointer to the same object. impl<T> Copy for Ref<T> {} impl<T> fmt::Debug for Ref<T> { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { write!(f, "Ref({:?})", self.0) } } impl<T> Ref<T> { /// Creates a `Ref` from a `Ptr`. Returns `None` if `ptr` is null. /// /// ### Safety /// /// `ptr` must be valid. See type level documentation. pub unsafe fn new(ptr: Ptr<T>) -> Option<Self> { Self::from_raw(ptr.as_raw_ptr()) } /// Creates a `Ref` from a raw pointer. Returns `None` if `ptr` is null. /// /// ### Safety /// /// `ptr` must be valid. See type level documentation. pub unsafe fn from_raw(ptr: *const T) -> Option<Self> { ptr::NonNull::new(ptr as *mut T).map(Ref) } /// Creates a `Ref` from a non-null pointer. /// /// ### Safety /// /// `ptr` must be valid. See type level documentation. pub unsafe fn from_raw_non_null(ptr: ptr::NonNull<T>) -> Self { Ref(ptr) } /// Converts `self` to a `Ptr`. /// /// ### Safety /// /// `self` must be valid. See type level documentation. pub unsafe fn as_ptr(self) -> Ptr<T> { Ptr::from_raw(self.as_raw_ptr()) } /// Returns a reference to the value. /// /// ### Safety /// /// `self` must be valid. /// The content must not be read or modified through other ways while the returned reference /// exists.See type level documentation. pub unsafe fn as_raw_ref<'a>(self) -> &'a T { &*self.0.as_ptr() } /// Returns a mutable reference to the value. /// /// ### Safety /// /// `self` must be valid. /// The content must not be read or modified through other ways while the returned reference /// exists.See type level documentation. pub unsafe fn as_mut_raw_ref<'a>(self) -> &'a mut T { &mut *self.0.as_ptr() } /// Returns constant raw pointer to the value. pub fn as_raw_ptr(self) -> *const T { self.0.as_ptr() } /// Returns constant raw pointer to the value. pub fn as_mut_raw_ptr(self) -> *mut T { self.0.as_ptr() } /// Converts the pointer to the base class type `U`. /// /// ### Safety /// /// This operation is safe as long as `self` is valid. pub unsafe fn static_upcast<U>(self) -> Ref<U> where T: StaticUpcast<U>, { StaticUpcast::static_upcast(self.as_ptr()) .as_ref() .expect("StaticUpcast returned null on Ref input") } /// Converts the pointer to the derived class type `U`. /// /// It's recommended to use `dynamic_cast` instead because it performs a checked conversion. /// /// ### Safety /// /// This operation is safe as long as `self` is valid and it's type is `U` or inherits from `U`. pub unsafe fn static_downcast<U>(self) -> Ref<U> where T: StaticDowncast<U>, { StaticDowncast::static_downcast(self.as_ptr()) .as_ref() .expect("StaticDowncast returned null on Ref input") } /// Converts the pointer to the derived class type `U`. Returns `None` if the object's type /// is not `U` and doesn't inherit `U`. /// /// ### Safety /// /// This operation is safe as long as `self` is valid. pub unsafe fn dynamic_cast<U>(self) -> Option<Ref<U>> where T: DynamicCast<U>, { DynamicCast::dynamic_cast(self.as_ptr()).as_ref() } } impl<V, T> Ref<V> where V: Data<Output = *const T> + Size, { /// Returns the content of the object as a slice, based on `data()` and `size()` methods. /// /// # Safety /// /// The caller must make sure `self` contains a valid pointer. The content must /// not be read or modified through other ways while the returned slice exists. /// This function /// may invoke arbitrary foreign code, so no safety guarantees can be made. pub unsafe fn as_slice<'a>(self) -> &'a [T] { let ptr = self.data(); let size = self.size(); slice::from_raw_parts(ptr, size) } } impl<V, T> Ref<V> where V: DataMut<Output = *mut T> + Size, { /// Returns the content of the vector as a mutable slice, /// based on `data()` and `size()` methods. /// /// # Safety /// /// The caller must make sure `self` contains a valid pointer. The content must /// not be read or modified through other ways while the returned slice exists. /// This function /// may invoke arbitrary foreign code, so no safety guarantees can be made. pub unsafe fn as_mut_slice<'a>(self) -> &'a mut [T] { let ptr = self.data_mut(); let size = self.size(); slice::from_raw_parts_mut(ptr, size) } } impl<T, T1, T2> Ref<T> where T: Begin<Output = CppBox<T1>> + End<Output = CppBox<T2>>, T1: CppDeletable + PartialEq<Ref<T2>> + Increment + Indirection, T2: CppDeletable, { /// Returns an iterator over the content of the object, /// based on `begin()` and `end()` methods. /// /// # Safety /// /// The caller must make sure `self` contains a valid pointer. The content must /// not be read or modified through other ways while the returned slice exists. /// This function /// may invoke arbitrary foreign code, so no safety guarantees can be made. pub unsafe fn iter(self) -> CppIterator<T1, T2> { cpp_iter(self.begin(), self.end()) } } impl<T, T1, T2> Ref<T> where T: BeginMut<Output = CppBox<T1>> + EndMut<Output = CppBox<T2>>, T1: CppDeletable + PartialEq<Ref<T2>> + Increment + Indirection, T2: CppDeletable, { /// Returns a mutable iterator over the content of the object, /// based on `begin()` and `end()` methods. /// /// # Safety /// /// The caller must make sure `self` contains a valid pointer. The content must /// not be read or modified through other ways while the returned slice exists. /// This function /// may invoke arbitrary foreign code, so no safety guarantees can be made. pub unsafe fn iter_mut(self) -> CppIterator<T1, T2> { cpp_iter(self.begin_mut(), self.end_mut()) } } /// Allows to call member functions of `T` and its base classes directly on the pointer. impl<T> Deref for Ref<T> { type Target = T; fn deref(&self) -> &T { unsafe { self.0.as_ref() } } }