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use crate::ops::{Begin, BeginMut, End, EndMut}; use crate::{DynamicCast, MutPtr, Ptr, StaticDowncast, StaticUpcast}; use std::ops::{Deref, DerefMut}; use std::{fmt, mem, ptr, slice}; /// A non-null, mutable pointer to a C++ object (similar to a C++ reference). /// /// `MutRef` never owns its content. /// /// Note that unlike Rust references, `MutRef` can be freely copied, /// producing multiple mutable pointers to the same object, which is usually necessary /// to do when working with C++ libraries. /// /// `MutRef` 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+`. /// /// `MutRef` implements `Deref` and `DerefMut`, 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, /// `MutRef` 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 `MutRef` exists. Note that /// with `MutRef`, 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 /// `MutRef` in a safe interface. pub struct MutRef<T>(ptr::NonNull<T>); /// Creates another pointer to the same object. impl<T> Clone for MutRef<T> { fn clone(&self) -> Self { MutRef(self.0) } } /// Creates another pointer to the same object. impl<T> Copy for MutRef<T> {} impl<T> fmt::Debug for MutRef<T> { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { write!(f, "MutRef({:?})", self.0) } } impl<T> MutRef<T> { /// Creates a `MutRef` from a `MutPtr`. Returns `None` if `ptr` is null. /// /// ### Safety /// /// `ptr` must be valid. See type level documentation. pub unsafe fn new(ptr: MutPtr<T>) -> Option<Self> { Self::from_raw(ptr.as_mut_raw_ptr()) } /// Creates a `MutRef` 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: *mut T) -> Option<Self> { ptr::NonNull::new(ptr).map(MutRef) } /// Creates a `MutRef` from a raw reference. /// /// ### Safety /// /// `value` must be alive as long as `MutRef` or pointers derived from it are used. /// See type level documentation. pub unsafe fn from_raw_ref(value: &mut T) -> Self { MutRef(value.into()) } /// Creates a `MutRef` 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 { MutRef(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()) } /// Converts `self` to a `MutPtr`. /// /// ### Safety /// /// `self` must be valid. See type level documentation. pub unsafe fn as_mut_ptr(self) -> MutPtr<T> { MutPtr::from_raw(self.as_mut_raw_ptr()) } /// Returns constant raw pointer to the value. pub fn as_raw_ptr(self) -> *const T { self.0.as_ptr() } /// Returns mutable 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() } /// 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_mut<U>(self) -> MutRef<U> where T: StaticUpcast<U>, { StaticUpcast::static_upcast_mut(self.as_mut_ptr()) .as_mut_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_mut<U>(self) -> MutRef<U> where T: StaticDowncast<U>, { StaticDowncast::static_downcast_mut(self.as_mut_ptr()) .as_mut_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_mut<U>(self) -> Option<MutRef<U>> where T: DynamicCast<U>, { DynamicCast::dynamic_cast_mut(self.as_mut_ptr()).as_mut_ref() } /// Returns a C++ const iterator object pointing to the beginning of the collection. /// /// It's recommended to iterate directly on a `MutRef<T>` when possible, using automatic /// `IntoIterator` implementation. /// /// ### Safety /// /// `self` must be valid. It's not possible to make any guarantees about safety, since /// this function calls arbitrary C++ library code. pub unsafe fn begin(self) -> <&'static T as Begin>::Output where &'static T: Begin, { (*self.as_raw_ptr()).begin() } /// Returns a C++ mutable iterator object pointing to the beginning of the collection. /// /// It's recommended to iterate directly on a `MutRef<T>` when possible, using automatic /// `IntoIterator` implementation. /// /// ### Safety /// /// `self` must be valid. It's not possible to make any guarantees about safety, since /// this function calls arbitrary C++ library code. pub unsafe fn begin_mut(self) -> <&'static mut T as BeginMut>::Output where &'static mut T: BeginMut, { (*self.as_mut_raw_ptr()).begin_mut() } /// Returns a C++ const iterator object pointing to the end of the collection. /// /// It's recommended to iterate directly on a `MutRef<T>` when possible, using automatic /// `IntoIterator` implementation. /// /// ### Safety /// /// `self` must be valid. It's not possible to make any guarantees about safety, since /// this function calls arbitrary C++ library code. pub unsafe fn end(self) -> <&'static T as End>::Output where &'static T: End, { (*self.as_raw_ptr()).end() } /// Returns a C++ mutable iterator object pointing to the end of the collection. /// /// It's recommended to iterate directly on a `MutRef<T>` when possible, using automatic /// `IntoIterator` implementation. /// /// ### Safety /// /// `self` must be valid. It's not possible to make any guarantees about safety, since /// this function calls arbitrary C++ library code. pub unsafe fn end_mut(self) -> <&'static mut T as EndMut>::Output where &'static mut T: EndMut, { (*self.as_mut_raw_ptr()).end_mut() } /// Returns a slice corresponding to the object. This function is available when `begin()` and /// `end()` functions of the object return pointers. /// /// ### Safety /// /// `self` must be valid. It's not possible to make any guarantees about safety, since /// this function calls arbitrary C++ library code. It's not recommended to store the slice /// because it may be modified by the C++ library, which would violate Rust's aliasing rules. pub unsafe fn as_slice<'a, T1>(self) -> &'a [T1] where T: 'static, &'static T: Begin<Output = Ptr<T1>> + End<Output = Ptr<T1>>, { let begin = self.begin().as_raw_ptr(); let end = self.end().as_raw_ptr(); let count = (end as usize).saturating_sub(begin as usize) / mem::size_of::<T1>(); slice::from_raw_parts(begin, count) } /// Returns a mutable slice corresponding to the object. /// This function is available when `begin()` and /// `end()` functions of the object return pointers. /// /// ### Safety /// /// `self` must be valid. It's not possible to make any guarantees about safety, since /// this function calls arbitrary C++ library code. It's not recommended to store the slice /// because it may be modified by the C++ library, which would violate Rust's aliasing rules. pub unsafe fn as_mut_slice<'a, T1>(self) -> &'a mut [T1] where T: 'static, &'static mut T: BeginMut<Output = MutPtr<T1>> + EndMut<Output = MutPtr<T1>>, { let begin = self.begin_mut().as_mut_raw_ptr(); let end = self.end_mut().as_mut_raw_ptr(); let count = (end as usize).saturating_sub(begin as usize) / mem::size_of::<T1>(); slice::from_raw_parts_mut(begin, count) } } /// Allows to call member functions of `T` and its base classes directly on the pointer. impl<T> Deref for MutRef<T> { type Target = T; fn deref(&self) -> &T { unsafe { self.0.as_ref() } } } /// Allows to call member functions of `T` and its base classes directly on the pointer. impl<T> DerefMut for MutRef<T> { fn deref_mut(&mut self) -> &mut T { unsafe { self.0.as_mut() } } } /// 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` and `DerefMut`, 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 raw reference. /// /// ### Safety /// /// `value` must be alive as long as `Ref` or pointers derived from it are used. /// See type level documentation. pub unsafe fn from_raw_ref(value: &T) -> Self { Ref(ptr::NonNull::new(value as *const T as *mut T).unwrap()) } /// 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 constant raw pointer to the value. pub fn as_raw_ptr(self) -> *const 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() } /// Returns a C++ const iterator object pointing to the beginning of the collection. /// /// It's recommended to iterate directly on a `Ref<T>` when possible, using automatic /// `IntoIterator` implementation. /// /// ### Safety /// /// `self` must be valid. It's not possible to make any guarantees about safety, since /// this function calls arbitrary C++ library code. pub unsafe fn begin(self) -> <&'static T as Begin>::Output where &'static T: Begin, { (*self.as_raw_ptr()).begin() } /// Returns a C++ const iterator object pointing to the end of the collection. /// /// It's recommended to iterate directly on a `Ref<T>` when possible, using automatic /// `IntoIterator` implementation. /// /// ### Safety /// /// `self` must be valid. It's not possible to make any guarantees about safety, since /// this function calls arbitrary C++ library code. pub unsafe fn end(self) -> <&'static T as End>::Output where &'static T: End, { (*self.as_raw_ptr()).end() } /// Returns a slice corresponding to the object. This function is available when `begin()` and /// `end()` functions of the object return pointers. /// /// ### Safety /// /// `self` must be valid. It's not possible to make any guarantees about safety, since /// this function calls arbitrary C++ library code. It's not recommended to store the slice /// because it may be modified by the C++ library, which would violate Rust's aliasing rules. pub unsafe fn as_slice<'a, T1>(self) -> &'a [T1] where T: 'static, &'static T: Begin<Output = Ptr<T1>> + End<Output = Ptr<T1>>, { let begin = self.begin().as_raw_ptr(); let end = self.end().as_raw_ptr(); let count = (end as usize).saturating_sub(begin as usize) / mem::size_of::<T1>(); slice::from_raw_parts(begin, count) } } /// 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() } } }