rust/repeated.rs - third_party/protobuf - Git at Google

 // Protocol Buffers - Google's data interchange format
 // Copyright 2023 Google LLC.  All rights reserved.
 //
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file or at
 // https://developers.google.com/open-source/licenses/bsd

 use std::fmt::{self, Debug};
 use std::iter;
 use std::iter::FusedIterator;
 /// Repeated scalar fields are implemented around the runtime-specific
 /// `RepeatedField` struct. `RepeatedField` stores an opaque pointer to the
 /// runtime-specific representation of a repeated scalar (`upb_Array*` on upb,
 /// and `RepeatedField<T>*` on cpp).
 use std::marker::PhantomData;
 use std::ops::Deref;

 use crate::{
     Mut, MutProxy, Proxied, SettableValue, View, ViewProxy,
     __internal::{Private, RawRepeatedField},
     __runtime::InnerRepeatedMut,
 };

 /// Views the elements in a `repeated` field of `T`.
 #[repr(transparent)]
 pub struct RepeatedView<'msg, T: ?Sized> {
     // This does not need to carry an arena in upb, so it can be just the raw repeated field
     raw: RawRepeatedField,
     _phantom: PhantomData<&'msg T>,
 }

 impl<'msg, T: ?Sized> Copy for RepeatedView<'msg, T> {}
 impl<'msg, T: ?Sized> Clone for RepeatedView<'msg, T> {
     fn clone(&self) -> Self {
         *self
     }
 }

 unsafe impl<'msg, T: ?Sized> Sync for RepeatedView<'msg, T> {}
 unsafe impl<'msg, T: ?Sized> Send for RepeatedView<'msg, T> {}

 impl<'msg, T: ?Sized> Debug for RepeatedView<'msg, T> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("RepeatedView").field("raw", &self.raw).finish()
     }
 }

 /// Mutates the elements in a `repeated` field of `T`.
 #[repr(transparent)]
 pub struct RepeatedMut<'msg, T: ?Sized> {
     pub(crate) inner: InnerRepeatedMut<'msg>,
     _phantom: PhantomData<&'msg mut T>,
 }

 unsafe impl<'msg, T: ?Sized> Sync for RepeatedMut<'msg, T> {}

 impl<'msg, T: ?Sized> Deref for RepeatedMut<'msg, T> {
     type Target = RepeatedView<'msg, T>;
     fn deref(&self) -> &Self::Target {
         // SAFETY:
         //   - `Repeated{View,Mut}<'msg, T>` are both `#[repr(transparent)]` over
         //     `RepeatedField<'msg, T>`.
         //   - `Repeated{View,Mut}<'msg, T>` are both `#[repr(transparent)]` over
         //     `RepeatedField<'msg, T>`.
         //   - `RepeatedField` is a type alias for `NonNull`.
         unsafe { &*(self as *const Self as *const RepeatedView<'msg, T>) }
     }
 }

 impl<'msg, T: ?Sized> Debug for RepeatedMut<'msg, T> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("RepeatedMut").field("raw", &self.raw).finish()
     }
 }

 impl<'msg, T> RepeatedView<'msg, T>
 where
     T: ProxiedInRepeated + ?Sized + 'msg,
 {
     #[doc(hidden)]
     pub fn as_raw(&self, _private: Private) -> RawRepeatedField {
         self.raw
     }

     /// # Safety
     /// - `inner` must be valid to read from for `'msg`
     #[doc(hidden)]
     pub unsafe fn from_raw(_private: Private, raw: RawRepeatedField) -> Self {
         Self { raw, _phantom: PhantomData }
     }

     /// Gets the length of the repeated field.
     pub fn len(&self) -> usize {
         T::repeated_len(*self)
     }

     /// Returns true if the repeated field has no values.
     pub fn is_empty(&self) -> bool {
         self.len() == 0
     }

     /// Gets the value at `index`.
     ///
     /// Returns `None` if `index > len`.
     pub fn get(self, index: usize) -> Option<View<'msg, T>> {
         if index >= self.len() {
             return None;
         }
         // SAFETY: `index` has been checked to be in-bounds
         Some(unsafe { self.get_unchecked(index) })
     }

     /// Gets the value at `index` without bounds-checking.
     ///
     /// # Safety
     /// Undefined behavior if `index >= len`
     pub unsafe fn get_unchecked(self, index: usize) -> View<'msg, T> {
         // SAFETY: in-bounds as promised
         unsafe { T::repeated_get_unchecked(self, index) }
     }

     /// Iterates over the values in the repeated field.
     pub fn iter(self) -> RepeatedIter<'msg, T> {
         self.into_iter()
     }
 }

 impl<'msg, T> RepeatedMut<'msg, T>
 where
     T: ProxiedInRepeated + ?Sized + 'msg,
 {
     /// # Safety
     /// - `inner` must be valid to read and write from for `'msg`
     /// - There must be no aliasing references or mutations on the same
     ///   underlying object.
     #[doc(hidden)]
     pub unsafe fn from_inner(_private: Private, inner: InnerRepeatedMut<'msg>) -> Self {
         Self { inner, _phantom: PhantomData }
     }

     /// # Safety
     /// - The return value must not be mutated through without synchronization.
     #[allow(dead_code)]
     pub(crate) unsafe fn into_inner(self) -> InnerRepeatedMut<'msg> {
         self.inner
     }

     #[doc(hidden)]
     pub fn as_raw(&mut self, _private: Private) -> RawRepeatedField {
         self.inner.raw
     }

     /// Appends `val` to the end of the repeated field.
     pub fn push(&mut self, val: View<T>) {
         T::repeated_push(self.as_mut(), val);
     }

     /// Sets the value at `index` to the value `val`.
     ///
     /// # Panics
     /// Panics if `index >= len`
     pub fn set(&mut self, index: usize, val: View<T>) {
         let len = self.len();
         if index >= len {
             panic!("index {index} >= repeated len {len}");
         }
         // SAFETY: `index` has been checked to be in-bounds.
         unsafe { self.set_unchecked(index, val) }
     }

     /// Sets the value at `index` to the value `val`.
     ///
     /// # Safety
     /// Undefined behavior if `index >= len`
     pub unsafe fn set_unchecked(&mut self, index: usize, val: View<T>) {
         // SAFETY: `index` is in-bounds as promised by the caller.
         unsafe { T::repeated_set_unchecked(self.as_mut(), index, val) }
     }

     /// Returns the value at `index`.
     // This is defined as an inherent function to prevent `MutProxy::get` from being
     // preferred over `RepeatedView::get`. The former gets priority as it does
     // not require a deref.
     pub fn get(&self, index: usize) -> Option<View<T>> {
         self.as_view().get(index)
     }

     /// Copies from the `src` repeated field into this one.
     ///
     /// Also provided by [`MutProxy::set`].
     pub fn copy_from(&mut self, src: RepeatedView<'_, T>) {
         T::repeated_copy_from(src, self.as_mut())
     }

     /// Clears the repeated field.
     pub fn clear(&mut self) {
         T::repeated_clear(self.as_mut())
     }
 }

 /// Types that can appear in a `Repeated<T>`.
 ///
 /// This trait is implemented by generated code to communicate how the proxied
 /// type can be manipulated for a repeated field.
 ///
 /// Scalars and messages implement `ProxiedInRepeated`.
 ///
 /// # Safety
 /// - It must be sound to call `*_unchecked*(x)` with an `index` less than
 ///   `repeated_len(x)`.
 pub unsafe trait ProxiedInRepeated: Proxied {
     /// Constructs a new owned `Repeated` field.
     #[doc(hidden)]
     fn repeated_new(_private: Private) -> Repeated<Self> {
         unimplemented!("not required")
     }

     /// Frees the repeated field in-place, for use in `Drop`.
     ///
     /// # Safety
     /// - After `repeated_free`, no other methods on the input are safe to call.
     #[doc(hidden)]
     unsafe fn repeated_free(_private: Private, _repeated: &mut Repeated<Self>) {
         unimplemented!("not required")
     }

     /// Gets the length of the repeated field.
     fn repeated_len(repeated: View<Repeated<Self>>) -> usize;

     /// Appends a new element to the end of the repeated field.
     fn repeated_push(repeated: Mut<Repeated<Self>>, val: View<Self>);

     /// Clears the repeated field of elements.
     fn repeated_clear(repeated: Mut<Repeated<Self>>);

     /// # Safety
     /// `index` must be less than `Self::repeated_len(repeated)`
     unsafe fn repeated_get_unchecked(repeated: View<Repeated<Self>>, index: usize) -> View<Self>;

     /// # Safety
     /// `index` must be less than `Self::repeated_len(repeated)`
     unsafe fn repeated_set_unchecked(repeated: Mut<Repeated<Self>>, index: usize, val: View<Self>);

     /// Copies the values in the `src` repeated field into `dest`.
     fn repeated_copy_from(src: View<Repeated<Self>>, dest: Mut<Repeated<Self>>);
 }

 /// An iterator over the values inside of a [`View<Repeated<T>>`](RepeatedView).
 pub struct RepeatedIter<'msg, T: ?Sized> {
     view: RepeatedView<'msg, T>,
     current_index: usize,
 }

 impl<'msg, T: ?Sized> Debug for RepeatedIter<'msg, T> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("RepeatedIter")
             .field("view", &self.view)
             .field("current_index", &self.current_index)
             .finish()
     }
 }

 /// An iterator over the mutators inside of a [`Mut<Repeated<T>>`](RepeatedMut).
 pub struct RepeatedIterMut<'msg, T: ?Sized> {
     mutator: RepeatedMut<'msg, T>,
     current_index: usize,
 }

 impl<'msg, T: ?Sized> Debug for RepeatedIterMut<'msg, T> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("RepeatedIterMut")
             .field("mutator", &self.mutator)
             .field("current_index", &self.current_index)
             .finish()
     }
 }

 /// A `repeated` field of `T`, used as the owned target for `Proxied`.
 ///
 /// Users will generally write [`View<Repeated<T>>`](RepeatedView) or
 /// [`Mut<Repeated<T>>`](RepeatedMut) to access the repeated elements
 pub struct Repeated<T: ?Sized + ProxiedInRepeated> {
     inner: InnerRepeatedMut<'static>,
     _phantom: PhantomData<T>,
 }

 impl<T: ?Sized + ProxiedInRepeated> Repeated<T> {
     #[allow(dead_code)]
     pub(crate) fn new() -> Self {
         T::repeated_new(Private)
     }

     pub(crate) unsafe fn from_inner(inner: InnerRepeatedMut<'static>) -> Self {
         Self { inner, _phantom: PhantomData }
     }

     #[allow(dead_code)]
     pub(crate) fn inner(&mut self) -> InnerRepeatedMut<'static> {
         self.inner
     }

     pub(crate) fn as_mut(&mut self) -> RepeatedMut<'_, T> {
         RepeatedMut { inner: self.inner, _phantom: PhantomData }
     }
 }

 impl<T: ?Sized + ProxiedInRepeated> Drop for Repeated<T> {
     fn drop(&mut self) {
         // SAFETY: only called once
         unsafe { T::repeated_free(Private, self) }
     }
 }

 // SAFETY: `Repeated` does not allow for shared mutability.
 unsafe impl<T: ProxiedInRepeated> Sync for Repeated<T> {}

 impl<T> Proxied for Repeated<T>
 where
     T: ProxiedInRepeated + ?Sized,
 {
     type View<'msg> = RepeatedView<'msg, T> where Repeated<T>: 'msg;
     type Mut<'msg> = RepeatedMut<'msg, T> where Repeated<T>: 'msg;
 }

 impl<'msg, T> ViewProxy<'msg> for RepeatedView<'msg, T>
 where
     T: ProxiedInRepeated + ?Sized + 'msg,
 {
     type Proxied = Repeated<T>;

     fn as_view(&self) -> View<'_, Self::Proxied> {
         *self
     }

     fn into_view<'shorter>(self) -> View<'shorter, Self::Proxied>
     where
         'msg: 'shorter,
     {
         RepeatedView { raw: self.raw, _phantom: PhantomData }
     }
 }

 impl<'msg, T> ViewProxy<'msg> for RepeatedMut<'msg, T>
 where
     T: ProxiedInRepeated + ?Sized + 'msg,
 {
     type Proxied = Repeated<T>;

     fn as_view(&self) -> View<'_, Self::Proxied> {
         **self
     }

     fn into_view<'shorter>(self) -> View<'shorter, Self::Proxied>
     where
         'msg: 'shorter,
     {
         *self.into_mut::<'shorter>()
     }
 }

 impl<'msg, T> MutProxy<'msg> for RepeatedMut<'msg, T>
 where
     T: ProxiedInRepeated + ?Sized + 'msg,
 {
     fn as_mut(&mut self) -> Mut<'_, Self::Proxied> {
         RepeatedMut { inner: self.inner, _phantom: PhantomData }
     }

     fn into_mut<'shorter>(self) -> Mut<'shorter, Self::Proxied>
     where
         'msg: 'shorter,
     {
         RepeatedMut { inner: self.inner, _phantom: PhantomData }
     }
 }

 impl<'msg, T> SettableValue<Repeated<T>> for RepeatedView<'msg, T>
 where
     T: ProxiedInRepeated + ?Sized + 'msg,
 {
     fn set_on<'b>(self, _private: Private, mutator: Mut<'b, Repeated<T>>)
     where
         Repeated<T>: 'b,
     {
         T::repeated_copy_from(self, mutator)
     }
 }

 // TODO: impl ExactSizeIterator
 impl<'msg, T> iter::Iterator for RepeatedIter<'msg, T>
 where
     T: ProxiedInRepeated + ?Sized + 'msg,
 {
     type Item = View<'msg, T>;

     fn next(&mut self) -> Option<Self::Item> {
         let val = self.view.get(self.current_index);
         if val.is_some() {
             self.current_index += 1;
         }
         val
     }
 }

 impl<'msg, T: ?Sized + ProxiedInRepeated> ExactSizeIterator for RepeatedIter<'msg, T> {
     fn len(&self) -> usize {
         self.view.len()
     }
 }

 impl<'msg, T: ?Sized + ProxiedInRepeated> FusedIterator for RepeatedIter<'msg, T> {}

 impl<'msg, T> iter::IntoIterator for RepeatedView<'msg, T>
 where
     T: ProxiedInRepeated + ?Sized + 'msg,
 {
     type Item = View<'msg, T>;
     type IntoIter = RepeatedIter<'msg, T>;

     fn into_iter(self) -> Self::IntoIter {
         RepeatedIter { view: self, current_index: 0 }
     }
 }

 #[cfg(test)]
 mod tests {
     use super::*;
     use googletest::prelude::*;

     #[test]
     fn test_primitive_repeated() {
         macro_rules! primitive_repeated_tests {
             ($($t:ty => [$($vals:expr),* $(,)?]),* $(,)?) => {
                 $({
                 // Constructs a new, owned, `Repeated`, only used for tests.
                 let mut r = Repeated::<$t>::new();
                 let mut r = r.as_mut();
                 assert_that!(r.len(), eq(0));
                 assert!(r.iter().next().is_none(), "starts with empty iter");
                 assert!(r.iter().next().is_none(), "starts with empty mut iter");
                 assert!(r.is_empty(), "starts is_empty");

                 let mut expected_len = 0usize;
                 $(
                     let val: View<$t> = $vals;
                     r.push(val);
                     assert_that!(r.get(expected_len), eq(Some(val)));
                     expected_len += 1;
                     assert_that!(r.len(), eq(expected_len));

                 )*
                 assert_that!(
                     r.iter().collect::<Vec<$t>>(), elements_are![$(eq($vals)),*]);
                 r.set(0, <$t as Default>::default());
                 assert_that!(r.get(0).expect("elem 0"), eq(<$t as Default>::default()));

                 r.clear();
                 assert!(r.is_empty(), "is_empty after clear");
                 assert!(r.iter().next().is_none(), "iter empty after clear");
                 assert!(r.into_iter().next().is_none(), "mut iter empty after clear");
                 })*
             }
         }
         primitive_repeated_tests!(
             u32 => [1,2,3],
             i32 => [1,2],
             f64 => [10.0, 0.1234f64],
             bool => [false, true, true, false],
         );
     }
 }
	// Protocol Buffers - Google's data interchange format
	// Copyright 2023 Google LLC. All rights reserved.
	//
	// Use of this source code is governed by a BSD-style
	// license that can be found in the LICENSE file or at
	// https://developers.google.com/open-source/licenses/bsd

	use std::fmt::{self, Debug};
	use std::iter;
	use std::iter::FusedIterator;
	/// Repeated scalar fields are implemented around the runtime-specific
	/// `RepeatedField` struct. `RepeatedField` stores an opaque pointer to the
	/// runtime-specific representation of a repeated scalar (`upb_Array*` on upb,
	/// and `RepeatedField<T>*` on cpp).
	use std::marker::PhantomData;
	use std::ops::Deref;

	use crate::{
	Mut, MutProxy, Proxied, SettableValue, View, ViewProxy,
	__internal::{Private, RawRepeatedField},
	__runtime::InnerRepeatedMut,
	};

	/// Views the elements in a `repeated` field of `T`.
	#[repr(transparent)]
	pub struct RepeatedView<'msg, T: ?Sized> {
	// This does not need to carry an arena in upb, so it can be just the raw repeated field
	raw: RawRepeatedField,
	_phantom: PhantomData<&'msg T>,
	}

	impl<'msg, T: ?Sized> Copy for RepeatedView<'msg, T> {}
	impl<'msg, T: ?Sized> Clone for RepeatedView<'msg, T> {
	fn clone(&self) -> Self {
	*self
	}
	}

	unsafe impl<'msg, T: ?Sized> Sync for RepeatedView<'msg, T> {}
	unsafe impl<'msg, T: ?Sized> Send for RepeatedView<'msg, T> {}

	impl<'msg, T: ?Sized> Debug for RepeatedView<'msg, T> {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
	f.debug_struct("RepeatedView").field("raw", &self.raw).finish()
	}
	}

	/// Mutates the elements in a `repeated` field of `T`.
	#[repr(transparent)]
	pub struct RepeatedMut<'msg, T: ?Sized> {
	pub(crate) inner: InnerRepeatedMut<'msg>,
	_phantom: PhantomData<&'msg mut T>,
	}

	unsafe impl<'msg, T: ?Sized> Sync for RepeatedMut<'msg, T> {}

	impl<'msg, T: ?Sized> Deref for RepeatedMut<'msg, T> {
	type Target = RepeatedView<'msg, T>;
	fn deref(&self) -> &Self::Target {
	// SAFETY:
	// - `Repeated{View,Mut}<'msg, T>` are both `#[repr(transparent)]` over
	// `RepeatedField<'msg, T>`.
	// - `Repeated{View,Mut}<'msg, T>` are both `#[repr(transparent)]` over
	// `RepeatedField<'msg, T>`.
	// - `RepeatedField` is a type alias for `NonNull`.
	unsafe { &(self as const Self as *const RepeatedView<'msg, T>) }
	}
	}

	impl<'msg, T: ?Sized> Debug for RepeatedMut<'msg, T> {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
	f.debug_struct("RepeatedMut").field("raw", &self.raw).finish()
	}
	}

	impl<'msg, T> RepeatedView<'msg, T>
	where
	T: ProxiedInRepeated + ?Sized + 'msg,
	{
	#[doc(hidden)]
	pub fn as_raw(&self, _private: Private) -> RawRepeatedField {
	self.raw
	}

	/// # Safety
	/// - `inner` must be valid to read from for `'msg`
	#[doc(hidden)]
	pub unsafe fn from_raw(_private: Private, raw: RawRepeatedField) -> Self {
	Self { raw, _phantom: PhantomData }
	}

	/// Gets the length of the repeated field.
	pub fn len(&self) -> usize {
	T::repeated_len(*self)
	}

	/// Returns true if the repeated field has no values.
	pub fn is_empty(&self) -> bool {
	self.len() == 0
	}

	/// Gets the value at `index`.
	///
	/// Returns `None` if `index > len`.
	pub fn get(self, index: usize) -> Option<View<'msg, T>> {
	if index >= self.len() {
	return None;
	}
	// SAFETY: `index` has been checked to be in-bounds
	Some(unsafe { self.get_unchecked(index) })
	}

	/// Gets the value at `index` without bounds-checking.
	///
	/// # Safety
	/// Undefined behavior if `index >= len`
	pub unsafe fn get_unchecked(self, index: usize) -> View<'msg, T> {
	// SAFETY: in-bounds as promised
	unsafe { T::repeated_get_unchecked(self, index) }
	}

	/// Iterates over the values in the repeated field.
	pub fn iter(self) -> RepeatedIter<'msg, T> {
	self.into_iter()
	}
	}

	impl<'msg, T> RepeatedMut<'msg, T>
	where
	T: ProxiedInRepeated + ?Sized + 'msg,
	{
	/// # Safety
	/// - `inner` must be valid to read and write from for `'msg`
	/// - There must be no aliasing references or mutations on the same
	/// underlying object.
	#[doc(hidden)]
	pub unsafe fn from_inner(_private: Private, inner: InnerRepeatedMut<'msg>) -> Self {
	Self { inner, _phantom: PhantomData }
	}

	/// # Safety
	/// - The return value must not be mutated through without synchronization.
	#[allow(dead_code)]
	pub(crate) unsafe fn into_inner(self) -> InnerRepeatedMut<'msg> {
	self.inner
	}

	#[doc(hidden)]
	pub fn as_raw(&mut self, _private: Private) -> RawRepeatedField {
	self.inner.raw
	}

	/// Appends `val` to the end of the repeated field.
	pub fn push(&mut self, val: View<T>) {
	T::repeated_push(self.as_mut(), val);
	}

	/// Sets the value at `index` to the value `val`.
	///
	/// # Panics
	/// Panics if `index >= len`
	pub fn set(&mut self, index: usize, val: View<T>) {
	let len = self.len();
	if index >= len {
	panic!("index {index} >= repeated len {len}");
	}
	// SAFETY: `index` has been checked to be in-bounds.
	unsafe { self.set_unchecked(index, val) }
	}

	/// Sets the value at `index` to the value `val`.
	///
	/// # Safety
	/// Undefined behavior if `index >= len`
	pub unsafe fn set_unchecked(&mut self, index: usize, val: View<T>) {
	// SAFETY: `index` is in-bounds as promised by the caller.
	unsafe { T::repeated_set_unchecked(self.as_mut(), index, val) }
	}

	/// Returns the value at `index`.
	// This is defined as an inherent function to prevent `MutProxy::get` from being
	// preferred over `RepeatedView::get`. The former gets priority as it does
	// not require a deref.
	pub fn get(&self, index: usize) -> Option<View<T>> {
	self.as_view().get(index)
	}

	/// Copies from the `src` repeated field into this one.
	///
	/// Also provided by [`MutProxy::set`].
	pub fn copy_from(&mut self, src: RepeatedView<'_, T>) {
	T::repeated_copy_from(src, self.as_mut())
	}

	/// Clears the repeated field.
	pub fn clear(&mut self) {
	T::repeated_clear(self.as_mut())
	}
	}

	/// Types that can appear in a `Repeated<T>`.
	///
	/// This trait is implemented by generated code to communicate how the proxied
	/// type can be manipulated for a repeated field.
	///
	/// Scalars and messages implement `ProxiedInRepeated`.
	///
	/// # Safety
	/// - It must be sound to call `_unchecked(x)` with an `index` less than
	/// `repeated_len(x)`.
	pub unsafe trait ProxiedInRepeated: Proxied {
	/// Constructs a new owned `Repeated` field.
	#[doc(hidden)]
	fn repeated_new(_private: Private) -> Repeated<Self> {
	unimplemented!("not required")
	}

	/// Frees the repeated field in-place, for use in `Drop`.
	///
	/// # Safety
	/// - After `repeated_free`, no other methods on the input are safe to call.
	#[doc(hidden)]
	unsafe fn repeated_free(_private: Private, _repeated: &mut Repeated<Self>) {
	unimplemented!("not required")
	}

	/// Gets the length of the repeated field.
	fn repeated_len(repeated: View<Repeated<Self>>) -> usize;

	/// Appends a new element to the end of the repeated field.
	fn repeated_push(repeated: Mut<Repeated<Self>>, val: View<Self>);

	/// Clears the repeated field of elements.
	fn repeated_clear(repeated: Mut<Repeated<Self>>);

	/// # Safety
	/// `index` must be less than `Self::repeated_len(repeated)`
	unsafe fn repeated_get_unchecked(repeated: View<Repeated<Self>>, index: usize) -> View<Self>;

	/// # Safety
	/// `index` must be less than `Self::repeated_len(repeated)`
	unsafe fn repeated_set_unchecked(repeated: Mut<Repeated<Self>>, index: usize, val: View<Self>);

	/// Copies the values in the `src` repeated field into `dest`.
	fn repeated_copy_from(src: View<Repeated<Self>>, dest: Mut<Repeated<Self>>);
	}

	/// An iterator over the values inside of a [`View<Repeated<T>>`](RepeatedView).
	pub struct RepeatedIter<'msg, T: ?Sized> {
	view: RepeatedView<'msg, T>,
	current_index: usize,
	}

	impl<'msg, T: ?Sized> Debug for RepeatedIter<'msg, T> {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
	f.debug_struct("RepeatedIter")
	.field("view", &self.view)
	.field("current_index", &self.current_index)
	.finish()
	}
	}

	/// An iterator over the mutators inside of a [`Mut<Repeated<T>>`](RepeatedMut).
	pub struct RepeatedIterMut<'msg, T: ?Sized> {
	mutator: RepeatedMut<'msg, T>,
	current_index: usize,
	}

	impl<'msg, T: ?Sized> Debug for RepeatedIterMut<'msg, T> {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
	f.debug_struct("RepeatedIterMut")
	.field("mutator", &self.mutator)
	.field("current_index", &self.current_index)
	.finish()
	}
	}

	/// A `repeated` field of `T`, used as the owned target for `Proxied`.
	///
	/// Users will generally write [`View<Repeated<T>>`](RepeatedView) or
	/// [`Mut<Repeated<T>>`](RepeatedMut) to access the repeated elements
	pub struct Repeated<T: ?Sized + ProxiedInRepeated> {
	inner: InnerRepeatedMut<'static>,
	_phantom: PhantomData<T>,
	}

	impl<T: ?Sized + ProxiedInRepeated> Repeated<T> {
	#[allow(dead_code)]
	pub(crate) fn new() -> Self {
	T::repeated_new(Private)
	}

	pub(crate) unsafe fn from_inner(inner: InnerRepeatedMut<'static>) -> Self {
	Self { inner, _phantom: PhantomData }
	}

	#[allow(dead_code)]
	pub(crate) fn inner(&mut self) -> InnerRepeatedMut<'static> {
	self.inner
	}

	pub(crate) fn as_mut(&mut self) -> RepeatedMut<'_, T> {
	RepeatedMut { inner: self.inner, _phantom: PhantomData }
	}
	}

	impl<T: ?Sized + ProxiedInRepeated> Drop for Repeated<T> {
	fn drop(&mut self) {
	// SAFETY: only called once
	unsafe { T::repeated_free(Private, self) }
	}
	}

	// SAFETY: `Repeated` does not allow for shared mutability.
	unsafe impl<T: ProxiedInRepeated> Sync for Repeated<T> {}

	impl<T> Proxied for Repeated<T>
	where
	T: ProxiedInRepeated + ?Sized,
	{
	type View<'msg> = RepeatedView<'msg, T> where Repeated<T>: 'msg;
	type Mut<'msg> = RepeatedMut<'msg, T> where Repeated<T>: 'msg;
	}

	impl<'msg, T> ViewProxy<'msg> for RepeatedView<'msg, T>
	where
	T: ProxiedInRepeated + ?Sized + 'msg,
	{
	type Proxied = Repeated<T>;

	fn as_view(&self) -> View<'_, Self::Proxied> {
	*self
	}

	fn into_view<'shorter>(self) -> View<'shorter, Self::Proxied>
	where
	'msg: 'shorter,
	{
	RepeatedView { raw: self.raw, _phantom: PhantomData }
	}
	}

	impl<'msg, T> ViewProxy<'msg> for RepeatedMut<'msg, T>
	where
	T: ProxiedInRepeated + ?Sized + 'msg,
	{
	type Proxied = Repeated<T>;

	fn as_view(&self) -> View<'_, Self::Proxied> {
	**self
	}

	fn into_view<'shorter>(self) -> View<'shorter, Self::Proxied>
	where
	'msg: 'shorter,
	{
	*self.into_mut::<'shorter>()
	}
	}

	impl<'msg, T> MutProxy<'msg> for RepeatedMut<'msg, T>
	where
	T: ProxiedInRepeated + ?Sized + 'msg,
	{
	fn as_mut(&mut self) -> Mut<'_, Self::Proxied> {
	RepeatedMut { inner: self.inner, _phantom: PhantomData }
	}

	fn into_mut<'shorter>(self) -> Mut<'shorter, Self::Proxied>
	where
	'msg: 'shorter,
	{
	RepeatedMut { inner: self.inner, _phantom: PhantomData }
	}
	}

	impl<'msg, T> SettableValue<Repeated<T>> for RepeatedView<'msg, T>
	where
	T: ProxiedInRepeated + ?Sized + 'msg,
	{
	fn set_on<'b>(self, _private: Private, mutator: Mut<'b, Repeated<T>>)
	where
	Repeated<T>: 'b,
	{
	T::repeated_copy_from(self, mutator)
	}
	}

	// TODO: impl ExactSizeIterator
	impl<'msg, T> iter::Iterator for RepeatedIter<'msg, T>
	where
	T: ProxiedInRepeated + ?Sized + 'msg,
	{
	type Item = View<'msg, T>;

	fn next(&mut self) -> Option<Self::Item> {
	let val = self.view.get(self.current_index);
	if val.is_some() {
	self.current_index += 1;
	}
	val
	}
	}

	impl<'msg, T: ?Sized + ProxiedInRepeated> ExactSizeIterator for RepeatedIter<'msg, T> {
	fn len(&self) -> usize {
	self.view.len()
	}
	}

	impl<'msg, T: ?Sized + ProxiedInRepeated> FusedIterator for RepeatedIter<'msg, T> {}

	impl<'msg, T> iter::IntoIterator for RepeatedView<'msg, T>
	where
	T: ProxiedInRepeated + ?Sized + 'msg,
	{
	type Item = View<'msg, T>;
	type IntoIter = RepeatedIter<'msg, T>;

	fn into_iter(self) -> Self::IntoIter {
	RepeatedIter { view: self, current_index: 0 }
	}
	}

	#[cfg(test)]
	mod tests {
	use super::*;
	use googletest::prelude::*;

	#[test]
	fn test_primitive_repeated() {
	macro_rules! primitive_repeated_tests {
	($($t:ty => [$($vals:expr),* $(,)?]),* $(,)?) => {
	$({
	// Constructs a new, owned, `Repeated`, only used for tests.
	let mut r = Repeated::<$t>::new();
	let mut r = r.as_mut();
	assert_that!(r.len(), eq(0));
	assert!(r.iter().next().is_none(), "starts with empty iter");
	assert!(r.iter().next().is_none(), "starts with empty mut iter");
	assert!(r.is_empty(), "starts is_empty");

	let mut expected_len = 0usize;
	$(
	let val: View<$t> = $vals;
	r.push(val);
	assert_that!(r.get(expected_len), eq(Some(val)));
	expected_len += 1;
	assert_that!(r.len(), eq(expected_len));

	)*
	assert_that!(
	r.iter().collect::<Vec<$t>>(), elements_are![$(eq($vals)),*]);
	r.set(0, <$t as Default>::default());
	assert_that!(r.get(0).expect("elem 0"), eq(<$t as Default>::default()));

	r.clear();
	assert!(r.is_empty(), "is_empty after clear");
	assert!(r.iter().next().is_none(), "iter empty after clear");
	assert!(r.into_iter().next().is_none(), "mut iter empty after clear");
	})*
	}
	}
	primitive_repeated_tests!(
	u32 => [1,2,3],
	i32 => [1,2],
	f64 => [10.0, 0.1234f64],
	bool => [false, true, true, false],
	);
	}
	}