1// SPDX-License-Identifier: Apache-2.0 OR MIT
  2
  3use crate::alloc::Allocator;
  4use crate::collections::TryReserveError;
  5use core::iter::TrustedLen;
  6use core::slice::{self};
  7
  8use super::{IntoIter, Vec};
  9
 10// Specialization trait used for Vec::extend
 11#[cfg(not(no_global_oom_handling))]
 12pub(super) trait SpecExtend<T, I> {
 13    fn spec_extend(&mut self, iter: I);
 14}
 15
 16// Specialization trait used for Vec::try_extend
 17pub(super) trait TrySpecExtend<T, I> {
 18    fn try_spec_extend(&mut self, iter: I) -> Result<(), TryReserveError>;
 19}
 20
 21#[cfg(not(no_global_oom_handling))]
 22impl<T, I, A: Allocator> SpecExtend<T, I> for Vec<T, A>
 23where
 24    I: Iterator<Item = T>,
 25{
 26    default fn spec_extend(&mut self, iter: I) {
 27        self.extend_desugared(iter)
 28    }
 29}
 30
 31impl<T, I, A: Allocator> TrySpecExtend<T, I> for Vec<T, A>
 32where
 33    I: Iterator<Item = T>,
 34{
 35    default fn try_spec_extend(&mut self, iter: I) -> Result<(), TryReserveError> {
 36        self.try_extend_desugared(iter)
 37    }
 38}
 39
 40#[cfg(not(no_global_oom_handling))]
 41impl<T, I, A: Allocator> SpecExtend<T, I> for Vec<T, A>
 42where
 43    I: TrustedLen<Item = T>,
 44{
 45    default fn spec_extend(&mut self, iterator: I) {
 46        self.extend_trusted(iterator)
 47    }
 48}
 49
 50impl<T, I, A: Allocator> TrySpecExtend<T, I> for Vec<T, A>
 51where
 52    I: TrustedLen<Item = T>,
 53{
 54    default fn try_spec_extend(&mut self, iterator: I) -> Result<(), TryReserveError> {
 55        self.try_extend_trusted(iterator)
 56    }
 57}
 58
 59#[cfg(not(no_global_oom_handling))]
 60impl<T, A: Allocator> SpecExtend<T, IntoIter<T>> for Vec<T, A> {
 61    fn spec_extend(&mut self, mut iterator: IntoIter<T>) {
 62        unsafe {
 63            self.append_elements(iterator.as_slice() as _);
 64        }
 65        iterator.forget_remaining_elements();
 66    }
 67}
 68
 69impl<T, A: Allocator> TrySpecExtend<T, IntoIter<T>> for Vec<T, A> {
 70    fn try_spec_extend(&mut self, mut iterator: IntoIter<T>) -> Result<(), TryReserveError> {
 71        unsafe {
 72            self.try_append_elements(iterator.as_slice() as _)?;
 73        }
 74        iterator.forget_remaining_elements();
 75        Ok(())
 76    }
 77}
 78
 79#[cfg(not(no_global_oom_handling))]
 80impl<'a, T: 'a, I, A: Allocator> SpecExtend<&'a T, I> for Vec<T, A>
 81where
 82    I: Iterator<Item = &'a T>,
 83    T: Clone,
 84{
 85    default fn spec_extend(&mut self, iterator: I) {
 86        self.spec_extend(iterator.cloned())
 87    }
 88}
 89
 90impl<'a, T: 'a, I, A: Allocator> TrySpecExtend<&'a T, I> for Vec<T, A>
 91where
 92    I: Iterator<Item = &'a T>,
 93    T: Clone,
 94{
 95    default fn try_spec_extend(&mut self, iterator: I) -> Result<(), TryReserveError> {
 96        self.try_spec_extend(iterator.cloned())
 97    }
 98}
 99
100#[cfg(not(no_global_oom_handling))]
101impl<'a, T: 'a, A: Allocator> SpecExtend<&'a T, slice::Iter<'a, T>> for Vec<T, A>
102where
103    T: Copy,
104{
105    fn spec_extend(&mut self, iterator: slice::Iter<'a, T>) {
106        let slice = iterator.as_slice();
107        unsafe { self.append_elements(slice) };
108    }
109}
110
111impl<'a, T: 'a, A: Allocator> TrySpecExtend<&'a T, slice::Iter<'a, T>> for Vec<T, A>
112where
113    T: Copy,
114{
115    fn try_spec_extend(&mut self, iterator: slice::Iter<'a, T>) -> Result<(), TryReserveError> {
116        let slice = iterator.as_slice();
117        unsafe { self.try_append_elements(slice) }
118    }
119}