Next we should implement Drop so that we don't massively leak tons of resources.
The easiest way is to just call pop
`popuntil it yields None, and then deallocate our buffer. Note that calling
popis unneeded if
T: !Drop. In theory we can ask Rust if
Tneeds_drop
and omit the calls to
pop`. However in practice
LLVM is really good at removing simple side-effect free code like this, so I
wouldn't bother unless you notice it's not being stripped (in this case it is).
We must not call heap::deallocate
when self.cap == 0
, as in this case we
haven't actually allocated any memory.
impl<T> Drop for Vec<T> { fn drop(&mut self) { if self.cap != 0 { while let Some(_) = self.pop() { } let align = mem::align_of::<T>(); let elem_size = mem::size_of::<T>(); let num_bytes = elem_size * self.cap; unsafe { heap::deallocate(*self.ptr, num_bytes, align); } } } }