| # Deallocating |
| |
| Next we should implement Drop so that we don't massively leak tons of resources. |
| The easiest way is to just call `pop` until it yields None, and then deallocate |
| our buffer. Note that calling `pop` is unneeded if `T: !Drop`. In theory we can |
| ask Rust if `T` `needs_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. |
| |
| |
| ```rust,ignore |
| 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.as_ptr() as *mut _, num_bytes, align); |
| } |
| } |
| } |
| } |
| ``` |
