Method push_bytes

src/repr/src/row.rs:3126–3161

(&'a self, bytes: B)

    /// the caller's allocation is not retained.
    #[allow(clippy::transmute_ptr_to_ptr)]
    pub fn push_bytes<'a, B: Deref<Target = [u8]>>(&'a self, bytes: B) -> &'a [u8] {
        let bytes: &[u8] = &bytes;
        let need = bytes.len();
        if need == 0 {
            return &[];
        }
        let mut inner = self.inner.borrow_mut();

        // Find or create a region with spare capacity for `need` bytes, never growing a region
        // that already holds data (see the type-level comment for why this preserves references).
        let has_room = inner
            .last()
            .map_or(false, |region| region.capacity() - region.len() >= need);
        if !has_room {
            let last_cap = inner.last().map_or(0, |region| region.capacity());
            let new_cap = std::cmp::max(need, last_cap.saturating_mul(2));
            inner.push(Vec::with_capacity(new_cap));
        }

        let region = inner.last_mut().expect("region present");
        let start = region.len();
        region.extend_from_slice(bytes);
        let copied = &region[start..];
        unsafe {
            // This is safe because:
            //   * `copied` references bytes inside `region`'s heap buffer, which we just sized to
            //     fit without reallocating; that buffer is never resized again while it holds data
            //     (we allocate a new region instead), so the reference stays valid.
            //   * The buffer lives as long as the arena: regions are only dropped by `clear`/`drop`,
            //     both of which take `&mut`/ownership, so no `&'a self`-tied reference can outlive
            //     them.
            //   * Pushing further regions may reallocate `self.inner`, but that moves only the
            //     `Vec<u8>` headers, not the heap buffers they own.
            transmute::<&[u8], &'a [u8]>(copied)
        }
    }

    /// Copies `string` into the arena and returns a reference valid for its lifetime.
    pub fn push_string<'a>(&'a self, string: String) -> &'a str {