Hi Al; Yeah, that's true. The ownership rules of Rust prevents resource ownership outside the container that the resource lifetime taken.
That's why there are buffer copies to take ownership and operate on it. Imo, it should be also removed from the docs if it's written like that (for Rust). Best, Theo On Apr 6, 2021, 17:03, at 17:03, Al Taylor <al.taylor1...@googlemail.com.invalid> wrote: >Hi, > >I was reading around the rust-arrow codebase, evaluating it for >potential future use. I'm particularly interested in zero-copy >processing. > >I could very well be wrong here, as I don't have a lot of rust >experience, but it looks like the code for reading buffers out of IPC >messages is copying the contents of the data. > >A buffer is constructed via Buffer::from(&[u8]) according to an >ipc::Buffer object here: >https://github.com/apache/arrow/blob/8e43f23dcc6a9e630516228f110c48b64d13cec6/rust/arrow/src/ipc/reader.rs#L39 > >The Buffer::from method is defined here: >https://github.com/apache/arrow/blob/8e43f23dcc6a9e630516228f110c48b64d13cec6/rust/arrow/src/buffer/immutable.rs#L222 >and appears to create an empty buffer, then copy data from the slice >into it. > >As far as I'm aware, the C++ implementation of arrow does not copy >buffer data out of IPC messages in this way. > >Is my understanding correct? Are there additional considerations in >rust which means it's not possible for objects accessed by application >code (e.g. record-batches, arrays) to keep their buffers in IPC >messages? > >Thanks, > >Al
