Use RawDocument/Buf in doc! about bson-rust HOT 3 CLOSED

Filed RUST-1747. Going to close this out but feel free to open another issue if you run into anything else!

from bson-rust.

Hey Dan, I'd recommend using the TryFrom<RawDocument> implementation for Document to convert between the two:

let raw_doc = RawDocument::from_bytes(b"raw document contents")?;
let update = doc! {
    "$set": Document::try_from(raw_doc)?,
};

This will allow you to avoid the additional allocation of a RawDocumentBuf.

it would be nice to have a usable RawDocument without extra/intermediate allocation

Because RawDocument and Document have different internal representations, it's not possible to avoid allocation if you want to nest a RawDocument inside of a Document. If you need to end up with a Document, it might be more efficient to construct that first doc as a regular non-raw document (if that works for your use case) to avoid conversion between types.

I think there's also some room for improvement in the driver API to accept raw documents in certain places we currently accept regular documents (like update documents, which I believe is your use case here) so that you don't need to allocate a Document in the first place. We'd have to wait until the next major version to change our API like this, but I will discuss this idea with the team as a consideration for 3.0!

from bson-rust.

If you need to end up with a Document, it might be more efficient to construct that first doc as a regular non-raw document (if that works for your use case) to avoid conversion between types.

Yeah, that makes sense but doesn't work for my use case since raw document bytes are being sent and then deserialized to RawDocument to avoid overhead (since we know it should always be a valid document).

Appreciate the tip, didn't know TryFrom was implemented! & thanks for the consideration for v3! Being able to accept a raw document for updates would be useful!

from bson-rust.