Align Rust API with C API and broaden functionality

[mcf06]

Description

The original onnxruntime-rs has evolved both into the newly added Rust API bindings in ms/onnxruntime/rust and, separately, into a version by @seddonm1 that much more tightly mirrors the C API and includes significant additional functionality, such as IoBinding support.

This Draft PR is an effort to incorporate much of the work by @seddonm1 into ms/onnxruntime, while also including improvements from ms/onnxruntime, particularly around safety and Environment and Session management. Some reworking was done of the safety constructs in ms/onnxruntime to fit within the framework of OrtValues as first-class structs. Feedback from the community is greatly appreciated.

Motivation and Context

• Represent OrtValue as its own struct, and allow direct use with Session::run().
• Provide safe containers to separately address OrtValues that do and do not own their own data.
• Allow use of Sessions across thread boundaries.
• Add support for IoBinding, Metadata, more compute hardware

Safely handling OrtValues that own their data memory:

• For graph inputs / outputs that have a fixed shape, MutableOrtValue / MutableOrtValueTyped couples the OrtValue to an ArrayViewMut that views the OrtValue's data memory. This allows seamless, repeated reads / writes to the OrtValue's data using the ndarray API, while preventing tensor shape changes that would require a new OrtValue. Easy to use with IoBindings and Session::run_with_iobinding().
• For graph outputs with variable shape, OrtValues may be viewed with OrtValue::array_view() or array_view_mut().

Safely handling OrtValues that do not own their data memory:

• For graph inputs with variable shape, NdArrayOrtValue transiently creates an OrtValue from an &ndarray::Array, borrowing the Array for the life of the OrtValue. Easy to use with Session::run_with_arrays(), a light wrapper around Session::run().

[mcf06]

@microsoft-github-policy-service agree company="3M"

[simgt]

Hi @mcf06 – What's the status of this PR?

I caught up with the other thread, I'd be super interested in having these changes available on the "official" binding. In the mean time pykeio/ort seems to contain everything in this PR with more additions.

[mcf06]

It looks like much of the community support around rust bindings for onnxruntime has coalesced around pykeio/ort, which I'm happy to see, so I'm going to close this draft PR.