Avoid modification of user input data

[ibc]

Fixes #1277

Details

Node

• Ensure that user data given to public API functions is not internally modified (so clone it before using it).
• Use proper utils.clone<T>(xxx) syntax everywhere.
• Remove no longer needed functions in ortc.ts (unused since Flatbuffers migration).
• Do not export unneeded functions in ortc.ts (keep them private).

[nazar-pc]

Please revert all Rust changes, they are not idiomatic and not necessary.

Rust APIs should clearly specify what they need and not more. In this example functions already receive owned value of rtp_parameters that will be dropped at the end of the function because it will need an owned value and will be modifying it. All you're doing by cloning it is once more unnecessary allocation. If caller does have a spare value to give away, no extra allocation will be necessary with old API, if there isn't, the caller will have to do explicit clone. But getting value as an argument that you know will always be cloned is anti-pattern in Rust because it introduces unnecessary allocations that caller can't prevent.

Also it is not pretty to add cloned_ prefix or similar suffix to a variable in Rust. You can redefine variable name even with a different type if you need to in contrast to TypeScript.

[ibc]

If caller does have a spare value to give away, no extra allocation will be necessary with old API, if there isn't, the caller will have to do explicit clone. But getting value as an argument that you know will always be cloned is anti-pattern in Rust because it introduces unnecessary allocations that caller can't prevent.

Example:

1. User defines media_codecs in a variable.
2. User passes media_codecs to router1 = worker.create_router(media_codecs).
3. media_codecs is internally modified by mediasoup. User doesn't know it.
4. User passes same media_codecs variable to router2 = worker.create_router(media_codecs). At that time he is passing a modified media_codecs.
5. Do we really want that?

Basically you are invalidating the whole purpose of this PR by arguing that the user should clone the data by himself if he doesn't want it to be potentially modified by mediasoup. I just don't get it.

[nazar-pc]

4. User passes same media_codecs variable to router2 = worker.create_router(media_codecs). At that time he is passing a modified media_codecs.

Not possible, ownership of media_codecs will be transferred during the first call. You'll have to clone it during the first call or else it will not compile. This is not TypeScript and not C++.

[ibc]

ownership of media_codecs will be transferred during the first call

Ok, that solves it.

May I know how such a ownership transfer is declared in the code?

[nazar-pc]

May I know how such a ownership transfer is declared in the code?

If you specify a variable - you transfer ownership, if you want to give a reference to the data/borrow it, you use &foo or &mut foo explicitly.

[ibc]

Rust changes reverted.

[nazar-pc]

Rust changes look fine to me 😂

[ibc]

Rust changes look fine to me 😂

Thanks, I had to investigate and learn a lot to write them properly.