XRPL Hooks Rust

Rust hook

Inspiration

I think it's not very convinient to write hooks in C and deals with raw pointers, buffer lenghts, tricky macros, segfaults. This is a wide area to commit errors. So the inspiration was to reduce the cognitive load, which, in turn, leads to a happier life :)

What it does

This allows you to write hooks in Rust, leveraging Rust's zero-cost abstractions, going up one level of abstraction and not worry too much about low-level api. The less worries the fewer errors.

How we built it

From simple to complex. It all started with the simplest hook. When it turned out that it worked, I moved on to more complicated things. There were obstacles at each stage, but after they were tinkered with, they disappeared.

Challenges we ran into

The compiler was trying so hard to inject forbidden function calls
The compiler was trying so hard to underoptimize or overoptimize the wasm binary
Rust forbids by default uninitialized variables
Rust in some cases generate "memset", "memcpy" functions and don't inline them
Rust std lib panic!() macro stuff don't inline function calls
Only "while" loop can guarantee that _g() call to be the first call in it
If you don't use macroses then providing a unique guard ID is quite a tricky task. But it's possible. Thanks, Generics.