Refactoring to Rust

4 Advanced FFI

This chapter covers

• Creating an NGINX extension module with Rust
• Generating Rust bindings for an existing C codebase
• Using a C memory allocator from Rust
• Sharing functions between Rust crates

The previous chapter centered around a simple example of calling a Rust function from C code. We used a single C stack–allocated string value from our Rust code, but the Rust code did not send any heap-allocated values to the C code, nor did it call any C functions. The API surface of our C calculator program was very small, and thus it was quite straightforward to add Rust to it. This chapter is an extension of the previous chapter’s calculator example. Instead of adding our calculator function to a simple CLI application, we’re ...