support conditional compilation of Nix C APIs

nixide/Cargo.toml

@@ -15,18 +15,16 @@ edition      = "2024"
 path = "src/lib.rs"
 
 [features]
-default = ["util"]
-expr = []
-fetchers = []
-flakes = []
-store = []
-util = []
-gc = []
+default = []
+store = ["nixide-sys/nix-store-c"]
+expr = ["store", "nixide-sys/nix-expr-c"]
+flake = ["store", "nixide-sys/nix-flake-c", "nixide-sys/nix-fetchers-c"]
 
 [dependencies]
 libc = "0.2.183"
 stdext = "0.3.3"
-nixide-sys = { path = "../nixide-sys", version = "0.1.0" }
+ctor = "0.6.3"
+nixide-sys = { path = "../nixide-sys", version = "0.1.0", features = ["nix-util-c", "nix-main-c"]}
 
 [dev-dependencies]
 serial_test = "3.4.0"

nixide/src/lib.rs

@@ -1,31 +1,93 @@
 // #![warn(missing_docs)]
 
-// #[allow(unused_extern_crates)]
 pub extern crate libc;
 pub extern crate nixide_sys as sys;
 
 pub(crate) mod errors;
-mod expr;
-// mod flake;
 mod stdext;
-mod store;
 pub(crate) mod util;
 mod verbosity;
 mod version;
 
+#[cfg(feature = "expr")]
+mod expr;
+#[cfg(feature = "store")]
+mod store;
+
+#[cfg(feature = "flake")]
+mod flake;
+
 pub use errors::{NixError, NixideError, NixideResult};
-pub use expr::{EvalState, EvalStateBuilder, Value, ValueType};
-pub use store::{Store, StorePath};
 pub use verbosity::NixVerbosity;
 pub use version::NixVersion;
 
-/// Sets the verbosity level
+#[cfg(feature = "expr")]
+pub use expr::{EvalState, EvalStateBuilder, Value, ValueType};
+#[cfg(feature = "store")]
+pub use store::{Store, StorePath};
+
+use ctor::ctor;
+use util::wrappers::AsInnerPtr as _;
+
+pub(crate) static mut INIT_LIBUTIL_STATUS: Option<NixideResult<()>> = None;
+#[cfg(feature = "store")]
+pub(crate) static mut INIT_LIBSTORE_STATUS: Option<NixideResult<()>> = None;
+#[cfg(feature = "expr")]
+pub(crate) static mut INIT_LIBEXPR_STATUS: Option<NixideResult<()>> = None;
+
+/// # Warning
 ///
-/// # Arguments
-///
-/// * `context` - additional error context, used as an output
-/// * `level` - verbosity level
-pub fn set_verbosity() {
-    // nix_err nix_set_verbosity(nix_c_context * context, nix_verbosity level);
-    // XXX: TODO: (implement Context first)
+/// > Rust's philosophy is that nothing happens before or after main and [ctor](https://github.com/mmastrac/rust-ctor)
+/// > explicitly subverts that. The code that runs in `ctor` functions
+/// > should be careful to limit itself to libc functions and code
+/// > that does not rely on Rust's stdlib services.
+/// >  - Excerpt from the [github:mmastrac/rust-ctor README.md](https://github.com/mmastrac/rust-ctor?tab=readme-ov-file#warnings)
+#[ctor]
+fn init_libutil() {
+    unsafe {
+        INIT_LIBUTIL_STATUS = Some(util::wrap::nix_fn!(|ctx: &errors::ErrorContext| unsafe {
+            sys::nix_libutil_init(ctx.as_ptr());
+        }));
+    }
+}
+
+/// # TODO
+/// **Only run this if the "store" feature flag was enabled**
+///
+/// # Warning
+///
+/// > Rust's philosophy is that nothing happens before or after main and [ctor](https://github.com/mmastrac/rust-ctor)
+/// > explicitly subverts that. The code that runs in `ctor` functions
+/// > should be careful to limit itself to libc functions and code
+/// > that does not rely on Rust's stdlib services.
+/// >  - Excerpt from the [github:mmastrac/rust-ctor README.md](https://github.com/mmastrac/rust-ctor?tab=readme-ov-file#warnings)
+#[ctor]
+#[cfg(feature = "store")]
+fn init_libstore() {
+    // XXX: TODO: how do I support `sys::nix_libstore_init_no_load_config(context)`?
+    unsafe {
+        INIT_LIBSTORE_STATUS = Some(util::wrap::nix_fn!(|ctx: &errors::ErrorContext| unsafe {
+            sys::nix_libutil_init(ctx.as_ptr());
+        }));
+    }
+}
+
+/// # TODO
+/// **Only run this if the "expr" feature flag was enabled**
+//
+/// # Warning
+///
+/// > Rust's philosophy is that nothing happens before or after main and [ctor](https://github.com/mmastrac/rust-ctor)
+/// > explicitly subverts that. The code that runs in `ctor` functions
+/// > should be careful to limit itself to libc functions and code
+/// > that does not rely on Rust's stdlib services.
+/// >  - Excerpt from the [github:mmastrac/rust-ctor README.md](https://github.com/mmastrac/rust-ctor?tab=readme-ov-file#warnings)
+#[ctor]
+#[cfg(feature = "expr")]
+fn init_libexpr() {
+    unsafe {
+        INIT_LIBEXPR_STATUS = Some(util::wrap::nix_fn!(|ctx: &errors::ErrorContext| unsafe {
+            sys::nix_libexpr_init(ctx.as_ptr());
+        }));
+    }
 }