feat(napi-sys): support load Node-API symbols dynamically (#2014)

.github/workflows/test-release.yaml

@@ -548,7 +548,7 @@ jobs:
       - name: Build
         run: |
           bun run build
-          bun run build:test
+          yarn workspace @examples/napi build --features dyn-symbols
       - name: Test
         continue-on-error: true
         run: bun run test:bun

crates/napi/Cargo.toml

@@ -55,6 +55,7 @@ tokio_stats = ["tokio/stats"]
 tokio_sync = ["tokio/sync"]
 tokio_test_util = ["tokio/test-util"]
 tokio_time = ["tokio/time"]
+dyn-symbols = ["napi-sys/dyn-symbols"]
 
 [dependencies]
 bitflags = "2"

crates/napi/src/bindgen_runtime/module_register.rs

@@ -243,7 +243,7 @@ pub fn get_c_callback(raw_fn: ExportRegisterCallback) -> Result<crate::Callback>
   })
 }
 
-#[cfg(all(windows, not(feature = "noop")))]
+#[cfg(all(any(windows, feature = "dyn-symbols"), not(feature = "noop")))]
 #[ctor::ctor]
 fn load_host() {
   unsafe {

crates/sys/Cargo.toml

@@ -12,6 +12,7 @@ rust-version = "1.65"
 version = "2.3.0"
 
 [features]
+dyn-symbols = ["libloading"]
 experimental = []
 napi1 = []
 napi2 = ["napi1"]
@@ -26,5 +27,8 @@ napi9 = ["napi8"]
 [package.metadata.workspaces]
 independent = true
 
-[target.'cfg(windows)'.dependencies.libloading]
-version = "0.8"
+[dependencies]
+libloading = { version = "0.8", optional = true }
+
+[target.'cfg(windows)'.dependencies]
+libloading = "0.8"

crates/sys/src/functions.rs

@@ -780,15 +780,13 @@ pub use napi8::*;
 #[cfg(feature = "napi9")]
 pub use napi9::*;
 
-#[cfg(windows)]
+#[cfg(any(windows, feature = "dyn-symbols"))]
 pub(super) unsafe fn load_all() -> Result<libloading::Library, libloading::Error> {
-  let host = match libloading::os::windows::Library::this() {
-    Ok(lib) => lib.into(),
-    Err(err) => {
-      eprintln!("Initialize libloading failed {}", err);
-      return Err(err);
-    }
-  };
+  #[cfg(windows)]
+  let host = libloading::os::windows::Library::this()?.into();
+
+  #[cfg(unix)]
+  let host = libloading::os::unix::Library::this().into();
 
   napi1::load(&host)?;
   #[cfg(feature = "napi2")]

crates/sys/src/lib.rs

@@ -1,73 +1,74 @@
+// borrowed from https://github.com/neon-bindings/neon/tree/main/crates/neon/src/sys/bindings
+
 #![allow(ambiguous_glob_reexports)]
 
-#[cfg(windows)]
+#[cfg(any(windows, feature = "dyn-symbols"))]
 macro_rules! generate {
   (extern "C" {
-      $(fn $name:ident($($param:ident: $ptype:ty$(,)?)*)$( -> $rtype:ty)?;)+
+    $(fn $name:ident($($param:ident: $ptype:ty$(,)?)*)$( -> $rtype:ty)?;)+
   }) => {
-      struct Napi {
-          $(
-              $name: unsafe extern "C" fn(
-                  $($param: $ptype,)*
-              )$( -> $rtype)*,
-          )*
-      }
+    struct Napi {
+      $(
+        $name: unsafe extern "C" fn(
+          $($param: $ptype,)*
+        )$( -> $rtype)*,
+      )*
+    }
 
-      #[inline(never)]
-      fn panic_load<T>() -> T {
-          panic!("Must load N-API bindings")
-      }
+    #[inline(never)]
+    fn panic_load<T>() -> T {
+      panic!("Node-API symbol has not been loaded")
+    }
 
-      static mut NAPI: Napi = {
-          $(
-              unsafe extern "C" fn $name($(_: $ptype,)*)$( -> $rtype)* {
-                  panic_load()
+    static mut NAPI: Napi = {
+      $(
+        unsafe extern "C" fn $name($(_: $ptype,)*)$( -> $rtype)* {
+          panic_load()
+        }
+      )*
+
+      Napi {
+        $(
+          $name,
+        )*
+      }
+    };
+
+    #[allow(clippy::missing_safety_doc)]
+    pub unsafe fn load(
+      host: &libloading::Library,
+    ) -> Result<(), libloading::Error> {
+      NAPI = Napi {
+        $(
+          $name: {
+            let symbol: Result<libloading::Symbol<unsafe extern "C" fn ($(_: $ptype,)*)$( -> $rtype)*>, libloading::Error> = host.get(stringify!($name).as_bytes());
+            match symbol {
+              Ok(f) => *f,
+              Err(e) => {
+                #[cfg(debug_assertions)] {
+                  eprintln!("Load Node-API [{}] from host runtime failed: {}", stringify!($name), e);
+                }
+                NAPI.$name
               }
-          )*
-
-          Napi {
-              $(
-                  $name,
-              )*
-          }
+            }
+          },
+        )*
       };
 
+      Ok(())
+    }
+
+    $(
+      #[inline]
       #[allow(clippy::missing_safety_doc)]
-      pub unsafe fn load(
-          host: &libloading::Library,
-      ) -> Result<(), libloading::Error> {
-          NAPI = Napi {
-              $(
-                  $name: {
-                    let symbol: Result<libloading::Symbol<unsafe extern "C" fn ($(_: $ptype,)*)$( -> $rtype)*>, libloading::Error> = host.get(stringify!($name).as_bytes());
-                    match symbol {
-                      Ok(f) => *f,
-                      Err(e) => {
-                        debug_assert!({
-                          println!("Load Node-API [{}] from host runtime failed: {}", stringify!($name), e);
-                          true
-                        });
-                        return Ok(());
-                      }
-                    }
-                  },
-              )*
-          };
-
-          Ok(())
+      pub unsafe fn $name($($param: $ptype,)*)$( -> $rtype)* {
+        (NAPI.$name)($($param,)*)
       }
-
-      $(
-          #[inline]
-          #[allow(clippy::missing_safety_doc)]
-          pub unsafe fn $name($($param: $ptype,)*)$( -> $rtype)* {
-              (NAPI.$name)($($param,)*)
-          }
-      )*
+    )*
   };
 }
 
-#[cfg(not(windows))]
+#[cfg(not(any(windows, feature = "dyn-symbols")))]
 macro_rules! generate {
   (extern "C" {
     $(fn $name:ident($($param:ident: $ptype:ty$(,)?)*)$( -> $rtype:ty)?;)+
@@ -90,7 +91,7 @@ pub use types::*;
 /// Must be called at least once before using any functions in bindings or
 /// they will panic.
 /// Safety: `env` must be a valid `napi_env` for the current thread
-#[cfg(windows)]
+#[cfg(any(windows, feature = "dyn-symbols"))]
 #[allow(clippy::missing_safety_doc)]
 pub unsafe fn setup() -> libloading::Library {
   match load_all() {

examples/napi-compat-mode/Cargo.toml

@@ -11,6 +11,7 @@ crate-type = ["cdylib"]
 [features]
 latest = ["napi/napi9"]
 napi3 = ["napi/napi3"]
+dyn-symbols = ["napi/dyn-symbols"]
 
 [dependencies]
 futures = "0.3"

examples/napi/Cargo.toml

@@ -10,6 +10,7 @@ crate-type = ["cdylib"]
 
 [features]
 snmalloc = ["snmalloc-rs"]
+dyn-symbols = ["napi/dyn-symbols"]
 
 [dependencies]
 chrono = "0.4"