refactor: let ONNX Runtime manage operator library handles

This removes the `libc` & `winapi` dependencies (though they were gated behind `operator-libraries`, so not really any impact...)

Author: decahedron1

Cargo.toml

@@ -56,8 +56,6 @@ default = [ "ndarray", "half", "download-binaries", "copy-dylibs" ]
 
 training = [ "ort-sys/training" ]
 
-operator-libraries = [ "libc", "winapi" ]
-
 fetch-models = [ "ureq", "sha2" ]
 download-binaries = [ "ort-sys/download-binaries" ]
 load-dynamic = [ "libloading", "ort-sys/load-dynamic" ]
@@ -91,12 +89,6 @@ sha2 = { version = "0.10", optional = true }
 tracing = { version = "0.1", default-features = false, features = [ "std" ] }
 half = { version = "2.1", optional = true }
 
-[target.'cfg(unix)'.dependencies]
-libc = { version = "0.2", optional = true }
-
-[target.'cfg(windows)'.dependencies]
-winapi = { version = "0.3", optional = true, features = [ "std", "libloaderapi" ] }
-
 [dev-dependencies]
 anyhow = "1.0"
 ureq = "2.1"

src/session/builder/impl_commit.rs

@@ -103,10 +103,7 @@ impl SessionBuilder {
 			.map(|i| dangerous::extract_output(session_ptr, &allocator, i))
 			.collect::<Result<Vec<Output>>>()?;
 
-		let extras = self.operator_domains.drain(..).map(|d| Box::new(d) as Box<dyn Any>);
-		#[cfg(feature = "operator-libraries")]
-		let extras = extras.chain(self.custom_runtime_handles.drain(..).map(|d| Box::new(d) as Box<dyn Any>));
-		let extras: Vec<Box<dyn Any>> = extras.collect();
+		let extras = self.operator_domains.drain(..).map(|d| Box::new(d) as Box<dyn Any>).collect();
 
 		Ok(Session {
 			inner: Arc::new(SharedSessionInner {
@@ -175,10 +172,7 @@ impl SessionBuilder {
 			.map(|i| dangerous::extract_output(session_ptr, &allocator, i))
 			.collect::<Result<Vec<Output>>>()?;
 
-		let extras = self.operator_domains.drain(..).map(|d| Box::new(d) as Box<dyn Any>);
-		#[cfg(feature = "operator-libraries")]
-		let extras = extras.chain(self.custom_runtime_handles.drain(..).map(|d| Box::new(d) as Box<dyn Any>));
-		let extras: Vec<Box<dyn Any>> = extras.collect();
+		let extras = self.operator_domains.drain(..).map(|d| Box::new(d) as Box<dyn Any>).collect();
 
 		let session = Session {
 			inner: Arc::new(SharedSessionInner {

src/session/builder/impl_options.rs

@@ -1,12 +1,12 @@
-#[cfg(any(feature = "operator-libraries", not(windows)))]
-use std::ffi::CString;
-use std::{rc::Rc, sync::Arc};
+use std::{path::Path, rc::Rc, sync::Arc};
 
 use super::SessionBuilder;
 use crate::{
 	error::Result,
 	execution_providers::{apply_execution_providers, ExecutionProviderDispatch},
-	ortsys, MemoryInfo, OperatorDomain
+	ortsys,
+	util::path_to_os_char,
+	MemoryInfo, OperatorDomain
 };
 
 impl SessionBuilder {
@@ -116,31 +116,9 @@ impl SessionBuilder {
 	}
 
 	/// Registers a custom operator library at the given library path.
-	#[cfg(feature = "operator-libraries")]
-	#[cfg_attr(docsrs, doc(cfg(feature = "operator-libraries")))]
-	pub fn with_operator_library(mut self, lib_path: impl AsRef<str>) -> Result<Self> {
-		use crate::error::status_to_result;
-
-		let path_cstr = CString::new(lib_path.as_ref())?;
-
-		let mut handle: *mut ::std::os::raw::c_void = std::ptr::null_mut();
-
-		let status = ortsys![unsafe RegisterCustomOpsLibrary(self.session_options_ptr.as_ptr(), path_cstr.as_ptr(), &mut handle)];
-
-		let handle = LibHandle(handle);
-		// per RegisterCustomOpsLibrary docs, release handle if there was an error and the handle
-		// is non-null
-		if let Err(e) = status_to_result(status) {
-			if !handle.is_null() {
-				// handle was written to, should release it
-				drop(handle);
-			}
-
-			return Err(e);
-		}
-
-		self.custom_runtime_handles.push(Arc::new(handle));
-
+	pub fn with_operator_library(self, lib_path: impl AsRef<Path>) -> Result<Self> {
+		let path_cstr = path_to_os_char(lib_path);
+		ortsys![unsafe RegisterCustomOpsLibrary_V2(self.session_options_ptr.as_ptr(), path_cstr.as_ptr())?];
 		Ok(self)
 	}
 
@@ -248,27 +226,3 @@ impl From<GraphOptimizationLevel> for ort_sys::GraphOptimizationLevel {
 		}
 	}
 }
-
-#[cfg(feature = "operator-libraries")]
-pub(super) struct LibHandle(*mut std::os::raw::c_void);
-
-#[cfg(feature = "operator-libraries")]
-impl LibHandle {
-	pub(self) fn is_null(&self) -> bool {
-		self.0.is_null()
-	}
-}
-
-#[cfg(feature = "operator-libraries")]
-impl Drop for LibHandle {
-	fn drop(&mut self) {
-		#[cfg(unix)]
-		unsafe {
-			libc::dlclose(self.0)
-		};
-		#[cfg(windows)]
-		unsafe {
-			winapi::um::libloaderapi::FreeLibrary(self.0 as winapi::shared::minwindef::HINSTANCE)
-		};
-	}
-}

src/session/builder/mod.rs

@@ -17,8 +17,6 @@ mod impl_config_keys;
 mod impl_options;
 
 pub use self::impl_options::GraphOptimizationLevel;
-#[cfg(feature = "operator-libraries")]
-use self::impl_options::LibHandle;
 
 /// Creates a session using the builder pattern.
 ///
@@ -38,8 +36,6 @@ use self::impl_options::LibHandle;
 pub struct SessionBuilder {
 	pub(crate) session_options_ptr: NonNull<ort_sys::OrtSessionOptions>,
 	memory_info: Option<Rc<MemoryInfo>>,
-	#[cfg(feature = "operator-libraries")]
-	custom_runtime_handles: Vec<Arc<LibHandle>>,
 	operator_domains: Vec<Arc<OperatorDomain>>
 }
 
@@ -52,8 +48,6 @@ impl Clone for SessionBuilder {
 		Self {
 			session_options_ptr: unsafe { NonNull::new_unchecked(session_options_ptr) },
 			memory_info: self.memory_info.clone(),
-			#[cfg(feature = "operator-libraries")]
-			custom_runtime_handles: self.custom_runtime_handles.clone(),
 			operator_domains: self.operator_domains.clone()
 		}
 	}
@@ -85,8 +79,6 @@ impl SessionBuilder {
 		Ok(Self {
 			session_options_ptr: unsafe { NonNull::new_unchecked(session_options_ptr) },
 			memory_info: None,
-			#[cfg(feature = "operator-libraries")]
-			custom_runtime_handles: Vec::new(),
 			operator_domains: Vec::new()
 		})
 	}