feat(ext/ffi): Non-blocking FFI (#12274)

Cargo.lock

@@ -778,6 +778,7 @@ dependencies = [
  "deno_core",
  "dlopen",
  "serde",
+ "tokio",
 ]
 
 [[package]]

ext/ffi/00_ffi.js

@@ -13,7 +13,14 @@
       this.#rid = core.opSync("op_ffi_load", { path, symbols });
 
       for (const symbol in symbols) {
-        this.symbols[symbol] = (...parameters) =>
+        this.symbols[symbol] = symbols[symbol].nonblocking
+          ? (...parameters) =>
+            core.opAsync("op_ffi_call_nonblocking", {
+              rid: this.#rid,
+              symbol,
+              parameters,
+            })
+          : (...parameters) =>
             core.opSync("op_ffi_call", { rid: this.#rid, symbol, parameters });
       }
     }

ext/ffi/Cargo.toml

@@ -18,3 +18,4 @@ deno_core = { version = "0.101.0", path = "../../core" }
 dlopen = "0.1.8"
 libffi = { version = "=0.0.7", package = "deno-libffi" }
 serde = { version = "1.0.129", features = ["derive"] }
+tokio = { version = "1.10.1", features = ["full"] }

ext/ffi/lib.rs

@@ -3,6 +3,7 @@
 use deno_core::error::bad_resource_id;
 use deno_core::error::AnyError;
 use deno_core::include_js_files;
+use deno_core::op_async;
 use deno_core::op_sync;
 use deno_core::serde_json::json;
 use deno_core::serde_json::Value;
@@ -14,6 +15,7 @@ use dlopen::raw::Library;
 use libffi::middle::Arg;
 use serde::Deserialize;
 use std::borrow::Cow;
+use std::cell::RefCell;
 use std::collections::HashMap;
 use std::convert::TryFrom;
 use std::ffi::c_void;
@@ -37,6 +39,7 @@ pub trait FfiPermissions {
   fn check(&mut self, path: &str) -> Result<(), AnyError>;
 }
 
+#[derive(Clone)]
 struct Symbol {
   cif: libffi::middle::Cif,
   ptr: libffi::middle::CodePtr,
@@ -44,6 +47,9 @@ struct Symbol {
   result_type: NativeType,
 }
 
+unsafe impl Send for Symbol {}
+unsafe impl Sync for Symbol {}
+
 struct DynamicLibraryResource {
   lib: Library,
   symbols: HashMap<String, Symbol>,
@@ -99,6 +105,7 @@ pub fn init<P: FfiPermissions + 'static>(unstable: bool) -> Extension {
     .ops(vec![
       ("op_ffi_load", op_sync(op_ffi_load::<P>)),
       ("op_ffi_call", op_sync(op_ffi_call)),
+      ("op_ffi_call_nonblocking", op_async(op_ffi_call_nonblocking)),
     ])
     .state(move |state| {
       // Stolen from deno_webgpu, is there a better option?
@@ -294,20 +301,7 @@ struct FfiCallArgs {
   parameters: Vec<Value>,
 }
 
-fn op_ffi_call(
-  state: &mut deno_core::OpState,
-  args: FfiCallArgs,
-  _: (),
-) -> Result<Value, AnyError> {
-  let resource = state
-    .resource_table
-    .get::<DynamicLibraryResource>(args.rid)?;
-
-  let symbol = resource
-    .symbols
-    .get(&args.symbol)
-    .ok_or_else(bad_resource_id)?;
-
+fn ffi_call(args: FfiCallArgs, symbol: &Symbol) -> Result<Value, AnyError> {
   let native_values = symbol
     .parameter_types
     .iter()
@@ -366,3 +360,41 @@ fn op_ffi_call(
     }
   })
 }
+
+fn op_ffi_call(
+  state: &mut deno_core::OpState,
+  args: FfiCallArgs,
+  _: (),
+) -> Result<Value, AnyError> {
+  let resource = state
+    .resource_table
+    .get::<DynamicLibraryResource>(args.rid)?;
+
+  let symbol = resource
+    .symbols
+    .get(&args.symbol)
+    .ok_or_else(bad_resource_id)?;
+
+  ffi_call(args, symbol)
+}
+
+/// A non-blocking FFI call.
+async fn op_ffi_call_nonblocking(
+  state: Rc<RefCell<deno_core::OpState>>,
+  args: FfiCallArgs,
+  _: (),
+) -> Result<Value, AnyError> {
+  let resource = state
+    .borrow()
+    .resource_table
+    .get::<DynamicLibraryResource>(args.rid)?;
+  let symbols = &resource.symbols;
+  let symbol = symbols
+    .get(&args.symbol)
+    .ok_or_else(bad_resource_id)?
+    .clone();
+
+  tokio::task::spawn_blocking(move || ffi_call(args, &symbol))
+    .await
+    .unwrap()
+}

test_ffi/src/lib.rs

@@ -1,3 +1,6 @@
+use std::thread::sleep;
+use std::time::Duration;
+
 #[no_mangle]
 pub extern "C" fn print_something() {
   println!("something");
@@ -42,3 +45,9 @@ pub extern "C" fn add_f32(a: f32, b: f32) -> f32 {
 pub extern "C" fn add_f64(a: f64, b: f64) -> f64 {
   a + b
 }
+
+#[no_mangle]
+pub extern "C" fn sleep_blocking(ms: u64) {
+  let duration = Duration::from_millis(ms);
+  sleep(duration);
+}

test_ffi/tests/integration_tests.rs

@@ -46,6 +46,10 @@ fn basic() {
     579\n\
     579.9119873046875\n\
     579.912\n\
+    Before\n\
+    true\n\
+    After\n\
+    true\n\
     Correct number of resources\n";
   assert_eq!(stdout, expected);
   assert_eq!(stderr, "");

test_ffi/tests/test.js

@@ -20,6 +20,7 @@ const dylib = Deno.dlopen(libPath, {
   "add_isize": { parameters: ["isize", "isize"], result: "isize" },
   "add_f32": { parameters: ["f32", "f32"], result: "f32" },
   "add_f64": { parameters: ["f64", "f64"], result: "f64" },
+  "sleep_blocking": { parameters: ["u64"], result: "void", nonblocking: true },
 });
 
 dylib.symbols.print_something();
@@ -32,7 +33,20 @@ console.log(dylib.symbols.add_isize(123, 456));
 console.log(dylib.symbols.add_f32(123.123, 456.789));
 console.log(dylib.symbols.add_f64(123.123, 456.789));
 
+// Test non blocking calls
+const start = performance.now();
+dylib.symbols.sleep_blocking(100).then(() => {
+  console.log("After");
+  console.log(performance.now() - start >= 100);
+  // Close after task is complete.
+  cleanup();
+});
+console.log("Before");
+console.log(performance.now() - start < 100);
+
+function cleanup() {
   dylib.close();
+
   const resourcesPost = Deno.resources();
 
   const preStr = JSON.stringify(resourcesPre, null, 2);
@@ -44,4 +58,6 @@ Before: ${preStr}
 After: ${postStr}`,
     );
   }
+
   console.log("Correct number of resources");
+}