Add interrupt handler callback support

src/bindings/compile.rs

@@ -28,7 +28,7 @@ pub fn compile<'a>(
     };
 
     // check for error
-    context.ensure_no_excpetion()?;
+    context.ensure_no_exception()?;
     Ok(value)
 }
 
@@ -45,7 +45,7 @@ pub fn run_compiled_function<'a>(
         OwnedJsValue::new(context, v)
     };
 
-    context.ensure_no_excpetion().map_err(|e| {
+    context.ensure_no_exception().map_err(|e| {
         if let ExecutionError::Internal(msg) = e {
             ExecutionError::Internal(format!("Could not evaluate compiled function: {}", msg))
         } else {

src/bindings/mod.rs

@@ -6,7 +6,7 @@ mod value;
 use std::{
     ffi::CString,
     os::raw::{c_int, c_void},
-    sync::Mutex,
+    sync::Mutex, panic::RefUnwindSafe,
 };
 
 use libquickjs_sys as q;
@@ -83,6 +83,30 @@ where
     ((boxed_f, data), Some(trampoline::<F>))
 }
 
+type InterruptHandlerWrapper = dyn Fn(*mut q::JSRuntime) -> i32;
+fn interrupt_handler_trampoline<F>(
+    closure: F,
+) -> ((Box<InterruptHandlerWrapper>, *mut c_void), unsafe extern "C" fn(*mut q::JSRuntime, *mut c_void) -> i32)
+where
+    F: Fn(*mut q::JSRuntime) -> i32 + 'static,
+{
+    unsafe extern "C" fn trampoline<F>(
+        rt: *mut q::JSRuntime,
+        closure_ptr: *mut c_void
+    ) -> i32
+    where
+        F: Fn(*mut q::JSRuntime) -> i32 + 'static,
+    {
+        let closure: &mut F = &mut *(closure_ptr as *mut F);
+        (*closure)(rt)
+    }
+
+    let boxed_f = Box::new(closure);
+    let data_ptr = (&*boxed_f) as *const F as *mut c_void;
+
+    ((boxed_f, data_ptr), trampoline::<F>)
+}
+
 /// OwnedValueRef wraps a Javascript value from the quickjs runtime.
 /// It prevents leaks by ensuring that the inner value is deallocated on drop.
 pub struct OwnedValueRef<'a> {
@@ -340,6 +364,7 @@ pub struct ContextWrapper {
     /// the closure.
     // A Mutex is used over a RefCell because it needs to be unwind-safe.
     callbacks: Mutex<Vec<(Box<WrappedCallback>, Box<q::JSValue>)>>,
+    interrupt_handler: Mutex<Option<Box<InterruptHandlerWrapper>>>
 }
 
 impl Drop for ContextWrapper {
@@ -380,6 +405,7 @@ impl ContextWrapper {
             runtime,
             context,
             callbacks: Mutex::new(Vec::new()),
+            interrupt_handler: Mutex::new(None)
         };
 
         Ok(wrapper)
@@ -501,7 +527,7 @@ impl ContextWrapper {
     }
 
     /// Returns `Result::Err` when an error ocurred.
-    pub(crate) fn ensure_no_excpetion(&self) -> Result<(), ExecutionError> {
+    pub(crate) fn ensure_no_exception(&self) -> Result<(), ExecutionError> {
         if let Some(e) = self.get_exception() {
             Err(e)
         } else {
@@ -734,4 +760,19 @@ impl ContextWrapper {
         global.set_property(name, cfunc.into_value())?;
         Ok(())
     }
+
+    pub fn set_interrupt_handler<'a, F: Fn() -> bool + 'static + RefUnwindSafe>(&'a self, handler: F) {
+        let wrapper = move |_rt: *mut q::JSRuntime| {
+            let result = std::panic::catch_unwind(|| handler());
+            match result {
+                Ok(false) => 0,
+                _ => 1
+            }
+        };
+        let pair = interrupt_handler_trampoline(wrapper);
+        *self.interrupt_handler.lock().unwrap() = Some(pair.0.0);
+        unsafe {
+            q::JS_SetInterruptHandler(self.runtime, Some(pair.1), pair.0.1)
+        };
+    }
 }

src/lib.rs

@@ -42,7 +42,7 @@ mod value;
 #[cfg(test)]
 mod tests;
 
-use std::{convert::TryFrom, error, fmt};
+use std::{convert::TryFrom, error, fmt, panic::RefUnwindSafe};
 
 pub use self::{
     callback::{Arguments, Callback},
@@ -355,7 +355,7 @@ impl Context {
     /// use quick_js::{Context, JsValue};
     /// let context = Context::new().unwrap();
     ///
-    /// // Register a closue as a callback under the "add" name.
+    /// // Register a closure as a callback under the "add" name.
     /// // The 'add' function can now be called from Javascript code.
     /// context.add_callback("add", |a: i32, b: i32| { a + b }).unwrap();
     ///
@@ -373,4 +373,11 @@ impl Context {
     ) -> Result<(), ExecutionError> {
         self.wrapper.add_callback(name, callback)
     }
+
+    /// Set an interrupt handler callback.
+    /// This is "regularly called by the engine when it is executing code".
+    /// This must return a `bool`. If its value is `true`, or the handler function panics, JS execution halts.
+    pub fn set_interrupt_handler<F: Fn() -> bool + 'static + RefUnwindSafe>(&self, handler: F) {
+        self.wrapper.set_interrupt_handler(handler);
+    }
 }

src/tests.rs

@@ -622,3 +622,17 @@ fn test_global_setter() {
     ctx.set_global("a", "a").unwrap();
     ctx.eval("a + 1").unwrap();
 }
+
+// test interrupt handler, ensuring that closure data works
+#[test]
+fn test_interrupt_handler() {
+    use std::sync::atomic::{AtomicUsize, Ordering};
+    let ctx = Context::new().unwrap();
+    let arg = AtomicUsize::new(0);
+    ctx.set_interrupt_handler(move || {
+        let counter = arg.fetch_add(1, Ordering::Relaxed);
+        println!("{}", counter);
+        counter == 10
+    });
+    assert_eq!(ctx.eval("while (1) {}"), Err(ExecutionError::Exception(JsValue::String("InternalError: interrupted".to_string()))));
+}