Add handling for unreported exceptions when invoking callback objects.

components/script/dom/bindings/callback.rs

@@ -9,19 +9,21 @@
 use dom::bindings::global::global_object_for_js_object;
 use dom::bindings::js::JSRef;
 use dom::bindings::utils::Reflectable;
-use js::jsapi::{JSContext, JSObject, JS_WrapObject, JS_ObjectIsCallable};
-use js::jsapi::JS_GetProperty;
+use js::jsapi::{JSContext, JSObject, JS_WrapObject, JS_ObjectIsCallable, JS_GetGlobalObject};
+use js::jsapi::{JS_GetProperty, JS_IsExceptionPending, JS_ReportPendingException};
+use js::jsapi::{JS_GetPendingException};
 use js::jsval::{JSVal, UndefinedValue};
+use js::rust::with_compartment;
 
 use std::ptr;
 
 /// The exception handling used for a call.
-#[deriving(Copy)]
+#[deriving(Copy, PartialEq)]
 pub enum ExceptionHandling {
     /// Report any exception and don't throw it to the caller code.
-    ReportExceptions,
+    Report,
     /// Throw any exception to the caller code.
-    RethrowExceptions
+    Rethrow
 }
 
 /// A common base class for representing IDL callback function types.
@@ -135,7 +137,7 @@ pub struct CallSetup {
     /// The `JSContext` used for the call.
     cx: *mut JSContext,
     /// The exception handling used for the call.
-    _handling: ExceptionHandling
+    handling: ExceptionHandling,
 }
 
 impl CallSetup {
@@ -145,9 +147,10 @@ impl CallSetup {
         let global = global_object_for_js_object(callback.callback());
         let global = global.root();
         let cx = global.r().get_cx();
+
         CallSetup {
             cx: cx,
-            _handling: handling
+            handling: handling,
         }
     }
 
@@ -156,3 +159,40 @@ impl CallSetup {
         self.cx
     }
 }
+
+impl Drop for CallSetup {
+    fn drop(&mut self) {
+        let mut need_to_deal_with_exception = unsafe { JS_IsExceptionPending(self.cx) } != 0;
+        if self.handling == ExceptionHandling::Rethrow && need_to_deal_with_exception {
+            let mut exn = UndefinedValue();
+            let got_exn = unsafe {
+                JS_GetPendingException(self.cx, &mut exn) != 0
+            };
+
+            if got_exn {
+                //TODO: actually rethrow instead of eagerly reporting.
+                //      Gecko stores a mutable reference to an ErrorResult
+                //      abstraction that can store a JS exception and
+                //      report it at content boundaries. Our return value
+                //      wrappers around Result<U,V> make that more difficult.
+                unsafe {
+                    JS_ReportPendingException(self.cx);
+                }
+                need_to_deal_with_exception = false;
+            }
+        }
+
+        if need_to_deal_with_exception {
+            // Either we're supposed to report our exceptions, or we're supposed to
+            // re-throw them but we failed to JS_GetPendingException.  Either way,
+            // just report the pending exception, if any.
+
+            unsafe {
+                let old_global = JS_GetGlobalObject(self.cx);
+                with_compartment(self.cx, old_global, || {
+                    JS_ReportPendingException(self.cx)
+                });
+            }
+        }
+    }
+}

components/script/dom/eventdispatcher.rs

@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::callback::ExceptionHandling::ReportExceptions;
+use dom::bindings::callback::ExceptionHandling::Report;
 use dom::bindings::codegen::Bindings::EventBinding::EventMethods;
 use dom::bindings::codegen::InheritTypes::{EventTargetCast, NodeCast, NodeDerived};
 use dom::bindings::js::{JS, JSRef, OptionalRootable, Root};
@@ -48,7 +48,7 @@ pub fn dispatch_event<'a, 'b>(target: JSRef<'a, EventTarget>,
                 event.set_current_target(cur_target.r());
                 for listener in listeners.iter() {
                     // Explicitly drop any exception on the floor.
-                    let _ = listener.HandleEvent_(cur_target.r(), event, ReportExceptions);
+                    let _ = listener.HandleEvent_(cur_target.r(), event, Report);
 
                     if event.stop_immediate() {
                         break;
@@ -74,7 +74,7 @@ pub fn dispatch_event<'a, 'b>(target: JSRef<'a, EventTarget>,
         for listeners in opt_listeners.iter() {
             for listener in listeners.iter() {
                 // Explicitly drop any exception on the floor.
-                let _ = listener.HandleEvent_(target, event, ReportExceptions);
+                let _ = listener.HandleEvent_(target, event, Report);
 
                 if event.stop_immediate() {
                     break;
@@ -93,7 +93,7 @@ pub fn dispatch_event<'a, 'b>(target: JSRef<'a, EventTarget>,
                     event.set_current_target(cur_target.r());
                     for listener in listeners.iter() {
                         // Explicitly drop any exception on the floor.
-                        let _ = listener.HandleEvent_(cur_target.r(), event, ReportExceptions);
+                        let _ = listener.HandleEvent_(cur_target.r(), event, Report);
 
                         if event.stop_immediate() {
                             break;

components/script/dom/treewalker.rs

@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::callback::ExceptionHandling::RethrowExceptions;
+use dom::bindings::callback::ExceptionHandling::Rethrow;
 use dom::bindings::codegen::Bindings::TreeWalkerBinding;
 use dom::bindings::codegen::Bindings::TreeWalkerBinding::TreeWalkerMethods;
 use dom::bindings::codegen::Bindings::NodeBinding::NodeMethods;
@@ -325,7 +325,7 @@ impl<'a> PrivateTreeWalkerHelpers<'a> for JSRef<'a, TreeWalker> {
         match self.filter {
             Filter::None => Ok(NodeFilterConstants::FILTER_ACCEPT),
             Filter::Native(f) => Ok((f)(node)),
-            Filter::JS(callback) => callback.AcceptNode_(self, node, RethrowExceptions)
+            Filter::JS(callback) => callback.AcceptNode_(self, node, Rethrow)
         }
     }
 

components/script/timers.rs

@@ -3,7 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use dom::bindings::cell::DOMRefCell;
-use dom::bindings::callback::ExceptionHandling::ReportExceptions;
+use dom::bindings::callback::ExceptionHandling::Report;
 use dom::bindings::codegen::Bindings::FunctionBinding::Function;
 use dom::bindings::js::JSRef;
 use dom::bindings::utils::Reflectable;
@@ -189,7 +189,7 @@ impl TimerManager {
         // TODO: Must handle rooting of funval and args when movable GC is turned on
         match data.callback {
             TimerCallback::FunctionTimerCallback(function) => {
-                let _ = function.Call_(this, data.args, ReportExceptions);
+                let _ = function.Call_(this, data.args, Report);
             }
             TimerCallback::StringTimerCallback(code_str) => {
                 this.evaluate_js_on_global_with_result(code_str.as_slice());

components/servo/Cargo.lock

@@ -419,7 +419,7 @@ dependencies = [
 [[package]]
 name = "js"
 version = "0.1.0"
-source = "git+https://github.com/servo/rust-mozjs#e01a846241bd98ac424878e3f8d3e9b989c79242"
+source = "git+https://github.com/servo/rust-mozjs#5a69e377d6ab7ea8601f711443994f1c8172c7a8"
 dependencies = [
  "mozjs-sys 0.0.0 (git+https://github.com/servo/mozjs)",
 ]

ports/cef/Cargo.lock

@@ -387,7 +387,7 @@ dependencies = [
 [[package]]
 name = "js"
 version = "0.1.0"
-source = "git+https://github.com/servo/rust-mozjs#e01a846241bd98ac424878e3f8d3e9b989c79242"
+source = "git+https://github.com/servo/rust-mozjs#5a69e377d6ab7ea8601f711443994f1c8172c7a8"
 dependencies = [
  "mozjs-sys 0.0.0 (git+https://github.com/servo/mozjs)",
 ]

ports/gonk/Cargo.lock

@@ -341,7 +341,7 @@ dependencies = [
 [[package]]
 name = "js"
 version = "0.1.0"
-source = "git+https://github.com/servo/rust-mozjs#e01a846241bd98ac424878e3f8d3e9b989c79242"
+source = "git+https://github.com/servo/rust-mozjs#5a69e377d6ab7ea8601f711443994f1c8172c7a8"
 dependencies = [
  "mozjs-sys 0.0.0 (git+https://github.com/servo/mozjs)",
 ]