Dispatch error events at the window object.

5 files changed, 86 insertions, 28 deletions

diff --git a/components/script/dom/bindings/callback.rs b/components/script/dom/bindings/callback.rs
index c7a09fcc4d8..7b837df1fed 100644
--- a/components/script/dom/bindings/callback.rs
+++ b/components/script/dom/bindings/callback.rs
@@ -191,7 +191,7 @@ impl<'a> Drop for CallSetup<'a> {
             JS_LeaveCompartment(self.cx, self.old_compartment);
             if self.handling == ExceptionHandling::Report {
                 let _ac = JSAutoCompartment::new(self.cx, *self.exception_compartment);
-                report_pending_exception(self.cx);
+                report_pending_exception(self.cx, true);
             }
         }
     }
diff --git a/components/script/dom/bindings/error.rs b/components/script/dom/bindings/error.rs
index 6c26ae8502c..752f0d75b49 100644
--- a/components/script/dom/bindings/error.rs
+++ b/components/script/dom/bindings/error.rs
@@ -8,7 +8,7 @@ use dom::bindings::codegen::Bindings::DOMExceptionBinding::DOMExceptionMethods;
 use dom::bindings::codegen::PrototypeList::proto_id_to_name;
 use dom::bindings::conversions::root_from_object;
 use dom::bindings::conversions::{ConversionResult, FromJSValConvertible, ToJSValConvertible};
-use dom::bindings::global::GlobalRef;
+use dom::bindings::global::{GlobalRef, global_root_from_context};
 use dom::bindings::str::USVString;
 use dom::domexception::{DOMErrorName, DOMException};
 use js::error::{throw_range_error, throw_type_error};
@@ -132,11 +132,16 @@ pub unsafe fn throw_dom_exception(cx: *mut JSContext, global: GlobalRef, result:
     JS_SetPendingException(cx, thrown.handle());
 }
 
-struct ErrorInfo {
-    filename: String,
-    message: String,
-    lineno: c_uint,
-    column: c_uint,
+/// A struct encapsulating information about a runtime script error.
+pub struct ErrorInfo {
+    /// The error message.
+    pub message: String,
+    /// The file name.
+    pub filename: String,
+    /// The line number.
+    pub lineno: c_uint,
+    /// The column number.
+    pub column: c_uint,
 }
 
 impl ErrorInfo {
@@ -192,7 +197,10 @@ impl ErrorInfo {
 }
 
 /// Report a pending exception, thereby clearing it.
-pub unsafe fn report_pending_exception(cx: *mut JSContext) {
+///
+/// The `dispatch_event` argument is temporary and non-standard; passing false
+/// prevents dispatching the `error` event.
+pub unsafe fn report_pending_exception(cx: *mut JSContext, dispatch_event: bool) {
     if JS_IsExceptionPending(cx) {
         rooted!(in(cx) let mut value = UndefinedValue());
         if !JS_GetPendingException(cx, value.handle_mut()) {
@@ -202,22 +210,31 @@ pub unsafe fn report_pending_exception(cx: *mut JSContext) {
         }
 
         JS_ClearPendingException(cx);
-        if !value.is_object() {
-            match USVString::from_jsval(cx, value.handle(), ()) {
-                Ok(ConversionResult::Success(USVString(string))) => error!("Uncaught exception: {}", string),
-                _ => error!("Uncaught exception: failed to stringify primitive"),
+        let error_info = if value.is_object() {
+            rooted!(in(cx) let object = value.to_object());
+            let error_info = ErrorInfo::from_native_error(cx, object.handle())
+                .or_else(|| ErrorInfo::from_dom_exception(object.handle()));
+            match error_info {
+                Some(error_info) => error_info,
+                None => {
+                    error!("Uncaught exception: failed to extract information");
+                    return;
+                }
             }
-            return;
-        }
-
-        rooted!(in(cx) let object = value.to_object());
-        let error_info = ErrorInfo::from_native_error(cx, object.handle())
-            .or_else(|| ErrorInfo::from_dom_exception(object.handle()));
-        let error_info = match error_info {
-            Some(error_info) => error_info,
-            None => {
-                error!("Uncaught exception: failed to extract information");
-                return;
+        } else {
+            match USVString::from_jsval(cx, value.handle(), ()) {
+                Ok(ConversionResult::Success(USVString(string))) => {
+                    ErrorInfo {
+                        message: format!("uncaught exception: {}", string),
+                        filename: String::new(),
+                        lineno: 0,
+                        column: 0,
+                    }
+                },
+                _ => {
+                    error!("Uncaught exception: failed to stringify primitive");
+                    return;
+                },
             }
         };
 
@@ -226,6 +243,13 @@ pub unsafe fn report_pending_exception(cx: *mut JSContext) {
                error_info.lineno,
                error_info.column,
                error_info.message);
+
+        if dispatch_event {
+            let global = global_root_from_context(cx);
+            if let GlobalRef::Window(window) = global.r() {
+                window.report_an_error(error_info, value.handle());
+            }
+        }
     }
 }
 
diff --git a/components/script/dom/eventtarget.rs b/components/script/dom/eventtarget.rs
index 29a6b4102f8..c941eb8e20e 100644
--- a/components/script/dom/eventtarget.rs
+++ b/components/script/dom/eventtarget.rs
@@ -427,7 +427,8 @@ impl EventTarget {
             // Step 1.8.2
             unsafe {
                 let _ac = JSAutoCompartment::new(cx, self.reflector().get_jsobject().get());
-                report_pending_exception(cx);
+                // FIXME(#13152): dispatch error event.
+                report_pending_exception(cx, false);
             }
             // Step 1.8.1 / 1.8.3
             return None;
diff --git a/components/script/dom/window.rs b/components/script/dom/window.rs
index b6bf6a35643..d1529b44b19 100644
--- a/components/script/dom/window.rs
+++ b/components/script/dom/window.rs
@@ -14,7 +14,7 @@ use dom::bindings::codegen::Bindings::FunctionBinding::Function;
 use dom::bindings::codegen::Bindings::NodeBinding::NodeMethods;
 use dom::bindings::codegen::Bindings::WindowBinding::{ScrollBehavior, ScrollToOptions};
 use dom::bindings::codegen::Bindings::WindowBinding::{self, FrameRequestCallback, WindowMethods};
-use dom::bindings::error::{Error, ErrorResult, Fallible, report_pending_exception};
+use dom::bindings::error::{Error, ErrorResult, Fallible, report_pending_exception, ErrorInfo};
 use dom::bindings::global::{GlobalRef, global_root_from_object};
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{JS, MutNullableHeap, Root};
@@ -30,7 +30,8 @@ use dom::crypto::Crypto;
 use dom::cssstyledeclaration::{CSSModificationAccess, CSSStyleDeclaration};
 use dom::document::Document;
 use dom::element::Element;
-use dom::event::Event;
+use dom::errorevent::ErrorEvent;
+use dom::event::{Event, EventBubbles, EventCancelable};
 use dom::eventtarget::EventTarget;
 use dom::history::History;
 use dom::htmliframeelement::build_mozbrowser_custom_event;
@@ -273,6 +274,9 @@ pub struct Window {
 
     /// A list of scroll offsets for each scrollable element.
     scroll_offsets: DOMRefCell<HashMap<UntrustedNodeAddress, Point2D<f32>>>,
+
+    /// https://html.spec.whatwg.org/multipage/#in-error-reporting-mode
+    in_error_reporting_mode: Cell<bool>
 }
 
 impl Window {
@@ -952,7 +956,7 @@ impl<'a, T: Reflectable> ScriptHelpers for &'a T {
                                   code.len() as libc::size_t,
                                   rval) {
                         debug!("error evaluating JS string");
-                        report_pending_exception(cx);
+                        report_pending_exception(cx, true);
                     }
                 }
 
@@ -1742,6 +1746,7 @@ impl Window {
             ignore_further_async_events: Arc::new(AtomicBool::new(false)),
             error_reporter: error_reporter,
             scroll_offsets: DOMRefCell::new(HashMap::new()),
+            in_error_reporting_mode: Cell::new(false),
         };
 
         WindowBinding::Wrap(runtime.cx(), win)
@@ -1749,6 +1754,34 @@ impl Window {
     pub fn live_devtools_updates(&self) -> bool {
         return self.devtools_wants_updates.get();
     }
+
+    /// https://html.spec.whatwg.org/multipage/#report-the-error
+    pub fn report_an_error(&self, error_info: ErrorInfo, value: HandleValue) {
+        // Step 1.
+        if self.in_error_reporting_mode.get() {
+            return;
+        }
+
+        // Step 2.
+        self.in_error_reporting_mode.set(true);
+
+        // Steps 3-12.
+        let event = ErrorEvent::new(GlobalRef::Window(self),
+                                    atom!("error"),
+                                    EventBubbles::DoesNotBubble,
+                                    EventCancelable::Cancelable,
+                                    error_info.message.into(),
+                                    error_info.filename.into(),
+                                    error_info.lineno,
+                                    error_info.column,
+                                    value);
+
+        // Step 13.
+        event.upcast::<Event>().fire(self.upcast::<EventTarget>());
+
+        // Step 14.
+        self.in_error_reporting_mode.set(false);
+    }
 }
 
 fn should_move_clip_rect(clip_rect: Rect<Au>, new_viewport: Rect<f32>) -> bool {
diff --git a/components/script/dom/workerglobalscope.rs b/components/script/dom/workerglobalscope.rs
index 1b3c48b9c12..9f61753ca64 100644
--- a/components/script/dom/workerglobalscope.rs
+++ b/components/script/dom/workerglobalscope.rs
@@ -384,7 +384,7 @@ impl WorkerGlobalScope {
                     unsafe {
                         let _ac = JSAutoCompartment::new(self.runtime.cx(),
                                                          self.reflector().get_jsobject().get());
-                        report_pending_exception(self.runtime.cx());
+                        report_pending_exception(self.runtime.cx(), true);
                     }
                 }
             }