Added a dedicated panic channel.

13 files changed, 108 insertions, 232 deletions

diff --git a/components/compositing/constellation.rs b/components/compositing/constellation.rs
index 3cd67edcbcd..4a4aec9d8c7 100644
--- a/components/compositing/constellation.rs
+++ b/components/compositing/constellation.rs
@@ -25,7 +25,7 @@ use gaol;
 #[cfg(not(target_os = "windows"))]
 use gaol::sandbox::{self, Sandbox, SandboxMethods};
 use gfx::font_cache_thread::FontCacheThread;
-use gfx_traits::{Epoch, PaintMsg as FromPaintMsg};
+use gfx_traits::Epoch;
 use ipc_channel::ipc::{self, IpcOneShotServer, IpcSender};
 use ipc_channel::router::ROUTER;
 use layout_traits::{LayoutControlChan, LayoutThreadFactory};
@@ -34,7 +34,7 @@ use msg::constellation_msg::{FrameId, PipelineId};
 use msg::constellation_msg::{Key, KeyModifiers, KeyState, LoadData};
 use msg::constellation_msg::{PipelineNamespace, PipelineNamespaceId, NavigationDirection};
 use msg::constellation_msg::{SubpageId, WindowSizeData};
-use msg::constellation_msg::{self, ConstellationChan, Failure};
+use msg::constellation_msg::{self, ConstellationChan, PanicMsg};
 use msg::webdriver_msg;
 use net_traits::image_cache_thread::ImageCacheThread;
 use net_traits::storage_thread::{StorageThread, StorageThreadMsg};
@@ -95,8 +95,8 @@ pub struct Constellation<LTF, STF> {
     /// A channel through which layout thread messages can be sent to this object.
     pub layout_sender: ConstellationChan<FromLayoutMsg>,
 
-    /// A channel through which paint thread messages can be sent to this object.
-    pub painter_sender: ConstellationChan<FromPaintMsg>,
+    /// A channel through which panic messages can be sent to this object.
+    pub panic_sender: ConstellationChan<PanicMsg>,
 
     /// Receives messages from scripts.
     pub script_receiver: Receiver<FromScriptMsg>,
@@ -107,8 +107,8 @@ pub struct Constellation<LTF, STF> {
     /// Receives messages from the layout thread
     pub layout_receiver: Receiver<FromLayoutMsg>,
 
-    /// Receives messages from paint thread.
-    pub painter_receiver: Receiver<FromPaintMsg>,
+    /// Receives panic messages.
+    pub panic_receiver: Receiver<PanicMsg>,
 
     /// A channel (the implementation of which is port-specific) through which messages can be sent
     /// to the compositor.
@@ -320,19 +320,19 @@ impl<LTF: LayoutThreadFactory, STF: ScriptThreadFactory> Constellation<LTF, STF>
         let (compositor_sender, compositor_receiver) = channel();
         let (ipc_layout_receiver, ipc_layout_sender) = ConstellationChan::<FromLayoutMsg>::new();
         let layout_receiver = ROUTER.route_ipc_receiver_to_new_mpsc_receiver(ipc_layout_receiver);
-        let (ipc_painter_receiver, ipc_painter_sender) = ConstellationChan::<FromPaintMsg>::new();
-        let painter_receiver = ROUTER.route_ipc_receiver_to_new_mpsc_receiver(ipc_painter_receiver);
+        let (ipc_panic_receiver, ipc_panic_sender) = ConstellationChan::<PanicMsg>::new();
+        let panic_receiver = ROUTER.route_ipc_receiver_to_new_mpsc_receiver(ipc_panic_receiver);
         let compositor_sender_clone = compositor_sender.clone();
         spawn_named("Constellation".to_owned(), move || {
             let mut constellation: Constellation<LTF, STF> = Constellation {
                 script_sender: ipc_script_sender,
                 compositor_sender: compositor_sender_clone,
                 layout_sender: ipc_layout_sender,
-                painter_sender: ipc_painter_sender,
                 script_receiver: script_receiver,
+                panic_sender: ipc_panic_sender,
                 compositor_receiver: compositor_receiver,
                 layout_receiver: layout_receiver,
-                painter_receiver: painter_receiver,
+                panic_receiver: panic_receiver,
                 compositor_proxy: state.compositor_proxy,
                 devtools_chan: state.devtools_chan,
                 resource_thread: state.resource_thread,
@@ -416,7 +416,7 @@ impl<LTF: LayoutThreadFactory, STF: ScriptThreadFactory> Constellation<LTF, STF>
                 parent_info: parent_info,
                 constellation_chan: self.script_sender.clone(),
                 layout_to_constellation_chan: self.layout_sender.clone(),
-                painter_chan: self.painter_sender.clone(),
+                panic_chan: self.panic_sender.clone(),
                 scheduler_chan: self.scheduler_chan.clone(),
                 compositor_proxy: self.compositor_proxy.clone_compositor_proxy(),
                 devtools_chan: self.devtools_chan.clone(),
@@ -548,7 +548,7 @@ impl<LTF: LayoutThreadFactory, STF: ScriptThreadFactory> Constellation<LTF, STF>
             Script(FromScriptMsg),
             Compositor(FromCompositorMsg),
             Layout(FromLayoutMsg),
-            Paint(FromPaintMsg)
+            Panic(PanicMsg)
         }
 
         // Get one incoming request.
@@ -566,16 +566,16 @@ impl<LTF: LayoutThreadFactory, STF: ScriptThreadFactory> Constellation<LTF, STF>
             let receiver_from_script = &self.script_receiver;
             let receiver_from_compositor = &self.compositor_receiver;
             let receiver_from_layout = &self.layout_receiver;
-            let receiver_from_paint = &self.painter_receiver;
+            let receiver_from_panic = &self.panic_receiver;
             select! {
                 msg = receiver_from_script.recv() =>
-                    Request::Script(msg.expect("Unexpected script failure in constellation")),
+                    Request::Script(msg.expect("Unexpected script channel panic in constellation")),
                 msg = receiver_from_compositor.recv() =>
-                    Request::Compositor(msg.expect("Unexpected compositor failure in constellation")),
+                    Request::Compositor(msg.expect("Unexpected compositor channel panic in constellation")),
                 msg = receiver_from_layout.recv() =>
-                    Request::Layout(msg.expect("Unexpected layout failure in constellation")),
-                msg = receiver_from_paint.recv() =>
-                    Request::Paint(msg.expect("Unexpected paint failure in constellation"))
+                    Request::Layout(msg.expect("Unexpected layout channel panic in constellation")),
+                msg = receiver_from_panic.recv() =>
+                    Request::Panic(msg.expect("Unexpected panic channel panic in constellation"))
             }
         };
 
@@ -655,10 +655,6 @@ impl<LTF: LayoutThreadFactory, STF: ScriptThreadFactory> Constellation<LTF, STF>
             // Messages from script
 
 
-            Request::Script(FromScriptMsg::Failure(failure)) => {
-                debug!("handling script failure message from pipeline {:?}", failure);
-                self.handle_failure_msg(failure);
-            }
             Request::Script(FromScriptMsg::ScriptLoadedURLInIFrame(load_info)) => {
                 debug!("constellation got iframe URL load message {:?} {:?} {:?}",
                        load_info.containing_pipeline_id,
@@ -803,10 +799,6 @@ impl<LTF: LayoutThreadFactory, STF: ScriptThreadFactory> Constellation<LTF, STF>
             Request::Layout(FromLayoutMsg::ChangeRunningAnimationsState(pipeline_id, animation_state)) => {
                 self.handle_change_running_animations_state(pipeline_id, animation_state)
             }
-            Request::Layout(FromLayoutMsg::Failure(failure)) => {
-                debug!("handling paint failure message from pipeline {:?}", failure);
-                self.handle_failure_msg(failure);
-            }
             Request::Layout(FromLayoutMsg::SetCursor(cursor)) => {
                 self.handle_set_cursor_msg(cursor)
             }
@@ -816,15 +808,12 @@ impl<LTF: LayoutThreadFactory, STF: ScriptThreadFactory> Constellation<LTF, STF>
             }
 
 
-            // Messages from paint thread
+            // Panic messages
 
-
-            // Notification that painting has finished and is requesting permission to paint.
-            Request::Paint(FromPaintMsg::Failure(failure)) => {
-                debug!("handling paint failure message from pipeline {:?}", failure);
-                self.handle_failure_msg(failure);
+            Request::Panic((pipeline_id, panic_reason)) => {
+                debug!("handling panic message ({:?})", pipeline_id);
+                self.handle_panic(pipeline_id, panic_reason);
             }
-
         }
         true
     }
@@ -851,17 +840,12 @@ impl<LTF: LayoutThreadFactory, STF: ScriptThreadFactory> Constellation<LTF, STF>
     }
 
     fn handle_send_error(&mut self, pipeline_id: PipelineId, err: IOError) {
-        let parent_info = match self.pipelines.get(&pipeline_id) {
-            None => return warn!("Pipeline {:?} send error after closure.", pipeline_id),
-            Some(pipeline) => pipeline.parent_info,
-        };
-        // Treat send error the same as receiving a failure message
+        // Treat send error the same as receiving a panic message
         debug!("Pipeline {:?} send error ({}).", pipeline_id, err);
-        let failure = Failure::new(pipeline_id, parent_info);
-        self.handle_failure_msg(failure);
+        self.handle_panic(Some(pipeline_id), format!("Send failed ({})", err));
     }
 
-    fn handle_failure_msg(&mut self, failure: Failure) {
+    fn handle_panic(&mut self, pipeline_id: Option<PipelineId>, reason: String) {
         if opts::get().hard_fail {
             // It's quite difficult to make Servo exit cleanly if some threads have failed.
             // Hard fail exists for test runners so we crash and that's good enough.
@@ -871,15 +855,26 @@ impl<LTF: LayoutThreadFactory, STF: ScriptThreadFactory> Constellation<LTF, STF>
             process::exit(1);
         }
 
-        let window_size = self.pipelines.get(&failure.pipeline_id).and_then(|pipeline| pipeline.size);
+        debug!("Panic handler for pipeline {:?}: {}.", pipeline_id, reason);
+
+        if let Some(pipeline_id) = pipeline_id {
+            self.replace_pipeline_with_about_failure(pipeline_id);
+        }
+
+    }
+
+    fn replace_pipeline_with_about_failure(&mut self, pipeline_id: PipelineId) {
+
+        let parent_info = self.pipelines.get(&pipeline_id).and_then(|pipeline| pipeline.parent_info);
+        let window_size = self.pipelines.get(&pipeline_id).and_then(|pipeline| pipeline.size);
 
         // Notify the browser chrome that the pipeline has failed
-        self.trigger_mozbrowsererror(failure.pipeline_id);
+        self.trigger_mozbrowsererror(pipeline_id);
 
-        self.close_pipeline(failure.pipeline_id, ExitPipelineMode::Force);
+        self.close_pipeline(pipeline_id, ExitPipelineMode::Force);
 
         while let Some(pending_pipeline_id) = self.pending_frames.iter().find(|pending| {
-            pending.old_pipeline_id == Some(failure.pipeline_id)
+            pending.old_pipeline_id == Some(pipeline_id)
         }).map(|frame| frame.new_pipeline_id) {
             warn!("removing pending frame change for failed pipeline");
             self.close_pipeline(pending_pipeline_id, ExitPipelineMode::Force);
@@ -889,12 +884,12 @@ impl<LTF: LayoutThreadFactory, STF: ScriptThreadFactory> Constellation<LTF, STF>
 
         let new_pipeline_id = PipelineId::new();
         self.new_pipeline(new_pipeline_id,
-                          failure.parent_info,
+                          parent_info,
                           window_size,
                           None,
                           LoadData::new(Url::parse("about:failure").expect("infallible")));
 
-        self.push_pending_frame(new_pipeline_id, Some(failure.pipeline_id));
+        self.push_pending_frame(new_pipeline_id, Some(pipeline_id));
 
     }
 
diff --git a/components/compositing/pipeline.rs b/components/compositing/pipeline.rs
index 3de923ba858..9facc11829c 100644
--- a/components/compositing/pipeline.rs
+++ b/components/compositing/pipeline.rs
@@ -10,12 +10,11 @@ use euclid::scale_factor::ScaleFactor;
 use euclid::size::TypedSize2D;
 use gfx::font_cache_thread::FontCacheThread;
 use gfx::paint_thread::{ChromeToPaintMsg, LayoutToPaintMsg, PaintThread};
-use gfx_traits::PaintMsg;
 use ipc_channel::ipc::{self, IpcReceiver, IpcSender};
 use ipc_channel::router::ROUTER;
 use layers::geometry::DevicePixel;
 use layout_traits::{LayoutControlChan, LayoutThreadFactory};
-use msg::constellation_msg::{ConstellationChan, Failure, FrameId, PipelineId, SubpageId};
+use msg::constellation_msg::{ConstellationChan, PanicMsg, FrameId, PipelineId, SubpageId};
 use msg::constellation_msg::{LoadData, WindowSizeData};
 use msg::constellation_msg::{PipelineNamespaceId};
 use net_traits::ResourceThread;
@@ -85,8 +84,8 @@ pub struct InitialPipelineState {
     pub constellation_chan: ConstellationChan<ScriptMsg>,
     /// A channel for the layout thread to send messages to the constellation.
     pub layout_to_constellation_chan: ConstellationChan<LayoutMsg>,
-    /// A channel to the associated paint thread.
-    pub painter_chan: ConstellationChan<PaintMsg>,
+    /// A channel to report panics
+    pub panic_chan: ConstellationChan<PanicMsg>,
     /// A channel to schedule timer events.
     pub scheduler_chan: IpcSender<TimerEventRequest>,
     /// A channel to the compositor.
@@ -140,8 +139,6 @@ impl Pipeline {
             .expect("Pipeline script to compositor chan");
         let mut pipeline_port = Some(pipeline_port);
 
-        let failure = Failure::new(state.id, state.parent_info);
-
         let window_size = state.window_size.map(|size| {
             WindowSizeData {
                 visible_viewport: size,
@@ -179,7 +176,7 @@ impl Pipeline {
                     subpage_id: subpage_id,
                     load_data: state.load_data.clone(),
                     paint_chan: layout_to_paint_chan.clone().to_opaque(),
-                    failure: failure.clone(),
+                    panic_chan: state.panic_chan.clone(),
                     pipeline_port: mem::replace(&mut pipeline_port, None)
                         .expect("script_pipeline != None but pipeline_port == None"),
                     layout_shutdown_chan: layout_shutdown_chan.clone(),
@@ -227,7 +224,7 @@ impl Pipeline {
             layout_to_constellation_chan: state.layout_to_constellation_chan,
             script_chan: script_chan,
             load_data: state.load_data.clone(),
-            failure: failure.clone(),
+            panic_chan: state.panic_chan.clone(),
             script_port: script_port,
             opts: (*opts::get()).clone(),
             prefs: prefs::get_cloned(),
@@ -246,13 +243,12 @@ impl Pipeline {
 
         let privileged_pipeline_content = PrivilegedPipelineContent {
             id: state.id,
-            painter_chan: state.painter_chan,
             compositor_proxy: state.compositor_proxy,
             font_cache_thread: state.font_cache_thread,
             time_profiler_chan: state.time_profiler_chan,
             mem_profiler_chan: state.mem_profiler_chan,
             load_data: state.load_data,
-            failure: failure,
+            panic_chan: state.panic_chan,
             layout_to_paint_port: layout_to_paint_port,
             chrome_to_paint_chan: chrome_to_paint_chan,
             chrome_to_paint_port: chrome_to_paint_port,
@@ -403,7 +399,7 @@ pub struct UnprivilegedPipelineContent {
     window_size: Option<WindowSizeData>,
     script_chan: IpcSender<ConstellationControlMsg>,
     load_data: LoadData,
-    failure: Failure,
+    panic_chan: ConstellationChan<PanicMsg>,
     script_port: Option<IpcReceiver<ConstellationControlMsg>>,
     layout_to_paint_chan: OptionalIpcSender<LayoutToPaintMsg>,
     opts: Opts,
@@ -433,7 +429,7 @@ impl UnprivilegedPipelineContent {
             constellation_chan: self.constellation_chan.clone(),
             layout_to_constellation_chan: self.layout_to_constellation_chan.clone(),
             scheduler_chan: self.scheduler_chan.clone(),
-            failure_info: self.failure.clone(),
+            panic_chan: self.panic_chan.clone(),
             resource_thread: self.resource_thread,
             storage_thread: self.storage_thread.clone(),
             image_cache_thread: self.image_cache_thread.clone(),
@@ -452,7 +448,7 @@ impl UnprivilegedPipelineContent {
                                   layout_pair,
                                   self.pipeline_port.expect("No pipeline port."),
                                   self.layout_to_constellation_chan,
-                                  self.failure,
+                                  self.panic_chan,
                                   self.script_chan.clone(),
                                   self.layout_to_paint_chan.clone(),
                                   self.image_cache_thread,
@@ -480,14 +476,13 @@ impl UnprivilegedPipelineContent {
 
 pub struct PrivilegedPipelineContent {
     id: PipelineId,
-    painter_chan: ConstellationChan<PaintMsg>,
     compositor_proxy: Box<CompositorProxy + Send + 'static>,
     script_to_compositor_port: IpcReceiver<ScriptToCompositorMsg>,
     font_cache_thread: FontCacheThread,
     time_profiler_chan: time::ProfilerChan,
     mem_profiler_chan: profile_mem::ProfilerChan,
     load_data: LoadData,
-    failure: Failure,
+    panic_chan: ConstellationChan<PanicMsg>,
     layout_to_paint_port: Receiver<LayoutToPaintMsg>,
     chrome_to_paint_chan: Sender<ChromeToPaintMsg>,
     chrome_to_paint_port: Receiver<ChromeToPaintMsg>,
@@ -502,9 +497,8 @@ impl PrivilegedPipelineContent {
                           self.layout_to_paint_port,
                           self.chrome_to_paint_port,
                           self.compositor_proxy.clone_compositor_proxy(),
-                          self.painter_chan,
+                          self.panic_chan,
                           self.font_cache_thread,
-                          self.failure,
                           self.time_profiler_chan,
                           self.mem_profiler_chan,
                           self.paint_shutdown_chan);
@@ -526,9 +520,8 @@ impl PrivilegedPipelineContent {
                           self.layout_to_paint_port,
                           self.chrome_to_paint_port,
                           self.compositor_proxy,
-                          self.painter_chan,
+                          self.panic_chan,
                           self.font_cache_thread,
-                          self.failure,
                           self.time_profiler_chan,
                           self.mem_profiler_chan,
                           self.paint_shutdown_chan);
diff --git a/components/gfx/paint_thread.rs b/components/gfx/paint_thread.rs
index 2ea708d39fb..fa515c44afc 100644
--- a/components/gfx/paint_thread.rs
+++ b/components/gfx/paint_thread.rs
@@ -15,12 +15,11 @@ use euclid::rect::Rect;
 use euclid::size::Size2D;
 use font_cache_thread::FontCacheThread;
 use font_context::FontContext;
-use gfx_traits::PaintMsg as ConstellationMsg;
 use gfx_traits::{Epoch, FrameTreeId, LayerId, LayerKind, LayerProperties, PaintListener};
 use ipc_channel::ipc::IpcSender;
 use layers::layers::{BufferRequest, LayerBuffer, LayerBufferSet};
 use layers::platform::surface::{NativeDisplay, NativeSurface};
-use msg::constellation_msg::{ConstellationChan, Failure, PipelineId};
+use msg::constellation_msg::{ConstellationChan, PanicMsg, PipelineId};
 use paint_context::PaintContext;
 use profile_traits::mem::{self, ReportsChan};
 use profile_traits::time;
@@ -394,14 +393,13 @@ impl<C> PaintThread<C> where C: PaintListener + Send + 'static {
                   layout_to_paint_port: Receiver<LayoutToPaintMsg>,
                   chrome_to_paint_port: Receiver<ChromeToPaintMsg>,
                   compositor: C,
-                  constellation_chan: ConstellationChan<ConstellationMsg>,
+                  panic_chan: ConstellationChan<PanicMsg>,
                   font_cache_thread: FontCacheThread,
-                  failure_msg: Failure,
                   time_profiler_chan: time::ProfilerChan,
                   mem_profiler_chan: mem::ProfilerChan,
                   shutdown_chan: IpcSender<()>) {
-        let ConstellationChan(c) = constellation_chan.clone();
-        thread::spawn_named_with_send_on_failure(format!("PaintThread {:?}", id),
+        let ConstellationChan(c) = panic_chan.clone();
+        thread::spawn_named_with_send_on_panic(format!("PaintThread {:?}", id),
                                                thread_state::PAINT,
                                                move || {
             {
@@ -441,7 +439,7 @@ impl<C> PaintThread<C> where C: PaintListener + Send + 'static {
 
             debug!("paint_thread: shutdown_chan send");
             shutdown_chan.send(()).unwrap();
-        }, failure_msg, c);
+        }, Some(id), c);
     }
 
     #[allow(unsafe_code)]
diff --git a/components/gfx_traits/lib.rs b/components/gfx_traits/lib.rs
index e75700c379c..0d13f45f4a3 100644
--- a/components/gfx_traits/lib.rs
+++ b/components/gfx_traits/lib.rs
@@ -25,21 +25,9 @@ pub use paint_listener::PaintListener;
 use azure::azure_hl::Color;
 use euclid::Matrix4D;
 use euclid::rect::Rect;
-use msg::constellation_msg::{Failure, PipelineId};
+use msg::constellation_msg::{PipelineId};
 use std::fmt::{self, Debug, Formatter};
 
-/// Messages from the paint task to the constellation.
-#[derive(Deserialize, Serialize)]
-pub enum PaintMsg {
-    Failure(Failure),
-}
-
-impl From<Failure> for PaintMsg {
-    fn from(failure: Failure) -> PaintMsg {
-        PaintMsg::Failure(failure)
-    }
-}
-
 #[derive(Clone, Copy, Debug, PartialEq)]
 pub enum LayerKind {
     NoTransform,
diff --git a/components/layout/layout_thread.rs b/components/layout/layout_thread.rs
index d226188f698..743e0edc526 100644
--- a/components/layout/layout_thread.rs
+++ b/components/layout/layout_thread.rs
@@ -37,7 +37,7 @@ use ipc_channel::router::ROUTER;
 use layout_debug;
 use layout_traits::LayoutThreadFactory;
 use log;
-use msg::constellation_msg::{ConstellationChan, ConvertPipelineIdToWebRender, Failure, PipelineId};
+use msg::constellation_msg::{ConstellationChan, ConvertPipelineIdToWebRender, PanicMsg, PipelineId};
 use net_traits::image_cache_thread::{ImageCacheChan, ImageCacheResult, ImageCacheThread};
 use net_traits::image_cache_thread::{UsePlaceholder};
 use parallel;
@@ -249,7 +249,7 @@ impl LayoutThreadFactory for LayoutThread {
               chan: OpaqueScriptLayoutChannel,
               pipeline_port: IpcReceiver<LayoutControlMsg>,
               constellation_chan: ConstellationChan<ConstellationMsg>,
-              failure_msg: Failure,
+              panic_chan: ConstellationChan<PanicMsg>,
               script_chan: IpcSender<ConstellationControlMsg>,
               paint_chan: OptionalIpcSender<LayoutToPaintMsg>,
               image_cache_thread: ImageCacheThread,
@@ -259,8 +259,8 @@ impl LayoutThreadFactory for LayoutThread {
               shutdown_chan: IpcSender<()>,
               content_process_shutdown_chan: IpcSender<()>,
               webrender_api_sender: Option<webrender_traits::RenderApiSender>) {
-        let ConstellationChan(con_chan) = constellation_chan.clone();
-        thread::spawn_named_with_send_on_failure(format!("LayoutThread {:?}", id),
+        let ConstellationChan(fail_chan) = panic_chan.clone();
+        thread::spawn_named_with_send_on_panic(format!("LayoutThread {:?}", id),
                                                thread_state::LAYOUT,
                                                move || {
             { // Ensures layout thread is destroyed before we send shutdown message
@@ -286,7 +286,7 @@ impl LayoutThreadFactory for LayoutThread {
             }
             let _ = shutdown_chan.send(());
             let _ = content_process_shutdown_chan.send(());
-        }, failure_msg, con_chan);
+        }, Some(id), fail_chan);
     }
 }
 
@@ -732,7 +732,7 @@ impl LayoutThread {
                                   info.layout_pair,
                                   info.pipeline_port,
                                   info.constellation_chan,
-                                  info.failure,
+                                  info.panic_chan,
                                   info.script_chan.clone(),
                                   info.paint_chan.to::<LayoutToPaintMsg>(),
                                   self.image_cache_thread.clone(),
diff --git a/components/layout_traits/lib.rs b/components/layout_traits/lib.rs
index f06dc14392d..61f9618f421 100644
--- a/components/layout_traits/lib.rs
+++ b/components/layout_traits/lib.rs
@@ -26,7 +26,7 @@ extern crate webrender_traits;
 use gfx::font_cache_thread::FontCacheThread;
 use gfx::paint_thread::LayoutToPaintMsg;
 use ipc_channel::ipc::{IpcReceiver, IpcSender};
-use msg::constellation_msg::{ConstellationChan, Failure, PipelineId};
+use msg::constellation_msg::{ConstellationChan, PanicMsg, PipelineId};
 use net_traits::image_cache_thread::ImageCacheThread;
 use profile_traits::{mem, time};
 use script_traits::LayoutMsg as ConstellationMsg;
@@ -49,7 +49,7 @@ pub trait LayoutThreadFactory {
               chan: OpaqueScriptLayoutChannel,
               pipeline_port: IpcReceiver<LayoutControlMsg>,
               constellation_chan: ConstellationChan<ConstellationMsg>,
-              failure_msg: Failure,
+              panic_chan: ConstellationChan<PanicMsg>,
               script_chan: IpcSender<ConstellationControlMsg>,
               layout_to_paint_chan: OptionalIpcSender<LayoutToPaintMsg>,
               image_cache_thread: ImageCacheThread,
diff --git a/components/msg/constellation_msg.rs b/components/msg/constellation_msg.rs
index c9b8d0acd88..cfdcdfea1ab 100644
--- a/components/msg/constellation_msg.rs
+++ b/components/msg/constellation_msg.rs
@@ -16,7 +16,6 @@ use std::cell::Cell;
 use std::fmt;
 use url::Url;
 use util::geometry::{PagePx, ViewportPx};
-use util::thread::AddFailureDetails;
 use webdriver_msg::{LoadStatus, WebDriverScriptCommand};
 use webrender_traits;
 
@@ -36,29 +35,7 @@ impl<T: Serialize + Deserialize> Clone for ConstellationChan<T> {
     }
 }
 
-// We pass this info to various threads, so it lives in a separate, cloneable struct.
-#[derive(Clone, Deserialize, Serialize, Debug)]
-pub struct Failure {
-    pub pipeline_id: PipelineId,
-    pub parent_info: Option<(PipelineId, SubpageId)>,
-    pub panic_message: Option<String>,
-}
-
-impl Failure {
-    pub fn new(pipeline_id: PipelineId, parent_info: Option<(PipelineId, SubpageId)>) -> Failure {
-        Failure {
-            pipeline_id: pipeline_id,
-            parent_info: parent_info,
-            panic_message: None,
-        }
-    }
-}
-
-impl AddFailureDetails for Failure {
-    fn add_panic_message(&mut self, message: String) {
-        self.panic_message = Some(message);
-    }
-}
+pub type PanicMsg = (Option<PipelineId>, String);
 
 #[derive(Copy, Clone, Deserialize, Serialize, HeapSizeOf)]
 pub struct WindowSizeData {
diff --git a/components/script/layout_interface.rs b/components/script/layout_interface.rs
index 07d8ac47edc..e72bb168f33 100644
--- a/components/script/layout_interface.rs
+++ b/components/script/layout_interface.rs
@@ -12,7 +12,7 @@ use euclid::point::Point2D;
 use euclid::rect::Rect;
 use gfx_traits::{Epoch, LayerId};
 use ipc_channel::ipc::{IpcReceiver, IpcSender};
-use msg::constellation_msg::{ConstellationChan, Failure, PipelineId};
+use msg::constellation_msg::{ConstellationChan, PanicMsg, PipelineId};
 use msg::constellation_msg::{WindowSizeData};
 use net_traits::image_cache_thread::ImageCacheThread;
 use profile_traits::mem::ReportsChan;
@@ -250,7 +250,7 @@ pub struct NewLayoutThreadInfo {
     pub layout_pair: OpaqueScriptLayoutChannel,
     pub pipeline_port: IpcReceiver<LayoutControlMsg>,
     pub constellation_chan: ConstellationChan<ConstellationMsg>,
-    pub failure: Failure,
+    pub panic_chan: ConstellationChan<PanicMsg>,
     pub script_chan: IpcSender<ConstellationControlMsg>,
     pub image_cache_thread: ImageCacheThread,
     pub paint_chan: OptionalOpaqueIpcSender,
diff --git a/components/script/script_thread.rs b/components/script/script_thread.rs
index 5f2ecd095ba..78c9aefc409 100644
--- a/components/script/script_thread.rs
+++ b/components/script/script_thread.rs
@@ -389,7 +389,7 @@ pub struct ScriptThread {
     content_process_shutdown_chan: IpcSender<()>,
 }
 
-/// In the event of thread failure, all data on the stack runs its destructor. However, there
+/// In the event of thread panic, all data on the stack runs its destructor. However, there
 /// are no reachable, owning pointers to the DOM memory, so it never gets freed by default
 /// when the script thread fails. The ScriptMemoryFailsafe uses the destructor bomb pattern
 /// to forcibly tear down the JS compartments for pages associated with the failing ScriptThread.
@@ -442,11 +442,11 @@ impl ScriptThreadFactory for ScriptThread {
               state: InitialScriptState,
               layout_chan: &OpaqueScriptLayoutChannel,
               load_data: LoadData) {
-        let ConstellationChan(const_chan) = state.constellation_chan.clone();
+        let ConstellationChan(panic_chan) = state.panic_chan.clone();
         let (script_chan, script_port) = channel();
         let layout_chan = LayoutChan(layout_chan.sender());
-        let failure_info = state.failure_info.clone();
-        thread::spawn_named_with_send_on_failure(format!("ScriptThread {:?}", state.id),
+        let pipeline_id = state.id;
+        thread::spawn_named_with_send_on_panic(format!("ScriptThread {:?}", state.id),
                                                thread_state::SCRIPT,
                                                move || {
             PipelineNamespace::install(state.pipeline_namespace_id);
@@ -481,7 +481,7 @@ impl ScriptThreadFactory for ScriptThread {
 
             // This must always be the very last operation performed before the thread completes
             failsafe.neuter();
-        }, failure_info, const_chan);
+        }, Some(pipeline_id), panic_chan);
     }
 }
 
@@ -1061,7 +1061,7 @@ impl ScriptThread {
             subpage_id,
             load_data,
             paint_chan,
-            failure,
+            panic_chan,
             pipeline_port,
             layout_shutdown_chan,
             content_process_shutdown_chan,
@@ -1079,7 +1079,7 @@ impl ScriptThread {
             layout_pair: layout_pair,
             pipeline_port: pipeline_port,
             constellation_chan: self.layout_to_constellation_chan.clone(),
-            failure: failure,
+            panic_chan: panic_chan,
             paint_chan: paint_chan,
             script_chan: self.control_chan.clone(),
             image_cache_thread: self.image_cache_thread.clone(),
diff --git a/components/script_traits/lib.rs b/components/script_traits/lib.rs
index 7175536f280..9b3fb014516 100644
--- a/components/script_traits/lib.rs
+++ b/components/script_traits/lib.rs
@@ -41,7 +41,7 @@ use gfx_traits::Epoch;
 use gfx_traits::LayerId;
 use ipc_channel::ipc::{IpcReceiver, IpcSender};
 use libc::c_void;
-use msg::constellation_msg::{ConstellationChan, Failure, PipelineId, WindowSizeData};
+use msg::constellation_msg::{ConstellationChan, PanicMsg, PipelineId, WindowSizeData};
 use msg::constellation_msg::{Key, KeyModifiers, KeyState, LoadData};
 use msg::constellation_msg::{PipelineNamespaceId, SubpageId};
 use msg::webdriver_msg::WebDriverScriptCommand;
@@ -93,10 +93,10 @@ pub struct NewLayoutInfo {
     /// The paint channel, cast to `OptionalOpaqueIpcSender`. This is really an
     /// `Sender<LayoutToPaintMsg>`.
     pub paint_chan: OptionalOpaqueIpcSender,
-    /// Information on what to do on thread failure.
-    pub failure: Failure,
     /// A port on which layout can receive messages from the pipeline.
     pub pipeline_port: IpcReceiver<LayoutControlMsg>,
+    /// A channel for sending panics on
+    pub panic_chan: ConstellationChan<PanicMsg>,
     /// A shutdown channel so that layout can notify others when it's done.
     pub layout_shutdown_chan: IpcSender<()>,
     /// A shutdown channel so that layout can tell the content process to shut down when it's done.
@@ -315,10 +315,10 @@ pub struct InitialScriptState {
     pub constellation_chan: ConstellationChan<ScriptMsg>,
     /// A channel for the layout thread to send messages to the constellation.
     pub layout_to_constellation_chan: ConstellationChan<LayoutMsg>,
+    /// A channel for sending panics to the constellation.
+    pub panic_chan: ConstellationChan<PanicMsg>,
     /// A channel to schedule timer events.
     pub scheduler_chan: IpcSender<TimerEventRequest>,
-    /// Information that script sends out when it panics.
-    pub failure_info: Failure,
     /// A channel to the resource manager thread.
     pub resource_thread: ResourceThread,
     /// A channel to the storage thread.
diff --git a/components/script_traits/script_msg.rs b/components/script_traits/script_msg.rs
index 23920d150d1..14aa50b6a83 100644
--- a/components/script_traits/script_msg.rs
+++ b/components/script_traits/script_msg.rs
@@ -12,8 +12,8 @@ use canvas_traits::CanvasMsg;
 use euclid::point::Point2D;
 use euclid::size::Size2D;
 use ipc_channel::ipc::IpcSender;
-use msg::constellation_msg::{Failure, NavigationDirection, PipelineId};
 use msg::constellation_msg::{LoadData, SubpageId};
+use msg::constellation_msg::{NavigationDirection, PipelineId};
 use offscreen_gl_context::{GLContextAttributes, GLLimits};
 use style_traits::cursor::Cursor;
 use style_traits::viewport::ViewportConstraints;
@@ -24,20 +24,12 @@ use url::Url;
 pub enum LayoutMsg {
     /// Indicates whether this pipeline is currently running animations.
     ChangeRunningAnimationsState(PipelineId, AnimationState),
-    /// Layout thread failure.
-    Failure(Failure),
     /// Requests that the constellation inform the compositor of the a cursor change.
     SetCursor(Cursor),
     /// Notifies the constellation that the viewport has been constrained in some manner
     ViewportConstrained(PipelineId, ViewportConstraints),
 }
 
-impl From<Failure> for LayoutMsg {
-    fn from(failure: Failure) -> LayoutMsg {
-        LayoutMsg::Failure(failure)
-    }
-}
-
 /// Messages from the script to the constellation.
 #[derive(Deserialize, Serialize)]
 pub enum ScriptMsg {
@@ -55,8 +47,6 @@ pub enum ScriptMsg {
     /// Causes a `load` event to be dispatched to any enclosing frame context element
     /// for the given pipeline.
     DOMLoad(PipelineId),
-    /// Script thread failure.
-    Failure(Failure),
     /// Notifies the constellation that this frame has received focus.
     Focus(PipelineId),
     /// Re-send a mouse button event that was sent to the parent window.
@@ -92,9 +82,3 @@ pub enum ScriptMsg {
     /// Update the pipeline Url, which can change after redirections.
     SetFinalUrl(PipelineId, Url),
 }
-
-impl From<Failure> for ScriptMsg {
-    fn from(failure: Failure) -> ScriptMsg {
-        ScriptMsg::Failure(failure)
-    }
-}
diff --git a/components/util/panicking.rs b/components/util/panicking.rs
index eecfd74b97f..95abf897e19 100644
--- a/components/util/panicking.rs
+++ b/components/util/panicking.rs
@@ -17,11 +17,16 @@ static HOOK_SET: Once = ONCE_INIT;
 /// TLS data pertaining to how failures should be reported
 pub struct PanicHandlerLocal {
     /// failure handler passed through spawn_named_with_send_on_failure
-    pub fail: Box<(FnBox(&(Any + Send))) + Send + 'static>
+    pub fail: Box<FnBox(&Any)>
 }
 
 thread_local!(pub static LOCAL_INFO: RefCell<Option<PanicHandlerLocal>> = RefCell::new(None));
 
+/// Set the thread-local panic hook
+pub fn set_thread_local_hook(local: Box<FnBox(&Any)>) {
+    LOCAL_INFO.with(|i| *i.borrow_mut() = Some(PanicHandlerLocal { fail: local }));
+}
+
 /// Initiates the custom panic hook
 /// Should be called in main() after arguments have been parsed
 pub fn initiate_panic_hook() {
diff --git a/components/util/thread.rs b/components/util/thread.rs
index 85a7c52adf8..f6bb72e20a3 100644
--- a/components/util/thread.rs
+++ b/components/util/thread.rs
@@ -6,97 +6,33 @@ use ipc_channel::ipc::IpcSender;
 use panicking;
 use serde::Serialize;
 use std::any::Any;
-use std::borrow::ToOwned;
-use std::sync::mpsc::Sender;
 use std::thread;
 use thread_state;
 
-pub type PanicReason = Option<String>;
-
 pub fn spawn_named<F>(name: String, f: F)
     where F: FnOnce() + Send + 'static
 {
-    spawn_named_with_send_on_failure_maybe(name, None, f, |_| {});
-}
-
-pub trait AddFailureDetails {
-    fn add_panic_message(&mut self, message: String);
-    fn add_panic_object(&mut self, object: &Any) {
-        if let Some(message) = object.downcast_ref::<String>() {
-            self.add_panic_message(message.to_owned());
-        } else if let Some(&message) = object.downcast_ref::<&'static str>() {
-            self.add_panic_message(message.to_owned());
-        }
-    }
-}
-
-/// An abstraction over `Sender<T>` and `IpcSender<T>`, for use in
-/// `spawn_named_with_send_on_failure`.
-pub trait SendOnFailure {
-    type Value;
-    fn send_on_failure(&mut self, value: Self::Value);
-}
-
-impl<T> SendOnFailure for Sender<T> where T: Send + 'static {
-    type Value = T;
-    fn send_on_failure(&mut self, value: T) {
-        // Discard any errors to avoid double-panic
-        let _ = self.send(value);
-    }
-}
-
-impl<T> SendOnFailure for IpcSender<T> where T: Send + Serialize + 'static {
-    type Value = T;
-    fn send_on_failure(&mut self, value: T) {
-        // Discard any errors to avoid double-panic
-        let _ = self.send(value);
-    }
+    thread::Builder::new().name(name).spawn(f).expect("Thread spawn failed");
 }
 
 /// Arrange to send a particular message to a channel if the thread fails.
-pub fn spawn_named_with_send_on_failure<F, T, S>(name: String,
-                                                 state: thread_state::ThreadState,
-                                                 f: F,
-                                                 mut msg: T,
-                                                 mut dest: S)
+pub fn spawn_named_with_send_on_panic<F, Id>(name: String,
+                                             state: thread_state::ThreadState,
+                                             f: F,
+                                             id: Id,
+                                             panic_chan: IpcSender<(Id, String)>)
     where F: FnOnce() + Send + 'static,
-          T: Send + AddFailureDetails + 'static,
-          S: Send + SendOnFailure + 'static,
-          S::Value: From<T>,
+          Id: Copy + Send + Serialize + 'static,
 {
-    spawn_named_with_send_on_failure_maybe(name, Some(state), f,
-                                           move |err| {
-                                               msg.add_panic_object(err);
-                                               dest.send_on_failure(S::Value::from(msg));
-                                           });
-}
-
-fn spawn_named_with_send_on_failure_maybe<F, G>(name: String,
-                                                 state: Option<thread_state::ThreadState>,
-                                                 f: F,
-                                                 fail: G)
-                                                 where F: FnOnce() + Send + 'static,
-                                                       G: FnOnce(&(Any + Send)) + Send + 'static {
-
-
-    let builder = thread::Builder::new().name(name.clone());
-
-    let local = panicking::PanicHandlerLocal {
-        fail: Box::new(fail),
-    };
-
-    let f_with_state = move || {
-        if let Some(state) = state {
-            thread_state::initialize(state);
-        }
-
-        // set the handler
-        panicking::LOCAL_INFO.with(|i| {
-            *i.borrow_mut() = Some(local);
-        });
-        f();
-    };
-
-
-    builder.spawn(f_with_state).unwrap();
+    thread::Builder::new().name(name).spawn(move || {
+        thread_state::initialize(state);
+        panicking::set_thread_local_hook(Box::new(move |payload: &Any| {
+            debug!("Thread failed, notifying constellation");
+            let reason = payload.downcast_ref::<String>().map(|s| String::from(&**s))
+                .or(payload.downcast_ref::<&'static str>().map(|s| String::from(*s)))
+                .unwrap_or_else(|| String::from("<unknown reason>"));
+            let _ = panic_chan.send((id, reason));
+        }));
+        f()
+    }).expect("Thread spawn failed");
 }