beforeunload and unload infrastructure

10 files changed, 222 insertions, 20 deletions

diff --git a/components/atoms/static_atoms.txt b/components/atoms/static_atoms.txt
index ba159bafdfa..8b168ae2fd5 100644
--- a/components/atoms/static_atoms.txt
+++ b/components/atoms/static_atoms.txt
@@ -48,6 +48,7 @@ none
 number
 onchange
 open
+pagehide
 pageshow
 password
 pause
@@ -77,6 +78,7 @@ time
 timeupdate
 toggle
 transitionend
+unload
 url
 waiting
 webglcontextcreationerror
diff --git a/components/constellation/constellation.rs b/components/constellation/constellation.rs
index 77305b4e153..ca5d4649bc7 100644
--- a/components/constellation/constellation.rs
+++ b/components/constellation/constellation.rs
@@ -1033,6 +1033,9 @@ impl<Message, LTF, STF> Constellation<Message, LTF, STF>
             FromScriptMsg::PipelineExited => {
                 self.handle_pipeline_exited(source_pipeline_id);
             }
+            FromScriptMsg::DiscardDocument => {
+                self.handle_discard_document(source_top_ctx_id, source_pipeline_id);
+            }
             FromScriptMsg::InitiateNavigateRequest(req_init, cancel_chan) => {
                 debug!("constellation got initiate navigate request message");
                 self.handle_navigate_request(source_pipeline_id, req_init, cancel_chan);
@@ -2547,6 +2550,8 @@ impl<Message, LTF, STF> Constellation<Message, LTF, STF>
                 self.notify_history_changed(change.top_level_browsing_context_id);
             },
             Some(old_pipeline_id) => {
+                // https://html.spec.whatwg.org/multipage/#unload-a-document
+                self.unload_document(old_pipeline_id);
                 // Deactivate the old pipeline, and activate the new one.
                 let (pipelines_to_close, states_to_close) = if let Some(replace_reloader) = change.replace {
                     let session_history = self.joint_session_histories
@@ -2997,6 +3002,28 @@ impl<Message, LTF, STF> Constellation<Message, LTF, STF>
         debug!("Closed browsing context children {}.", browsing_context_id);
     }
 
+    // Discard the pipeline for a given document, udpdate the joint session history.
+    fn handle_discard_document(&mut self,
+                               top_level_browsing_context_id: TopLevelBrowsingContextId,
+                               pipeline_id: PipelineId) {
+        let load_data = match self.pipelines.get(&pipeline_id) {
+            Some(pipeline) => pipeline.load_data.clone(),
+            None => return
+        };
+        self.joint_session_histories
+            .entry(top_level_browsing_context_id).or_insert(JointSessionHistory::new())
+            .replace_reloader(NeedsToReload::No(pipeline_id), NeedsToReload::Yes(pipeline_id, load_data));
+       self.close_pipeline(pipeline_id, DiscardBrowsingContext::No, ExitPipelineMode::Normal);
+    }
+
+    // Send a message to script requesting the document associated with this pipeline runs the 'unload' algorithm.
+    fn unload_document(&self, pipeline_id: PipelineId) {
+        if let Some(pipeline) = self.pipelines.get(&pipeline_id) {
+            let msg = ConstellationControlMsg::UnloadDocument(pipeline_id);
+            let _ = pipeline.event_loop.send(msg);
+        }
+    }
+
     // Close all pipelines at and beneath a given browsing context
     fn close_pipeline(&mut self, pipeline_id: PipelineId, dbc: DiscardBrowsingContext, exit_mode: ExitPipelineMode) {
         debug!("Closing pipeline {:?}.", pipeline_id);
diff --git a/components/script/dom/document.rs b/components/script/dom/document.rs
index 9a33121b5ae..4fa33056253 100644
--- a/components/script/dom/document.rs
+++ b/components/script/dom/document.rs
@@ -63,7 +63,8 @@ use dom::keyboardevent::KeyboardEvent;
 use dom::location::Location;
 use dom::messageevent::MessageEvent;
 use dom::mouseevent::MouseEvent;
-use dom::node::{self, CloneChildrenFlag, Node, NodeDamage, window_from_node, NodeFlags, LayoutNodeHelpers};
+use dom::node::{self, CloneChildrenFlag, document_from_node, window_from_node};
+use dom::node::{Node, NodeDamage, NodeFlags, LayoutNodeHelpers};
 use dom::node::VecPreOrderInsertionHelper;
 use dom::nodeiterator::NodeIterator;
 use dom::nodelist::NodeList;
@@ -348,6 +349,8 @@ pub struct Document {
     last_click_info: DomRefCell<Option<(Instant, Point2D<f32>)>>,
     /// <https://html.spec.whatwg.org/multipage/#ignore-destructive-writes-counter>
     ignore_destructive_writes_counter: Cell<u32>,
+    /// <https://html.spec.whatwg.org/multipage/#ignore-opens-during-unload-counter>
+    ignore_opens_during_unload_counter: Cell<u32>,
     /// The number of spurious `requestAnimationFrame()` requests we've received.
     ///
     /// A rAF request is considered spurious if nothing was actually reflowed.
@@ -375,6 +378,10 @@ pub struct Document {
     throw_on_dynamic_markup_insertion_counter: Cell<u64>,
     /// https://html.spec.whatwg.org/multipage/#page-showing
     page_showing: Cell<bool>,
+    /// Whether the document is salvageable.
+    salvageable: Cell<bool>,
+    /// Whether the unload event has already been fired.
+    fired_unload: Cell<bool>,
 }
 
 #[derive(JSTraceable, MallocSizeOf)]
@@ -483,18 +490,21 @@ impl Document {
                 self.dirty_all_nodes();
                 self.window().reflow(ReflowGoal::Full, ReflowReason::CachedPageNeededReflow);
                 self.window().resume();
-                // html.spec.whatwg.org/multipage/browsing-the-web.html#history-traversal
-                // Step 6
+                // html.spec.whatwg.org/multipage/#history-traversal
+                // Step 4.6
                 if self.ready_state.get() == DocumentReadyState::Complete {
                     let document = Trusted::new(self);
                     self.window.dom_manipulation_task_source().queue(
                         task!(fire_pageshow_event: move || {
                             let document = document.root();
                             let window = document.window();
-                            if document.page_showing.get() || !window.is_alive() {
+                            // Step 4.6.1
+                            if document.page_showing.get() {
                                 return;
                             }
+                            // Step 4.6.2
                             document.page_showing.set(true);
+                            // Step 4.6.4
                             let event = PageTransitionEvent::new(
                                 window,
                                 atom!("pageshow"),
@@ -1623,6 +1633,112 @@ impl Document {
         ScriptThread::mark_document_with_no_blocked_loads(self);
     }
 
+    // https://html.spec.whatwg.org/multipage/#prompt-to-unload-a-document
+    pub fn prompt_to_unload(&self, recursive_flag: bool) -> bool {
+        // TODO: Step 1, increase the event loop's termination nesting level by 1.
+        // Step 2
+        self.incr_ignore_opens_during_unload_counter();
+        //Step 3-5.
+        let document = Trusted::new(self);
+        let beforeunload_event = BeforeUnloadEvent::new(&self.window,
+                                           atom!("beforeunload"),
+                                           EventBubbles::Bubbles,
+                                           EventCancelable::Cancelable);
+        let event = beforeunload_event.upcast::<Event>();
+        event.set_trusted(true);
+        self.window.upcast::<EventTarget>().dispatch_event_with_target(
+            document.root().upcast(),
+            &event,
+        );
+        // TODO: Step 6, decrease the event loop's termination nesting level by 1.
+        // Step 7
+        if event.get_cancel_state() != EventDefault::Allowed {
+            self.salvageable.set(false);
+        }
+        let mut can_unload = true;
+        // TODO: Step 8 send a message to embedder to prompt user.
+        // Step 9
+        if !recursive_flag {
+            for iframe in self.iter_iframes() {
+                // TODO: handle the case of cross origin iframes.
+                let document = document_from_node(&*iframe);
+                if !document.prompt_to_unload(true) {
+                    self.salvageable.set(document.salvageable());
+                    can_unload = false;
+                    break;
+                }
+            }
+        }
+        // Step 10
+        self.decr_ignore_opens_during_unload_counter();
+        can_unload
+    }
+
+    // https://html.spec.whatwg.org/multipage/#unload-a-document
+    pub fn unload(&self, recursive_flag: bool, recycle: bool) {
+        // TODO: Step 1, increase the event loop's termination nesting level by 1.
+        // Step 2
+        self.incr_ignore_opens_during_unload_counter();
+        let document = Trusted::new(self);
+        // Step 3-6
+        if self.page_showing.get() {
+            self.page_showing.set(false);
+            let event = PageTransitionEvent::new(
+                &self.window,
+                atom!("pagehide"),
+                false, // bubbles
+                false, // cancelable
+                self.salvageable.get(), // persisted
+            );
+            let event = event.upcast::<Event>();
+            event.set_trusted(true);
+            let _ = self.window.upcast::<EventTarget>().dispatch_event_with_target(
+                document.root().upcast(),
+                &event,
+            );
+            // TODO Step 6, document visibility steps.
+        }
+        let mut event_handled = false;
+        // Step 7
+        if !self.fired_unload.get() {
+            let event = Event::new(
+                &self.window.upcast(),
+                atom!("unload"),
+                EventBubbles::Bubbles,
+                EventCancelable::Cancelable,
+            );
+            event.set_trusted(true);
+            let _ = self.window.upcast::<EventTarget>().dispatch_event_with_target(
+                document.root().upcast(),
+                &event,
+            );
+            self.fired_unload.set(true);
+            event_handled = event.get_cancel_state() != EventDefault::Allowed;
+        }
+        // TODO: Step 8, decrease the event loop's termination nesting level by 1.
+        // Step 9
+        self.salvageable.set(!event_handled);
+        // Step 13
+        if !recursive_flag {
+            for iframe in self.iter_iframes() {
+                // TODO: handle the case of cross origin iframes.
+                let document = document_from_node(&*iframe);
+                document.unload(true, recycle);
+                if !document.salvageable() {
+                    self.salvageable.set(false);
+                }
+            }
+        }
+        // Step 10, 14
+        if !self.salvageable.get() {
+            // https://html.spec.whatwg.org/multipage/#unloading-document-cleanup-steps
+            let msg = ScriptMsg::DiscardDocument;
+            let _ = self.window.upcast::<GlobalScope>().script_to_constellation_chan().send(msg);
+        }
+        // Step 15, End
+        self.decr_ignore_opens_during_unload_counter();
+    }
+
     // https://html.spec.whatwg.org/multipage/#the-end
     pub fn maybe_queue_document_completion(&self) {
         if self.loader.borrow().is_blocked() {
@@ -2297,6 +2413,7 @@ impl Document {
             target_element: MutNullableDom::new(None),
             last_click_info: DomRefCell::new(None),
             ignore_destructive_writes_counter: Default::default(),
+            ignore_opens_during_unload_counter: Default::default(),
             spurious_animation_frames: Cell::new(0),
             dom_count: Cell::new(1),
             fullscreen_element: MutNullableDom::new(None),
@@ -2306,6 +2423,8 @@ impl Document {
             canceller: canceller,
             throw_on_dynamic_markup_insertion_counter: Cell::new(0),
             page_showing: Cell::new(false),
+            salvageable: Cell::new(true),
+            fired_unload: Cell::new(false)
         }
     }
 
@@ -2485,6 +2604,10 @@ impl Document {
         self.stylesheets.borrow().len()
     }
 
+    pub fn salvageable(&self) -> bool {
+        self.salvageable.get()
+    }
+
     pub fn stylesheet_at(&self, index: usize) -> Option<DomRoot<CSSStyleSheet>> {
         let stylesheets = self.stylesheets.borrow();
 
@@ -2608,6 +2731,20 @@ impl Document {
             self.ignore_destructive_writes_counter.get() - 1);
     }
 
+    pub fn is_prompting_or_unloading(&self) -> bool {
+        self.ignore_opens_during_unload_counter.get() > 0
+    }
+
+    fn incr_ignore_opens_during_unload_counter(&self) {
+        self.ignore_opens_during_unload_counter.set(
+            self.ignore_opens_during_unload_counter.get() + 1);
+    }
+
+    fn decr_ignore_opens_during_unload_counter(&self) {
+        self.ignore_opens_during_unload_counter.set(
+            self.ignore_opens_during_unload_counter.get() - 1);
+    }
+
     /// Whether we've seen so many spurious animation frames (i.e. animation frames that didn't
     /// mutate the DOM) that we've decided to fall back to fake ones.
     fn is_faking_animation_frames(&self) -> bool {
diff --git a/components/script/dom/event.rs b/components/script/dom/event.rs
index 607469ca6bd..aab86758e23 100644
--- a/components/script/dom/event.rs
+++ b/components/script/dom/event.rs
@@ -482,7 +482,14 @@ fn invoke(window: Option<&Window>,
     event.current_target.set(Some(object));
 
     // Step 5.
-    inner_invoke(window, object, event, &listeners);
+    if inner_invoke(window, object, event, &listeners) {
+        // <https://html.spec.whatwg.org/multipage/#unload-a-document>
+        // Step 9.
+        // Required to establish the 'salvageable' state of document as part of unloading.
+        if event.canceled.get() != EventDefault::Prevented {
+            event.mark_as_handled();
+        }
+    }
 
     // TODO: step 6.
 }
diff --git a/components/script/dom/eventtarget.rs b/components/script/dom/eventtarget.rs
index f909d97e253..df15ff1b2bc 100644
--- a/components/script/dom/eventtarget.rs
+++ b/components/script/dom/eventtarget.rs
@@ -187,22 +187,21 @@ impl CompiledEventListener {
 
                     CommonEventHandler::BeforeUnloadEventHandler(ref handler) => {
                         if let Some(event) = event.downcast::<BeforeUnloadEvent>() {
-                            let rv = event.ReturnValue();
-
+                            // Step 5
                             if let Ok(value) = handler.Call_(object,
                                                              event.upcast::<Event>(),
                                                              exception_handle) {
-                                match value {
-                                    Some(value) => {
-                                        if rv.is_empty() {
-                                            event.SetReturnValue(value);
-                                        }
-                                    }
-                                    None => {
-                                        event.upcast::<Event>().PreventDefault();
+                                let rv = event.ReturnValue();
+                                if let Some(v) =  value {
+                                    if rv.is_empty() {
+                                        event.SetReturnValue(v);
                                     }
+                                    event.upcast::<Event>().PreventDefault();
                                 }
                             }
+                        } else {
+                            // Step 5, "Otherwise" clause
+                            let _ = handler.Call_(object, event.upcast::<Event>(), exception_handle);
                         }
                     }
 
diff --git a/components/script/dom/window.rs b/components/script/dom/window.rs
index 3a672291e8d..88156737e11 100644
--- a/components/script/dom/window.rs
+++ b/components/script/dom/window.rs
@@ -1550,7 +1550,7 @@ impl Window {
         // https://html.spec.whatwg.org/multipage/#navigating-across-documents
         if !force_reload && url.as_url()[..Position::AfterQuery] ==
             doc.url().as_url()[..Position::AfterQuery] {
-                // Step 5
+                // Step 6
                 if let Some(fragment) = url.fragment() {
                     doc.check_and_scroll_fragment(fragment);
                     doc.set_url(url.clone());
@@ -1559,9 +1559,24 @@ impl Window {
         }
 
         let pipeline_id = self.upcast::<GlobalScope>().pipeline_id();
-        self.main_thread_script_chan().send(
-            MainThreadScriptMsg::Navigate(pipeline_id,
-                LoadData::new(url, Some(pipeline_id), referrer_policy, Some(doc.url())), replace)).unwrap();
+
+        // Step 4
+        let window_proxy = self.window_proxy();
+        if let Some(active) = window_proxy.currently_active() {
+            if pipeline_id == active {
+                if doc.is_prompting_or_unloading() {
+                    return;
+                }
+            }
+        }
+
+        // Step 7
+        if doc.prompt_to_unload(false) {
+            self.main_thread_script_chan().send(
+                MainThreadScriptMsg::Navigate(pipeline_id,
+                    LoadData::new(url, Some(pipeline_id), referrer_policy, Some(doc.url())), replace)).unwrap();
+        };
+
     }
 
     pub fn handle_fire_timer(&self, timer_id: TimerEventId) {
diff --git a/components/script/script_thread.rs b/components/script/script_thread.rs
index 6ee0ec46d33..613918f6a76 100644
--- a/components/script/script_thread.rs
+++ b/components/script/script_thread.rs
@@ -1157,6 +1157,7 @@ impl ScriptThread {
                     AttachLayout(ref new_layout_info) => Some(new_layout_info.new_pipeline_id),
                     Resize(id, ..) => Some(id),
                     ResizeInactive(id, ..) => Some(id),
+                    UnloadDocument(id) => Some(id),
                     ExitPipeline(id, ..) => Some(id),
                     ExitScriptThread => None,
                     SendEvent(id, ..) => Some(id),
@@ -1275,6 +1276,8 @@ impl ScriptThread {
             },
             ConstellationControlMsg::Navigate(parent_pipeline_id, browsing_context_id, load_data, replace) =>
                 self.handle_navigate(parent_pipeline_id, Some(browsing_context_id), load_data, replace),
+            ConstellationControlMsg::UnloadDocument(pipeline_id) =>
+                self.handle_unload_document(pipeline_id),
             ConstellationControlMsg::SendEvent(id, event) =>
                 self.handle_event(id, event),
             ConstellationControlMsg::ResizeInactive(id, new_size) =>
@@ -1668,6 +1671,13 @@ impl ScriptThread {
         }
     }
 
+    fn handle_unload_document(&self, pipeline_id: PipelineId) {
+        let document = self.documents.borrow().find_document(pipeline_id);
+        if let Some(document) = document {
+            document.unload(false, false);
+        }
+    }
+
     fn handle_update_pipeline_id(&self,
                                  parent_pipeline_id: PipelineId,
                                  browsing_context_id: BrowsingContextId,
diff --git a/components/script/timers.rs b/components/script/timers.rs
index 50f95d8400a..202a8edc8ae 100644
--- a/components/script/timers.rs
+++ b/components/script/timers.rs
@@ -241,7 +241,7 @@ impl OneshotTimers {
     }
 
     pub fn resume(&self) {
-        // Suspend is idempotent: do nothing if the timers are already suspended.
+        // Resume is idempotent: do nothing if the timers are already resumed.
         let additional_offset = match self.suspended_since.get() {
             Some(suspended_since) => precise_time_ms() - suspended_since,
             None => return warn!("Resuming an already resumed timer."),
diff --git a/components/script_traits/lib.rs b/components/script_traits/lib.rs
index 98cf57116a7..5cbdd8456d7 100644
--- a/components/script_traits/lib.rs
+++ b/components/script_traits/lib.rs
@@ -262,6 +262,8 @@ pub enum ConstellationControlMsg {
     Resize(PipelineId, WindowSizeData, WindowSizeType),
     /// Notifies script that window has been resized but to not take immediate action.
     ResizeInactive(PipelineId, WindowSizeData),
+    /// Notifies the script that the document associated with this pipeline should 'unload'.
+    UnloadDocument(PipelineId),
     /// Notifies the script that a pipeline should be closed.
     ExitPipeline(PipelineId, DiscardBrowsingContext),
     /// Notifies the script that the whole thread should be closed.
@@ -335,6 +337,7 @@ impl fmt::Debug for ConstellationControlMsg {
             AttachLayout(..) => "AttachLayout",
             Resize(..) => "Resize",
             ResizeInactive(..) => "ResizeInactive",
+            UnloadDocument(..) => "UnloadDocument",
             ExitPipeline(..) => "ExitPipeline",
             ExitScriptThread => "ExitScriptThread",
             SendEvent(..) => "SendEvent",
diff --git a/components/script_traits/script_msg.rs b/components/script_traits/script_msg.rs
index efc368e0761..379c73b66b2 100644
--- a/components/script_traits/script_msg.rs
+++ b/components/script_traits/script_msg.rs
@@ -148,6 +148,8 @@ pub enum ScriptMsg {
     TouchEventProcessed(EventResult),
     /// A log entry, with the top-level browsing context id and thread name
     LogEntry(Option<String>, LogEntry),
+    /// Discard the document.
+    DiscardDocument,
     /// Notifies the constellation that this pipeline has exited.
     PipelineExited,
     /// Send messages from postMessage calls from serviceworker