Implement non-visible pipeline and iframe visibility methods

components/script/dom/htmliframeelement.rs

@@ -11,12 +11,13 @@ use dom::bindings::codegen::Bindings::BrowserElementBinding::BrowserElementLocat
 use dom::bindings::codegen::Bindings::BrowserElementBinding::BrowserElementOpenTabEventDetail;
 use dom::bindings::codegen::Bindings::BrowserElementBinding::BrowserElementOpenWindowEventDetail;
 use dom::bindings::codegen::Bindings::BrowserElementBinding::BrowserElementSecurityChangeDetail;
+use dom::bindings::codegen::Bindings::BrowserElementBinding::BrowserElementVisibilityChangeEventDetail;
 use dom::bindings::codegen::Bindings::BrowserElementBinding::BrowserShowModalPromptEventDetail;
 use dom::bindings::codegen::Bindings::HTMLIFrameElementBinding;
 use dom::bindings::codegen::Bindings::HTMLIFrameElementBinding::HTMLIFrameElementMethods;
 use dom::bindings::codegen::Bindings::WindowBinding::WindowMethods;
 use dom::bindings::conversions::ToJSValConvertible;
-use dom::bindings::error::{Error, ErrorResult};
+use dom::bindings::error::{Error, ErrorResult, Fallible};
 use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{Root, LayoutJS};
@@ -66,6 +67,7 @@ pub struct HTMLIFrameElement {
     subpage_id: Cell<Option<SubpageId>>,
     sandbox: Cell<Option<u8>>,
     load_blocker: DOMRefCell<Option<LoadBlocker>>,
+    visibility: Cell<bool>,
 }
 
 impl HTMLIFrameElement {
@@ -196,6 +198,7 @@ impl HTMLIFrameElement {
             subpage_id: Cell::new(None),
             sandbox: Cell::new(None),
             load_blocker: DOMRefCell::new(None),
+            visibility: Cell::new(true),
         }
     }
 
@@ -221,6 +224,26 @@ impl HTMLIFrameElement {
         self.pipeline_id.get()
     }
 
+    pub fn change_visibility_status(&self, visibility: bool) {
+        if self.visibility.get() != visibility {
+            self.visibility.set(visibility);
+
+            // Visibility changes are only exposed to Mozbrowser iframes
+            if self.Mozbrowser() {
+                self.dispatch_mozbrowser_event(MozBrowserEvent::VisibilityChange(visibility));
+            }
+        }
+    }
+
+    pub fn set_visible(&self, visible: bool) {
+        if let Some(pipeline_id) = self.pipeline_id.get() {
+            let window = window_from_node(self);
+            let window = window.r();
+            let msg = ConstellationMsg::SetVisible(pipeline_id, visible);
+            window.constellation_chan().send(msg).unwrap();
+        }
+    }
+
     /// https://html.spec.whatwg.org/multipage/#iframe-load-event-steps steps 1-4
     pub fn iframe_load_event_steps(&self, loaded_pipeline: PipelineId) {
         // TODO(#9592): assert that the load blocker is present at all times when we
@@ -387,6 +410,11 @@ impl MozBrowserEventDetailBuilder for HTMLIFrameElement {
                     returnValue: Some(DOMString::from(return_value)),
                 }.to_jsval(cx, rval)
             }
+            MozBrowserEvent::VisibilityChange(visibility) => {
+                BrowserElementVisibilityChangeEventDetail {
+                    visible: Some(visibility),
+                }.to_jsval(cx, rval);
+            }
         }
     }
 }
@@ -498,6 +526,30 @@ impl HTMLIFrameElementMethods for HTMLIFrameElement {
         }
     }
 
+    // https://developer.mozilla.org/en-US/docs/Web/API/HTMLIFrameElement/setVisible
+    fn SetVisible(&self, visible: bool) -> ErrorResult {
+        if self.Mozbrowser() {
+            self.set_visible(visible);
+            Ok(())
+        } else {
+            debug!("this frame is not mozbrowser: mozbrowser attribute missing, or not a top
+                level window, or mozbrowser preference not set (use --pref dom.mozbrowser.enabled)");
+            Err(Error::NotSupported)
+        }
+    }
+
+    // https://developer.mozilla.org/en-US/docs/Web/API/HTMLIFrameElement/getVisible
+    fn GetVisible(&self) -> Fallible<bool> {
+        if self.Mozbrowser() {
+            Ok(self.visibility.get())
+        } else {
+            debug!("this frame is not mozbrowser: mozbrowser attribute missing, or not a top
+                level window, or mozbrowser preference not set (use --pref dom.mozbrowser.enabled)");
+            Err(Error::NotSupported)
+        }
+    }
+
+
     // https://developer.mozilla.org/en-US/docs/Web/API/HTMLIFrameElement/stop
     fn Stop(&self) -> ErrorResult {
         Err(Error::NotSupported)

components/script/dom/webidls/BrowserElement.webidl

@@ -96,20 +96,24 @@ dictionary BrowserElementOpenWindowEventDetail {
   // Element frameElement;
 };
 
+dictionary BrowserElementVisibilityChangeEventDetail {
+  boolean visible;
+};
+
 BrowserElement implements BrowserElementCommon;
 BrowserElement implements BrowserElementPrivileged;
 
 [NoInterfaceObject]
 interface BrowserElementCommon {
-  //[Throws,
-  // Pref="dom.mozBrowserFramesEnabled",
-  // CheckAnyPermissions="browser embed-widgets"]
-  //void setVisible(boolean visible);
+  [Throws,
+   Pref="dom.mozbrowser.enabled",
+   CheckAnyPermissions="browser embed-widgets"]
+  void setVisible(boolean visible);
 
-  //[Throws,
-  // Pref="dom.mozBrowserFramesEnabled",
-  // CheckAnyPermissions="browser embed-widgets"]
-  //DOMRequest getVisible();
+  [Throws,
+   Pref="dom.mozbrowser.enabled",
+   CheckAnyPermissions="browser embed-widgets"]
+  boolean getVisible();
 
   //[Throws,
   // Pref="dom.mozBrowserFramesEnabled",

components/script/dom/window.rs

@@ -1477,6 +1477,14 @@ impl Window {
         self.timers.suspend();
     }
 
+    pub fn slow_down_timers(&self) {
+        self.timers.slow_down();
+    }
+
+    pub fn speed_up_timers(&self) {
+        self.timers.speed_up();
+    }
+
     pub fn need_emit_timeline_marker(&self, timeline_type: TimelineMarkerType) -> bool {
         let markers = self.devtools_markers.borrow();
         markers.contains(&timeline_type)

components/script/script_thread.rs

@@ -139,6 +139,8 @@ struct InProgressLoad {
     clip_rect: Option<Rect<f32>>,
     /// Window is frozen (navigated away while loading for example).
     is_frozen: bool,
+    /// Window is visible.
+    is_visible: bool,
     /// The requested URL of the load.
     url: Url,
 }
@@ -157,6 +159,7 @@ impl InProgressLoad {
             window_size: window_size,
             clip_rect: None,
             is_frozen: false,
+            is_visible: true,
             url: url,
         }
     }
@@ -918,6 +921,10 @@ impl ScriptThread {
                 self.handle_freeze_msg(pipeline_id),
             ConstellationControlMsg::Thaw(pipeline_id) =>
                 self.handle_thaw_msg(pipeline_id),
+            ConstellationControlMsg::ChangeFrameVisibilityStatus(pipeline_id, visible) =>
+                self.handle_visibility_change_msg(pipeline_id, visible),
+            ConstellationControlMsg::NotifyVisibilityChange(containing_id, pipeline_id, visible) =>
+                self.handle_visibility_change_complete_msg(containing_id, pipeline_id, visible),
             ConstellationControlMsg::MozBrowserEvent(parent_pipeline_id,
                                                      subpage_id,
                                                      event) =>
@@ -1217,6 +1224,55 @@ impl ScriptThread {
         reports_chan.send(reports);
     }
 
+    /// To slow/speed up timers and manage any other script thread resource based on visibility.
+    /// Returns true if successful.
+    fn alter_resource_utilization(&self, id: PipelineId, visible: bool) -> bool {
+        if let Some(root_context) = self.browsing_context.get() {
+            if let Some(ref inner_context) = root_context.find(id) {
+                let window = inner_context.active_window();
+                if visible {
+                    window.speed_up_timers();
+                } else {
+                    window.slow_down_timers();
+                }
+                return true;
+            }
+        }
+        false
+    }
+
+    /// Updates iframe element after a change in visibility
+    fn handle_visibility_change_complete_msg(&self, containing_id: PipelineId, id: PipelineId, visible: bool) {
+        if let Some(root_context) = self.browsing_context.get() {
+            if let Some(ref inner_context) = root_context.find(containing_id) {
+                if let Some(iframe) = inner_context.active_document().find_iframe_by_pipeline(id) {
+                    iframe.change_visibility_status(visible);
+                }
+            }
+        }
+    }
+
+    /// Handle visibility change message
+    fn handle_visibility_change_msg(&self, id: PipelineId, visible: bool) {
+        let resources_altered = self.alter_resource_utilization(id, visible);
+
+        // Separate message sent since parent script thread could be different (Iframe of different
+        // domain)
+        self.constellation_chan.send(ConstellationMsg::VisibilityChangeComplete(id, visible)).unwrap();
+
+        if !resources_altered {
+            let mut loads = self.incomplete_loads.borrow_mut();
+            if let Some(ref mut load) = loads.iter_mut().find(|load| load.pipeline_id == id) {
+                load.is_visible = visible;
+                return;
+            }
+        } else {
+            return;
+        }
+
+        warn!("change visibility message sent to nonexistent pipeline");
+    }
+
     /// Handles freeze message
     fn handle_freeze_msg(&self, id: PipelineId) {
         if let Some(root_context) = self.browsing_context.get() {
@@ -1692,6 +1748,10 @@ impl ScriptThread {
             window.freeze();
         }
 
+        if !incomplete.is_visible {
+            self.alter_resource_utilization(browsing_context.pipeline(), false);
+        }
+
         context_remover.neuter();
 
         document.get_current_parser().unwrap()

components/script/timers.rs

@@ -22,6 +22,7 @@ use std::cmp::{self, Ord, Ordering};
 use std::collections::HashMap;
 use std::default::Default;
 use std::rc::Rc;
+use util::prefs::get_pref;
 
 #[derive(JSTraceable, PartialEq, Eq, Copy, Clone, HeapSizeOf, Hash, PartialOrd, Ord, Debug)]
 pub struct OneshotTimerHandle(i32);
@@ -209,6 +210,15 @@ impl OneshotTimers {
         }
     }
 
+    pub fn slow_down(&self) {
+        let duration = get_pref("js.timers.minimum_duration").as_u64().unwrap_or(1000);
+        self.js_timers.set_min_duration(MsDuration::new(duration));
+    }
+
+    pub fn speed_up(&self) {
+        self.js_timers.remove_min_duration();
+    }
+
     pub fn suspend(&self) {
         assert!(self.suspended_since.get().is_none());
 
@@ -287,6 +297,8 @@ pub struct JsTimers {
     active_timers: DOMRefCell<HashMap<JsTimerHandle, JsTimerEntry>>,
     /// The nesting level of the currently executing timer task or 0.
     nesting_level: Cell<u32>,
+    /// Used to introduce a minimum delay in event intervals
+    min_duration: Cell<Option<MsDuration>>,
 }
 
 #[derive(JSTraceable, HeapSizeOf)]
@@ -341,6 +353,7 @@ impl JsTimers {
             next_timer_handle: Cell::new(JsTimerHandle(1)),
             active_timers: DOMRefCell::new(HashMap::new()),
             nesting_level: Cell::new(0),
+            min_duration: Cell::new(None),
         }
     }
 
@@ -404,6 +417,24 @@ impl JsTimers {
         }
     }
 
+    pub fn set_min_duration(&self, duration: MsDuration) {
+        self.min_duration.set(Some(duration));
+    }
+
+    pub fn remove_min_duration(&self) {
+        self.min_duration.set(None);
+    }
+
+    // see step 13 of https://html.spec.whatwg.org/multipage/#timer-initialisation-steps
+    fn user_agent_pad(&self, current_duration: MsDuration) -> MsDuration {
+        match self.min_duration.get() {
+            Some(min_duration) => {
+                cmp::max(min_duration, current_duration)
+            },
+            None => current_duration
+        }
+    }
+
     // see https://html.spec.whatwg.org/multipage/#timer-initialisation-steps
     fn initialize_and_schedule(&self, global: GlobalRef, mut task: JsTimerTask) {
         let handle = task.handle;
@@ -412,13 +443,12 @@ impl JsTimers {
         // step 6
         let nesting_level = self.nesting_level.get();
 
-        // step 7
-        let duration = clamp_duration(nesting_level, task.duration);
-
+        // step 7, 13
+        let duration = self.user_agent_pad(clamp_duration(nesting_level, task.duration));
         // step 8, 9
         task.nesting_level = nesting_level + 1;
 
-        // essentially step 11-14
+        // essentially step 11, 12, and 14
         let callback = OneshotTimerCallback::JsTimer(task);
         let oneshot_handle = global.schedule_callback(callback, duration);