servo: Merge #4852 - Add flag to send live updates to devtools (from jdm:buffermessages); r=jdm

Rebased and squashed version of #4191.

Source-Repo: https://github.com/servo/servo
Source-Revision: 0a2bde1b6ea97b68dfa0e62440dc92ef80fb1fd2

servo/components/devtools/actors/tab.rs

@@ -8,6 +8,7 @@
 
 use actor::{Actor, ActorRegistry};
 use actors::console::ConsoleActor;
+use devtools_traits::WantsLiveNotifications;
 use protocol::JsonPacketStream;
 
 use serialize::json;
@@ -99,6 +100,7 @@ impl Actor for TabActor {
                 let console_actor = registry.find::<ConsoleActor>(self.console.as_slice());
                 console_actor.streams.borrow_mut().push(stream.clone());
                 stream.write_json_packet(&msg);
+                console_actor.script_chan.send(WantsLiveNotifications(console_actor.pipeline, true));
                 true
             }
 
@@ -112,6 +114,7 @@ impl Actor for TabActor {
                 let console_actor = registry.find::<ConsoleActor>(self.console.as_slice());
                 console_actor.streams.borrow_mut().pop();
                 stream.write_json_packet(&msg);
+                console_actor.script_chan.send(WantsLiveNotifications(console_actor.pipeline, false));
                 true
             }
 

servo/components/devtools_traits/lib.rs

@@ -94,6 +94,7 @@ pub enum DevtoolScriptControlMsg {
     GetChildren(PipelineId, String, Sender<Vec<NodeInfo>>),
     GetLayout(PipelineId, String, Sender<(f32, f32)>),
     ModifyAttribute(PipelineId, String, Vec<Modification>),
+    WantsLiveNotifications(PipelineId, bool),
 }
 
 /// Messages to instruct devtools server to update its state relating to a particular

servo/components/script/devtools.rs

@@ -108,3 +108,8 @@ pub fn handle_modify_attribute(page: &Rc<Page>, pipeline: PipelineId, node_id: S
         }
     }
 }
+
+pub fn handle_wants_live_notifications(page: &Rc<Page>, pipeline_id: PipelineId, send_notifications: bool) {
+    let page = get_page(&*page, pipeline_id);
+    page.devtools_wants_updates.set(send_notifications);
+}

servo/components/script/page.rs

@@ -96,6 +96,10 @@ pub struct Page {
     /// An enlarged rectangle around the page contents visible in the viewport, used
     /// to prevent creating display list items for content that is far away from the viewport.
     pub page_clip_rect: Cell<Rect<Au>>,
+
+    /// A flag to indicate whether the developer tools have requested live updates of
+    /// page changes.
+    pub devtools_wants_updates: Cell<bool>,
 }
 
 pub struct PageIterator {
@@ -161,6 +165,7 @@ impl Page {
             constellation_chan: constellation_chan,
             children: DOMRefCell::new(vec!()),
             page_clip_rect: Cell::new(MAX_RECT),
+            devtools_wants_updates: Cell::new(false),
         }
     }
 

servo/components/script/script_task.rs

@@ -41,7 +41,7 @@ use devtools;
 
 use devtools_traits::{DevtoolsControlChan, DevtoolsControlPort, NewGlobal, GetRootNode, DevtoolsPageInfo};
 use devtools_traits::{DevtoolScriptControlMsg, EvaluateJS, GetDocumentElement};
-use devtools_traits::{GetChildren, GetLayout, ModifyAttribute};
+use devtools_traits::{GetChildren, GetLayout, ModifyAttribute, WantsLiveNotifications};
 use script_traits::CompositorEvent;
 use script_traits::CompositorEvent::{ResizeEvent, ReflowEvent, ClickEvent};
 use script_traits::CompositorEvent::{MouseDownEvent, MouseUpEvent};
@@ -637,6 +637,8 @@ impl ScriptTask {
                 devtools::handle_get_layout(&*self.page.borrow(), id, node_id, reply),
             ModifyAttribute(id, node_id, modifications) =>
                 devtools::handle_modify_attribute(&*self.page.borrow(), id, node_id, modifications),
+            WantsLiveNotifications(pipeline_id, to_send) =>
+                devtools::handle_wants_live_notifications(&*self.page.borrow(), pipeline_id, to_send),
         }
     }