From ad937a61673464daeeb979c4e8abb59838c5cf21 Mon Sep 17 00:00:00 2001
From: Brian Anderson <banderson@mozilla.com>
Date: Sun, 14 Oct 2012 00:03:38 -0700
Subject: [PATCH] Add lots of logging to content and layout messages

---
 src/servo/content/content_task.rs | 32 ++++++++++++++++++++++++++-----
 src/servo/gfx/render_task.rs      |  8 +++++++-
 src/servo/layout/layout_task.rs   | 18 ++++++++++-------
 3 files changed, 45 insertions(+), 13 deletions(-)

diff --git a/src/servo/content/content_task.rs b/src/servo/content/content_task.rs
index 8b2681624c1..0d4186126d2 100644
--- a/src/servo/content/content_task.rs
+++ b/src/servo/content/content_task.rs
@@ -8,6 +8,7 @@ export ControlMsg, ExecuteMsg, ParseMsg, ExitMsg, Timer;
 export PingMsg, PongMsg;
 export task_from_context;
 
+use core::util::replace;
 use std::arc::{ARC, clone};
 use comm::{Port, Chan, listen, select2};
 use task::{spawn, spawn_listener};
@@ -74,6 +75,8 @@ fn ContentTask<S: Compositor Send Copy>(layout_task: LayoutTask,
 
 struct Content {
     layout_task: LayoutTask,
+    mut layout_join_port: Option<pipes::Port<()>>,
+
     image_cache_task: ImageCacheTask,
     from_master: comm::Port<ControlMsg>,
     event_port: comm::Port<Event>,
@@ -111,6 +114,7 @@ fn Content(layout_task: LayoutTask,
 
     let content = @Content {
         layout_task : layout_task,
+        layout_join_port : None,
         image_cache_task : img_cache_task,
         from_master : from_master,
         event_port : event_port,
@@ -239,11 +243,23 @@ impl Content {
        pending layout request messages).
     */
     fn join_layout() {
+        assert self.scope.is_reader_forked() == self.layout_join_port.is_some();
+
         if self.scope.is_reader_forked() {
-            listen(|response_from_layout| {
-                self.layout_task.send(layout_task::PingMsg(response_from_layout));
-                response_from_layout.recv();
-            });
+
+            let join_port = replace(&mut self.layout_join_port, None);
+
+            match join_port {
+                Some(ref join_port) => {
+                    if !join_port.peek() {
+                        warn!("content: waiting on layout");
+                    }
+                    join_port.recv();
+                    debug!("content: layout joined");
+                }
+                None => fail ~"reader forked but no join port?"
+            }
+
             self.scope.reader_joined();
         }
     }
@@ -260,14 +276,20 @@ impl Content {
         // changes we have made.
         self.join_layout();
 
+        // Layout will let us know when it's done
+        let (join_chan, join_port) = pipes::stream();
+        self.layout_join_port = move Some(join_port);
+
         // Send new document and relevant styles to layout
         // FIXME: Put CSS rules in an arc or something.
         self.layout_task.send(BuildMsg(document.root, clone(&document.css_rules), copy *doc_url,
-                                       self.event_port.chan(), self.window_size));
+                                       self.event_port.chan(), self.window_size, join_chan));
 
         // Indicate that reader was forked so any further
         // changes will be isolated.
         self.scope.reader_forked();
+
+        debug!("content: layout forked");
     }
 
      fn query_layout(query: layout_task::LayoutQuery) -> layout_task::LayoutQueryResponse {
diff --git a/src/servo/gfx/render_task.rs b/src/servo/gfx/render_task.rs
index f4382ebb34d..0ee4ca61dbd 100644
--- a/src/servo/gfx/render_task.rs
+++ b/src/servo/gfx/render_task.rs
@@ -66,7 +66,13 @@ pub fn RenderTask<C: Compositor Send>(compositor: C) -> RenderTask {
         loop {
             match po.recv() {
                 RenderMsg(move render_layer) => {
-                    #debug("renderer: got render request");
+                    debug!("renderer: got render request");
+
+                    if !layer_buffer_port.peek() {
+                        warn!("renderer: no layer buffer. skipping frame");
+                        loop;
+                    }
+
                     let layer_buffer_cell = Cell(layer_buffer_port.recv());
 
                     let (layer_buffer_channel, new_layer_buffer_port) = pipes::stream();
diff --git a/src/servo/layout/layout_task.rs b/src/servo/layout/layout_task.rs
index 910b6b9f538..34f29212d13 100644
--- a/src/servo/layout/layout_task.rs
+++ b/src/servo/layout/layout_task.rs
@@ -27,6 +27,7 @@ use resource::local_image_cache::LocalImageCache;
 use servo_text::font_cache::FontCache;
 use std::arc::ARC;
 use std::net::url::Url;
+use core::util::replace;
 
 use layout::traverse::*;
 use comm::*;
@@ -45,8 +46,7 @@ enum LayoutQueryResponse_ {
 }
 
 pub enum Msg {
-    BuildMsg(Node, ARC<Stylesheet>, Url, comm::Chan<Event>, Size2D<uint>),
-    PingMsg(comm::Chan<content_task::PingMsg>),
+    BuildMsg(Node, ARC<Stylesheet>, Url, comm::Chan<Event>, Size2D<uint>, pipes::Chan<()>),
     QueryMsg(LayoutQuery, comm::Chan<LayoutQueryResponse>),
     ExitMsg
 }
@@ -118,20 +118,20 @@ impl Layout {
     }
 
     fn start() {
-        while self.handle_request(self.from_content) {
+        while self.handle_request() {
             // loop indefinitely
         }
     }
         
-    fn handle_request(request: comm::Port<Msg>) -> bool {
-        match request.recv() {
-            PingMsg(ping_channel) => ping_channel.send(content_task::PongMsg),
+    fn handle_request() -> bool {
+
+        match self.from_content.recv() {
             QueryMsg(query, chan) => self.handle_query(query, chan),
             ExitMsg => {
                 debug!("layout: ExitMsg received");
                 return false
             },
-            BuildMsg(node, styles, doc_url, to_content, window_size) => {
+            BuildMsg(node, styles, doc_url, to_content, window_size, join_chan) => {
                 debug!("layout: received layout request for: %s", doc_url.to_str());
                 debug!("layout: parsed Node tree");
                 debug!("%?", node.dump());
@@ -193,6 +193,10 @@ impl Layout {
                                                    &render_layer.display_list);
                     self.render_task.send(render_task::RenderMsg(move render_layer));
                 } // time(layout: display list building)
+
+                // Tell content we're done
+                join_chan.send(());
+
             } // BuildMsg
         } // match