Auto merge of #17298 - asajeffrey:script-more-debug-impls, r=mbrubeck

Added Debug implementations.

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Added enough `Debug` implementations to be able to debug script thread message processing.

---
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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes do not require tests because we don't test debugging

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4 files changed, 39 insertions, 0 deletions

diff --git a/components/script/script_runtime.rs b/components/script/script_runtime.rs
index 8c243b18695..efbdb6bdc40 100644
--- a/components/script/script_runtime.rs
+++ b/components/script/script_runtime.rs
@@ -27,6 +27,7 @@ use script_thread::{Runnable, STACK_ROOTS, trace_thread};
 use servo_config::opts;
 use servo_config::prefs::PREFS;
 use std::cell::Cell;
+use std::fmt;
 use std::io::{Write, stdout};
 use std::marker::PhantomData;
 use std::os;
@@ -45,6 +46,15 @@ pub enum CommonScriptMsg {
     RunnableMsg(ScriptThreadEventCategory, Box<Runnable + Send>),
 }
 
+impl fmt::Debug for CommonScriptMsg {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            CommonScriptMsg::CollectReports(_) => write!(f, "CollectReports(...)"),
+            CommonScriptMsg::RunnableMsg(category, _) => write!(f, "RunnableMsg({:?}, ...)", category),
+        }
+    }
+}
+
 /// A cloneable interface for communicating with an event loop.
 pub trait ScriptChan: JSTraceable {
     /// Send a message to the associated event loop.
diff --git a/components/script/script_thread.rs b/components/script/script_thread.rs
index 8dabb29c81b..fcb351cebb2 100644
--- a/components/script/script_thread.rs
+++ b/components/script/script_thread.rs
@@ -232,6 +232,7 @@ pub trait Runnable {
     fn main_thread_handler(self: Box<Self>, _script_thread: &ScriptThread) { self.handler(); }
 }
 
+#[derive(Debug)]
 enum MixedMessage {
     FromConstellation(ConstellationControlMsg),
     FromScript(MainThreadScriptMsg),
@@ -241,6 +242,7 @@ enum MixedMessage {
 }
 
 /// Messages used to control the script event loop
+#[derive(Debug)]
 pub enum MainThreadScriptMsg {
     /// Common variants associated with the script messages
     Common(CommonScriptMsg),
@@ -983,6 +985,7 @@ impl ScriptThread {
 
         // Process the gathered events.
         for msg in sequential {
+            debug!("Processing event {:?}.", msg);
             let category = self.categorize_msg(&msg);
 
             let result = self.profile_event(category, move || {
diff --git a/components/script/task_source/dom_manipulation.rs b/components/script/task_source/dom_manipulation.rs
index 75fd4021168..12deff1880e 100644
--- a/components/script/task_source/dom_manipulation.rs
+++ b/components/script/task_source/dom_manipulation.rs
@@ -9,6 +9,7 @@ use dom::eventtarget::EventTarget;
 use dom::window::Window;
 use script_thread::{MainThreadScriptMsg, Runnable, RunnableWrapper, ScriptThread};
 use servo_atoms::Atom;
+use std::fmt;
 use std::result::Result;
 use std::sync::mpsc::Sender;
 use task_source::TaskSource;
@@ -16,6 +17,12 @@ use task_source::TaskSource;
 #[derive(JSTraceable, Clone)]
 pub struct DOMManipulationTaskSource(pub Sender<MainThreadScriptMsg>);
 
+impl fmt::Debug for DOMManipulationTaskSource {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "DOMManipulationTaskSource(...)")
+    }
+}
+
 impl TaskSource for DOMManipulationTaskSource {
     fn queue_with_wrapper<T>(&self,
                              msg: Box<T>,
@@ -56,6 +63,12 @@ impl DOMManipulationTaskSource {
 
 pub struct DOMManipulationTask(pub Box<Runnable + Send>);
 
+impl fmt::Debug for DOMManipulationTask {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "DOMManipulationTask(...)")
+    }
+}
+
 impl DOMManipulationTask {
     pub fn handle_task(self, script_thread: &ScriptThread) {
         if !self.0.is_cancelled() {
diff --git a/components/script/task_source/user_interaction.rs b/components/script/task_source/user_interaction.rs
index c97e1e1895a..2878a347eb4 100644
--- a/components/script/task_source/user_interaction.rs
+++ b/components/script/task_source/user_interaction.rs
@@ -9,6 +9,7 @@ use dom::eventtarget::EventTarget;
 use dom::window::Window;
 use script_thread::{MainThreadScriptMsg, Runnable, RunnableWrapper, ScriptThread};
 use servo_atoms::Atom;
+use std::fmt;
 use std::result::Result;
 use std::sync::mpsc::Sender;
 use task_source::TaskSource;
@@ -16,6 +17,12 @@ use task_source::TaskSource;
 #[derive(JSTraceable, Clone)]
 pub struct UserInteractionTaskSource(pub Sender<MainThreadScriptMsg>);
 
+impl fmt::Debug for UserInteractionTaskSource {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "UserInteractionTaskSource(...)")
+    }
+}
+
 impl TaskSource for UserInteractionTaskSource {
     fn queue_with_wrapper<T>(&self,
                              msg: Box<T>,
@@ -47,6 +54,12 @@ impl UserInteractionTaskSource {
 
 pub struct UserInteractionTask(pub Box<Runnable + Send>);
 
+impl fmt::Debug for UserInteractionTask {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "UserInteractionTask(...)")
+    }
+}
+
 impl UserInteractionTask {
     pub fn handle_task(self, script_thread: &ScriptThread) {
         if !self.0.is_cancelled() {