Split devtools implementation into sensible modules.

components/devtools/actor.rs

@@ -0,0 +1,120 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/// General actor system infrastructure.
+
+use std::any::{Any, AnyRefExt, AnyMutRefExt};
+use std::collections::hashmap::HashMap;
+use std::io::TcpStream;
+use std::mem::{transmute, transmute_copy};
+use std::raw::TraitObject;
+use serialize::json;
+
+/// A common trait for all devtools actors that encompasses an immutable name
+/// and the ability to process messages that are directed to particular actors.
+/// TODO: ensure the name is immutable
+pub trait Actor: Any {
+    fn handle_message(&self,
+                      registry: &ActorRegistry,
+                      msg_type: &String,
+                      msg: &json::Object,
+                      stream: &mut TcpStream) -> bool;
+    fn name(&self) -> String;
+}
+
+impl<'a> AnyMutRefExt<'a> for &'a mut Actor {
+    fn downcast_mut<T: 'static>(self) -> Option<&'a mut T> {
+        if self.is::<T>() {
+            unsafe {
+                // Get the raw representation of the trait object
+                let to: TraitObject = transmute_copy(&self);
+
+                // Extract the data pointer
+                Some(transmute(to.data))
+            }
+        } else {
+            None
+        }
+    }
+}
+
+impl<'a> AnyRefExt<'a> for &'a Actor {
+    fn is<T: 'static>(self) -> bool {
+        //FIXME: This implementation is bogus since get_type_id is private now.
+        //       However, this implementation is only needed so long as there's a Rust bug
+        //       that prevents downcast_ref from giving realistic return values, and this is
+        //       ok since we're careful with the types we pull out of the hashmap.
+        /*let t = TypeId::of::<T>();
+        let boxed = self.get_type_id();
+        t == boxed*/
+        true
+    }
+
+    fn downcast_ref<T: 'static>(self) -> Option<&'a T> {
+        if self.is::<T>() {
+            unsafe {
+                // Get the raw representation of the trait object
+                let to: TraitObject = transmute_copy(&self);
+
+                // Extract the data pointer
+                Some(transmute(to.data))
+            }
+        } else {
+            None
+        }
+    }
+}
+
+/// A list of known, owned actors.
+pub struct ActorRegistry {
+    actors: HashMap<String, Box<Actor+Send+Sized>>,
+}
+
+impl ActorRegistry {
+    /// Create an empty registry.
+    pub fn new() -> ActorRegistry {
+        ActorRegistry {
+            actors: HashMap::new(),
+        }
+    }
+
+    /// Add an actor to the registry of known actors that can receive messages.
+    pub fn register(&mut self, actor: Box<Actor+Send+Sized>) {
+        self.actors.insert(actor.name().to_string(), actor);
+    }
+
+    /// Find an actor by registered name
+    pub fn find<'a, T: 'static>(&'a self, name: &str) -> &'a T {
+        //FIXME: Rust bug forces us to implement bogus Any for Actor since downcast_ref currently
+        //       fails for unknown reasons.
+        /*let actor: &Actor+Send+Sized = *self.actors.find(&name.to_string()).unwrap();
+        (actor as &Any).downcast_ref::<T>().unwrap()*/
+        self.actors.find(&name.to_string()).unwrap().as_ref::<T>().unwrap()
+    }
+
+    /// Find an actor by registered name
+    pub fn find_mut<'a, T: 'static>(&'a mut self, name: &str) -> &'a mut T {
+        //FIXME: Rust bug forces us to implement bogus Any for Actor since downcast_ref currently
+        //       fails for unknown reasons.
+        /*let actor: &mut Actor+Send+Sized = *self.actors.find_mut(&name.to_string()).unwrap();
+        (actor as &mut Any).downcast_mut::<T>().unwrap()*/
+        self.actors.find_mut(&name.to_string()).unwrap().downcast_mut::<T>().unwrap()
+    }
+
+    /// Attempt to process a message as directed by its `to` property. If the actor is not
+    /// found or does not indicate that it knew how to process the message, ignore the failure.
+    pub fn handle_message(&self, msg: &json::Object, stream: &mut TcpStream) {
+        let to = msg.find(&"to".to_string()).unwrap().as_string().unwrap();
+        match self.actors.find(&to.to_string()) {
+            None => println!("message received for unknown actor \"{:s}\"", to),
+            Some(actor) => {
+                let msg_type = msg.find(&"type".to_string()).unwrap().as_string().unwrap();
+                if !actor.handle_message(self, &msg_type.to_string(), msg, stream) {
+                    println!("unexpected message type \"{:s}\" found for actor \"{:s}\"",
+                             msg_type, to);
+                }
+            }
+        }
+    }
+}

components/devtools/actors/console.rs

@@ -0,0 +1,284 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/// Liberally derived from the [Firefox JS implementation](http://mxr.mozilla.org/mozilla-central/source/toolkit/devtools/server/actors/webconsole.js).
+/// Mediates interaction between the remote web console and equivalent functionality (object
+/// inspection, JS evaluation, autocompletion) in Servo.
+
+use actor::{Actor, ActorRegistry};
+use protocol::JsonPacketSender;
+
+use devtools_traits::{EvaluateJS, NullValue, VoidValue, NumberValue, StringValue, BooleanValue};
+use devtools_traits::{ActorValue, DevtoolScriptControlMsg};
+use servo_msg::constellation_msg::PipelineId;
+
+use collections::TreeMap;
+use serialize::json;
+use serialize::json::ToJson;
+use std::io::TcpStream;
+
+#[deriving(Encodable)]
+struct StartedListenersTraits {
+    customNetworkRequest: bool,
+}
+
+#[deriving(Encodable)]
+struct StartedListenersReply {
+    from: String,
+    nativeConsoleAPI: bool,
+    startedListeners: Vec<String>,
+    traits: StartedListenersTraits,
+}
+
+#[deriving(Encodable)]
+struct ConsoleAPIMessage {
+    _type: String, //FIXME: should this be __type__ instead?
+}
+
+#[deriving(Encodable)]
+struct PageErrorMessage {
+    _type: String, //FIXME: should this be __type__ instead?
+    errorMessage: String,
+    sourceName: String,
+    lineText: String,
+    lineNumber: uint,
+    columnNumber: uint,
+    category: String,
+    timeStamp: uint,
+    warning: bool,
+    error: bool,
+    exception: bool,
+    strict: bool,
+    private: bool,
+}
+
+#[deriving(Encodable)]
+struct LogMessage {
+    _type: String, //FIXME: should this be __type__ instead?
+    timeStamp: uint,
+    message: String,
+}
+
+#[deriving(Encodable)]
+enum ConsoleMessageType {
+    ConsoleAPIType(ConsoleAPIMessage),
+    PageErrorType(PageErrorMessage),
+    LogMessageType(LogMessage),
+}
+
+#[deriving(Encodable)]
+struct GetCachedMessagesReply {
+    from: String,
+    messages: Vec<json::Object>,
+}
+
+#[deriving(Encodable)]
+struct StopListenersReply {
+    from: String,
+    stoppedListeners: Vec<String>,
+}
+
+#[deriving(Encodable)]
+struct AutocompleteReply {
+    from: String,
+    matches: Vec<String>,
+    matchProp: String,
+}
+
+#[deriving(Encodable)]
+struct EvaluateJSReply {
+    from: String,
+    input: String,
+    result: json::Json,
+    timestamp: uint,
+    exception: json::Json,
+    exceptionMessage: String,
+    helperResult: json::Json,
+}
+
+pub struct ConsoleActor {
+    pub name: String,
+    pub pipeline: PipelineId,
+    pub script_chan: Sender<DevtoolScriptControlMsg>,
+}
+
+impl Actor for ConsoleActor {
+    fn name(&self) -> String {
+        self.name.clone()
+    }
+
+    fn handle_message(&self,
+                      _registry: &ActorRegistry,
+                      msg_type: &String,
+                      msg: &json::Object,
+                      stream: &mut TcpStream) -> bool {
+        match msg_type.as_slice() {
+            "getCachedMessages" => {
+                let types = msg.find(&"messageTypes".to_string()).unwrap().as_list().unwrap();
+                let /*mut*/ messages = vec!();
+                for msg_type in types.iter() {
+                    let msg_type = msg_type.as_string().unwrap();
+                    match msg_type.as_slice() {
+                        "ConsoleAPI" => {
+                            //TODO: figure out all consoleapi properties from FFOX source
+                        }
+
+                        "PageError" => {
+                            //TODO: make script error reporter pass all reported errors
+                            //      to devtools and cache them for returning here.
+
+                            /*let message = PageErrorMessage {
+                                _type: msg_type.to_string(),
+                                sourceName: "".to_string(),
+                                lineText: "".to_string(),
+                                lineNumber: 0,
+                                columnNumber: 0,
+                                category: "".to_string(),
+                                warning: false,
+                                error: true,
+                                exception: false,
+                                strict: false,
+                                private: false,
+                                timeStamp: 0,
+                                errorMessage: "page error test".to_string(),
+                            };
+                            messages.push(json::from_str(json::encode(&message).as_slice()).unwrap().as_object().unwrap().clone());*/
+                        }
+
+                        "LogMessage" => {
+                            //TODO: figure out when LogMessage is necessary
+                            /*let message = LogMessage {
+                                _type: msg_type.to_string(),
+                                timeStamp: 0,
+                                message: "log message test".to_string(),
+                            };
+                            messages.push(json::from_str(json::encode(&message).as_slice()).unwrap().as_object().unwrap().clone());*/
+                        }
+
+                        s => println!("unrecognized message type requested: \"{:s}\"", s),
+                    }
+                }
+
+                let msg = GetCachedMessagesReply {
+                    from: self.name(),
+                    messages: messages,
+                };
+                stream.write_json_packet(&msg);
+                true
+            }
+
+            "startListeners" => {
+                //TODO: actually implement listener filters that support starting/stopping
+                let msg = StartedListenersReply {
+                    from: self.name(),
+                    nativeConsoleAPI: true,
+                    startedListeners:
+                        vec!("PageError".to_string(), "ConsoleAPI".to_string()),
+                    traits: StartedListenersTraits {
+                        customNetworkRequest: true,
+                    }
+                };
+                stream.write_json_packet(&msg);
+                true
+            }
+
+            "stopListeners" => {
+                //TODO: actually implement listener filters that support starting/stopping
+                let msg = StopListenersReply {
+                    from: self.name(),
+                    stoppedListeners: msg.find(&"listeners".to_string())
+                                         .unwrap()
+                                         .as_list()
+                                         .unwrap_or(&vec!())
+                                         .iter()
+                                         .map(|listener| listener.as_string().unwrap().to_string())
+                                         .collect(),
+                };
+                stream.write_json_packet(&msg);
+                true
+            }
+
+            //TODO: implement autocompletion like onAutocomplete in
+            //      http://mxr.mozilla.org/mozilla-central/source/toolkit/devtools/server/actors/webconsole.js
+            "autocomplete" => {
+                let msg = AutocompleteReply {
+                    from: self.name(),
+                    matches: vec!(),
+                    matchProp: "".to_string(),
+                };
+                stream.write_json_packet(&msg);
+                true
+            }
+
+            "evaluateJS" => {
+                let input = msg.find(&"text".to_string()).unwrap().as_string().unwrap().to_string();
+                let (chan, port) = channel();
+                self.script_chan.send(EvaluateJS(self.pipeline, input.clone(), chan));
+
+                //TODO: extract conversion into protocol module or some other useful place
+                let result = match port.recv() {
+                    VoidValue => {
+                        let mut m = TreeMap::new();
+                        m.insert("type".to_string(), "undefined".to_string().to_json());
+                        json::Object(m)
+                    }
+                    NullValue => {
+                        let mut m = TreeMap::new();
+                        m.insert("type".to_string(), "null".to_string().to_json());
+                        json::Object(m)
+                    }
+                    BooleanValue(val) => val.to_json(),
+                    NumberValue(val) => {
+                        if val.is_nan() {
+                            let mut m = TreeMap::new();
+                            m.insert("type".to_string(), "NaN".to_string().to_json());
+                            json::Object(m)
+                        } else if val.is_infinite() {
+                            let mut m = TreeMap::new();
+                            if val < 0. {
+                                m.insert("type".to_string(), "Infinity".to_string().to_json());
+                            } else {
+                                m.insert("type".to_string(), "-Infinity".to_string().to_json());
+                            }
+                            json::Object(m)
+                        } else if val == Float::neg_zero() {
+                            let mut m = TreeMap::new();
+                            m.insert("type".to_string(), "-0".to_string().to_json());
+                            json::Object(m)
+                        } else {
+                            val.to_json()
+                        }
+                    }
+                    StringValue(s) => s.to_json(),
+                    ActorValue(s) => {
+                        //TODO: make initial ActorValue message include these properties.
+                        let mut m = TreeMap::new();
+                        m.insert("type".to_string(), "object".to_string().to_json());
+                        m.insert("class".to_string(), "???".to_string().to_json());
+                        m.insert("actor".to_string(), s.to_json());
+                        m.insert("extensible".to_string(), true.to_json());
+                        m.insert("frozen".to_string(), false.to_json());
+                        m.insert("sealed".to_string(), false.to_json());
+                        json::Object(m)
+                    }
+                };
+
+                //TODO: catch and return exception values from JS evaluation
+                let msg = EvaluateJSReply {
+                    from: self.name(),
+                    input: input,
+                    result: result,
+                    timestamp: 0,
+                    exception: json::Object(TreeMap::new()),
+                    exceptionMessage: "".to_string(),
+                    helperResult: json::Object(TreeMap::new()),
+                };
+                stream.write_json_packet(&msg);
+                true
+            }
+
+            _ => false
+        }
+    }
+}

components/devtools/actors/root.rs

@@ -0,0 +1,96 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/// Liberally derived from the [Firefox JS implementation](http://mxr.mozilla.org/mozilla-central/source/toolkit/devtools/server/actors/root.js).
+/// Connection point for all new remote devtools interactions, providing lists of know actors
+/// that perform more specific actions (tabs, addons, browser chrome, etc.)
+
+use actor::{Actor, ActorRegistry};
+use actors::tab::{TabActor, TabActorMsg};
+use protocol::JsonPacketSender;
+
+use serialize::json;
+use std::io::TcpStream;
+
+#[deriving(Encodable)]
+struct ActorTraits {
+    sources: bool
+}
+
+#[deriving(Encodable)]
+struct ErrorReply {
+    from: String,
+    error: String,
+    message: String,
+}
+
+#[deriving(Encodable)]
+struct ListTabsReply {
+    from: String,
+    selected: uint,
+    tabs: Vec<TabActorMsg>,
+}
+
+#[deriving(Encodable)]
+struct RootActorMsg {
+    from: String,
+    applicationType: String,
+    traits: ActorTraits,
+}
+
+pub struct RootActor {
+    pub next: u32,
+    pub tabs: Vec<String>,
+}
+
+impl Actor for RootActor {
+    fn name(&self) -> String {
+        "root".to_string()
+    }
+
+    fn handle_message(&self,
+                      registry: &ActorRegistry,
+                      msg_type: &String,
+                      _msg: &json::Object,
+                      stream: &mut TcpStream) -> bool {
+        match msg_type.as_slice() {
+            "listAddons" => {
+                let actor = ErrorReply {
+                    from: "root".to_string(),
+                    error: "noAddons".to_string(),
+                    message: "This root actor has no browser addons.".to_string(),
+                };
+                stream.write_json_packet(&actor);
+                true
+            }
+
+            //https://wiki.mozilla.org/Remote_Debugging_Protocol#Listing_Browser_Tabs
+            "listTabs" => {
+                let actor = ListTabsReply {
+                    from: "root".to_string(),
+                    selected: 0,
+                    tabs: self.tabs.iter().map(|tab| {
+                        registry.find::<TabActor>(tab.as_slice()).encodable()
+                    }).collect()
+                };
+                stream.write_json_packet(&actor);
+                true
+            }
+
+            _ => false
+        }
+    }
+}
+
+impl RootActor {
+    pub fn encodable(&self) -> RootActorMsg {
+        RootActorMsg {
+            from: "root".to_string(),
+            applicationType: "browser".to_string(),
+            traits: ActorTraits {
+                sources: true,
+            },
+        }
+    }
+}

components/devtools/actors/tab.rs

@@ -0,0 +1,108 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/// Liberally derived from the [Firefox JS implementation](http://mxr.mozilla.org/mozilla-central/source/toolkit/devtools/server/actors/webbrowser.js).
+/// Connection point for remote devtools that wish to investigate a particular tab's contents.
+/// Supports dynamic attaching and detaching which control notifications of navigation, etc.
+
+use actor::{Actor, ActorRegistry};
+use protocol::JsonPacketSender;
+
+use serialize::json;
+use std::io::TcpStream;
+
+#[deriving(Encodable)]
+struct TabTraits;
+
+#[deriving(Encodable)]
+struct TabAttachedReply {
+    from: String,
+    __type__: String,
+    threadActor: String,
+    cacheDisabled: bool,
+    javascriptEnabled: bool,
+    traits: TabTraits,
+}
+
+#[deriving(Encodable)]
+struct TabDetachedReply {
+    from: String,
+    __type__: String,
+}
+
+#[deriving(Encodable)]
+struct ReconfigureReply {
+    from: String
+}
+
+#[deriving(Encodable)]
+pub struct TabActorMsg {
+    actor: String,
+    title: String,
+    url: String,
+    outerWindowID: uint,
+    consoleActor: String,
+}
+
+pub struct TabActor {
+    pub name: String,
+    pub title: String,
+    pub url: String,
+}
+
+impl Actor for TabActor {
+    fn name(&self) -> String {
+        self.name.clone()
+    }
+
+    fn handle_message(&self,
+                      _registry: &ActorRegistry,
+                      msg_type: &String,
+                      _msg: &json::Object,
+                      stream: &mut TcpStream) -> bool {
+        match msg_type.as_slice() {
+            "reconfigure" => {
+                stream.write_json_packet(&ReconfigureReply { from: self.name() });
+                true
+            }
+
+            // https://wiki.mozilla.org/Remote_Debugging_Protocol#Listing_Browser_Tabs
+            // (see "To attach to a _tabActor_")
+            "attach" => {
+                let msg = TabAttachedReply {
+                    from: self.name(),
+                    __type__: "tabAttached".to_string(),
+                    threadActor: self.name(),
+                    cacheDisabled: false,
+                    javascriptEnabled: true,
+                    traits: TabTraits,
+                };
+                stream.write_json_packet(&msg);
+                true
+            }
+
+            "detach" => {
+                let msg = TabDetachedReply {
+                    from: self.name(),
+                    __type__: "detached".to_string(),
+                };
+                stream.write_json_packet(&msg);
+                true
+            }
+            _ => false
+        }
+    }
+}
+
+impl TabActor {
+    pub fn encodable(&self) -> TabActorMsg {
+        TabActorMsg {
+            actor: self.name(),
+            title: self.title.clone(),
+            url: self.url.clone(),
+            outerWindowID: 0, //FIXME: this should probably be the pipeline id
+            consoleActor: "console0".to_string(), //FIXME: this should be the actual actor name
+        }
+    }
+}

components/devtools/lib.rs

@@ -14,6 +14,10 @@
 #[phase(plugin, link)]
 extern crate log;
 
+/// An actor-based remote devtools server implementation. Only tested with nightly Firefox
+/// versions at time of writing. Largely based on reverse-engineering of Firefox chrome
+/// devtool logs and reading of [code](http://mxr.mozilla.org/mozilla-central/source/toolkit/devtools/server/).
+
 extern crate collections;
 extern crate core;
 extern crate devtools_traits;
@@ -23,552 +27,35 @@ extern crate serialize;
 extern crate sync;
 extern crate servo_msg = "msg";
 
+use actor::ActorRegistry;
+use actors::console::ConsoleActor;
+use actors::root::RootActor;
+use actors::tab::TabActor;
+use protocol::JsonPacketSender;
+
 use devtools_traits::{ServerExitMsg, DevtoolsControlMsg, NewGlobal, DevtoolScriptControlMsg};
-use devtools_traits::{EvaluateJS, NullValue, VoidValue, NumberValue, StringValue, BooleanValue};
-use devtools_traits::ActorValue;
 use servo_msg::constellation_msg::PipelineId;
 
-use collections::TreeMap;
-use std::any::{Any, AnyRefExt, AnyMutRefExt};
-use std::collections::hashmap::HashMap;
 use std::comm;
 use std::comm::{Disconnected, Empty};
 use std::io::{TcpListener, TcpStream};
-use std::io::{Acceptor, Listener, EndOfFile, IoError, TimedOut};
-use std::mem::{transmute, transmute_copy};
+use std::io::{Acceptor, Listener, EndOfFile, TimedOut};
 use std::num;
-use std::raw::TraitObject;
 use std::task::TaskBuilder;
-use serialize::{json, Encodable};
-use serialize::json::ToJson;
+use serialize::json;
 use sync::{Arc, Mutex};
 
-#[deriving(Encodable)]
-struct ActorTraits {
-    sources: bool
-}
-
-#[deriving(Encodable)]
-struct RootActorMsg {
-    from: String,
-    applicationType: String,
-    traits: ActorTraits,
-}
-
-struct RootActor {
-    next: u32,
-    tabs: Vec<String>,
-}
-
-#[deriving(Encodable)]
-struct ErrorReply {
-    from: String,
-    error: String,
-    message: String,
-}
-
-#[deriving(Encodable)]
-struct TabActorMsg {
-    actor: String,
-    title: String,
-    url: String,
-    outerWindowID: uint,
-    consoleActor: String,
-}
-
-struct TabActor {
-    name: String,
-    title: String,
-    url: String,
-}
-
-struct ConsoleActor {
-    name: String,
-    pipeline: PipelineId,
-    script_chan: Sender<DevtoolScriptControlMsg>,
-}
-
-#[deriving(Encodable)]
-struct ListTabsReply {
-    from: String,
-    selected: uint,
-    tabs: Vec<TabActorMsg>,
-}
-
-#[deriving(Encodable)]
-struct TabTraits;
-
-#[deriving(Encodable)]
-struct TabAttachedReply {
-    from: String,
-    __type__: String,
-    threadActor: String,
-    cacheDisabled: bool,
-    javascriptEnabled: bool,
-    traits: TabTraits,
-}
-
-#[deriving(Encodable)]
-struct TabDetachedReply {
-    from: String,
-    __type__: String,
-}
-
-
-#[deriving(Encodable)]
-struct StartedListenersTraits {
-    customNetworkRequest: bool,
-}
-
-#[deriving(Encodable)]
-struct StartedListenersReply {
-    from: String,
-    nativeConsoleAPI: bool,
-    startedListeners: Vec<String>,
-    traits: StartedListenersTraits,
-}
-
-#[deriving(Encodable)]
-struct ConsoleAPIMessage {
-    _type: String,
-}
-
-#[deriving(Encodable)]
-struct PageErrorMessage {
-    _type: String,
-    errorMessage: String,
-    sourceName: String,
-    lineText: String,
-    lineNumber: uint,
-    columnNumber: uint,
-    category: String,
-    timeStamp: uint,
-    warning: bool,
-    error: bool,
-    exception: bool,
-    strict: bool,
-    private: bool,
-}
-
-#[deriving(Encodable)]
-struct LogMessage {
-    _type: String,
-    timeStamp: uint,
-    message: String,
-}
-
-#[deriving(Encodable)]
-enum ConsoleMessageType {
-    ConsoleAPIType(ConsoleAPIMessage),
-    PageErrorType(PageErrorMessage),
-    LogMessageType(LogMessage),
-}
-
-#[deriving(Encodable)]
-struct GetCachedMessagesReply {
-    from: String,
-    messages: Vec<json::Object>,
-}
-
-#[deriving(Encodable)]
-struct StopListenersReply {
-    from: String,
-    stoppedListeners: Vec<String>,
-}
-
-#[deriving(Encodable)]
-struct AutocompleteReply {
-    from: String,
-    matches: Vec<String>,
-    matchProp: String,
-}
-
-#[deriving(Encodable)]
-struct EvaluateJSReply {
-    from: String,
-    input: String,
-    result: json::Json,
-    timestamp: uint,
-    exception: json::Json,
-    exceptionMessage: String,
-    helperResult: json::Json,
-}
-
-struct ActorRegistry {
-    actors: HashMap<String, Box<Actor+Send+Sized>>,
-}
-
-impl ActorRegistry {
-    fn new() -> ActorRegistry {
-        ActorRegistry {
-            actors: HashMap::new(),
-        }
-    }
-
-    fn register<T: 'static>(&mut self, actor: Box<Actor+Send+Sized>) {
-        /*{
-            let actor2: &Actor+Send+Sized = actor;
-            assert!((actor2 as &Any).is::<T>());
-        };*/
-        self.actors.insert(actor.name().to_string(), actor);
-    }
-
-    fn find<'a, T: 'static>(&'a self, name: &str) -> &'a T {
-        /*let actor: &Actor+Send+Sized = *self.actors.find(&name.to_string()).unwrap();
-        (actor as &Any).downcast_ref::<T>().unwrap()*/
-        self.actors.find(&name.to_string()).unwrap().as_ref::<T>().unwrap()
-    }
-
-    fn find_mut<'a, T: 'static>(&'a mut self, name: &str) -> &'a mut T {
-        /*let actor: &mut Actor+Send+Sized = *self.actors.find_mut(&name.to_string()).unwrap();
-        (actor as &mut Any).downcast_mut::<T>().unwrap()*/
-        self.actors.find_mut(&name.to_string()).unwrap().downcast_mut::<T>().unwrap()
-    }
-
-    fn handle_message(&self, msg: &json::Object, stream: &mut TcpStream) {
-        let to = msg.find(&"to".to_string()).unwrap().as_string().unwrap();
-        match self.actors.find(&to.to_string()) {
-            None => println!("message received for unknown actor \"{:s}\"", to),
-            Some(actor) => {
-                let msg_type = msg.find(&"type".to_string()).unwrap()
-                    .as_string().unwrap();
-                if !actor.handle_message(self, &msg_type.to_string(), msg, stream) {
-                    println!("unexpected message type \"{:s}\" found for actor \"{:s}\"",
-                             msg_type, to);
-                }
-            }
-        }
-    }
-}
-
-trait Actor: Any {
-    fn handle_message(&self,
-                      registry: &ActorRegistry,
-                      msg_type: &String,
-                      msg: &json::Object,
-                      stream: &mut TcpStream) -> bool;
-    fn name(&self) -> String;
-}
-
-impl<'a> AnyMutRefExt<'a> for &'a mut Actor {
-    fn downcast_mut<T: 'static>(self) -> Option<&'a mut T> {
-        if self.is::<T>() {
-            unsafe {
-                // Get the raw representation of the trait object
-                let to: TraitObject = transmute_copy(&self);
-
-                // Extract the data pointer
-                Some(transmute(to.data))
-            }
-        } else {
-            None
-        }
-    }
-}
-
-impl<'a> AnyRefExt<'a> for &'a Actor {
-    fn is<T: 'static>(self) -> bool {
-        /*let t = TypeId::of::<T>();
-        let boxed = self.get_type_id();
-        t == boxed*/
-        true
-    }
-
-    fn downcast_ref<T: 'static>(self) -> Option<&'a T> {
-        if self.is::<T>() {
-            unsafe {
-                // Get the raw representation of the trait object
-                let to: TraitObject = transmute_copy(&self);
-
-                // Extract the data pointer
-                Some(transmute(to.data))
-            }
-        } else {
-            None
-        }
-    }
-}
-
-impl Actor for RootActor {
-    fn name(&self) -> String {
-        "root".to_string()
-    }
-
-    fn handle_message(&self,
-                      registry: &ActorRegistry,
-                      msg_type: &String,
-                      _msg: &json::Object,
-                      stream: &mut TcpStream) -> bool {
-        match msg_type.as_slice() {
-            "listAddons" => {
-                let actor = ErrorReply {
-                    from: "root".to_string(),
-                    error: "noAddons".to_string(),
-                    message: "This root actor has no browser addons.".to_string(),
-                };
-                stream.write_json_packet(&actor);
-                true
-            }
-            "listTabs" => {
-                let actor = ListTabsReply {
-                    from: "root".to_string(),
-                    selected: 0,
-                    tabs: self.tabs.iter().map(|tab| {
-                        registry.find::<TabActor>(tab.as_slice()).encodable()
-                    }).collect()
-                };
-                stream.write_json_packet(&actor);
-                true
-            }
-            _ => false
-        }
-    }
-}
-
-impl RootActor {
-    fn encodable(&self) -> RootActorMsg {
-        RootActorMsg {
-            from: "root".to_string(),
-            applicationType: "browser".to_string(),
-            traits: ActorTraits {
-                sources: true,
-            },
-        }
-    }
-}
-
-#[deriving(Encodable)]
-struct ReconfigureReply {
-    from: String
-}
-
-impl Actor for TabActor {
-    fn name(&self) -> String {
-        self.name.clone()
-    }
-
-    fn handle_message(&self,
-                      _registry: &ActorRegistry,
-                      msg_type: &String,
-                      _msg: &json::Object,
-                      stream: &mut TcpStream) -> bool {
-        match msg_type.as_slice() {
-            "reconfigure" => {
-                stream.write_json_packet(&ReconfigureReply { from: self.name() });
-                true
-            }
-            "attach" => {
-                let msg = TabAttachedReply {
-                    from: self.name(),
-                    __type__: "tabAttached".to_string(),
-                    threadActor: self.name(),
-                    cacheDisabled: false,
-                    javascriptEnabled: true,
-                    traits: TabTraits,
-                };
-                stream.write_json_packet(&msg);
-                true
-            }
-            "detach" => {
-                let msg = TabDetachedReply {
-                    from: self.name(),
-                    __type__: "detached".to_string(),
-                };
-                stream.write_json_packet(&msg);
-                true
-            }
-            _ => false
-        }
-    }
-}
-
-impl TabActor {
-    fn encodable(&self) -> TabActorMsg {
-        TabActorMsg {
-            actor: self.name(),
-            title: self.title.clone(),
-            url: self.url.clone(),
-            outerWindowID: 0,
-            consoleActor: "console0".to_string(),
-        }
-    }
-}
-
-impl Actor for ConsoleActor {
-    fn name(&self) -> String {
-        self.name.clone()
-    }
-
-    fn handle_message(&self,
-                      _registry: &ActorRegistry,
-                      msg_type: &String,
-                      msg: &json::Object,
-                      stream: &mut TcpStream) -> bool {
-        match msg_type.as_slice() {
-            "getCachedMessages" => {
-                let types = msg.find(&"messageTypes".to_string()).unwrap().as_list().unwrap();
-                let mut messages = vec!();
-                for msg_type in types.iter() {
-                    let msg_type = msg_type.as_string().unwrap();
-                    match msg_type.as_slice() {
-                        "ConsoleAPI" => {
-                            //XXX need more info about consoleapi properties
-                        }
-                        "PageError" => {
-                            let message = PageErrorMessage {
-                                _type: msg_type.to_string(),
-                                sourceName: "".to_string(),
-                                lineText: "".to_string(),
-                                lineNumber: 0,
-                                columnNumber: 0,
-                                category: "".to_string(),
-                                warning: false,
-                                error: true,
-                                exception: false,
-                                strict: false,
-                                private: false,
-                                timeStamp: 0,
-                                errorMessage: "page error test".to_string(),
-                            };
-                            messages.push(json::from_str(json::encode(&message).as_slice()).unwrap().as_object().unwrap().clone());
-                        }
-                        "LogMessage" => {
-                            let message = LogMessage {
-                                _type: msg_type.to_string(),
-                                timeStamp: 0,
-                                message: "log message test".to_string(),
-                            };
-                            messages.push(json::from_str(json::encode(&message).as_slice()).unwrap().as_object().unwrap().clone());
-                        }
-                        s => println!("unrecognized message type requested: \"{:s}\"", s),
-                    }
-                }
-                let msg = GetCachedMessagesReply {
-                    from: self.name(),
-                    messages: messages,
-                };
-                stream.write_json_packet(&msg);
-                true
-            }
-            "startListeners" => {
-                let msg = StartedListenersReply {
-                    from: self.name(),
-                    nativeConsoleAPI: true,
-                    startedListeners:
-                        vec!("PageError".to_string(), "ConsoleAPI".to_string(),
-                             "NetworkActivity".to_string(), "FileActivity".to_string()),
-                    traits: StartedListenersTraits {
-                        customNetworkRequest: true,
-                    }
-                };
-                stream.write_json_packet(&msg);
-                true
-            }
-            "stopListeners" => {
-                let msg = StopListenersReply {
-                    from: self.name(),
-                    stoppedListeners: msg.find(&"listeners".to_string())
-                                         .unwrap()
-                                         .as_list()
-                                         .unwrap_or(&vec!())
-                                         .iter()
-                                         .map(|listener| listener.as_string().unwrap().to_string())
-                                         .collect(),
-                };
-                stream.write_json_packet(&msg);
-                true
-            }
-            "autocomplete" => {
-                let msg = AutocompleteReply {
-                    from: self.name(),
-                    matches: vec!(),
-                    matchProp: "".to_string(),
-                };
-                stream.write_json_packet(&msg);
-                true
-            }
-            "evaluateJS" => {
-                let input = msg.find(&"text".to_string()).unwrap().as_string().unwrap().to_string();
-                let (chan, port) = channel();
-                self.script_chan.send(EvaluateJS(self.pipeline, input.clone(), chan));
-
-                let result = match port.recv() {
-                    VoidValue => {
-                        let mut m = TreeMap::new();
-                        m.insert("type".to_string(), "undefined".to_string().to_json());
-                        json::Object(m)
-                    }
-                    NullValue => {
-                        let mut m = TreeMap::new();
-                        m.insert("type".to_string(), "null".to_string().to_json());
-                        json::Object(m)
-                    }
-                    BooleanValue(val) => val.to_json(),
-                    NumberValue(val) => {
-                        if val.is_nan() {
-                            let mut m = TreeMap::new();
-                            m.insert("type".to_string(), "NaN".to_string().to_json());
-                            json::Object(m)
-                        } else if val.is_infinite() {
-                            let mut m = TreeMap::new();
-                            if val < 0. {
-                                m.insert("type".to_string(), "Infinity".to_string().to_json());
-                            } else {
-                                m.insert("type".to_string(), "-Infinity".to_string().to_json());
-                            }
-                            json::Object(m)
-                        } else if val == Float::neg_zero() {
-                            let mut m = TreeMap::new();
-                            m.insert("type".to_string(), "-0".to_string().to_json());
-                            json::Object(m)
-                        } else {
-                            val.to_json()
-                        }
-                    }
-                    StringValue(s) => s.to_json(),
-                    ActorValue(s) => {
-                        let mut m = TreeMap::new();
-                        m.insert("type".to_string(), "object".to_string().to_json());
-                        m.insert("class".to_string(), "???".to_string().to_json());
-                        m.insert("actor".to_string(), s.to_json());
-                        m.insert("extensible".to_string(), true.to_json());
-                        m.insert("frozen".to_string(), false.to_json());
-                        m.insert("sealed".to_string(), false.to_json());
-                        json::Object(m)
-                    }
-                };
-
-                let msg = EvaluateJSReply {
-                    from: self.name(),
-                    input: input,
-                    result: result,
-                    timestamp: 0,
-                    exception: json::Object(TreeMap::new()),
-                    exceptionMessage: "".to_string(),
-                    helperResult: json::Object(TreeMap::new()),
-                };
-                stream.write_json_packet(&msg);
-                true
-            }
-            _ => false
-        }
-    }
-}
-
-trait JsonPacketSender {
-    fn write_json_packet<'a, T: Encodable<json::Encoder<'a>,IoError>>(&mut self, obj: &T);
-}
-
-impl JsonPacketSender for TcpStream {
-    fn write_json_packet<'a, T: Encodable<json::Encoder<'a>,IoError>>(&mut self, obj: &T) {
-        let s = json::encode(obj).replace("__type__", "type");
-        println!("<- {:s}", s);
-        self.write_str(s.len().to_string().as_slice()).unwrap();
-        self.write_u8(':' as u8).unwrap();
-        self.write_str(s.as_slice()).unwrap();
-    }
+mod actor;
+/// Corresponds to http://mxr.mozilla.org/mozilla-central/source/toolkit/devtools/server/actors/
+mod actors {
+    pub mod console;
+    pub mod tab;
+    pub mod root;
 }
+mod protocol;
 
+/// Spin up a devtools server that listens for connections. Defaults to port 6000.
+/// TODO: allow specifying a port
 pub fn start_server() -> Sender<DevtoolsControlMsg> {
     let (chan, port) = comm::channel();
     TaskBuilder::new().named("devtools").spawn(proc() {
@@ -593,11 +80,12 @@ fn run_server(port: Receiver<DevtoolsControlMsg>) {
         tabs: vec!(),
     };
 
-    registry.register::<RootActor>(root);
+    registry.register(root);
     registry.find::<RootActor>("root");
 
     let actors = Arc::new(Mutex::new(registry));
 
+    /// Process the input from a single devtools client until EOF.
     fn handle_client(actors: Arc<Mutex<ActorRegistry>>, mut stream: TcpStream) {
         println!("connection established to {:?}", stream.peer_name().unwrap());
 
@@ -607,6 +95,9 @@ fn run_server(port: Receiver<DevtoolsControlMsg>) {
             stream.write_json_packet(&msg);
         }
 
+        // https://wiki.mozilla.org/Remote_Debugging_Protocol_Stream_Transport
+        // In short, each JSON packet is [ascii length]:[JSON data of given length]
+        // TODO: this really belongs in the protocol module.
         'outer: loop {
             let mut buffer = vec!();
             loop {
@@ -637,10 +128,12 @@ fn run_server(port: Receiver<DevtoolsControlMsg>) {
         }
     }
 
+    // We need separate actor representations for each script global that exists;
+    // clients can theoretically connect to multiple globals simultaneously.
+    // TODO: move this into the root or tab modules?
     fn handle_new_global(actors: Arc<Mutex<ActorRegistry>>,
                          pipeline: PipelineId,
                          sender: Sender<DevtoolScriptControlMsg>) {
-        {
         let mut actors = actors.lock();
 
         let (tab, console) = {
@@ -656,15 +149,24 @@ fn run_server(port: Receiver<DevtoolsControlMsg>) {
                 script_chan: sender,
                 pipeline: pipeline,
             };
+
             root.next += 1;
             root.tabs.push(tab.name.clone());
             (tab, console)
         };
-            actors.register::<TabActor>(box tab);
-            actors.register::<ConsoleActor>(box console);
-        }
+
+        actors.register(box tab);
+        actors.register(box console);
     }
 
+    //TODO: figure out some system that allows us to watch for new connections,
+    //      shut down existing ones at arbitrary times, and also watch for messages
+    //      from multiple script tasks simultaneously. Polling for new connections
+    //      for 300ms and then checking the receiver is not a good compromise
+    //      (and makes Servo hang on exit if there's an open connection, no less).
+
+    //TODO: make constellation send ServerExitMsg on shutdown.
+
     // accept connections and process them, spawning a new tasks for each one
     for stream in acceptor.incoming() {
         match stream {

components/devtools/protocol.rs

@@ -0,0 +1,22 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/// Low-level wire protocol implementation. Currently only supports [JSON packets](https://wiki.mozilla.org/Remote_Debugging_Protocol_Stream_Transport#JSON_Packets).
+
+use serialize::{json, Encodable};
+use std::io::{IoError, TcpStream};
+
+pub trait JsonPacketSender {
+    fn write_json_packet<'a, T: Encodable<json::Encoder<'a>,IoError>>(&mut self, obj: &T);
+}
+
+impl JsonPacketSender for TcpStream {
+    fn write_json_packet<'a, T: Encodable<json::Encoder<'a>,IoError>>(&mut self, obj: &T) {
+        let s = json::encode(obj).replace("__type__", "type");
+        println!("<- {:s}", s);
+        self.write_str(s.len().to_string().as_slice()).unwrap();
+        self.write_u8(':' as u8).unwrap();
+        self.write_str(s.as_slice()).unwrap();
+    }
+}

components/devtools_traits/lib.rs

@@ -10,16 +10,24 @@
 
 extern crate servo_msg = "msg";
 
+/// This module contains shared types and messages for use by devtools/script.
+/// The traits are here instead of in script so that the devtools crate can be
+/// modified independently of the rest of Servo.
+
 use servo_msg::constellation_msg::PipelineId;
 
 pub type DevtoolsControlChan = Sender<DevtoolsControlMsg>;
 pub type DevtoolsControlPort = Receiver<DevtoolScriptControlMsg>;
 
+/// Messages to the instruct the devtools server to update its known actors/state
+/// according to changes in the browser.
 pub enum DevtoolsControlMsg {
     NewGlobal(PipelineId, Sender<DevtoolScriptControlMsg>),
     ServerExitMsg
 }
 
+/// Serialized JS return values
+/// TODO: generalize this beyond the EvaluateJS message?
 pub enum EvaluateJSReply {
     VoidValue,
     NullValue,
@@ -29,10 +37,14 @@ pub enum EvaluateJSReply {
     ActorValue(String),
 }
 
+/// Messages to process in a particular script task, as instructed by a devtools client.
 pub enum DevtoolScriptControlMsg {
     EvaluateJS(PipelineId, String, Sender<EvaluateJSReply>),
 }
 
+/// Messages to instruct devtools server to update its state relating to a particular
+/// tab.
 pub enum ScriptDevtoolControlMsg {
+    /// Report a new JS error message
     ReportConsoleMsg(String),
 }