Allow to specify port with --devtools option (fixes #3597)

Note that using `servo --devtools http://example.org` doesn't work. In
that case either the port must be specified or the option moved to the
end. This is done by getopts and is the same for other such options,
e.g. `--profile`.

components/devtools/lib.rs

@@ -58,20 +58,19 @@ mod actors {
 }
 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();
+/// Spin up a devtools server that listens for connections on the specified port.
+pub fn start_server(port: u16) -> Sender<DevtoolsControlMsg> {
+    let (sender, receiver) = comm::channel();
     TaskBuilder::new().named("devtools").spawn(proc() {
-        run_server(port)
+        run_server(receiver, port)
     });
-    chan
+    sender
 }
 
 static POLL_TIMEOUT: u64 = 300;
 
-fn run_server(port: Receiver<DevtoolsControlMsg>) {
-    let listener = TcpListener::bind("127.0.0.1", 6000);
+fn run_server(receiver: Receiver<DevtoolsControlMsg>, port: u16) {
+    let listener = TcpListener::bind("127.0.0.1", port);
 
     // bind the listener to the specified address
     let mut acceptor = listener.listen().unwrap();
@@ -185,7 +184,7 @@ fn run_server(port: Receiver<DevtoolsControlMsg>) {
     loop {
         match acceptor.accept() {
             Err(ref e) if e.kind == TimedOut => {
-                match port.try_recv() {
+                match receiver.try_recv() {
                     Ok(ServerExitMsg) | Err(Disconnected) => break,
                     Ok(NewGlobal(id, sender)) => handle_new_global(actors.clone(), id, sender),
                     Err(Empty) => acceptor.set_timeout(Some(POLL_TIMEOUT)),

components/util/opts.rs

@@ -85,8 +85,9 @@ pub struct Opts {
     /// and render.
     pub trace_layout: bool,
 
-    /// True if we should start a server to listen to remote Firefox devtools connections.
-    pub devtools_server: bool,
+    /// `None` to disable devtools or `Some` with a port number to start a server to listen to
+    /// remote Firefox devtools connections.
+    pub devtools_port: Option<u16>,
 
     /// The initial requested size of the window.
     pub initial_window_size: TypedSize2D<ScreenPx, uint>,
@@ -127,7 +128,7 @@ pub fn from_cmdline_args(args: &[String]) -> Option<Opts> {
         getopts::optflag("", "show-debug-borders", "Show debugging borders on layers and tiles."),
         getopts::optflag("", "disable-text-aa", "Disable antialiasing for text rendering."),
         getopts::optflag("", "trace-layout", "Write layout trace to external file for debugging."),
-        getopts::optflag("", "devtools", "Start remote devtools server"),
+        getopts::optflagopt("", "devtools", "Start remote devtools server on port", "6000"),
         getopts::optopt("", "resolution", "Set window resolution.", "800x600"),
         getopts::optopt("u", "user-agent", "Set custom user agent string", "NCSA Mosaic/1.0 (X11;SunOS 4.1.4 sun4m)"),
         getopts::optflag("h", "help", "Print this message")
@@ -211,6 +212,10 @@ pub fn from_cmdline_args(args: &[String]) -> Option<Opts> {
         bubble_inline_sizes_separately = true;
     }
 
+    let devtools_port = opt_match.opt_default("devtools", "6000").map(|port| {
+        from_str(port.as_slice()).unwrap()
+    });
+
     let initial_window_size = match opt_match.opt_str("resolution") {
         Some(res_string) => {
             let res: Vec<uint> = res_string.as_slice().split('x').map(|r| from_str(r).unwrap()).collect();
@@ -240,7 +245,7 @@ pub fn from_cmdline_args(args: &[String]) -> Option<Opts> {
         show_debug_borders: opt_match.opt_present("show-debug-borders"),
         enable_text_antialiasing: !opt_match.opt_present("disable-text-aa"),
         trace_layout: trace_layout,
-        devtools_server: opt_match.opt_present("devtools"),
+        devtools_port: devtools_port,
         initial_window_size: initial_window_size,
         user_agent: opt_match.opt_str("u"),
     })

ports/cef/core.rs

@@ -68,7 +68,7 @@ pub extern "C" fn cef_run_message_loop() {
         show_debug_borders: false,
         enable_text_antialiasing: true,
         trace_layout: false,
-        devtools_server: false,
+        devtools_port: None,
         initial_window_size: TypedSize2D(800, 600),
         user_agent: None,
     };

src/lib.rs

@@ -95,11 +95,9 @@ pub fn run(opts: opts::Opts) {
     let (compositor_port, compositor_chan) = CompositorChan::new();
     let time_profiler_chan = TimeProfiler::create(opts.time_profiler_period);
     let memory_profiler_chan = MemoryProfiler::create(opts.memory_profiler_period);
-    let devtools_chan = if opts.devtools_server {
-        Some(devtools::start_server())
-    } else {
-        None
-    };
+    let devtools_chan = opts.devtools_port.map(|port| {
+        devtools::start_server(port)
+    });
 
     let opts_clone = opts.clone();
     let time_profiler_chan_clone = time_profiler_chan.clone();