servo: Merge #13204 - Implement a WebSocket server for debugging (from ejpbruel:debugger); r=jdm

<!-- Please describe your changes on the following line: -->

This pull request adds a very simple WebSocket server to Servo, that we intend to use for debugging. It currently only echoes back messages, but eventually we want this server to implement the Chrome Debugging Protocol.

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [ ] These changes fix #__ (github issue number if applicable).

<!-- Either: -->
- [ ] There are tests for these changes OR
- [X] These changes do not require tests because this is a prototype.

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Source-Repo: https://github.com/servo/servo
Source-Revision: f834c893c7cfde631e458564499d85e8895b4482

servo/components/debugger/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "debugger"
+version = "0.0.1"
+authors = ["The Servo Project Developers"]
+license = "MPL-2.0"
+publish = false
+
+[lib]
+name = "debugger"
+path = "lib.rs"
+crate_type = ["rlib"]
+
+[dependencies]
+util = { path = "../util" }
+websocket = "0.17.1"

servo/components/debugger/lib.rs

@@ -0,0 +1,50 @@
+/* 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/. */
+
+extern crate util;
+extern crate websocket;
+
+use util::thread::spawn_named;
+use websocket::{Message, Receiver, Sender, Server};
+use websocket::message::Type;
+
+pub fn start_server(port: u16) {
+    println!("Starting debugger server.");
+    spawn_named("debugger-server".to_owned(), move || {
+        run_server(port)
+    });
+}
+
+fn run_server(port: u16) {
+    let server = Server::bind(("127.0.0.1", port)).unwrap();
+    for connection in server {
+        spawn_named("debugger-connection".to_owned(), move || {
+            let connection = connection.unwrap();
+            let request = connection.read_request().unwrap();
+            let response = request.accept();
+            let client = response.send().unwrap();
+            let (mut sender, mut receiver) = client.split();
+            for message in receiver.incoming_messages() {
+                let message: Message = message.unwrap();
+                match message.opcode {
+                    Type::Close => {
+                        let message = Message::close();
+                        sender.send_message(&message).unwrap();
+                        break;
+                    }
+                    Type::Ping => {
+                        let message = Message::pong(message.payload);
+                        sender.send_message(&message).unwrap();
+                    }
+                    Type::Text => {
+                        sender.send_message(&message).unwrap();
+                    }
+                    _ => {
+                        panic!("Unexpected message type.");
+                    }
+                }
+            }
+        });
+    }
+}

servo/components/servo/Cargo.lock

@@ -10,6 +10,7 @@ dependencies = [
  "compiletest_helper 0.0.1",
  "compositing 0.0.1",
  "constellation 0.0.1",
+ "debugger 0.0.1",
  "devtools 0.0.1",
  "devtools_traits 0.0.1",
  "env_logger 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -481,6 +482,14 @@ dependencies = [
  "unreachable 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "debugger"
+version = "0.0.1"
+dependencies = [
+ "util 0.0.1",
+ "websocket 0.17.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "deque"
 version = "0.3.1"

servo/components/servo/Cargo.toml

@@ -49,6 +49,7 @@ canvas = {path = "../canvas"}
 canvas_traits = {path = "../canvas_traits"}
 compositing = {path = "../compositing"}
 constellation = {path = "../constellation"}
+debugger = {path = "../debugger"}
 devtools = {path = "../devtools"}
 devtools_traits = {path = "../devtools_traits"}
 env_logger = "0.3"

servo/components/servo/lib.rs

@@ -28,6 +28,7 @@ pub extern crate canvas;
 pub extern crate canvas_traits;
 pub extern crate compositing;
 pub extern crate constellation;
+pub extern crate debugger;
 pub extern crate devtools;
 pub extern crate devtools_traits;
 pub extern crate euclid;
@@ -125,6 +126,9 @@ impl<Window> Browser<Window> where Window: WindowMethods + 'static {
         let time_profiler_chan = profile_time::Profiler::create(&opts.time_profiling,
                                                                 opts.time_profiler_trace_path.clone());
         let mem_profiler_chan = profile_mem::Profiler::create(opts.mem_profiler_period);
+        if let Some(port) = opts.debugger_port {
+            debugger::start_server(port)
+        }
         let devtools_chan = opts.devtools_port.map(|port| {
             devtools::start_server(port)
         });

servo/components/util/opts.rs

@@ -123,6 +123,10 @@ pub struct Opts {
     /// Enable all heartbeats for profiling.
     pub profile_heartbeats: bool,
 
+    /// `None` to disable debugger or `Some` with a port number to start a server to listen to
+    /// remote Firefox debugger connections.
+    pub debugger_port: Option<u16>,
+
     /// `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>,
@@ -502,6 +506,7 @@ pub fn default_opts() -> Opts {
         enable_text_antialiasing: false,
         enable_canvas_antialiasing: false,
         trace_layout: false,
+        debugger_port: None,
         devtools_port: None,
         webdriver_port: None,
         initial_window_size: TypedSize2D::new(1024, 740),
@@ -562,6 +567,7 @@ pub fn from_cmdline_args(args: &[String]) -> ArgumentParsingResult {
     opts.optflag("z", "headless", "Headless mode");
     opts.optflag("f", "hard-fail", "Exit on thread failure instead of displaying about:failure");
     opts.optflag("F", "soft-fail", "Display about:failure on thread failure instead of exiting");
+    opts.optflagopt("", "remote-debugging-port", "Start remote debugger server on port", "2794");
     opts.optflagopt("", "devtools", "Start remote devtools server on port", "6000");
     opts.optflagopt("", "webdriver", "Start remote WebDriver server on port", "7000");
     opts.optopt("", "resolution", "Set window resolution.", "1024x740");
@@ -721,6 +727,11 @@ pub fn from_cmdline_args(args: &[String]) -> ArgumentParsingResult {
         bubble_inline_sizes_separately = true;
     }
 
+    let debugger_port = opt_match.opt_default("remote-debugging-port", "2794").map(|port| {
+        port.parse()
+            .unwrap_or_else(|err| args_fail(&format!("Error parsing option: --remote-debugging-port ({})", err)))
+    });
+
     let devtools_port = opt_match.opt_default("devtools", "6000").map(|port| {
         port.parse().unwrap_or_else(|err| args_fail(&format!("Error parsing option: --devtools ({})", err)))
     });
@@ -802,6 +813,7 @@ pub fn from_cmdline_args(args: &[String]) -> ArgumentParsingResult {
         profile_script_events: debug_options.profile_script_events,
         profile_heartbeats: debug_options.profile_heartbeats,
         trace_layout: debug_options.trace_layout,
+        debugger_port: debugger_port,
         devtools_port: devtools_port,
         webdriver_port: webdriver_port,
         initial_window_size: initial_window_size,

servo/ports/cef/Cargo.lock

@@ -439,6 +439,14 @@ dependencies = [
  "unreachable 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "debugger"
+version = "0.0.1"
+dependencies = [
+ "util 0.0.1",
+ "websocket 0.17.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "deque"
 version = "0.3.1"
@@ -1971,6 +1979,7 @@ dependencies = [
  "canvas_traits 0.0.1",
  "compositing 0.0.1",
  "constellation 0.0.1",
+ "debugger 0.0.1",
  "devtools 0.0.1",
  "devtools_traits 0.0.1",
  "env_logger 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",