Add enough Webdriver support to enable Get().

This is incomplete in several ways:

* It assumes that there's only one constellation (i.e. top level browsing context), ever.
* The session support is very basic indeed (no capabilities)
* Passing channels over channels may not sit well with IPC
* The error handling is mostly missing

components/webdriver_server/lib.rs

@@ -6,27 +6,125 @@
 #![crate_type = "rlib"]
 
 #![feature(net)]
+#![feature(rustc_private)]
+
+#[macro_use]
+extern crate log;
 
 extern crate webdriver;
+extern crate msg;
+extern crate url;
+extern crate util;
+extern crate "rustc-serialize" as rustc_serialize;
+extern crate uuid;
 
-use webdriver::command::WebDriverMessage;
-use webdriver::error::WebDriverResult;
-use webdriver::response::WebDriverResponse;
+use msg::constellation_msg::{ConstellationChan, LoadData};
+use msg::constellation_msg::Msg as ConstellationMsg;
+use std::sync::mpsc::channel;
+
+use url::Url;
+use webdriver::command::{WebDriverMessage, WebDriverCommand};
+use webdriver::command::GetParameters;
+use webdriver::response::{
+    WebDriverResponse, NewSessionResponse, ValueResponse};
 use webdriver::server::{self, WebDriverHandler, Session};
+use webdriver::error::{WebDriverResult, WebDriverError, ErrorStatus};
+use util::task::spawn_named;
+use uuid::Uuid;
 
+use std::borrow::ToOwned;
 use std::net::IpAddr;
+use rustc_serialize::json::{Json, ToJson};
+use std::collections::BTreeMap;
 
-pub fn start_server(port: u16) {
-    server::start(IpAddr::new_v4(0, 0, 0, 0), port, Handler);
+pub fn start_server(port: u16, constellation_chan: ConstellationChan) {
+    let handler = Handler::new(constellation_chan);
+
+    spawn_named("WebdriverHttpServer".to_owned(), move || {
+        server::start(IpAddr::new_v4(0, 0, 0, 0), port, handler);
+    });
 }
 
-struct Handler;
+struct WebdriverSession {
+    id: Uuid
+}
 
-impl WebDriverHandler for Handler {
-    fn handle_command(&mut self, _session: &Option<Session>, _msg: &WebDriverMessage) -> WebDriverResult<WebDriverResponse> {
+struct Handler {
+    session: Option<WebdriverSession>,
+    constellation_chan: ConstellationChan
+}
+
+impl WebdriverSession {
+    pub fn new() -> WebdriverSession {
+        WebdriverSession {
+            id: Uuid::new_v4()
+        }
+    }
+}
+
+impl Handler {
+    pub fn new(constellation_chan: ConstellationChan) -> Handler {
+        Handler {
+            session: None,
+            constellation_chan: constellation_chan
+        }
+    }
+
+    fn handle_new_session(&mut self) -> WebDriverResult<WebDriverResponse> {
+        if self.session.is_none() {
+            let session = WebdriverSession::new();
+            let rv = Ok(WebDriverResponse::NewSession(
+                NewSessionResponse::new(
+                    session.id.to_string(),
+                    Json::Object(BTreeMap::new()))));
+            self.session = Some(session);
+            rv
+        } else {
+            Err(WebDriverError::new(ErrorStatus::UnknownError,
+                                    "Session already created"))
+        }
+    }
+
+    fn handle_get(&self, parameters: &GetParameters) -> WebDriverResult<WebDriverResponse> {
+        let url = match Url::parse(&parameters.url[..]) {
+            Ok(url) => url,
+            Err(_) => return Err(WebDriverError::new(ErrorStatus::InvalidArgument,
+                                               "Invalid URL"))
+        };
+
+        let (sender, reciever) = channel();
+        let ConstellationChan(ref const_chan) = self.constellation_chan;
+        const_chan.send(ConstellationMsg::GetRootPipeline(sender)).unwrap();
+
+        let pipeline_id = reciever.recv().unwrap().unwrap();
+
+        let load_data = LoadData::new(url);
+        const_chan.send(ConstellationMsg::LoadUrl(pipeline_id, load_data)).unwrap();
+        //TODO: Now we ought to wait until we get a load event
         Ok(WebDriverResponse::Void)
     }
 
-    fn delete_session(&mut self, _session: &Option<Session>) {
+    fn handle_get_window_handle(&self) -> WebDriverResult<WebDriverResponse> {
+        // For now we assume there's only one window so just use the session
+        // id as the window id
+        let handle = self.session.as_ref().unwrap().id.to_string();
+        Ok(WebDriverResponse::Generic(ValueResponse::new(handle.to_json())))
+    }
+}
+
+impl WebDriverHandler for Handler {
+    fn handle_command(&mut self, _session: &Option<Session>, msg: &WebDriverMessage) -> WebDriverResult<WebDriverResponse> {
+
+        match msg.command {
+            WebDriverCommand::NewSession => self.handle_new_session(),
+            WebDriverCommand::Get(ref parameters) => self.handle_get(parameters),
+            WebDriverCommand::GetWindowHandle => self.handle_get_window_handle(),
+            _ => Err(WebDriverError::new(ErrorStatus::UnsupportedOperation,
+                                         "Command not implemented"))
+        }
+    }
+
+    fn delete_session(&mut self, _session: &Option<Session>) {
+        self.session = None;
     }
 }