Cargoify servo

components/net/resource_task.rs

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+/* 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/. */
+
+//! A task that takes a URL and streams back the binary data.
+
+use file_loader;
+use http_loader;
+use data_loader;
+
+use std::comm::{channel, Receiver, Sender};
+use std::task::TaskBuilder;
+use std::os;
+use http::headers::content_type::MediaType;
+use ResponseHeaderCollection = http::headers::response::HeaderCollection;
+use RequestHeaderCollection = http::headers::request::HeaderCollection;
+use http::method::{Method, Get};
+use url::Url;
+
+use StatusOk = http::status::Ok;
+use http::status::Status;
+
+
+pub enum ControlMsg {
+    /// Request the data associated with a particular URL
+    Load(LoadData, Sender<LoadResponse>),
+    Exit
+}
+
+#[deriving(Clone)]
+pub struct LoadData {
+    pub url: Url,
+    pub method: Method,
+    pub headers: RequestHeaderCollection,
+    pub data: Option<Vec<u8>>,
+    pub cors: Option<ResourceCORSData>
+}
+
+impl LoadData {
+    pub fn new(url: Url) -> LoadData {
+        LoadData {
+            url: url,
+            method: Get,
+            headers: RequestHeaderCollection::new(),
+            data: None,
+            cors: None
+        }
+    }
+}
+
+#[deriving(Clone)]
+pub struct ResourceCORSData {
+    /// CORS Preflight flag
+    pub preflight: bool,
+    /// Origin of CORS Request
+    pub origin: Url
+}
+
+/// Metadata about a loaded resource, such as is obtained from HTTP headers.
+pub struct Metadata {
+    /// Final URL after redirects.
+    pub final_url: Url,
+
+    /// MIME type / subtype.
+    pub content_type: Option<(String, String)>,
+
+    /// Character set.
+    pub charset: Option<String>,
+
+    /// Headers
+    pub headers: Option<ResponseHeaderCollection>,
+
+    /// HTTP Status
+    pub status: Status
+}
+
+impl Metadata {
+    /// Metadata with defaults for everything optional.
+    pub fn default(url: Url) -> Metadata {
+        Metadata {
+            final_url:    url,
+            content_type: None,
+            charset:      None,
+            headers: None,
+            status: StatusOk // http://fetch.spec.whatwg.org/#concept-response-status-message
+        }
+    }
+
+    /// Extract the parts of a MediaType that we care about.
+    pub fn set_content_type(&mut self, content_type: &Option<MediaType>) {
+        match *content_type {
+            None => (),
+            Some(MediaType { type_:      ref type_,
+                             subtype:    ref subtype,
+                             parameters: ref parameters }) => {
+                self.content_type = Some((type_.clone(), subtype.clone()));
+                for &(ref k, ref v) in parameters.iter() {
+                    if "charset" == k.as_slice() {
+                        self.charset = Some(v.clone());
+                    }
+                }
+            }
+        }
+    }
+}
+
+/// Message sent in response to `Load`.  Contains metadata, and a port
+/// for receiving the data.
+///
+/// Even if loading fails immediately, we send one of these and the
+/// progress_port will provide the error.
+pub struct LoadResponse {
+    /// Metadata, such as from HTTP headers.
+    pub metadata: Metadata,
+    /// Port for reading data.
+    pub progress_port: Receiver<ProgressMsg>,
+}
+
+/// Messages sent in response to a `Load` message
+#[deriving(PartialEq,Show)]
+pub enum ProgressMsg {
+    /// Binary data - there may be multiple of these
+    Payload(Vec<u8>),
+    /// Indicates loading is complete, either successfully or not
+    Done(Result<(), String>)
+}
+
+/// For use by loaders in responding to a Load message.
+pub fn start_sending(start_chan: Sender<LoadResponse>, metadata: Metadata) -> Sender<ProgressMsg> {
+    start_sending_opt(start_chan, metadata).ok().unwrap()
+}
+
+/// For use by loaders in responding to a Load message.
+pub fn start_sending_opt(start_chan: Sender<LoadResponse>, metadata: Metadata) -> Result<Sender<ProgressMsg>, ()> {
+    let (progress_chan, progress_port) = channel();
+    let result = start_chan.send_opt(LoadResponse {
+        metadata:      metadata,
+        progress_port: progress_port,
+    });
+    match result {
+        Ok(_) => Ok(progress_chan),
+        Err(_) => Err(())
+    }
+}
+
+/// Convenience function for synchronously loading a whole resource.
+pub fn load_whole_resource(resource_task: &ResourceTask, url: Url)
+        -> Result<(Metadata, Vec<u8>), String> {
+    let (start_chan, start_port) = channel();
+    resource_task.send(Load(LoadData::new(url), start_chan));
+    let response = start_port.recv();
+
+    let mut buf = vec!();
+    loop {
+        match response.progress_port.recv() {
+            Payload(data) => buf.push_all(data.as_slice()),
+            Done(Ok(()))  => return Ok((response.metadata, buf)),
+            Done(Err(e))  => return Err(e)
+        }
+    }
+}
+
+/// Handle to a resource task
+pub type ResourceTask = Sender<ControlMsg>;
+
+pub type LoaderTask = proc(load_data: LoadData, Sender<LoadResponse>);
+
+/**
+Creates a task to load a specific resource
+
+The ResourceManager delegates loading to a different type of loader task for
+each URL scheme
+*/
+type LoaderTaskFactory = extern "Rust" fn() -> LoaderTask;
+
+/// Create a ResourceTask
+pub fn new_resource_task() -> ResourceTask {
+    let (setup_chan, setup_port) = channel();
+    let builder = TaskBuilder::new().named("ResourceManager");
+    builder.spawn(proc() {
+        ResourceManager::new(setup_port).start();
+    });
+    setup_chan
+}
+
+struct ResourceManager {
+    from_client: Receiver<ControlMsg>,
+}
+
+
+impl ResourceManager {
+    fn new(from_client: Receiver<ControlMsg>) -> ResourceManager {
+        ResourceManager {
+            from_client : from_client,
+        }
+    }
+}
+
+
+impl ResourceManager {
+    fn start(&self) {
+        loop {
+            match self.from_client.recv() {
+              Load(load_data, start_chan) => {
+                self.load(load_data, start_chan)
+              }
+              Exit => {
+                break
+              }
+            }
+        }
+    }
+
+    fn load(&self, mut load_data: LoadData, start_chan: Sender<LoadResponse>) {
+        let loader = match load_data.url.scheme.as_slice() {
+            "file" => file_loader::factory(),
+            "http" | "https" => http_loader::factory(),
+            "data" => data_loader::factory(),
+            "about" => {
+                match load_data.url.non_relative_scheme_data().unwrap() {
+                    "crash" => fail!("Loading the about:crash URL."),
+                    "failure" => {
+                        // FIXME: Find a way to load this without relying on the `../src` directory.
+                        let mut path = os::self_exe_path().expect("can't get exe path");
+                        path.pop();
+                        path.push_many(["src", "test", "html", "failure.html"]);
+                        load_data.url = Url::from_file_path(&path).unwrap();
+                        file_loader::factory()
+                    }
+                    _ => {
+                        start_sending(start_chan, Metadata::default(load_data.url))
+                            .send(Done(Err("Unknown about: URL.".to_string())));
+                        return
+                    }
+                }
+            },
+            _ => {
+                debug!("resource_task: no loader for scheme {:s}", load_data.url.scheme);
+                start_sending(start_chan, Metadata::default(load_data.url))
+                    .send(Done(Err("no loader for scheme".to_string())));
+                return
+            }
+        };
+        debug!("resource_task: loading url: {:s}", load_data.url.serialize());
+        loader(load_data, start_chan);
+    }
+}
+
+#[test]
+fn test_exit() {
+    let resource_task = new_resource_task();
+    resource_task.send(Exit);
+}
+
+#[test]
+fn test_bad_scheme() {
+    let resource_task = new_resource_task();
+    let (start_chan, start) = channel();
+    let url = Url::parse("bogus://whatever").unwrap();
+    resource_task.send(Load(LoadData::new(url), start_chan));
+    let response = start.recv();
+    match response.progress_port.recv() {
+      Done(result) => { assert!(result.is_err()) }
+      _ => fail!("bleh")
+    }
+    resource_task.send(Exit);
+}