Auto merge of #10896 - vramana:basic_fetch_file, r=KiChjang

Implement fetching file URL's

closes #10166

<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="35" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/10896)
<!-- Reviewable:end -->

components/net/fetch/methods.rs

@@ -14,6 +14,7 @@ use hyper::header::{IfNoneMatch, Pragma, Location, QualityItem, Referer as Refer
 use hyper::method::Method;
 use hyper::mime::{Mime, SubLevel, TopLevel};
 use hyper::status::StatusCode;
+use mime_guess::guess_mime_type;
 use net_traits::AsyncFetchListener;
 use net_traits::request::{CacheMode, CredentialsMode, Type, Origin, Window};
 use net_traits::request::{RedirectMode, Referer, Request, RequestMode, ResponseTainting};
@@ -21,6 +22,7 @@ use net_traits::response::{HttpsState, TerminationReason};
 use net_traits::response::{Response, ResponseBody, ResponseType};
 use resource_thread::CancellationListener;
 use std::collections::HashSet;
+use std::fs::File;
 use std::io::Read;
 use std::iter::FromIterator;
 use std::rc::Rc;
@@ -157,6 +159,7 @@ fn main_fetch(request: Rc<Request>, cache: &mut CORSCache, cors_flag: bool, recu
 
             if (same_origin && !cors_flag ) ||
                 (current_url.scheme() == "data" && request.same_origin_data.get()) ||
+                (current_url.scheme() == "file" && request.same_origin_data.get()) ||
                 current_url.scheme() == "about" ||
                 request.mode == RequestMode::Navigate {
 
@@ -317,7 +320,29 @@ fn basic_fetch(request: Rc<Request>, cache: &mut CORSCache) -> Response {
             }
         },
 
-        "blob" | "file" | "ftp" => {
+        "file" => {
+            if *request.method.borrow() == Method::Get {
+                match url.to_file_path() {
+                    Ok(file_path) => {
+                        File::open(file_path.clone()).ok().map_or(Response::network_error(), |mut file| {
+                            let mut bytes = vec![];
+                            let _ = file.read_to_end(&mut bytes);
+                            let mime = guess_mime_type(file_path);
+
+                            let mut response = Response::new();
+                            *response.body.lock().unwrap() = ResponseBody::Done(bytes);
+                            response.headers.set(ContentType(mime));
+                            response
+                        })
+                    },
+                    _ => Response::network_error()
+                }
+            } else {
+                Response::network_error()
+            }
+        },
+
+        "blob" | "ftp" => {
             // XXXManishearth handle these
             panic!("Unimplemented scheme for Fetch")
         },

tests/unit/net/fetch.rs

@@ -18,6 +18,8 @@ use net::fetch::methods::{fetch, fetch_async, fetch_with_cors_cache};
 use net_traits::AsyncFetchListener;
 use net_traits::request::{Origin, RedirectMode, Referer, Request, RequestMode};
 use net_traits::response::{CacheState, Response, ResponseBody, ResponseType};
+use std::fs::File;
+use std::io::Read;
 use std::rc::Rc;
 use std::sync::atomic::{AtomicUsize, Ordering};
 use std::sync::mpsc::{Sender, channel};
@@ -25,6 +27,7 @@ use std::sync::{Arc, Mutex};
 use time::{self, Duration};
 use unicase::UniCase;
 use url::{Origin as UrlOrigin, Url};
+use util::resource_files::resources_dir_path;
 
 // TODO write a struct that impls Handler for storing test values
 
@@ -140,6 +143,36 @@ fn test_fetch_data() {
     }
 }
 
+#[test]
+fn test_fetch_file() {
+
+    let mut path = resources_dir_path();
+    path.push("servo.css");
+
+    let url = Url::from_file_path(path.clone()).unwrap();
+    let origin = Origin::Origin(url.origin());
+    let request = Request::new(url, Some(origin), false);
+    request.same_origin_data.set(true);
+
+    let fetch_response = fetch(Rc::new(request));
+    assert!(!fetch_response.is_network_error());
+    assert_eq!(fetch_response.headers.len(), 1);
+    let content_type: &ContentType = fetch_response.headers.get().unwrap();
+    assert!(**content_type == Mime(TopLevel::Text, SubLevel::Css, vec![]));
+
+    let resp_body = fetch_response.body.lock().unwrap();
+    let mut file = File::open(path).unwrap();
+    let mut bytes = vec![];
+    let _ = file.read_to_end(&mut bytes);
+
+    match *resp_body {
+        ResponseBody::Done(ref val) => {
+            assert_eq!(val, &bytes);
+        },
+        _ => panic!()
+    }
+}
+
 #[test]
 fn test_cors_preflight_fetch() {
     static ACK: &'static [u8] = b"ACK";