Add ImmutableOrigin to allow for serializing origins

21 files changed, 270 insertions, 152 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 7f2a649894e..e6354423afb 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2596,8 +2596,11 @@ dependencies = [
  "heapsize 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "heapsize_derive 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 0.9.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_derive 0.9.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "servo_rand 0.0.1",
  "url 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "url_serde 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "uuid 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
diff --git a/components/net/http_loader.rs b/components/net/http_loader.rs
index 63fa745707b..56750d60f05 100644
--- a/components/net/http_loader.rs
+++ b/components/net/http_loader.rs
@@ -37,7 +37,7 @@ use net_traits::response::{HttpsState, Response, ResponseBody, ResponseType};
 use openssl;
 use openssl::ssl::error::{OpensslError, SslError};
 use resource_thread::AuthCache;
-use servo_url::ServoUrl;
+use servo_url::{ImmutableOrigin, ServoUrl};
 use std::collections::HashSet;
 use std::error::Error;
 use std::io::{self, Read, Write};
@@ -51,7 +51,6 @@ use std::thread;
 use time;
 use time::Tm;
 use unicase::UniCase;
-use url::Origin as UrlOrigin;
 use uuid;
 
 fn read_block<R: Read>(reader: &mut R) -> Result<Data, ()> {
@@ -389,7 +388,7 @@ fn send_response_to_devtools(devtools_chan: &Sender<DevtoolsControlMsg>,
     let _ = devtools_chan.send(DevtoolsControlMsg::FromChrome(msg));
 }
 
-fn auth_from_cache(auth_cache: &Arc<RwLock<AuthCache>>, origin: &UrlOrigin) -> Option<Basic> {
+fn auth_from_cache(auth_cache: &Arc<RwLock<AuthCache>>, origin: &ImmutableOrigin) -> Option<Basic> {
     if let Some(ref auth_entry) = auth_cache.read().unwrap().entries.get(&origin.ascii_serialization()) {
         let user_name = auth_entry.user_name.clone();
         let password  = Some(auth_entry.password.clone());
@@ -767,7 +766,7 @@ fn http_redirect_fetch(request: Rc<Request>,
 
     // Step 9
     if cors_flag && !same_origin {
-        *request.origin.borrow_mut() = Origin::Origin(UrlOrigin::new_opaque());
+        *request.origin.borrow_mut() = Origin::Origin(ImmutableOrigin::new_opaque());
     }
 
     // Step 10
diff --git a/components/net_traits/request.rs b/components/net_traits/request.rs
index dcdd87ac4b0..7178ec8ca99 100644
--- a/components/net_traits/request.rs
+++ b/components/net_traits/request.rs
@@ -6,10 +6,9 @@ use ReferrerPolicy;
 use hyper::header::Headers;
 use hyper::method::Method;
 use msg::constellation_msg::PipelineId;
-use servo_url::ServoUrl;
+use servo_url::{ImmutableOrigin, ServoUrl};
 use std::cell::{Cell, RefCell};
 use std::default::Default;
-use url::Origin as UrlOrigin;
 
 /// An [initiator](https://fetch.spec.whatwg.org/#concept-request-initiator)
 #[derive(Copy, Clone, PartialEq, HeapSizeOf)]
@@ -55,10 +54,10 @@ pub enum Destination {
 }
 
 /// A request [origin](https://fetch.spec.whatwg.org/#concept-request-origin)
-#[derive(Clone, PartialEq, Debug, HeapSizeOf)]
+#[derive(Clone, PartialEq, Debug, Serialize, Deserialize, HeapSizeOf)]
 pub enum Origin {
     Client,
-    Origin(UrlOrigin),
+    Origin(ImmutableOrigin),
 }
 
 /// A [referer](https://fetch.spec.whatwg.org/#concept-request-referrer)
diff --git a/components/script/dom/bindings/trace.rs b/components/script/dom/bindings/trace.rs
index aeddcdabe4b..0e605780a20 100644
--- a/components/script/dom/bindings/trace.rs
+++ b/components/script/dom/bindings/trace.rs
@@ -79,7 +79,7 @@ use script_traits::{UntrustedNodeAddress, WindowSizeData, WindowSizeType};
 use selectors::matching::ElementSelectorFlags;
 use serde::{Deserialize, Serialize};
 use servo_atoms::Atom;
-use servo_url::ServoUrl;
+use servo_url::{ImmutableOrigin, MutableOrigin, ServoUrl};
 use smallvec::SmallVec;
 use std::cell::{Cell, RefCell, UnsafeCell};
 use std::collections::{BTreeMap, HashMap, HashSet, VecDeque};
@@ -104,7 +104,6 @@ use style::stylesheets::SupportsRule;
 use style::values::specified::Length;
 use style::viewport::ViewportRule;
 use time::Duration;
-use url::Origin as UrlOrigin;
 use uuid::Uuid;
 use webrender_traits::{WebGLBufferId, WebGLError, WebGLFramebufferId, WebGLProgramId};
 use webrender_traits::{WebGLRenderbufferId, WebGLShaderId, WebGLTextureId};
@@ -317,9 +316,10 @@ unsafe impl<A: JSTraceable, B: JSTraceable, C: JSTraceable> JSTraceable for (A,
     }
 }
 
-unsafe_no_jsmanaged_fields!(bool, f32, f64, String, ServoUrl, AtomicBool, AtomicUsize, UrlOrigin, Uuid, char);
+unsafe_no_jsmanaged_fields!(bool, f32, f64, String, AtomicBool, AtomicUsize, Uuid, char);
 unsafe_no_jsmanaged_fields!(usize, u8, u16, u32, u64);
 unsafe_no_jsmanaged_fields!(isize, i8, i16, i32, i64);
+unsafe_no_jsmanaged_fields!(ServoUrl, ImmutableOrigin, MutableOrigin);
 unsafe_no_jsmanaged_fields!(Image, ImageMetadata, ImageCacheChan, ImageCacheThread);
 unsafe_no_jsmanaged_fields!(Metadata);
 unsafe_no_jsmanaged_fields!(NetworkError);
diff --git a/components/script/dom/document.rs b/components/script/dom/document.rs
index 56053555f7c..c836a46f1da 100644
--- a/components/script/dom/document.rs
+++ b/components/script/dom/document.rs
@@ -105,7 +105,6 @@ use net_traits::CoreResourceMsg::{GetCookiesForUrl, SetCookiesForUrl};
 use net_traits::request::RequestInit;
 use net_traits::response::HttpsState;
 use num_traits::ToPrimitive;
-use origin::Origin;
 use script_layout_interface::message::{Msg, ReflowQueryType};
 use script_runtime::{CommonScriptMsg, ScriptThreadEventCategory};
 use script_thread::{MainThreadScriptMsg, Runnable};
@@ -116,7 +115,7 @@ use script_traits::{TouchEventType, TouchId};
 use script_traits::UntrustedNodeAddress;
 use servo_atoms::Atom;
 use servo_config::prefs::PREFS;
-use servo_url::ServoUrl;
+use servo_url::{ImmutableOrigin, MutableOrigin, ServoUrl};
 use std::ascii::AsciiExt;
 use std::borrow::ToOwned;
 use std::cell::{Cell, Ref, RefMut};
@@ -136,6 +135,7 @@ use style::str::{HTML_SPACE_CHARACTERS, split_html_space_chars, str_join};
 use style::stylesheets::Stylesheet;
 use task_source::TaskSource;
 use time;
+use url::Host;
 use url::percent_encoding::percent_decode;
 
 pub enum TouchEventResult {
@@ -277,7 +277,7 @@ pub struct Document {
     https_state: Cell<HttpsState>,
     touchpad_pressure_phase: Cell<TouchpadPressurePhase>,
     /// The document's origin.
-    origin: Origin,
+    origin: MutableOrigin,
     ///  https://w3c.github.io/webappsec-referrer-policy/#referrer-policy-states
     referrer_policy: Cell<Option<ReferrerPolicy>>,
     /// https://html.spec.whatwg.org/multipage/#dom-document-referrer
@@ -424,7 +424,7 @@ impl Document {
         }
     }
 
-    pub fn origin(&self) -> &Origin {
+    pub fn origin(&self) -> &MutableOrigin {
         &self.origin
     }
 
@@ -1949,7 +1949,7 @@ impl Document {
     pub fn new_inherited(window: &Window,
                          has_browsing_context: HasBrowsingContext,
                          url: Option<ServoUrl>,
-                         origin: Origin,
+                         origin: MutableOrigin,
                          is_html_document: IsHTMLDocument,
                          content_type: Option<DOMString>,
                          last_modified: Option<String>,
@@ -2053,7 +2053,7 @@ impl Document {
         Ok(Document::new(window,
                          HasBrowsingContext::No,
                          None,
-                         doc.origin().alias(),
+                         doc.origin().clone(),
                          IsHTMLDocument::NonHTMLDocument,
                          None,
                          None,
@@ -2067,7 +2067,7 @@ impl Document {
     pub fn new(window: &Window,
                has_browsing_context: HasBrowsingContext,
                url: Option<ServoUrl>,
-               origin: Origin,
+               origin: MutableOrigin,
                doctype: IsHTMLDocument,
                content_type: Option<DOMString>,
                last_modified: Option<String>,
@@ -2154,7 +2154,7 @@ impl Document {
                                         HasBrowsingContext::No,
                                         None,
                                         // https://github.com/whatwg/html/issues/2109
-                                        Origin::opaque_identifier(),
+                                        MutableOrigin::new(ImmutableOrigin::new_opaque()),
                                         doctype,
                                         None,
                                         None,
@@ -2411,16 +2411,17 @@ impl DocumentMethods for Document {
     // https://html.spec.whatwg.org/multipage/#relaxing-the-same-origin-restriction
     fn Domain(&self) -> DOMString {
         // Step 1.
-        if self.browsing_context().is_none() {
+        if !self.has_browsing_context {
             return DOMString::new();
         }
 
-        if let Some(host) = self.origin.host() {
-            // Step 4.
-            DOMString::from(host.to_string())
-        } else {
+        // Step 2.
+        match self.origin.effective_domain() {
             // Step 3.
-            DOMString::new()
+            None => DOMString::new(),
+            // Step 4.
+            Some(Host::Domain(domain)) => DOMString::from(domain),
+            Some(host) => DOMString::from(host.to_string()),
         }
     }
 
@@ -3077,7 +3078,7 @@ impl DocumentMethods for Document {
             return Ok(DOMString::new());
         }
 
-        if !self.origin.is_scheme_host_port_tuple() {
+        if !self.origin.is_tuple() {
             return Err(Error::Security);
         }
 
@@ -3097,7 +3098,7 @@ impl DocumentMethods for Document {
             return Ok(());
         }
 
-        if !self.origin.is_scheme_host_port_tuple() {
+        if !self.origin.is_tuple() {
             return Err(Error::Security);
         }
 
diff --git a/components/script/dom/domimplementation.rs b/components/script/dom/domimplementation.rs
index 4ec27cc5b36..1de0a24863b 100644
--- a/components/script/dom/domimplementation.rs
+++ b/components/script/dom/domimplementation.rs
@@ -80,7 +80,7 @@ impl DOMImplementationMethods for DOMImplementation {
         let doc = XMLDocument::new(win,
                                    HasBrowsingContext::No,
                                    None,
-                                   self.document.origin().alias(),
+                                   self.document.origin().clone(),
                                    IsHTMLDocument::NonHTMLDocument,
                                    Some(DOMString::from(content_type)),
                                    None,
@@ -127,7 +127,7 @@ impl DOMImplementationMethods for DOMImplementation {
         let doc = Document::new(win,
                                 HasBrowsingContext::No,
                                 None,
-                                self.document.origin().alias(),
+                                self.document.origin().clone(),
                                 IsHTMLDocument::HTMLDocument,
                                 None,
                                 None,
diff --git a/components/script/dom/domparser.rs b/components/script/dom/domparser.rs
index d89ec3c1595..67d16934c66 100644
--- a/components/script/dom/domparser.rs
+++ b/components/script/dom/domparser.rs
@@ -61,7 +61,7 @@ impl DOMParserMethods for DOMParser {
                 let document = Document::new(&self.window,
                                              HasBrowsingContext::No,
                                              Some(url.clone()),
-                                             doc.origin().alias(),
+                                             doc.origin().clone(),
                                              IsHTMLDocument::HTMLDocument,
                                              Some(content_type),
                                              None,
@@ -79,7 +79,7 @@ impl DOMParserMethods for DOMParser {
                 let document = Document::new(&self.window,
                                              HasBrowsingContext::No,
                                              Some(url.clone()),
-                                             doc.origin().alias(),
+                                             doc.origin().clone(),
                                              IsHTMLDocument::NonHTMLDocument,
                                              Some(content_type),
                                              None,
diff --git a/components/script/dom/htmliframeelement.rs b/components/script/dom/htmliframeelement.rs
index 3a1c9daf1c9..4ab82735384 100644
--- a/components/script/dom/htmliframeelement.rs
+++ b/components/script/dom/htmliframeelement.rs
@@ -167,7 +167,7 @@ impl HTMLIFrameElement {
                 layout_threads: PREFS.get("layout.threads").as_u64().expect("count") as usize,
             };
 
-            ScriptThread::process_attach_layout(new_layout_info, document.origin().alias());
+            ScriptThread::process_attach_layout(new_layout_info, document.origin().clone());
         } else {
             let load_info = IFrameLoadInfoWithData {
                 info: load_info,
diff --git a/components/script/dom/node.rs b/components/script/dom/node.rs
index df335be75a6..96d3fceaff5 100644
--- a/components/script/dom/node.rs
+++ b/components/script/dom/node.rs
@@ -1729,7 +1729,7 @@ impl Node {
                 let document = Document::new(window, HasBrowsingContext::No,
                                              Some(document.url()),
                                              // https://github.com/whatwg/dom/issues/378
-                                             document.origin().alias(),
+                                             document.origin().clone(),
                                              is_html_doc, None,
                                              None, DocumentActivity::Inactive,
                                              DocumentSource::NotFromParser, loader,
diff --git a/components/script/dom/servoparser/mod.rs b/components/script/dom/servoparser/mod.rs
index 39077930200..149957576a2 100644
--- a/components/script/dom/servoparser/mod.rs
+++ b/components/script/dom/servoparser/mod.rs
@@ -110,7 +110,7 @@ impl ServoParser {
         let document = Document::new(window,
                                      HasBrowsingContext::No,
                                      Some(url.clone()),
-                                     context_document.origin().alias(),
+                                     context_document.origin().clone(),
                                      IsHTMLDocument::HTMLDocument,
                                      None,
                                      None,
diff --git a/components/script/dom/window.rs b/components/script/dom/window.rs
index 1fbe57ba165..b6392fbdd19 100644
--- a/components/script/dom/window.rs
+++ b/components/script/dom/window.rs
@@ -62,7 +62,6 @@ use net_traits::image_cache_thread::{ImageCacheChan, ImageCacheThread};
 use net_traits::storage_thread::StorageType;
 use num_traits::ToPrimitive;
 use open;
-use origin::Origin;
 use profile_traits::mem::ProfilerChan as MemProfilerChan;
 use profile_traits::time::ProfilerChan as TimeProfilerChan;
 use rustc_serialize::base64::{FromBase64, STANDARD, ToBase64};
@@ -83,7 +82,7 @@ use servo_atoms::Atom;
 use servo_config::opts;
 use servo_config::prefs::PREFS;
 use servo_geometry::{f32_rect_to_au_rect, max_rect};
-use servo_url::ServoUrl;
+use servo_url::{ImmutableOrigin, ServoUrl};
 use std::ascii::AsciiExt;
 use std::borrow::ToOwned;
 use std::cell::Cell;
@@ -660,10 +659,10 @@ impl WindowMethods for Window {
             "/" => {
                 // TODO(#12715): Should be the origin of the incumbent settings
                 //               object, not self's.
-                Some(self.Document().origin().copy())
+                Some(self.Document().origin().immutable().clone())
             },
             url => match ServoUrl::parse(&url) {
-                Ok(url) => Some(Origin::new(&url)),
+                Ok(url) => Some(url.origin().clone()),
                 Err(_) => return Err(Error::Syntax),
             }
         };
@@ -1793,13 +1792,13 @@ fn debug_reflow_events(id: PipelineId, goal: &ReflowGoal, query_type: &ReflowQue
 
 struct PostMessageHandler {
     destination: Trusted<Window>,
-    origin: Option<Origin>,
+    origin: Option<ImmutableOrigin>,
     message: StructuredCloneData,
 }
 
 impl PostMessageHandler {
     fn new(window: &Window,
-           origin: Option<Origin>,
+           origin: Option<ImmutableOrigin>,
            message: StructuredCloneData) -> PostMessageHandler {
         PostMessageHandler {
             destination: Trusted::new(window),
diff --git a/components/script/dom/xmldocument.rs b/components/script/dom/xmldocument.rs
index eaf90fbfe01..c832e018360 100644
--- a/components/script/dom/xmldocument.rs
+++ b/components/script/dom/xmldocument.rs
@@ -15,9 +15,8 @@ use dom::location::Location;
 use dom::node::Node;
 use dom::window::Window;
 use js::jsapi::{JSContext, JSObject};
-use origin::Origin;
 use script_traits::DocumentActivity;
-use servo_url::ServoUrl;
+use servo_url::{MutableOrigin, ServoUrl};
 
 // https://dom.spec.whatwg.org/#xmldocument
 #[dom_struct]
@@ -29,7 +28,7 @@ impl XMLDocument {
     fn new_inherited(window: &Window,
                      has_browsing_context: HasBrowsingContext,
                      url: Option<ServoUrl>,
-                     origin: Origin,
+                     origin: MutableOrigin,
                      is_html_document: IsHTMLDocument,
                      content_type: Option<DOMString>,
                      last_modified: Option<String>,
@@ -55,7 +54,7 @@ impl XMLDocument {
     pub fn new(window: &Window,
                has_browsing_context: HasBrowsingContext,
                url: Option<ServoUrl>,
-               origin: Origin,
+               origin: MutableOrigin,
                doctype: IsHTMLDocument,
                content_type: Option<DOMString>,
                last_modified: Option<String>,
diff --git a/components/script/dom/xmlhttprequest.rs b/components/script/dom/xmlhttprequest.rs
index 6fe89476994..c5c3c635129 100644
--- a/components/script/dom/xmlhttprequest.rs
+++ b/components/script/dom/xmlhttprequest.rs
@@ -1225,7 +1225,7 @@ impl XMLHttpRequest {
         Document::new(win,
                       HasBrowsingContext::No,
                       parsed_url,
-                      doc.origin().alias(),
+                      doc.origin().clone(),
                       is_html_document,
                       content_type,
                       None,
diff --git a/components/script/lib.rs b/components/script/lib.rs
index 8a2829059c0..e5c93357bd2 100644
--- a/components/script/lib.rs
+++ b/components/script/lib.rs
@@ -114,7 +114,6 @@ pub mod layout_wrapper;
 mod mem;
 mod microtask;
 mod network_listener;
-pub mod origin;
 pub mod script_runtime;
 #[allow(unsafe_code)]
 pub mod script_thread;
diff --git a/components/script/origin.rs b/components/script/origin.rs
deleted file mode 100644
index 067eb77dcda..00000000000
--- a/components/script/origin.rs
+++ /dev/null
@@ -1,61 +0,0 @@
-/* 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/. */
-
-use servo_url::ServoUrl;
-use std::sync::Arc;
-use url::Host;
-use url::Origin as UrlOrigin;
-
-/// A representation of an [origin](https://html.spec.whatwg.org/multipage/#origin-2).
-#[derive(HeapSizeOf, JSTraceable)]
-pub struct Origin {
-    #[ignore_heap_size_of = "Arc<T> has unclear ownership semantics"]
-    inner: Arc<UrlOrigin>,
-}
-
-impl Origin {
-    /// Create a new origin comprising a unique, opaque identifier.
-    pub fn opaque_identifier() -> Origin {
-        Origin {
-            inner: Arc::new(UrlOrigin::new_opaque()),
-        }
-    }
-
-    /// Create a new origin for the given URL.
-    pub fn new(url: &ServoUrl) -> Origin {
-        Origin {
-            inner: Arc::new(url.origin()),
-        }
-    }
-
-    /// Does this origin represent a host/scheme/port tuple?
-    pub fn is_scheme_host_port_tuple(&self) -> bool {
-        self.inner.is_tuple()
-    }
-
-    /// Return the host associated with this origin.
-    pub fn host(&self) -> Option<&Host<String>> {
-        match *self.inner {
-            UrlOrigin::Tuple(_, ref host, _) => Some(host),
-            UrlOrigin::Opaque(..) => None,
-        }
-    }
-
-    /// https://html.spec.whatwg.org/multipage/#same-origin
-    pub fn same_origin(&self, other: &Origin) -> bool {
-        self.inner == other.inner
-    }
-
-    pub fn copy(&self) -> Origin {
-        Origin {
-            inner: Arc::new((*self.inner).clone()),
-        }
-    }
-
-    pub fn alias(&self) -> Origin {
-        Origin {
-            inner: self.inner.clone(),
-        }
-    }
-}
diff --git a/components/script/script_thread.rs b/components/script/script_thread.rs
index ac093a7a5df..2ab421c707b 100644
--- a/components/script/script_thread.rs
+++ b/components/script/script_thread.rs
@@ -77,7 +77,6 @@ use net_traits::image_cache_thread::{ImageCacheChan, ImageCacheResult, ImageCach
 use net_traits::request::{CredentialsMode, Destination, RequestInit};
 use net_traits::storage_thread::StorageType;
 use network_listener::NetworkListener;
-use origin::Origin;
 use profile_traits::mem::{self, OpaqueSender, Report, ReportKind, ReportsChan};
 use profile_traits::time::{self, ProfilerCategory, profile};
 use script_layout_interface::message::{self, NewLayoutThreadInfo, ReflowQueryType};
@@ -95,7 +94,7 @@ use script_traits::WebVREventMsg;
 use script_traits::webdriver_msg::WebDriverScriptCommand;
 use serviceworkerjob::{Job, JobQueue, AsyncJobHandler};
 use servo_config::opts;
-use servo_url::ServoUrl;
+use servo_url::{MutableOrigin, ServoUrl};
 use std::cell::Cell;
 use std::collections::{hash_map, HashMap, HashSet};
 use std::default::Default;
@@ -155,7 +154,8 @@ struct InProgressLoad {
     is_visible: bool,
     /// The requested URL of the load.
     url: ServoUrl,
-    origin: Origin,
+    /// The origin for the document
+    origin: MutableOrigin,
 }
 
 impl InProgressLoad {
@@ -166,7 +166,7 @@ impl InProgressLoad {
            layout_chan: Sender<message::Msg>,
            window_size: Option<WindowSizeData>,
            url: ServoUrl,
-           origin: Origin) -> InProgressLoad {
+           origin: MutableOrigin) -> InProgressLoad {
         InProgressLoad {
             pipeline_id: id,
             frame_id: frame_id,
@@ -545,7 +545,7 @@ impl ScriptThreadFactory for ScriptThread {
 
             let mut failsafe = ScriptMemoryFailsafe::new(&script_thread);
 
-            let origin = Origin::new(&load_data.url);
+            let origin = MutableOrigin::new(load_data.url.origin());
             let new_load = InProgressLoad::new(id, frame_id, parent_info, layout_chan, window_size,
                                                load_data.url.clone(), origin);
             script_thread.start_page_load(new_load, load_data);
@@ -611,7 +611,7 @@ impl ScriptThread {
         });
     }
 
-    pub fn process_attach_layout(new_layout_info: NewLayoutInfo, origin: Origin) {
+    pub fn process_attach_layout(new_layout_info: NewLayoutInfo, origin: MutableOrigin) {
         SCRIPT_THREAD_ROOT.with(|root| {
             if let Some(script_thread) = root.get() {
                 let script_thread = unsafe { &*script_thread };
@@ -791,7 +791,7 @@ impl ScriptThread {
                 FromConstellation(ConstellationControlMsg::AttachLayout(
                         new_layout_info)) => {
                     self.profile_event(ScriptThreadEventCategory::AttachLayout, || {
-                        let origin = Origin::new(&new_layout_info.load_data.url);
+                        let origin = MutableOrigin::new(new_layout_info.load_data.url.origin());
                         self.handle_new_layout(new_layout_info, origin);
                     })
                 }
@@ -1208,7 +1208,7 @@ impl ScriptThread {
         window.set_scroll_offsets(scroll_offsets)
     }
 
-    fn handle_new_layout(&self, new_layout_info: NewLayoutInfo, origin: Origin) {
+    fn handle_new_layout(&self, new_layout_info: NewLayoutInfo, origin: MutableOrigin) {
         let NewLayoutInfo {
             parent_info,
             new_pipeline_id,
diff --git a/components/url/Cargo.toml b/components/url/Cargo.toml
index e6acfe07649..4cefa0611c6 100644
--- a/components/url/Cargo.toml
+++ b/components/url/Cargo.toml
@@ -10,11 +10,14 @@ name = "servo_url"
 path = "lib.rs"
 
 [features]
-servo = ["heapsize", "heapsize_derive", "serde", "url/heap_size", "url_serde"]
+servo = ["heapsize", "heapsize_derive", "serde", "serde_derive", "uuid/serde", "url/heap_size", "url_serde"]
 
 [dependencies]
 heapsize = {version = "0.3.0", optional = true}
 heapsize_derive = {version = "0.1", optional = true}
 serde = {version = "0.9", optional = true}
+serde_derive = {version = "0.9", optional = true}
+servo_rand = {path = "../rand"}
 url = "1.2"
-url_serde = {version = "0.1", optional = true}
+url_serde = {version = "0.1.3", optional = true}
+uuid = {version = "0.4.0", features = ["v4"]}
diff --git a/components/url/lib.rs b/components/url/lib.rs
index 85933a509c7..e8d8d363fbf 100644
--- a/components/url/lib.rs
+++ b/components/url/lib.rs
@@ -7,19 +7,26 @@
 #![crate_name = "servo_url"]
 #![crate_type = "rlib"]
 
-#[cfg(feature = "servo")] extern crate heapsize;
+#[cfg(feature = "servo")] #[macro_use] extern crate heapsize;
 #[cfg(feature = "servo")] #[macro_use] extern crate heapsize_derive;
 #[cfg(feature = "servo")] extern crate serde;
+#[cfg(feature = "servo")] #[macro_use] extern crate serde_derive;
 #[cfg(feature = "servo")] extern crate url_serde;
 
+extern crate servo_rand;
 extern crate url;
+extern crate uuid;
+
+pub mod origin;
+
+pub use origin::{OpaqueOrigin, ImmutableOrigin, MutableOrigin};
 
 use std::fmt;
 use std::net::IpAddr;
 use std::ops::{Range, RangeFrom, RangeTo, RangeFull, Index};
 use std::path::Path;
 use std::sync::Arc;
-use url::{Url, Origin, Position};
+use url::{Url, Position};
 
 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
@@ -68,8 +75,8 @@ impl ServoUrl {
         self.0.path()
     }
 
-    pub fn origin(&self) -> Origin {
-        self.0.origin()
+    pub fn origin(&self) -> ImmutableOrigin {
+        ImmutableOrigin::new(self.0.origin())
     }
 
     pub fn scheme(&self) -> &str {
diff --git a/components/url/origin.rs b/components/url/origin.rs
new file mode 100644
index 00000000000..3795b73fb61
--- /dev/null
+++ b/components/url/origin.rs
@@ -0,0 +1,172 @@
+/* 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/. */
+
+use servo_rand;
+use servo_rand::Rng;
+use std::cell::RefCell;
+use std::rc::Rc;
+use url::{Host, Origin};
+#[cfg(feature = "servo")] use url_serde;
+use uuid::Uuid;
+
+/// The origin of an URL
+#[derive(PartialEq, Eq, Clone, Debug)]
+#[cfg_attr(feature = "servo", derive(HeapSizeOf, Deserialize, Serialize))]
+pub enum ImmutableOrigin {
+    /// A globally unique identifier
+    Opaque(OpaqueOrigin),
+
+    /// Consists of the URL's scheme, host and port
+    Tuple(
+        String,
+        #[cfg_attr(feature = "servo",
+                   serde(deserialize_with = "url_serde::deserialize", serialize_with = "url_serde::serialize"))]
+        Host,
+        u16,
+    )
+}
+
+impl ImmutableOrigin {
+    pub fn new(origin: Origin) -> ImmutableOrigin {
+        match origin {
+            Origin::Opaque(_) => ImmutableOrigin::new_opaque(),
+            Origin::Tuple(scheme, host, port) => ImmutableOrigin::Tuple(scheme, host, port),
+        }
+    }
+
+    pub fn same_origin(&self, other: &MutableOrigin) -> bool {
+        self == other.immutable()
+    }
+
+    pub fn same_origin_domain(&self, other: &MutableOrigin) -> bool {
+        !other.has_domain() && self == other.immutable()
+    }
+
+    /// Creates a new opaque origin that is only equal to itself.
+    pub fn new_opaque() -> ImmutableOrigin {
+        ImmutableOrigin::Opaque(OpaqueOrigin(servo_rand::thread_rng().gen()))
+    }
+
+    pub fn scheme(&self) -> Option<&str> {
+        match *self {
+            ImmutableOrigin::Opaque(_) => None,
+            ImmutableOrigin::Tuple(ref scheme, _, _) => Some(&**scheme),
+        }
+    }
+
+    pub fn host(&self) -> Option<&Host> {
+        match *self {
+            ImmutableOrigin::Opaque(_) => None,
+            ImmutableOrigin::Tuple(_, ref host, _) => Some(host),
+        }
+    }
+
+    pub fn port(&self) -> Option<u16> {
+        match *self {
+            ImmutableOrigin::Opaque(_) => None,
+            ImmutableOrigin::Tuple(_, _, port) => Some(port),
+        }
+    }
+
+    pub fn into_url_origin(self) -> Origin {
+        match self {
+            ImmutableOrigin::Opaque(_) => Origin::new_opaque(),
+            ImmutableOrigin::Tuple(scheme, host, port) => Origin::Tuple(scheme, host, port),
+        }
+    }
+
+    /// Return whether this origin is a (scheme, host, port) tuple
+    /// (as opposed to an opaque origin).
+    pub fn is_tuple(&self) -> bool {
+        match *self {
+            ImmutableOrigin::Opaque(..) => false,
+            ImmutableOrigin::Tuple(..) => true,
+        }
+    }
+
+    /// https://html.spec.whatwg.org/multipage/#ascii-serialisation-of-an-origin
+    pub fn ascii_serialization(&self) -> String {
+        self.clone().into_url_origin().ascii_serialization()
+    }
+
+    /// https://html.spec.whatwg.org/multipage/#unicode-serialisation-of-an-origin
+    pub fn unicode_serialization(&self) -> String {
+        self.clone().into_url_origin().unicode_serialization()
+    }
+}
+
+/// Opaque identifier for URLs that have file or other schemes
+#[derive(Eq, PartialEq, Clone, Debug)]
+#[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
+pub struct OpaqueOrigin(Uuid);
+
+#[cfg(feature = "servo")]
+known_heap_size!(0, OpaqueOrigin);
+
+/// A representation of an [origin](https://html.spec.whatwg.org/multipage/#origin-2).
+#[derive(Clone, Debug)]
+pub struct MutableOrigin(Rc<(ImmutableOrigin, RefCell<Option<Host>>)>);
+
+#[cfg(feature = "servo")]
+known_heap_size!(0, MutableOrigin);
+
+impl MutableOrigin {
+    pub fn new(origin: ImmutableOrigin) -> MutableOrigin {
+        MutableOrigin(Rc::new((origin, RefCell::new(None))))
+    }
+
+    pub fn immutable(&self) -> &ImmutableOrigin {
+        &(self.0).0
+    }
+
+    pub fn is_tuple(&self) -> bool {
+        self.immutable().is_tuple()
+    }
+
+    pub fn scheme(&self) -> Option<&str> {
+        self.immutable().scheme()
+    }
+
+    pub fn host(&self) -> Option<&Host> {
+        self.immutable().host()
+    }
+
+    pub fn port(&self) -> Option<u16> {
+        self.immutable().port()
+    }
+
+    pub fn same_origin(&self, other: &MutableOrigin) -> bool {
+        self.immutable() == other.immutable()
+    }
+
+    pub fn same_origin_domain(&self, other: &MutableOrigin) -> bool {
+        if let Some(ref self_domain) = *(self.0).1.borrow() {
+            if let Some(ref other_domain) = *(other.0).1.borrow() {
+                self_domain == other_domain &&
+                    self.immutable().scheme() == other.immutable().scheme()
+            } else {
+                false
+            }
+        } else {
+            self.immutable().same_origin_domain(other)
+        }
+    }
+
+    pub fn domain(&self) -> Option<Host> {
+        (self.0).1.borrow().clone()
+    }
+
+    pub fn set_domain(&self, domain: Host) {
+        *(self.0).1.borrow_mut() = Some(domain);
+    }
+
+    pub fn has_domain(&self) -> bool {
+        (self.0).1.borrow().is_some()
+    }
+
+    pub fn effective_domain(&self) -> Option<Host> {
+        self.immutable().host()
+            .map(|host| self.domain().unwrap_or_else(|| host.clone()))
+    }
+}
diff --git a/tests/unit/net/fetch.rs b/tests/unit/net/fetch.rs
index 4329e44884d..43940f28a9f 100644
--- a/tests/unit/net/fetch.rs
+++ b/tests/unit/net/fetch.rs
@@ -34,7 +34,7 @@ use net_traits::ReferrerPolicy;
 use net_traits::request::{Origin, RedirectMode, Referrer, Request, RequestMode};
 use net_traits::response::{CacheState, Response, ResponseBody, ResponseType};
 use servo_config::resource_files::resources_dir_path;
-use servo_url::ServoUrl;
+use servo_url::{ImmutableOrigin, ServoUrl};
 use std::fs::File;
 use std::io::Read;
 use std::rc::Rc;
@@ -43,7 +43,6 @@ use std::sync::atomic::{AtomicUsize, Ordering};
 use std::sync::mpsc::{Sender, channel};
 use time::{self, Duration};
 use unicase::UniCase;
-use url::Origin as UrlOrigin;
 
 // TODO write a struct that impls Handler for storing test values
 
@@ -223,7 +222,7 @@ fn test_cors_preflight_fetch() {
 
     let target_url = url.clone().join("a.html").unwrap();
 
-    let origin = Origin::Origin(UrlOrigin::new_opaque());
+    let origin = Origin::Origin(ImmutableOrigin::new_opaque());
     let mut request = Request::new(url.clone(), Some(origin), false, None);
     *request.referrer.borrow_mut() = Referrer::ReferrerUrl(target_url);
     *request.referrer_policy.get_mut() = Some(ReferrerPolicy::Origin);
@@ -260,7 +259,7 @@ fn test_cors_preflight_cache_fetch() {
     };
     let (mut server, url) = make_server(handler);
 
-    let origin = Origin::Origin(UrlOrigin::new_opaque());
+    let origin = Origin::Origin(ImmutableOrigin::new_opaque());
     let mut request = Request::new(url.clone(), Some(origin.clone()), false, None);
     *request.referrer.borrow_mut() = Referrer::NoReferrer;
     request.use_cors_preflight = true;
@@ -309,7 +308,7 @@ fn test_cors_preflight_fetch_network_error() {
     };
     let (mut server, url) = make_server(handler);
 
-    let origin = Origin::Origin(UrlOrigin::new_opaque());
+    let origin = Origin::Origin(ImmutableOrigin::new_opaque());
     let mut request = Request::new(url, Some(origin), false, None);
     *request.method.borrow_mut() = Method::Extension("CHICKEN".to_owned());
     *request.referrer.borrow_mut() = Referrer::NoReferrer;
@@ -378,7 +377,7 @@ fn test_fetch_response_is_cors_filtered() {
     let (mut server, url) = make_server(handler);
 
     // an origin mis-match will stop it from defaulting to a basic filtered response
-    let origin = Origin::Origin(UrlOrigin::new_opaque());
+    let origin = Origin::Origin(ImmutableOrigin::new_opaque());
     let mut request = Request::new(url, Some(origin), false, None);
     *request.referrer.borrow_mut() = Referrer::NoReferrer;
     request.mode = RequestMode::CorsMode;
@@ -410,7 +409,7 @@ fn test_fetch_response_is_opaque_filtered() {
     let (mut server, url) = make_server(handler);
 
     // an origin mis-match will fall through to an Opaque filtered response
-    let origin = Origin::Origin(UrlOrigin::new_opaque());
+    let origin = Origin::Origin(ImmutableOrigin::new_opaque());
     let request = Request::new(url, Some(origin), false, None);
     *request.referrer.borrow_mut() = Referrer::NoReferrer;
     let fetch_response = fetch(request, None);
@@ -800,7 +799,7 @@ fn test_opaque_filtered_fetch_async_returns_complete_response() {
     let (mut server, url) = make_server(handler);
 
     // an origin mis-match will fall through to an Opaque filtered response
-    let origin = Origin::Origin(UrlOrigin::new_opaque());
+    let origin = Origin::Origin(ImmutableOrigin::new_opaque());
     let request = Request::new(url, Some(origin), false, None);
     *request.referrer.borrow_mut() = Referrer::NoReferrer;
 
diff --git a/tests/unit/script/origin.rs b/tests/unit/script/origin.rs
index 6357587da89..526b12bf0f9 100644
--- a/tests/unit/script/origin.rs
+++ b/tests/unit/script/origin.rs
@@ -2,46 +2,45 @@
  * 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/. */
 
-use script::origin::Origin;
-use servo_url::ServoUrl;
+use servo_url::{ImmutableOrigin, MutableOrigin, ServoUrl};
 
 #[test]
 fn same_origin() {
-    let a = Origin::new(&ServoUrl::parse("http://example.com/a.html").unwrap());
-    let b = Origin::new(&ServoUrl::parse("http://example.com/b.html").unwrap());
+    let a = MutableOrigin::new(ServoUrl::parse("http://example.com/a.html").unwrap().origin());
+    let b = MutableOrigin::new(ServoUrl::parse("http://example.com/b.html").unwrap().origin());
     assert!(a.same_origin(&b));
-    assert_eq!(a.is_scheme_host_port_tuple(), true);
+    assert_eq!(a.is_tuple(), true);
 }
 
 #[test]
 fn identical_origin() {
-    let a = Origin::new(&ServoUrl::parse("http://example.com/a.html").unwrap());
+    let a = MutableOrigin::new(ServoUrl::parse("http://example.com/a.html").unwrap().origin());
     assert!(a.same_origin(&a));
 }
 
 #[test]
 fn cross_origin() {
-    let a = Origin::new(&ServoUrl::parse("http://example.com/a.html").unwrap());
-    let b = Origin::new(&ServoUrl::parse("http://example.org/b.html").unwrap());
+    let a = MutableOrigin::new(ServoUrl::parse("http://example.com/a.html").unwrap().origin());
+    let b = MutableOrigin::new(ServoUrl::parse("http://example.org/b.html").unwrap().origin());
     assert!(!a.same_origin(&b));
 }
 
 #[test]
-fn alias_same_origin() {
-    let a = Origin::new(&ServoUrl::parse("http://example.com/a.html").unwrap());
-    let b = Origin::new(&ServoUrl::parse("http://example.com/b.html").unwrap());
-    let c = b.alias();
+fn clone_same_origin() {
+    let a = MutableOrigin::new(ServoUrl::parse("http://example.com/a.html").unwrap().origin());
+    let b = MutableOrigin::new(ServoUrl::parse("http://example.com/b.html").unwrap().origin());
+    let c = b.clone();
     assert!(a.same_origin(&c));
     assert!(b.same_origin(&b));
     assert!(c.same_origin(&b));
-    assert_eq!(c.is_scheme_host_port_tuple(), true);
+    assert_eq!(c.is_tuple(), true);
 }
 
 #[test]
-fn alias_cross_origin() {
-    let a = Origin::new(&ServoUrl::parse("http://example.com/a.html").unwrap());
-    let b = Origin::new(&ServoUrl::parse("http://example.org/b.html").unwrap());
-    let c = b.alias();
+fn clone_cross_origin() {
+    let a = MutableOrigin::new(ServoUrl::parse("http://example.com/a.html").unwrap().origin());
+    let b = MutableOrigin::new(ServoUrl::parse("http://example.org/b.html").unwrap().origin());
+    let c = b.clone();
     assert!(!a.same_origin(&c));
     assert!(b.same_origin(&c));
     assert!(c.same_origin(&c));
@@ -49,16 +48,16 @@ fn alias_cross_origin() {
 
 #[test]
 fn opaque() {
-    let a = Origin::opaque_identifier();
-    let b = Origin::opaque_identifier();
+    let a = MutableOrigin::new(ImmutableOrigin::new_opaque());
+    let b = MutableOrigin::new(ImmutableOrigin::new_opaque());
     assert!(!a.same_origin(&b));
-    assert_eq!(a.is_scheme_host_port_tuple(), false);
+    assert_eq!(a.is_tuple(), false);
 }
 
 #[test]
 fn opaque_clone() {
-    let a = Origin::opaque_identifier();
-    let b = a.alias();
+    let a = MutableOrigin::new(ImmutableOrigin::new_opaque());
+    let b = a.clone();
     assert!(a.same_origin(&b));
-    assert_eq!(a.is_scheme_host_port_tuple(), false);
+    assert_eq!(a.is_tuple(), false);
 }