Auto merge of #22714 - aditj:patch-3, r=jdm

Added fetch_start functionality

<!-- Please describe your changes on the following line: -->
Added the fetch_start functionality in http_loader.rs (http_fetch function)

---
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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #21258 (GitHub issue number if applicable)

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- [X] There are tests for these changes OR
- [ ] These changes do not require tests because ___

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components/net/fetch/methods.rs

@@ -23,6 +23,7 @@ use net_traits::filemanager_thread::RelativePos;
 use net_traits::request::{CredentialsMode, Destination, Referrer, Request, RequestMode};
 use net_traits::request::{Origin, ResponseTainting, Window};
 use net_traits::response::{Response, ResponseBody, ResponseType};
+use net_traits::ResourceAttribute;
 use net_traits::{FetchTaskTarget, NetworkError, ReferrerPolicy, ResourceFetchTiming};
 use servo_url::ServoUrl;
 use std::borrow::Cow;
@@ -88,6 +89,12 @@ pub type DoneChannel = Option<(Sender<Data>, Receiver<Data>)>;
 
 /// [Fetch](https://fetch.spec.whatwg.org#concept-fetch)
 pub fn fetch(request: &mut Request, target: Target, context: &FetchContext) {
+    // Step 7 of https://w3c.github.io/resource-timing/#processing-model
+    context
+        .timing
+        .lock()
+        .unwrap()
+        .set_attribute(ResourceAttribute::FetchStart);
     fetch_with_cors_cache(request, &mut CorsCache::new(), target, context);
 }
 

components/net/http_loader.rs

@@ -525,8 +525,6 @@ pub fn http_fetch(
             request.service_workers_mode = ServiceWorkersMode::None;
         }
 
-        // Substep 3
-        // TODO(#21258) maybe set fetch_start (if this is the last resource)
         // Generally, we use a persistent connection, so we will also set other PerformanceResourceTiming
         //   attributes to this as well (domain_lookup_start, domain_lookup_end, connect_start, connect_end,
         //   secure_connection_start)
@@ -660,6 +658,13 @@ pub fn http_redirect_fetch(
         Some(Ok(url)) => url,
     };
 
+    // Step 1 of https://w3c.github.io/resource-timing/#dom-performanceresourcetiming-fetchstart
+    context
+        .timing
+        .lock()
+        .unwrap()
+        .set_attribute(ResourceAttribute::FetchStart);
+
     // Step 5
     if request.redirect_count >= 20 {
         return Response::network_error(NetworkError::Internal("Too many redirects".into()));

components/net_traits/lib.rs

@@ -447,6 +447,7 @@ pub struct ResourceFetchTiming {
     pub redirect_count: u16,
     pub request_start: u64,
     pub response_start: u64,
+    pub fetch_start: u64,
     // pub response_end: u64,
     // pub redirect_start: u64,
     // pub redirect_end: u64,
@@ -458,6 +459,7 @@ pub enum ResourceAttribute {
     RedirectCount(u16),
     RequestStart,
     ResponseStart,
+    FetchStart,
 }
 
 #[derive(Clone, Copy, Debug, Deserialize, MallocSizeOf, PartialEq, Serialize)]
@@ -475,6 +477,7 @@ impl ResourceFetchTiming {
             redirect_count: 0,
             request_start: 0,
             response_start: 0,
+            fetch_start: 0,
         }
     }
 
@@ -485,6 +488,7 @@ impl ResourceFetchTiming {
             ResourceAttribute::RedirectCount(count) => self.redirect_count = count,
             ResourceAttribute::RequestStart => self.request_start = precise_time_ns(),
             ResourceAttribute::ResponseStart => self.response_start = precise_time_ns(),
+            ResourceAttribute::FetchStart => self.fetch_start = precise_time_ns(),
         }
     }
 }

components/script/dom/performanceresourcetiming.rs

@@ -78,7 +78,7 @@ impl PerformanceResourceTiming {
             entry: PerformanceEntry::new_inherited(
                 DOMString::from(url.into_string()),
                 DOMString::from("resource"),
-                fetch_start,
+                0.,
                 0.,
             ),
             initiator_type: initiator_type,
@@ -118,7 +118,7 @@ impl PerformanceResourceTiming {
             worker_start: 0.,
             redirect_start: 0.,
             redirect_end: 0.,
-            fetch_start: 0.,
+            fetch_start: resource_timing.fetch_start as f64,
             domain_lookup_start: 0.,
             domain_lookup_end: 0.,
             connect_start: 0.,
@@ -184,4 +184,9 @@ impl PerformanceResourceTimingMethods for PerformanceResourceTiming {
         // TODO
         Finite::wrap(self.response_start)
     }
+
+    // https://w3c.github.io/resource-timing/#dom-performanceresourcetiming-fetchstart
+    fn FetchStart(&self) -> DOMHighResTimeStamp {
+        Finite::wrap(self.fetch_start)
+    }
 }

components/script/dom/webidls/PerformanceResourceTiming.webidl

@@ -6,6 +6,7 @@
  * https://w3c.github.io/resource-timing/
  */
 
+// https://w3c.github.io/resource-timing/#sec-performanceresourcetiming
 [Exposed=(Window,Worker)]
 interface PerformanceResourceTiming : PerformanceEntry {
     readonly attribute DOMString           initiatorType;
@@ -13,7 +14,7 @@ interface PerformanceResourceTiming : PerformanceEntry {
     // readonly attribute DOMHighResTimeStamp workerStart;
     // readonly attribute DOMHighResTimeStamp redirectStart;
     // readonly attribute DOMHighResTimeStamp redirectEnd;
-    // readonly attribute DOMHighResTimeStamp fetchStart;
+    readonly attribute DOMHighResTimeStamp fetchStart;
     // readonly attribute DOMHighResTimeStamp domainLookupStart;
     // readonly attribute DOMHighResTimeStamp domainLookupEnd;
     // readonly attribute DOMHighResTimeStamp connectStart;
@@ -27,9 +28,3 @@ interface PerformanceResourceTiming : PerformanceEntry {
     /// readonly attribute unsigned long long  decodedBodySize;
     // [Default] object toJSON();
 };
-
-// partial interface Performance {
-//  void clearResourceTimings();
-//  void setResourceTimingBufferSize(unsigned long maxSize);
-//              attribute EventHandler onresourcetimingbufferfull;
-// };

tests/wpt/metadata/resource-timing/idlharness.any.js.ini

@@ -41,9 +41,6 @@
   [PerformanceResourceTiming interface: attribute secureConnectionStart]
     expected: FAIL
 
-  [PerformanceResourceTiming interface: attribute fetchStart]
-    expected: FAIL
-
   [PerformanceResourceTiming interface: resource must inherit property "secureConnectionStart" with the proper type]
     expected: FAIL
 
@@ -83,9 +80,6 @@
   [PerformanceResourceTiming interface: attribute domainLookupEnd]
     expected: FAIL
 
-  [PerformanceResourceTiming interface: resource must inherit property "fetchStart" with the proper type]
-    expected: FAIL
-
   [PerformanceResourceTiming interface: attribute redirectStart]
     expected: FAIL
 
@@ -175,9 +169,6 @@
   [PerformanceResourceTiming interface: attribute secureConnectionStart]
     expected: FAIL
 
-  [PerformanceResourceTiming interface: attribute fetchStart]
-    expected: FAIL
-
   [PerformanceResourceTiming interface: attribute workerStart]
     expected: FAIL