htmlimageelement: Reject decode promises on the current request mutation (#37828)

Follow the HTML specification and reject the pending image decode
promises
on any current request mutation.
https://html.spec.whatwg.org/multipage/#updating-the-image-data (step
18)
https://html.spec.whatwg.org/multipage/#dom-img-decode (step 3)

Fulfill and reject image decode promises by queueing
a global tasks on the DOM manipulation task source.

Testing: Improvements in the following tests
- html/semantics/embedded-content/the-img-element/decode/*

Signed-off-by: Andrei Volykhin <andrei.volykhin@gmail.com>

components/script/dom/bindings/error.rs

@@ -97,6 +97,7 @@ pub(crate) fn throw_dom_exception(
         Error::NotReadable => DOMErrorName::NotReadableError,
         Error::Operation => DOMErrorName::OperationError,
         Error::NotAllowed => DOMErrorName::NotAllowedError,
+        Error::Encoding => DOMErrorName::EncodingError,
         Error::Type(message) => unsafe {
             assert!(!JS_IsExceptionPending(*cx));
             throw_type_error(*cx, &message);

components/script/dom/htmlimageelement.rs

@@ -43,8 +43,6 @@ use style::values::specified::source_size_list::SourceSizeList;
 use style_traits::ParsingMode;
 use url::Url;
 
-use super::domexception::DOMErrorName;
-use super::types::DOMException;
 use crate::document_loader::{LoadBlocker, LoadType};
 use crate::dom::activation::Activatable;
 use crate::dom::attr::Attr;
@@ -57,7 +55,7 @@ use crate::dom::bindings::codegen::Bindings::NodeBinding::Node_Binding::NodeMeth
 use crate::dom::bindings::codegen::Bindings::WindowBinding::WindowMethods;
 use crate::dom::bindings::error::{Error, Fallible};
 use crate::dom::bindings::inheritance::Castable;
-use crate::dom::bindings::refcounted::Trusted;
+use crate::dom::bindings::refcounted::{Trusted, TrustedPromise};
 use crate::dom::bindings::reflector::DomGlobal;
 use crate::dom::bindings::root::{DomRoot, LayoutDom, MutNullableDom};
 use crate::dom::bindings::str::{DOMString, USVString};
@@ -486,7 +484,7 @@ impl HTMLImageElement {
         LoadBlocker::terminate(&self.current_request.borrow().blocker, can_gc);
         // Mark the node dirty
         self.upcast::<Node>().dirty(NodeDamage::Other);
-        self.resolve_image_decode_promises(can_gc);
+        self.resolve_image_decode_promises();
     }
 
     /// Step 24 of <https://html.spec.whatwg.org/multipage/#update-the-image-data>
@@ -597,9 +595,9 @@ impl HTMLImageElement {
         request.metadata = None;
 
         if matches!(state, State::Broken) {
-            self.reject_image_decode_promises(can_gc);
+            self.reject_image_decode_promises();
         } else if matches!(state, State::CompletelyAvailable) {
-            self.resolve_image_decode_promises(can_gc);
+            self.resolve_image_decode_promises();
         }
     }
 
@@ -894,6 +892,7 @@ impl HTMLImageElement {
                         // Step 17
                         current_request.current_pixel_density = Some(selected_pixel_density);
                         self.init_image_request(&mut current_request, url, src, can_gc);
+                        self.reject_image_decode_promises();
                     },
                     (_, _) => {
                         // step 17
@@ -1186,10 +1185,7 @@ impl HTMLImageElement {
         if !document.is_fully_active() ||
             matches!(self.current_request.borrow().state, State::Broken)
         {
-            promise.reject_native(
-                &DOMException::new(&document.global(), DOMErrorName::EncodingError, can_gc),
-                can_gc,
-            );
+            promise.reject_error(Error::Encoding, can_gc);
         } else if matches!(
             self.current_request.borrow().state,
             State::CompletelyAvailable
@@ -1203,22 +1199,59 @@ impl HTMLImageElement {
         }
     }
 
-    fn resolve_image_decode_promises(&self, can_gc: CanGc) {
-        for promise in self.image_decode_promises.borrow().iter() {
-            promise.resolve_native(&(), can_gc);
+    /// <https://html.spec.whatwg.org/multipage/#dom-img-decode>
+    fn resolve_image_decode_promises(&self) {
+        if self.image_decode_promises.borrow().is_empty() {
+            return;
         }
+
+        // Step 3. If the decoding process completes successfully, then queue a
+        // global task on the DOM manipulation task source with global to
+        // resolve promise with undefined.
+        let trusted_image_decode_promises: Vec<TrustedPromise> = self
+            .image_decode_promises
+            .borrow()
+            .iter()
+            .map(|promise| TrustedPromise::new(promise.clone()))
+            .collect();
+
         self.image_decode_promises.borrow_mut().clear();
+
+        self.owner_global()
+            .task_manager()
+            .dom_manipulation_task_source()
+            .queue(task!(fulfill_image_decode_promises: move || {
+                for trusted_promise in trusted_image_decode_promises {
+                    trusted_promise.root().resolve_native(&(), CanGc::note());
+                }
+            }));
     }
 
-    fn reject_image_decode_promises(&self, can_gc: CanGc) {
-        let document = self.owner_document();
-        for promise in self.image_decode_promises.borrow().iter() {
-            promise.reject_native(
-                &DOMException::new(&document.global(), DOMErrorName::EncodingError, can_gc),
-                can_gc,
-            );
+    /// <https://html.spec.whatwg.org/multipage/#dom-img-decode>
+    fn reject_image_decode_promises(&self) {
+        if self.image_decode_promises.borrow().is_empty() {
+            return;
         }
+
+        // Step 3. Queue a global task on the DOM manipulation task source with
+        // global to reject promise with an "EncodingError" DOMException.
+        let trusted_image_decode_promises: Vec<TrustedPromise> = self
+            .image_decode_promises
+            .borrow()
+            .iter()
+            .map(|promise| TrustedPromise::new(promise.clone()))
+            .collect();
+
         self.image_decode_promises.borrow_mut().clear();
+
+        self.owner_global()
+            .task_manager()
+            .dom_manipulation_task_source()
+            .queue(task!(reject_image_decode_promises: move || {
+                for trusted_promise in trusted_image_decode_promises {
+                    trusted_promise.root().reject_error(Error::Encoding, CanGc::note());
+                }
+            }));
     }
 
     /// Step 15 for <https://html.spec.whatwg.org/multipage/#img-environment-changes>

components/script_bindings/error.rs

@@ -9,6 +9,7 @@ use crate::codegen::PrototypeList::proto_id_to_name;
 use crate::script_runtime::JSContext as SafeJSContext;
 
 /// DOM exceptions that can be thrown by a native DOM method.
+/// <https://webidl.spec.whatwg.org/#dfn-error-names-table>
 #[derive(Clone, Debug, MallocSizeOf)]
 pub enum Error {
     /// IndexSizeError DOMException
@@ -67,6 +68,8 @@ pub enum Error {
     Operation,
     /// NotAllowedError DOMException
     NotAllowed,
+    /// EncodingError DOMException
+    Encoding,
 
     /// TypeError JavaScript Error
     Type(String),

tests/wpt/meta/html/semantics/embedded-content/the-img-element/decode/image-decode-path-changes.html.ini

@@ -1,15 +0,0 @@
-[image-decode-path-changes.html]
-  [HTMLImageElement.prototype.decode(), src/srcset mutation tests. src changes fail decode; following good png decode succeeds.]
-    expected: FAIL
-
-  [HTMLImageElement.prototype.decode(), src/srcset mutation tests. src changes fail decode; following good svg decode succeeds.]
-    expected: FAIL
-
-  [HTMLImageElement.prototype.decode(), src/srcset mutation tests. srcset changes fail decode; following good decode succeeds.]
-    expected: FAIL
-
-  [HTMLImageElement.prototype.decode(), src/srcset mutation tests. src changes fail decode.]
-    expected: FAIL
-
-  [HTMLImageElement.prototype.decode(), src/srcset mutation tests. srcset changes fail decode.]
-    expected: FAIL

tests/wpt/meta/html/semantics/embedded-content/the-img-element/decode/image-decode-with-quick-attach.html.ini

@@ -1,15 +1,3 @@
 [image-decode-with-quick-attach.html]
-  [HTMLImageElement.prototype.decode(), attach to DOM before promise resolves.: src in empty picture not cached]
-    expected: FAIL
-
-  [HTMLImageElement.prototype.decode(), attach to DOM before promise resolves.: srcset in empty picture]
-    expected: FAIL
-
-  [HTMLImageElement.prototype.decode(), attach to DOM before promise resolves.: src in picture with source not cached]
-    expected: FAIL
-
-  [HTMLImageElement.prototype.decode(), attach to DOM before promise resolves.: src in picture with source cached]
-    expected: FAIL
-
-  [HTMLImageElement.prototype.decode(), attach to DOM before promise resolves.: srcset in picture with source]
+  [HTMLImageElement.prototype.decode(), attach to DOM before promise resolves.: src in empty picture cached]
     expected: FAIL