media element: support seekable attribute (#36541)

support seekable attribute in `htmlmediaelement`, modify `seek`
algorithm to use `seekable` attribute.

related
[specs](https://html.spec.whatwg.org/multipage/media.html#dom-media-seekable)
Testing: Run WPT Test
Fixes: https://github.com/servo/servo/issues/22297

Will wait for https://github.com/servo/media/pull/435 before turning
this to ready for review.
cc @jdm @xiaochengh

Signed-off-by: rayguo17 <rayguo17@gmail.com>

5 files changed, 59 insertions, 39 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 4ffa4b4058c..e9af4b24fdd 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -6600,7 +6600,7 @@ dependencies = [
 [[package]]
 name = "servo-media"
 version = "0.1.0"
-source = "git+https://github.com/servo/media#c7eab1ae326b8b95b938741660553342f7cd94b7"
+source = "git+https://github.com/servo/media#eb96030cdd153ebcbbe3836dc6471303187740e9"
 dependencies = [
  "once_cell",
  "servo-media-audio",
@@ -6613,7 +6613,7 @@ dependencies = [
 [[package]]
 name = "servo-media-audio"
 version = "0.2.0"
-source = "git+https://github.com/servo/media#c7eab1ae326b8b95b938741660553342f7cd94b7"
+source = "git+https://github.com/servo/media#eb96030cdd153ebcbbe3836dc6471303187740e9"
 dependencies = [
  "byte-slice-cast",
  "euclid",
@@ -6634,7 +6634,7 @@ dependencies = [
 [[package]]
 name = "servo-media-derive"
 version = "0.1.0"
-source = "git+https://github.com/servo/media#c7eab1ae326b8b95b938741660553342f7cd94b7"
+source = "git+https://github.com/servo/media#eb96030cdd153ebcbbe3836dc6471303187740e9"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -6644,7 +6644,7 @@ dependencies = [
 [[package]]
 name = "servo-media-dummy"
 version = "0.1.0"
-source = "git+https://github.com/servo/media#c7eab1ae326b8b95b938741660553342f7cd94b7"
+source = "git+https://github.com/servo/media#eb96030cdd153ebcbbe3836dc6471303187740e9"
 dependencies = [
  "ipc-channel",
  "servo-media",
@@ -6658,7 +6658,7 @@ dependencies = [
 [[package]]
 name = "servo-media-gstreamer"
 version = "0.1.0"
-source = "git+https://github.com/servo/media#c7eab1ae326b8b95b938741660553342f7cd94b7"
+source = "git+https://github.com/servo/media#eb96030cdd153ebcbbe3836dc6471303187740e9"
 dependencies = [
  "byte-slice-cast",
  "glib",
@@ -6691,7 +6691,7 @@ dependencies = [
 [[package]]
 name = "servo-media-gstreamer-render"
 version = "0.1.0"
-source = "git+https://github.com/servo/media#c7eab1ae326b8b95b938741660553342f7cd94b7"
+source = "git+https://github.com/servo/media#eb96030cdd153ebcbbe3836dc6471303187740e9"
 dependencies = [
  "gstreamer",
  "gstreamer-video",
@@ -6701,7 +6701,7 @@ dependencies = [
 [[package]]
 name = "servo-media-gstreamer-render-android"
 version = "0.1.0"
-source = "git+https://github.com/servo/media#c7eab1ae326b8b95b938741660553342f7cd94b7"
+source = "git+https://github.com/servo/media#eb96030cdd153ebcbbe3836dc6471303187740e9"
 dependencies = [
  "glib",
  "gstreamer",
@@ -6715,7 +6715,7 @@ dependencies = [
 [[package]]
 name = "servo-media-gstreamer-render-unix"
 version = "0.1.0"
-source = "git+https://github.com/servo/media#c7eab1ae326b8b95b938741660553342f7cd94b7"
+source = "git+https://github.com/servo/media#eb96030cdd153ebcbbe3836dc6471303187740e9"
 dependencies = [
  "glib",
  "gstreamer",
@@ -6730,7 +6730,7 @@ dependencies = [
 [[package]]
 name = "servo-media-player"
 version = "0.1.0"
-source = "git+https://github.com/servo/media#c7eab1ae326b8b95b938741660553342f7cd94b7"
+source = "git+https://github.com/servo/media#eb96030cdd153ebcbbe3836dc6471303187740e9"
 dependencies = [
  "ipc-channel",
  "serde",
@@ -6742,7 +6742,7 @@ dependencies = [
 [[package]]
 name = "servo-media-streams"
 version = "0.1.0"
-source = "git+https://github.com/servo/media#c7eab1ae326b8b95b938741660553342f7cd94b7"
+source = "git+https://github.com/servo/media#eb96030cdd153ebcbbe3836dc6471303187740e9"
 dependencies = [
  "uuid",
 ]
@@ -6750,12 +6750,12 @@ dependencies = [
 [[package]]
 name = "servo-media-traits"
 version = "0.1.0"
-source = "git+https://github.com/servo/media#c7eab1ae326b8b95b938741660553342f7cd94b7"
+source = "git+https://github.com/servo/media#eb96030cdd153ebcbbe3836dc6471303187740e9"
 
 [[package]]
 name = "servo-media-webrtc"
 version = "0.1.0"
-source = "git+https://github.com/servo/media#c7eab1ae326b8b95b938741660553342f7cd94b7"
+source = "git+https://github.com/servo/media#eb96030cdd153ebcbbe3836dc6471303187740e9"
 dependencies = [
  "log",
  "servo-media-streams",
diff --git a/components/script/dom/htmlmediaelement.rs b/components/script/dom/htmlmediaelement.rs
index d1baab7d6d2..8ddef6d33cb 100644
--- a/components/script/dom/htmlmediaelement.rs
+++ b/components/script/dom/htmlmediaelement.rs
@@ -29,6 +29,7 @@ use net_traits::{
     ResourceTimingType,
 };
 use pixels::Image;
+use script_bindings::codegen::GenericBindings::TimeRangesBinding::TimeRangesMethods;
 use script_bindings::codegen::InheritTypes::{
     ElementTypeId, HTMLElementTypeId, HTMLMediaElementTypeId, NodeTypeId,
 };
@@ -1277,15 +1278,40 @@ impl HTMLMediaElement {
         let time = f64::max(time, 0.);
 
         // Step 8.
-        // XXX(ferjm) seekable attribute: we need to get the information about
-        //            what's been decoded and buffered so far from servo-media
-        //            and add the seekable attribute as a TimeRange.
-        if let Some(ref current_fetch_context) = *self.current_fetch_context.borrow() {
-            if !current_fetch_context.is_seekable() {
-                self.seeking.set(false);
-                return;
+        let seekable = self.Seekable();
+        if seekable.Length() == 0 {
+            self.seeking.set(false);
+            return;
+        }
+        let mut nearest_seekable_position = 0.0;
+        let mut in_seekable_range = false;
+        let mut nearest_seekable_distance = f64::MAX;
+        for i in 0..seekable.Length() {
+            let start = seekable.Start(i).unwrap().abs();
+            let end = seekable.End(i).unwrap().abs();
+            if time >= start && time <= end {
+                nearest_seekable_position = time;
+                in_seekable_range = true;
+                break;
+            } else if time < start {
+                let distance = start - time;
+                if distance < nearest_seekable_distance {
+                    nearest_seekable_distance = distance;
+                    nearest_seekable_position = start;
+                }
+            } else {
+                let distance = time - end;
+                if distance < nearest_seekable_distance {
+                    nearest_seekable_distance = distance;
+                    nearest_seekable_position = end;
+                }
             }
         }
+        let time = if in_seekable_range {
+            time
+        } else {
+            nearest_seekable_position
+        };
 
         // Step 9.
         // servo-media with gstreamer does not support inaccurate seeking for now.
@@ -2402,6 +2428,19 @@ impl HTMLMediaElementMethods<crate::DomTypeHolder> for HTMLMediaElement {
         )
     }
 
+    // https://html.spec.whatwg.org/multipage/#dom-media-seekable
+    fn Seekable(&self) -> DomRoot<TimeRanges> {
+        let mut seekable = TimeRangesContainer::default();
+        if let Some(ref player) = *self.player.borrow() {
+            if let Ok(ranges) = player.lock().unwrap().seekable() {
+                for range in ranges {
+                    let _ = seekable.add(range.start, range.end);
+                }
+            }
+        }
+        TimeRanges::new(self.global().as_window(), seekable, CanGc::note())
+    }
+
     // https://html.spec.whatwg.org/multipage/#dom-media-buffered
     fn Buffered(&self) -> DomRoot<TimeRanges> {
         let mut buffered = TimeRangesContainer::default();
diff --git a/components/script_bindings/webidls/HTMLMediaElement.webidl b/components/script_bindings/webidls/HTMLMediaElement.webidl
index a2c7866a3fe..7ceae06f151 100644
--- a/components/script_bindings/webidls/HTMLMediaElement.webidl
+++ b/components/script_bindings/webidls/HTMLMediaElement.webidl
@@ -45,7 +45,7 @@ interface HTMLMediaElement : HTMLElement {
   [Throws] attribute double defaultPlaybackRate;
   [Throws] attribute double playbackRate;
   readonly attribute TimeRanges played;
-  // readonly attribute TimeRanges seekable;
+  readonly attribute TimeRanges seekable;
   readonly attribute boolean ended;
   [CEReactions] attribute boolean autoplay;
   [CEReactions] attribute boolean loop;
diff --git a/tests/wpt/meta/html/dom/idlharness.https.html.ini b/tests/wpt/meta/html/dom/idlharness.https.html.ini
index 7cc9f5ba321..a60e9fcd4af 100644
--- a/tests/wpt/meta/html/dom/idlharness.https.html.ini
+++ b/tests/wpt/meta/html/dom/idlharness.https.html.ini
@@ -2322,9 +2322,6 @@
   [HTMLSelectElement interface: document.createElement("select") must inherit property "autocomplete" with the proper type]
     expected: FAIL
 
-  [HTMLMediaElement interface: attribute seekable]
-    expected: FAIL
-
   [HTMLTableSectionElement interface: attribute align]
     expected: FAIL
 
@@ -6487,36 +6484,24 @@
   [HTMLMediaElement interface: document.createElement("video") must inherit property "preservesPitch" with the proper type]
     expected: FAIL
 
-  [HTMLMediaElement interface: document.createElement("video") must inherit property "seekable" with the proper type]
-    expected: FAIL
-
   [HTMLMediaElement interface: document.createElement("audio") must inherit property "getStartDate()" with the proper type]
     expected: FAIL
 
   [HTMLMediaElement interface: document.createElement("audio") must inherit property "preservesPitch" with the proper type]
     expected: FAIL
 
-  [HTMLMediaElement interface: document.createElement("audio") must inherit property "seekable" with the proper type]
-    expected: FAIL
-
   [HTMLMediaElement interface: new Audio() must inherit property "getStartDate()" with the proper type]
     expected: FAIL
 
   [HTMLMediaElement interface: new Audio() must inherit property "preservesPitch" with the proper type]
     expected: FAIL
 
-  [HTMLMediaElement interface: new Audio() must inherit property "seekable" with the proper type]
-    expected: FAIL
-
   [HTMLMediaElement interface: operation getStartDate()]
     expected: FAIL
 
   [HTMLMediaElement interface: attribute preservesPitch]
     expected: FAIL
 
-  [HTMLMediaElement interface: attribute seekable]
-    expected: FAIL
-
   [HTMLMapElement interface: attribute name]
     expected: FAIL
 
diff --git a/tests/wpt/meta/html/semantics/embedded-content/media-elements/seeking/seek-to-currentTime.html.ini b/tests/wpt/meta/html/semantics/embedded-content/media-elements/seeking/seek-to-currentTime.html.ini
deleted file mode 100644
index 589a58e234d..00000000000
--- a/tests/wpt/meta/html/semantics/embedded-content/media-elements/seeking/seek-to-currentTime.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[seek-to-currentTime.html]
-  [seek to currentTime]
-    expected: FAIL
-