Bug 1676791 - Part 1: Add ScrollTimeline class. r=hiro

Define a simple version of ScrollTimeline.

Differential Revision: https://phabricator.services.mozilla.com/D129099

dom/animation/ScrollTimeline.cpp

@@ -0,0 +1,41 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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/. */
+
+#include "ScrollTimeline.h"
+
+#include "mozilla/dom/Animation.h"
+#include "mozilla/dom/Document.h"
+
+namespace mozilla::dom {
+
+NS_IMPL_CYCLE_COLLECTION_CLASS(ScrollTimeline)
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(ScrollTimeline,
+                                                AnimationTimeline)
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mDocument)
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mSource)
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(ScrollTimeline,
+                                                  AnimationTimeline)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mDocument)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mSource)
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN_INHERITED(ScrollTimeline,
+                                               AnimationTimeline)
+NS_IMPL_CYCLE_COLLECTION_TRACE_END
+
+NS_IMPL_ISUPPORTS_CYCLE_COLLECTION_INHERITED_0(ScrollTimeline,
+                                               AnimationTimeline)
+
+ScrollTimeline::ScrollTimeline(Document* aDocument, Element* aScroller)
+    : AnimationTimeline(aDocument->GetParentObject()),
+      mDocument(aDocument),
+      mSource(aScroller),
+      mDirection(StyleScrollDirection::Auto) {
+  // TODO: Register the timeline to the soruce element in the next patch.
+}
+
+}  // namespace mozilla::dom

dom/animation/ScrollTimeline.h

@@ -0,0 +1,64 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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/. */
+
+#ifndef mozilla_dom_ScrollTimeline_h
+#define mozilla_dom_ScrollTimeline_h
+
+#include "mozilla/dom/AnimationTimeline.h"
+#include "mozilla/ServoStyleConsts.h"
+
+namespace mozilla {
+namespace dom {
+
+class ScrollTimeline final : public AnimationTimeline {
+ public:
+  ScrollTimeline() = delete;
+  ScrollTimeline(Document* aDocument, Element* aScroller);
+
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS_INHERITED(ScrollTimeline,
+                                                         AnimationTimeline)
+
+  JSObject* WrapObject(JSContext* aCx,
+                       JS::Handle<JSObject*> aGivenProto) override {
+    // FIXME: Bug 1676794: Implement ScrollTimeline interface.
+    return nullptr;
+  }
+
+  // AnimationTimeline methods.
+  Nullable<TimeDuration> GetCurrentTimeAsDuration() const override {
+    // FIXME: We will update this function in the patch series.
+    return nullptr;
+  }
+  bool TracksWallclockTime() const override { return false; }
+  Nullable<TimeDuration> ToTimelineTime(
+      const TimeStamp& aTimeStamp) const override {
+    // It's unclear to us what should we do for this function now, so return
+    // nullptr.
+    return nullptr;
+  }
+  TimeStamp ToTimeStamp(const TimeDuration& aTimelineTime) const override {
+    // It's unclear to us what should we do for this function now, so return
+    // zero time.
+    return {};
+  }
+  Document* GetDocument() const override { return mDocument; }
+
+ protected:
+  virtual ~ScrollTimeline() = default;
+
+ private:
+  RefPtr<Document> mDocument;
+
+  // FIXME: We will use these data members in the following patches.
+  RefPtr<Element> mSource;
+  StyleScrollDirection mDirection;
+};
+
+}  // namespace dom
+}  // namespace mozilla
+
+#endif  // mozilla_dom_ScrollTimeline_h

dom/animation/moz.build

@@ -19,6 +19,7 @@ EXPORTS.mozilla.dom += [
     "CSSTransition.h",
     "DocumentTimeline.h",
     "KeyframeEffect.h",
+    "ScrollTimeline.h",
 ]
 
 EXPORTS.mozilla += [
@@ -58,6 +59,7 @@ UNIFIED_SOURCES += [
     "KeyframeEffect.cpp",
     "KeyframeUtils.cpp",
     "PendingAnimationTracker.cpp",
+    "ScrollTimeline.cpp",
     "TimingParams.cpp",
 ]
 

layout/style/ServoBindings.toml

@@ -438,6 +438,7 @@ cbindgen-types = [
     { gecko = "StyleBreakWithin", servo = "crate::values::computed::BreakWithin" },
     { gecko = "StyleBorderStyle", servo = "crate::values::computed::BorderStyle" },
     { gecko = "StyleOutlineStyle", servo = "crate::values::computed::OutlineStyle" },
+    { gecko = "StyleScrollDirection", servo = "crate::stylesheets::scroll_timeline_rule::ScrollDirection" },
     { gecko = "StyleScrollSnapAlign", servo = "crate::values::computed::ScrollSnapAlign" },
     { gecko = "StyleScrollSnapStrictness", servo = "crate::values::computed::ScrollSnapStrictness" },
     { gecko = "StyleScrollSnapType", servo = "crate::values::computed::ScrollSnapType" },

servo/components/style/stylesheets/scroll_timeline_rule.rs

@@ -182,7 +182,8 @@ impl Default for Source {
 /// definition of ScrollTimelineOptions (WebIDL API).
 /// https://drafts.csswg.org/scroll-animations/#dom-scrolltimelineoptions-orientation
 #[derive(Clone, Copy, Debug, MallocSizeOf, Eq, Parse, PartialEq, PartialOrd, ToCss, ToShmem)]
-pub enum Orientation {
+#[repr(u8)]
+pub enum ScrollDirection {
     /// The initial value.
     Auto,
     /// The direction along the block axis. This is the default value.
@@ -195,12 +196,15 @@ pub enum Orientation {
     Vertical,
 }
 
-impl Default for Orientation {
+impl Default for ScrollDirection {
     fn default() -> Self {
-        Orientation::Auto
+        ScrollDirection::Auto
     }
 }
 
+// Avoid name collision in cbindgen with StyleOrientation.
+pub use self::ScrollDirection as Orientation;
+
 /// Scroll-timeline offsets. We treat None as an empty vector.
 /// value: none | <scroll-timeline-offset>#
 ///

servo/ports/geckolib/cbindgen.toml

@@ -236,6 +236,7 @@ include = [
   "DProperty",
   "ImageRendering",
   "ScrollbarGutter",
+  "ScrollDirection",
 ]
 item_types = ["enums", "structs", "unions", "typedefs", "functions", "constants"]
 renaming_overrides_prefixing = true