Bug 1744573: Cache the transform matrix r=eeejay,Jamie

Differential Revision: https://phabricator.services.mozilla.com/D133134

accessible/base/AccAttributes.cpp

@@ -5,6 +5,7 @@
 
 #include "AccAttributes.h"
 #include "StyleInfo.h"
+#include "mozilla/ToString.h"
 
 using namespace mozilla::a11y;
 
@@ -65,6 +66,9 @@ void AccAttributes::StringFromValueAndName(nsAtom* aAttrName,
       [&aValueString](const uint64_t& val) { aValueString.AppendInt(val); },
       [&aValueString](const UniquePtr<AccGroupInfo>& val) {
         aValueString.Assign(u"AccGroupInfo{...}");
+      },
+      [&aValueString](const UniquePtr<gfx::Matrix4x4>& val) {
+        aValueString.AppendPrintf("Matrix4x4=%s", ToString(*val).c_str());
       });
 }
 
@@ -157,6 +161,10 @@ void AccAttributes::CopyTo(AccAttributes* aDest) const {
         [](const UniquePtr<AccGroupInfo>& val) {
           MOZ_ASSERT_UNREACHABLE(
               "Trying to copy an AccAttributes containing an AccGroupInfo");
+        },
+        [](const UniquePtr<gfx::Matrix4x4>& val) {
+          MOZ_ASSERT_UNREACHABLE(
+              "Trying to copy an AccAttributes containing a matrix");
         });
   }
 }

accessible/base/AccAttributes.h

@@ -12,6 +12,7 @@
 #include "nsTHashMap.h"
 #include "nsAtom.h"
 #include "nsStringFwd.h"
+#include "mozilla/gfx/Matrix.h"
 
 class nsVariant;
 
@@ -68,7 +69,8 @@ class AccAttributes {
   using AttrValueType =
       Variant<bool, float, double, int32_t, RefPtr<nsAtom>, nsTArray<int32_t>,
               CSSCoord, FontSize, Color, DeleteEntry, UniquePtr<nsString>,
-              RefPtr<AccAttributes>, uint64_t, UniquePtr<AccGroupInfo>>;
+              RefPtr<AccAttributes>, uint64_t, UniquePtr<AccGroupInfo>,
+              UniquePtr<gfx::Matrix4x4>>;
   static_assert(sizeof(AttrValueType) <= 16);
   using AtomVariantMap = nsTHashMap<nsRefPtrHashKey<nsAtom>, AttrValueType>;
 
@@ -87,6 +89,7 @@ class AccAttributes {
   template <typename T, typename std::enable_if<
                             !std::is_convertible_v<T, nsString> &&
                                 !std::is_convertible_v<T, AccGroupInfo*> &&
+                                !std::is_convertible_v<T, gfx::Matrix4x4> &&
                                 !std::is_convertible_v<T, nsAtom*>,
                             bool>::type = true>
   void SetAttribute(nsAtom* aAttrName, T&& aAttrValue) {
@@ -101,6 +104,11 @@ class AccAttributes {
 
   void SetAttribute(nsAtom* aAttrName, AccGroupInfo* aAttrValue) {
     UniquePtr<AccGroupInfo> value(aAttrValue);
+  }
+
+  void SetAttribute(nsAtom* aAttrName, gfx::Matrix4x4&& aAttrValue) {
+    UniquePtr<gfx::Matrix4x4> value = MakeUnique<gfx::Matrix4x4>();
+    *value = std::forward<gfx::Matrix4x4>(aAttrValue);
     mData.InsertOrUpdate(aAttrName, AsVariant(std::move(value)));
   }
 
@@ -120,6 +128,11 @@ class AccAttributes {
           const T& val = *(value->as<UniquePtr<nsString>>().get());
           return SomeRef(val);
         }
+      } else if constexpr (std::is_same_v<gfx::Matrix4x4, T>) {
+        if (value->is<UniquePtr<gfx::Matrix4x4>>()) {
+          const T& val = *(value->as<UniquePtr<gfx::Matrix4x4>>());
+          return SomeRef(val);
+        }
       } else {
         if (value->is<T>()) {
           const T& val = value->as<T>();
@@ -184,6 +197,11 @@ class AccAttributes {
           const T& val = *(mValue->as<UniquePtr<nsString>>().get());
           return SomeRef(val);
         }
+      } else if constexpr (std::is_same_v<gfx::Matrix4x4, T>) {
+        if (mValue->is<UniquePtr<gfx::Matrix4x4>>()) {
+          const T& val = *(mValue->as<UniquePtr<gfx::Matrix4x4>>());
+          return SomeRef(val);
+        }
       } else {
         if (mValue->is<T>()) {
           const T& val = mValue->as<T>();

accessible/base/CacheConstants.h

@@ -22,6 +22,7 @@ class CacheDomain {
   static constexpr uint64_t GroupInfo = ((uint64_t)0x1) << 7;
   static constexpr uint64_t Actions = ((uint64_t)0x1) << 8;
   static constexpr uint64_t Style = ((uint64_t)0x1) << 9;
+  static constexpr uint64_t TransformMatrix = ((uint64_t)0x1) << 10;
   static constexpr uint64_t All = ~((uint64_t)0x0);
 };
 

accessible/generic/LocalAccessible.cpp

@@ -44,6 +44,7 @@
 #include "mozilla/dom/Document.h"
 #include "mozilla/dom/HTMLFormElement.h"
 #include "mozilla/dom/HTMLAnchorElement.h"
+#include "mozilla/gfx/Matrix.h"
 #include "nsIContent.h"
 #include "nsIFormControl.h"
 
@@ -606,8 +607,44 @@ LocalAccessible* LocalAccessible::LocalChildAtPoint(
   return accessible;
 }
 
-nsRect LocalAccessible::ParentRelativeBounds() {
+nsIFrame* LocalAccessible::FindNearestAccessibleAncestorFrame() {
+  nsIFrame* frame = GetFrame();
   nsIFrame* boundingFrame = nullptr;
+
+  if (IsDoc() &&
+      nsCoreUtils::IsTopLevelContentDocInProcess(AsDoc()->DocumentNode())) {
+    // Tab documents and OOP iframe docs won't have ancestor accessibles
+    // with frames. Instead, bound by their presshell's root frame.
+    boundingFrame = nsLayoutUtils::GetContainingBlockForClientRect(frame);
+  }
+
+  // Iterate through accessible's ancestors to find one with a frame.
+  LocalAccessible* ancestor = mParent;
+  while (ancestor && !boundingFrame) {
+    if (ancestor->IsDoc()) {
+      // If we find a doc accessible, use its presshell's root frame
+      // (since doc accessibles themselves don't have frames).
+      boundingFrame = nsLayoutUtils::GetContainingBlockForClientRect(frame);
+      break;
+    }
+
+    if ((boundingFrame = ancestor->GetFrame())) {
+      // Otherwise, if the ancestor has a frame, use that
+      break;
+    }
+
+    ancestor = ancestor->LocalParent();
+  }
+
+  if (!boundingFrame) {
+    MOZ_ASSERT_UNREACHABLE("No ancestor with frame?");
+    boundingFrame = nsLayoutUtils::GetContainingBlockForClientRect(frame);
+  }
+
+  return boundingFrame;
+}
+
+nsRect LocalAccessible::ParentRelativeBounds() {
   nsIFrame* frame = GetFrame();
   if (frame && mContent) {
     if (mContent->GetProperty(nsGkAtoms::hitregion) && mContent->IsElement()) {
@@ -632,43 +669,7 @@ nsRect LocalAccessible::ParentRelativeBounds() {
       }
     }
 
-    // We need to find a frame to make our bounds relative to. We'll store this
-    // in `boundingFrame`. Ultimately, we'll create screen-relative coordinates
-    // by summing the x, y offsets of our ancestors' bounds in
-    // RemoteAccessibleBase::Bounds(), so it is important that our bounding
-    // frame have a corresponding accessible.
-    if (IsDoc() &&
-        nsCoreUtils::IsTopLevelContentDocInProcess(AsDoc()->DocumentNode())) {
-      // Tab documents and OOP iframe docs won't have ancestor accessibles with
-      // frames. We'll use their presshell root frame instead.
-      // XXX bug 1736635: Should DocAccessibles return their presShell frame on
-      // GetFrame()?
-      boundingFrame = nsLayoutUtils::GetContainingBlockForClientRect(frame);
-    }
-
-    // Iterate through ancestors to find one with a frame.
-    LocalAccessible* parent = mParent;
-    while (parent && !boundingFrame) {
-      if (parent->IsDoc()) {
-        // If we find a doc accessible, use its presshell's root frame
-        // (since doc accessibles themselves don't have frames).
-        boundingFrame = nsLayoutUtils::GetContainingBlockForClientRect(frame);
-        break;
-      }
-
-      if ((boundingFrame = parent->GetFrame())) {
-        // Otherwise, if the parent has a frame, use that
-        break;
-      }
-
-      parent = parent->LocalParent();
-    }
-
-    if (!boundingFrame) {
-      MOZ_ASSERT_UNREACHABLE("No ancestor with frame?");
-      boundingFrame = nsLayoutUtils::GetContainingBlockForClientRect(frame);
-    }
-
+    nsIFrame* boundingFrame = FindNearestAccessibleAncestorFrame();
     nsRect unionRect = nsLayoutUtils::GetAllInFlowRectsUnion(
         frame, boundingFrame, nsLayoutUtils::RECTS_ACCOUNT_FOR_TRANSFORMS);
 
@@ -3246,6 +3247,34 @@ already_AddRefed<AccAttributes> LocalAccessible::BundleFieldsForCache(
     }
   }
 
+  if (aCacheDomain & CacheDomain::TransformMatrix) {
+    nsIFrame* frame = GetFrame();
+
+    if (frame && frame->IsTransformed()) {
+      // We need to find a frame to make our transform relative to.
+      // It's important this frame have a corresponding accessible,
+      // because this transform is applied while walking the accessibility
+      // tree (in the parent process), not the frame tree.
+      nsIFrame* boundingFrame = FindNearestAccessibleAncestorFrame();
+      // This matrix is only valid when applied to CSSPixel points/rects
+      // in the coordinate space of `frame`. It also includes the translation
+      // to the parent space.
+      gfx::Matrix4x4 mtx = nsLayoutUtils::GetTransformToAncestor(
+                               RelativeTo{frame}, RelativeTo{boundingFrame},
+                               nsIFrame::IN_CSS_UNITS)
+                               .GetMatrix();
+
+      UniquePtr<gfx::Matrix4x4> ptr = MakeUnique<gfx::Matrix4x4>(mtx);
+      fields->SetAttribute(nsGkAtoms::transform, std::move(ptr));
+    } else {
+      // Otherwise, if we're bundling a transform update but this
+      // frame isn't transformed (or doesn't exist), we need
+      // to send a DeleteEntry() to remove any
+      // transform that was previously cached for this frame.
+      fields->SetAttribute(nsGkAtoms::transform, DeleteEntry());
+    }
+  }
+
   if (aCacheDomain & CacheDomain::DOMNodeID && mContent) {
     nsAtom* id = mContent->GetID();
     if (id) {
@@ -3327,6 +3356,11 @@ already_AddRefed<AccAttributes> LocalAccessible::BundleFieldsForCache(
       // Note our frame's current computed style so we can track style changes
       // later on.
       mOldComputedStyle = frame->Style();
+      if (frame->IsTransformed()) {
+        mStateFlags |= eOldFrameHasValidTransformStyle;
+      } else {
+        mStateFlags &= ~eOldFrameHasValidTransformStyle;
+      }
     }
   }
 
@@ -3352,7 +3386,39 @@ void LocalAccessible::MaybeQueueCacheUpdateForStyleChanges() {
       mDoc->QueueCacheUpdate(this, CacheDomain::Style);
     }
 
+    bool newHasValidTransformStyle = frame->IsTransformed();
+    bool oldHasValidTransformStyle =
+        (mStateFlags & eOldFrameHasValidTransformStyle) != 0;
+
+    // We should send a transform update if we're adding or
+    // removing transform styling altogether.
+    bool sendTransformUpdate =
+        newHasValidTransformStyle || oldHasValidTransformStyle;
+
+    if (newHasValidTransformStyle && oldHasValidTransformStyle) {
+      // If we continue to have transform styling, verify
+      // our transform has actually changed.
+      nsChangeHint transformHint =
+          newStyle->StyleDisplay()->CalcTransformPropertyDifference(
+              *mOldComputedStyle->StyleDisplay());
+      // If this hint exists, it implies we found a property difference
+      sendTransformUpdate = !!transformHint;
+    }
+
+    if (sendTransformUpdate) {
+      // Queuing a cache update for the TransformMatrix domain doesn't
+      // necessarily mean we'll send the matrix itself, we may
+      // send a DeleteEntry() instead. See BundleFieldsForCache for
+      // more information.
+      mDoc->QueueCacheUpdate(this, CacheDomain::TransformMatrix);
+    }
+
     mOldComputedStyle = newStyle;
+    if (newHasValidTransformStyle) {
+      mStateFlags |= eOldFrameHasValidTransformStyle;
+    } else {
+      mStateFlags &= ~eOldFrameHasValidTransformStyle;
+    }
   }
 }
 

accessible/generic/LocalAccessible.h

@@ -861,8 +861,11 @@ class LocalAccessible : public nsISupports, public Accessible {
     eRelocated = 1 << 7,         // accessible was moved in tree
     eNoKidsFromDOM = 1 << 8,     // accessible doesn't allow children from DOM
     eHasTextKids = 1 << 9,       // accessible have a text leaf in children
+    eOldFrameHasValidTransformStyle =
+        1 << 10,  // frame prior to most recent style change both has transform
+                  // styling and supports transforms
 
-    eLastStateFlag = eHasTextKids
+    eLastStateFlag = eOldFrameHasValidTransformStyle
   };
 
   /**
@@ -1045,6 +1048,13 @@ class LocalAccessible : public nsISupports, public Accessible {
   LocalAccessible() = delete;
   LocalAccessible(const LocalAccessible&) = delete;
   LocalAccessible& operator=(const LocalAccessible&) = delete;
+
+  /**
+   * Traverses the accessible's parent chain in search of an accessible with
+   * a frame. Returns the frame when found. Includes special handling for
+   * OOP iframe docs and tab documents.
+   */
+  nsIFrame* FindNearestAccessibleAncestorFrame();
 };
 
 NS_DEFINE_STATIC_IID_ACCESSOR(LocalAccessible, NS_ACCESSIBLE_IMPL_IID)

accessible/ipc/other/PDocAccessible.ipdl

@@ -20,6 +20,7 @@ using mozilla::a11y::AccType from "mozilla/a11y/IPCTypes.h";
 using mozilla::a11y::AccGenericType from "mozilla/a11y/IPCTypes.h";
 [RefCounted] using mozilla::a11y::AccAttributes from "mozilla/a11y/IPCTypes.h";
 using mozilla::a11y::CacheUpdateType from "mozilla/a11y/IPCTypes.h";
+using mozilla::gfx::Matrix4x4 from "mozilla/gfx/Matrix.h";
 
 namespace mozilla {
 namespace a11y {

accessible/ipc/win/PDocAccessible.ipdl

@@ -20,6 +20,7 @@ using mozilla::a11y::CacheUpdateType from "mozilla/a11y/IPCTypes.h";
 [RefCounted] using mozilla::a11y::AccAttributes from "mozilla/a11y/IPCTypes.h";
 using mozilla::WindowsHandle from "mozilla/ipc/IPCTypes.h";
 using mozilla::LayoutDeviceIntRect from "Units.h";
+using mozilla::gfx::Matrix4x4 from "mozilla/gfx/Matrix.h";
 
 namespace mozilla {
 namespace a11y {

layout/style/nsStyleStruct.cpp

@@ -2560,28 +2560,7 @@ nsChangeHint nsStyleDisplay::CalcDifference(
      * comparisons but turn all the resulting change hints into
      * nsChangeHint_NeutralChange.
      */
-    nsChangeHint transformHint = nsChangeHint(0);
-
-    transformHint |= CompareTransformValues(mTransform, aNewData.mTransform);
-    transformHint |= CompareTransformValues(mRotate, aNewData.mRotate);
-    transformHint |= CompareTransformValues(mTranslate, aNewData.mTranslate);
-    transformHint |= CompareTransformValues(mScale, aNewData.mScale);
-    transformHint |= CompareMotionValues(*this, aNewData);
-
-    if (mTransformOrigin != aNewData.mTransformOrigin) {
-      transformHint |= nsChangeHint_UpdateTransformLayer |
-                       nsChangeHint_UpdatePostTransformOverflow;
-    }
-
-    if (mPerspectiveOrigin != aNewData.mPerspectiveOrigin ||
-        mTransformStyle != aNewData.mTransformStyle ||
-        mTransformBox != aNewData.mTransformBox) {
-      transformHint |= nsChangeHint_UpdateOverflow | nsChangeHint_RepaintFrame;
-    }
-
-    if (mBackfaceVisibility != aNewData.mBackfaceVisibility) {
-      transformHint |= nsChangeHint_RepaintFrame;
-    }
+    nsChangeHint transformHint = CalcTransformPropertyDifference(aNewData);
 
     if (transformHint) {
       if (HasTransformStyle()) {
@@ -2692,6 +2671,34 @@ nsChangeHint nsStyleDisplay::CalcDifference(
   return hint;
 }
 
+nsChangeHint nsStyleDisplay::CalcTransformPropertyDifference(
+    const nsStyleDisplay& aNewData) const {
+  nsChangeHint transformHint = nsChangeHint(0);
+
+  transformHint |= CompareTransformValues(mTransform, aNewData.mTransform);
+  transformHint |= CompareTransformValues(mRotate, aNewData.mRotate);
+  transformHint |= CompareTransformValues(mTranslate, aNewData.mTranslate);
+  transformHint |= CompareTransformValues(mScale, aNewData.mScale);
+  transformHint |= CompareMotionValues(*this, aNewData);
+
+  if (mTransformOrigin != aNewData.mTransformOrigin) {
+    transformHint |= nsChangeHint_UpdateTransformLayer |
+                     nsChangeHint_UpdatePostTransformOverflow;
+  }
+
+  if (mPerspectiveOrigin != aNewData.mPerspectiveOrigin ||
+      mTransformStyle != aNewData.mTransformStyle ||
+      mTransformBox != aNewData.mTransformBox) {
+    transformHint |= nsChangeHint_UpdateOverflow | nsChangeHint_RepaintFrame;
+  }
+
+  if (mBackfaceVisibility != aNewData.mBackfaceVisibility) {
+    transformHint |= nsChangeHint_RepaintFrame;
+  }
+
+  return transformHint;
+}
+
 // --------------------
 // nsStyleVisibility
 //

layout/style/nsStyleStruct.h

@@ -1191,6 +1191,9 @@ struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleDisplay {
   nsChangeHint CalcDifference(const nsStyleDisplay& aNewData,
                               const nsStylePosition& aOldPosition) const;
 
+  nsChangeHint CalcTransformPropertyDifference(
+      const nsStyleDisplay& aNewData) const;
+
   nsStyleAutoArray<mozilla::StyleTransition> mTransitions;
   // The number of elements in mTransitions that are not from repeating
   // a list due to another property being longer.