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+/* -*- 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 DOM_SMIL_SMILCOMPOSITOR_H_
+#define DOM_SMIL_SMILCOMPOSITOR_H_
+
+#include <utility>
+
+#include "PLDHashTable.h"
+#include "SMILTargetIdentifier.h"
+#include "mozilla/SMILAnimationFunction.h"
+#include "mozilla/SMILCompositorTable.h"
+#include "mozilla/UniquePtr.h"
+#include "nsCSSPropertyID.h"
+#include "nsString.h"
+#include "nsTHashtable.h"
+
+namespace mozilla {
+
+class ComputedStyle;
+
+//----------------------------------------------------------------------
+// SMILCompositor
+//
+// Performs the composition of the animation sandwich by combining the results
+// of a series animation functions according to the rules of SMIL composition
+// including prioritising animations.
+
+class SMILCompositor : public PLDHashEntryHdr {
+ public:
+ using KeyType = SMILTargetIdentifier;
+ using KeyTypeRef = const KeyType&;
+ using KeyTypePointer = const KeyType*;
+
+ explicit SMILCompositor(KeyTypePointer aKey)
+ : mKey(*aKey), mForceCompositing(false) {}
+ SMILCompositor(SMILCompositor&& toMove) noexcept
+ : PLDHashEntryHdr(std::move(toMove)),
+ mKey(std::move(toMove.mKey)),
+ mAnimationFunctions(std::move(toMove.mAnimationFunctions)),
+ mForceCompositing(false) {}
+
+ // PLDHashEntryHdr methods
+ KeyTypeRef GetKey() const { return mKey; }
+ bool KeyEquals(KeyTypePointer aKey) const;
+ static KeyTypePointer KeyToPointer(KeyTypeRef aKey) { return &aKey; }
+ static PLDHashNumber HashKey(KeyTypePointer aKey);
+ enum { ALLOW_MEMMOVE = false };
+
+ // Adds the given animation function to this Compositor's list of functions
+ void AddAnimationFunction(SMILAnimationFunction* aFunc);
+
+ // Composes the attribute's current value with the list of animation
+ // functions, and assigns the resulting value to this compositor's target
+ // attribute. If a change is made that might produce style updates,
+ // aMightHavePendingStyleUpdates is set to true. Otherwise it is not modified.
+ void ComposeAttribute(bool& aMightHavePendingStyleUpdates);
+
+ // Clears animation effects on my target attribute
+ void ClearAnimationEffects();
+
+ // Cycle-collection support
+ void Traverse(nsCycleCollectionTraversalCallback* aCallback);
+
+ // Toggles a bit that will force us to composite (bypassing early-return
+ // optimizations) when we hit ComposeAttribute.
+ void ToggleForceCompositing() { mForceCompositing = true; }
+
+ // Transfers |aOther|'s mCachedBaseValue to |this|
+ void StealCachedBaseValue(SMILCompositor* aOther) {
+ mCachedBaseValue = std::move(aOther->mCachedBaseValue);
+ }
+
+ private:
+ // Create a SMILAttr for my target, on the heap.
+ //
+ // @param aBaseComputedStyle An optional ComputedStyle which, if set, will be
+ // used when fetching the base style.
+ UniquePtr<SMILAttr> CreateSMILAttr(const ComputedStyle* aBaseComputedStyle);
+
+ // Returns the CSS property this compositor should animate, or
+ // eCSSProperty_UNKNOWN if this compositor does not animate a CSS property.
+ nsCSSPropertyID GetCSSPropertyToAnimate() const;
+
+ // Returns true if we might need to refer to base styles (i.e. we are
+ // targeting a CSS property and have one or more animation functions that
+ // don't just replace the underlying value).
+ //
+ // This might return true in some cases where we don't actually need the base
+ // style since it doesn't build up the animation sandwich to check if the
+ // functions that appear to need the base style are actually replaced by
+ // a function further up the stack.
+ bool MightNeedBaseStyle() const;
+
+ // Finds the index of the first function that will affect our animation
+ // sandwich. Also toggles the 'mForceCompositing' flag if it finds that any
+ // (used) functions have changed.
+ uint32_t GetFirstFuncToAffectSandwich();
+
+ // If the passed-in base value differs from our cached base value, this
+ // method updates the cached value (and toggles the 'mForceCompositing' flag)
+ void UpdateCachedBaseValue(const SMILValue& aBaseValue);
+
+ // The hash key (tuple of element and attributeName)
+ KeyType mKey;
+
+ // Hash Value: List of animation functions that animate the specified attr
+ nsTArray<SMILAnimationFunction*> mAnimationFunctions;
+
+ // Member data for detecting when we need to force-recompose
+ // ---------------------------------------------------------
+ // Flag for tracking whether we need to compose. Initialized to false, but
+ // gets flipped to true if we detect that something has changed.
+ bool mForceCompositing;
+
+ // Cached base value, so we can detect & force-recompose when it changes
+ // from one sample to the next. (SMILAnimationController moves this
+ // forward from the previous sample's compositor by calling
+ // StealCachedBaseValue.)
+ SMILValue mCachedBaseValue;
+};
+
+} // namespace mozilla
+
+#endif // DOM_SMIL_SMILCOMPOSITOR_H_