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 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

 /* 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 "nsSMILCompositor.h"

 #include "nsSMILCSSProperty.h"

 #include "nsCSSProps.h"

 #include "nsHashKeys.h"

 // PLDHashEntryHdr methods

 bool

 nsSMILCompositor::KeyEquals(KeyTypePointer aKey) const

 {

   return aKey && aKey->Equals(mKey);

 }

 /*static*/ PLDHashNumber

 nsSMILCompositor::HashKey(KeyTypePointer aKey)

 {

   // Combine the 3 values into one numeric value, which will be hashed.

   // NOTE: We right-shift one of the pointers by 2 to get some randomness in

   // its 2 lowest-order bits. (Those shifted-off bits will always be 0 since

   // our pointers will be word-aligned.)

   return (NS_PTR_TO_UINT32(aKey->mElement.get()) >> 2) +

     NS_PTR_TO_UINT32(aKey->mAttributeName.get()) +

     (aKey->mIsCSS ? 1 : 0);

 }

 // Cycle-collection support

 void

 nsSMILCompositor::Traverse(nsCycleCollectionTraversalCallback* aCallback)

 {

   if (!mKey.mElement)

     return;

   NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(*aCallback, "Compositor mKey.mElement");

   aCallback->NoteXPCOMChild(mKey.mElement);

 }

 // Other methods

 void

 nsSMILCompositor::AddAnimationFunction(nsSMILAnimationFunction* aFunc)

 {

   if (aFunc) {

     mAnimationFunctions.AppendElement(aFunc);

   }

 }

 void

 nsSMILCompositor::ComposeAttribute()

 {

   if (!mKey.mElement)

     return;

   // FIRST: Get the nsISMILAttr (to grab base value from, and to eventually

   // give animated value to)

   nsAutoPtr<nsISMILAttr> smilAttr(CreateSMILAttr());

   if (!smilAttr) {

     // Target attribute not found (or, out of memory)

     return;

   }

   if (mAnimationFunctions.IsEmpty()) {

     // No active animation functions. (We can still have a nsSMILCompositor in

     // that case if an animation function has *just* become inactive)

     smilAttr->ClearAnimValue();

     return;

   }

   // SECOND: Sort the animationFunctions, to prepare for compositing.

   nsSMILAnimationFunction::Comparator comparator;

   mAnimationFunctions.Sort(comparator);

   // THIRD: Step backwards through animation functions to find out

   // which ones we actually care about.

   uint32_t firstFuncToCompose = GetFirstFuncToAffectSandwich();

   // FOURTH: Get & cache base value

   nsSMILValue sandwichResultValue;

   if (!mAnimationFunctions[firstFuncToCompose]->WillReplace()) {

     sandwichResultValue = smilAttr->GetBaseValue();

   }

   UpdateCachedBaseValue(sandwichResultValue);

   if (!mForceCompositing) {

     return;

   }

   // FIFTH: Compose animation functions

   uint32_t length = mAnimationFunctions.Length();

   for (uint32_t i = firstFuncToCompose; i < length; ++i) {

     mAnimationFunctions[i]->ComposeResult(*smilAttr, sandwichResultValue);

   }

   if (sandwichResultValue.IsNull()) {

     smilAttr->ClearAnimValue();

     return;

   }

   // SIXTH: Set the animated value to the final composited result.

   nsresult rv = smilAttr->SetAnimValue(sandwichResultValue);

   if (NS_FAILED(rv)) {

     NS_WARNING("nsISMILAttr::SetAnimValue failed");

   }

 }

 void

 nsSMILCompositor::ClearAnimationEffects()

 {

   if (!mKey.mElement || !mKey.mAttributeName)

     return;

   nsAutoPtr<nsISMILAttr> smilAttr(CreateSMILAttr());

   if (!smilAttr) {

     // Target attribute not found (or, out of memory)

     return;

   }

   smilAttr->ClearAnimValue();

 }

 // Protected Helper Functions

 // --------------------------

 nsISMILAttr*

 nsSMILCompositor::CreateSMILAttr()

 {

   if (mKey.mIsCSS) {

     nsCSSProperty propId =

       nsCSSProps::LookupProperty(nsDependentAtomString(mKey.mAttributeName),

                                  nsCSSProps::eEnabledForAllContent);

     if (nsSMILCSSProperty::IsPropertyAnimatable(propId)) {

       return new nsSMILCSSProperty(propId, mKey.mElement.get());

     }

   } else {

     return mKey.mElement->GetAnimatedAttr(mKey.mAttributeNamespaceID,

                                           mKey.mAttributeName);

   }

   return nullptr;

 }

 uint32_t

 nsSMILCompositor::GetFirstFuncToAffectSandwich()

 {

   uint32_t i;

   for (i = mAnimationFunctions.Length(); i > 0; --i) {

     nsSMILAnimationFunction* curAnimFunc = mAnimationFunctions[i-1];

     // In the following, the lack of short-circuit behavior of |= means that we

     // will ALWAYS run UpdateCachedTarget (even if mForceCompositing is true)

     // but only call HasChanged and WasSkippedInPrevSample if necessary.  This

     // is important since we need UpdateCachedTarget to run in order to detect

     // changes to the target in subsequent samples.

     mForceCompositing |=

       curAnimFunc->UpdateCachedTarget(mKey) ||

       curAnimFunc->HasChanged() ||

       curAnimFunc->WasSkippedInPrevSample();

     if (curAnimFunc->WillReplace()) {

       --i;

       break;

     }

   }

   // Mark remaining animation functions as having been skipped so if we later

   // use them we'll know to force compositing.

   // Note that we only really need to do this if something has changed

   // (otherwise we would have set the flag on a previous sample) and if

   // something has changed mForceCompositing will be true.

   if (mForceCompositing) {

     for (uint32_t j = i; j > 0; --j) {

       mAnimationFunctions[j-1]->SetWasSkipped();

     }

   }

   return i;

 }

 void

 nsSMILCompositor::UpdateCachedBaseValue(const nsSMILValue& aBaseValue)

 {

   if (!mCachedBaseValue) {

     // We don't have last sample's base value cached. Assume it's changed.

     mCachedBaseValue = new nsSMILValue(aBaseValue);

     NS_WARN_IF_FALSE(mCachedBaseValue, "failed to cache base value (OOM?)");

     mForceCompositing = true;

   } else if (*mCachedBaseValue != aBaseValue) {

     // Base value has changed since last sample.

     *mCachedBaseValue = aBaseValue;

     mForceCompositing = true;

   }

 }