/* -*- 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 "nsSMILCompositor.h"

#include "nsComputedDOMStyle.h"

#include "nsCSSProps.h"

#include "nsHashKeys.h"

#include "nsSMILCSSProperty.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());

}

// 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(bool& aMightHavePendingStyleUpdates)

{

  if (!mKey.mElement)

    return;

  // If we might need to resolve base styles, grab a suitable ComputedStyle

  // for initializing our nsISMILAttr with.

  RefPtr<ComputedStyle> baseComputedStyle;

  if (MightNeedBaseStyle()) {

    baseComputedStyle =

      nsComputedDOMStyle::GetUnanimatedComputedStyleNoFlush(mKey.mElement,

                                                            nullptr);

  }

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

  // give animated value to)

  UniquePtr<nsISMILAttr> smilAttr = CreateSMILAttr(baseComputedStyle);

  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();

    // Removing the animation effect may require a style update.

    aMightHavePendingStyleUpdates = true;

    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

  aMightHavePendingStyleUpdates = true;

  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;

  UniquePtr<nsISMILAttr> smilAttr = CreateSMILAttr(nullptr);

  if (!smilAttr) {

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

    return;

  }

  smilAttr->ClearAnimValue();

}

// Protected Helper Functions

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

UniquePtr<nsISMILAttr>

nsSMILCompositor::CreateSMILAttr(ComputedStyle* aBaseComputedStyle)

{

  nsCSSPropertyID propID = GetCSSPropertyToAnimate();

  if (propID != eCSSProperty_UNKNOWN) {

    return MakeUnique<nsSMILCSSProperty>(propID, mKey.mElement.get(),

                                         aBaseComputedStyle);

  }

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

                                        mKey.mAttributeName);

}

nsCSSPropertyID

nsSMILCompositor::GetCSSPropertyToAnimate() const

{

  if (mKey.mAttributeNamespaceID != kNameSpaceID_None) {

    return eCSSProperty_UNKNOWN;

  }

  nsCSSPropertyID propID =

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

  if (!nsSMILCSSProperty::IsPropertyAnimatable(propID)) {

    return eCSSProperty_UNKNOWN;

  }

  // If we are animating the 'width' or 'height' of an outer SVG

  // element we should animate it as a CSS property, but for other elements

  // (e.g. <rect>) we should animate it as a length attribute.

  // The easiest way to test for an outer SVG element, is to see if it is an

  // SVG-namespace element mapping its width/height attribute to style.

  //

  // If we have animation of 'width' or 'height' on an SVG element that is

  // NOT mapping that attributes to style then it must not be an outermost SVG

  // element so we should return eCSSProperty_UNKNOWN to indicate that we

  // should animate as an attribute instead.

  if ((mKey.mAttributeName == nsGkAtoms::width ||

       mKey.mAttributeName == nsGkAtoms::height) &&

      mKey.mElement->GetNameSpaceID() == kNameSpaceID_SVG &&

      !mKey.mElement->IsAttributeMapped(mKey.mAttributeName)) {

    return eCSSProperty_UNKNOWN;

  }

  return propID;

}

bool

nsSMILCompositor::MightNeedBaseStyle() const

{

  if (GetCSSPropertyToAnimate() == eCSSProperty_UNKNOWN) {

    return false;

  }

  // We should return true if at least one animation function might build on

  // the base value.

  for (const nsSMILAnimationFunction* func : mAnimationFunctions) {

    if (!func->WillReplace()) {

      return true;

    }

  }

  return false;

}

uint32_t

nsSMILCompositor::GetFirstFuncToAffectSandwich()

{

  // For performance reasons, we throttle most animations on elements in

  // display:none subtrees. (We can't throttle animations that target the

  // "display" property itself, though -- if we did, display:none elements

  // could never be dynamically displayed via animations.)

  // To determine whether we're in a display:none subtree, we will check the

  // element's primary frame since element in display:none subtree doesn't have

  // a primary frame. Before this process, we will construct frame when we

  // append an element to subtree. So we will not need to worry about pending

  // frame construction in this step.

  bool canThrottle = mKey.mAttributeName != nsGkAtoms::display &&

                     !mKey.mElement->GetPrimaryFrame();

  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() && !canThrottle) ||

      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 != aBaseValue) {

    // Base value has changed since last sample.

    mCachedBaseValue = aBaseValue;

    mForceCompositing = true;

  }

}