dom/smil/SMILAnimationFunction.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "SMILAnimationFunction.h"
   8
   9 #include <math.h>
  10
  11 #include <algorithm>
  12 #include <utility>
  13
  14 #include "mozilla/DebugOnly.h"
  15 #include "mozilla/SMILAttr.h"
  16 #include "mozilla/SMILCSSValueType.h"
  17 #include "mozilla/SMILNullType.h"
  18 #include "mozilla/SMILParserUtils.h"
  19 #include "mozilla/SMILTimedElement.h"
  20 #include "mozilla/dom/SVGAnimationElement.h"
  21 #include "nsAttrValueInlines.h"
  22 #include "nsCOMArray.h"
  23 #include "nsCOMPtr.h"
  24 #include "nsContentUtils.h"
  25 #include "nsGkAtoms.h"
  26 #include "nsIContent.h"
  27 #include "nsReadableUtils.h"
  28 #include "nsString.h"
  29
  30 using namespace mozilla::dom;
  31
  32 namespace mozilla {
  33
  34 //----------------------------------------------------------------------
  35 // Static members
  36
  37 nsAttrValue::EnumTable SMILAnimationFunction::sAccumulateTable[] = {
  38     {"none", false}, {"sum", true}, {nullptr, 0}};
  39
  40 nsAttrValue::EnumTable SMILAnimationFunction::sAdditiveTable[] = {
  41     {"replace", false}, {"sum", true}, {nullptr, 0}};
  42
  43 nsAttrValue::EnumTable SMILAnimationFunction::sCalcModeTable[] = {
  44     {"linear", CALC_LINEAR},
  45     {"discrete", CALC_DISCRETE},
  46     {"paced", CALC_PACED},
  47     {"spline", CALC_SPLINE},
  48     {nullptr, 0}};
  49
  50 // Any negative number should be fine as a sentinel here,
  51 // because valid distances are non-negative.
  52 #define COMPUTE_DISTANCE_ERROR (-1)
  53
  54 //----------------------------------------------------------------------
  55 // Constructors etc.
  56
  57 SMILAnimationFunction::SMILAnimationFunction()
  58     : mSampleTime(-1),
  59       mRepeatIteration(0),
  60       mBeginTime(INT64_MIN),
  61       mAnimationElement(nullptr),
  62       mErrorFlags(0),
  63       mIsActive(false),
  64       mIsFrozen(false),
  65       mLastValue(false),
  66       mHasChanged(true),
  67       mValueNeedsReparsingEverySample(false),
  68       mPrevSampleWasSingleValueAnimation(false),
  69       mWasSkippedInPrevSample(false) {}
  70
  71 void SMILAnimationFunction::SetAnimationElement(
  72     SVGAnimationElement* aAnimationElement) {
  73   mAnimationElement = aAnimationElement;
  74 }
  75
  76 bool SMILAnimationFunction::SetAttr(nsAtom* aAttribute, const nsAString& aValue,
  77                                     nsAttrValue& aResult,
  78                                     nsresult* aParseResult) {
  79   // Some elements such as set and discard don't support all possible attributes
  80   if (IsDisallowedAttribute(aAttribute)) {
  81     aResult.SetTo(aValue);
  82     if (aParseResult) {
  83       *aParseResult = NS_OK;
  84     }
  85     return true;
  86   }
  87
  88   bool foundMatch = true;
  89   nsresult parseResult = NS_OK;
  90
  91   // The attributes 'by', 'from', 'to', and 'values' may be parsed differently
  92   // depending on the element & attribute we're animating.  So instead of
  93   // parsing them now we re-parse them at every sample.
  94   if (aAttribute == nsGkAtoms::by || aAttribute == nsGkAtoms::from ||
  95       aAttribute == nsGkAtoms::to || aAttribute == nsGkAtoms::values) {
  96     // We parse to, from, by, values at sample time.
  97     // XXX Need to flag which attribute has changed and then when we parse it at
  98     // sample time, report any errors and reset the flag
  99     mHasChanged = true;
 100     aResult.SetTo(aValue);
 101   } else if (aAttribute == nsGkAtoms::accumulate) {
 102     parseResult = SetAccumulate(aValue, aResult);
 103   } else if (aAttribute == nsGkAtoms::additive) {
 104     parseResult = SetAdditive(aValue, aResult);
 105   } else if (aAttribute == nsGkAtoms::calcMode) {
 106     parseResult = SetCalcMode(aValue, aResult);
 107   } else if (aAttribute == nsGkAtoms::keyTimes) {
 108     parseResult = SetKeyTimes(aValue, aResult);
 109   } else if (aAttribute == nsGkAtoms::keySplines) {
 110     parseResult = SetKeySplines(aValue, aResult);
 111   } else {
 112     foundMatch = false;
 113   }
 114
 115   if (foundMatch && aParseResult) {
 116     *aParseResult = parseResult;
 117   }
 118
 119   return foundMatch;
 120 }
 121
 122 bool SMILAnimationFunction::UnsetAttr(nsAtom* aAttribute) {
 123   if (IsDisallowedAttribute(aAttribute)) {
 124     return true;
 125   }
 126
 127   bool foundMatch = true;
 128
 129   if (aAttribute == nsGkAtoms::by || aAttribute == nsGkAtoms::from ||
 130       aAttribute == nsGkAtoms::to || aAttribute == nsGkAtoms::values) {
 131     mHasChanged = true;
 132   } else if (aAttribute == nsGkAtoms::accumulate) {
 133     UnsetAccumulate();
 134   } else if (aAttribute == nsGkAtoms::additive) {
 135     UnsetAdditive();
 136   } else if (aAttribute == nsGkAtoms::calcMode) {
 137     UnsetCalcMode();
 138   } else if (aAttribute == nsGkAtoms::keyTimes) {
 139     UnsetKeyTimes();
 140   } else if (aAttribute == nsGkAtoms::keySplines) {
 141     UnsetKeySplines();
 142   } else {
 143     foundMatch = false;
 144   }
 145
 146   return foundMatch;
 147 }
 148
 149 void SMILAnimationFunction::SampleAt(SMILTime aSampleTime,
 150                                      const SMILTimeValue& aSimpleDuration,
 151                                      uint32_t aRepeatIteration) {
 152   // * Update mHasChanged ("Might this sample be different from prev one?")
 153   // Were we previously sampling a fill="freeze" final val? (We're not anymore.)
 154   mHasChanged |= mLastValue;
 155
 156   // Are we sampling at a new point in simple duration? And does that matter?
 157   mHasChanged |=
 158       (mSampleTime != aSampleTime || mSimpleDuration != aSimpleDuration) &&
 159       !IsValueFixedForSimpleDuration();
 160
 161   // Are we on a new repeat and accumulating across repeats?
 162   if (!mErrorFlags) {  // (can't call GetAccumulate() if we've had parse errors)
 163     mHasChanged |= (mRepeatIteration != aRepeatIteration) && GetAccumulate();
 164   }
 165
 166   mSampleTime = aSampleTime;
 167   mSimpleDuration = aSimpleDuration;
 168   mRepeatIteration = aRepeatIteration;
 169   mLastValue = false;
 170 }
 171
 172 void SMILAnimationFunction::SampleLastValue(uint32_t aRepeatIteration) {
 173   if (!mLastValue || mRepeatIteration != aRepeatIteration) {
 174     mHasChanged = true;
 175   }
 176
 177   mRepeatIteration = aRepeatIteration;
 178   mLastValue = true;
 179 }
 180
 181 void SMILAnimationFunction::Activate(SMILTime aBeginTime) {
 182   mBeginTime = aBeginTime;
 183   mIsActive = true;
 184   mIsFrozen = false;
 185   mHasChanged = true;
 186 }
 187
 188 void SMILAnimationFunction::Inactivate(bool aIsFrozen) {
 189   mIsActive = false;
 190   mIsFrozen = aIsFrozen;
 191   mHasChanged = true;
 192 }
 193
 194 void SMILAnimationFunction::ComposeResult(const SMILAttr& aSMILAttr,
 195                                           SMILValue& aResult) {
 196   mHasChanged = false;
 197   mPrevSampleWasSingleValueAnimation = false;
 198   mWasSkippedInPrevSample = false;
 199
 200   // Skip animations that are inactive or in error
 201   if (!IsActiveOrFrozen() || mErrorFlags != 0) return;
 202
 203   // Get the animation values
 204   SMILValueArray values;
 205   nsresult rv = GetValues(aSMILAttr, values);
 206   if (NS_FAILED(rv)) return;
 207
 208   // Check that we have the right number of keySplines and keyTimes
 209   CheckValueListDependentAttrs(values.Length());
 210   if (mErrorFlags != 0) return;
 211
 212   // If this interval is active, we must have a non-negative mSampleTime
 213   MOZ_ASSERT(mSampleTime >= 0 || !mIsActive,
 214              "Negative sample time for active animation");
 215   MOZ_ASSERT(mSimpleDuration.IsResolved() || mLastValue,
 216              "Unresolved simple duration for active or frozen animation");
 217
 218   // If we want to add but don't have a base value then just fail outright.
 219   // This can happen when we skipped getting the base value because there's an
 220   // animation function in the sandwich that should replace it but that function
 221   // failed unexpectedly.
 222   bool isAdditive = IsAdditive();
 223   if (isAdditive && aResult.IsNull()) return;
 224
 225   SMILValue result;
 226
 227   if (values.Length() == 1 && !IsToAnimation()) {
 228     // Single-valued animation
 229     result = values[0];
 230     mPrevSampleWasSingleValueAnimation = true;
 231
 232   } else if (mLastValue) {
 233     // Sampling last value
 234     const SMILValue& last = values.LastElement();
 235     result = last;
 236
 237     // See comment in AccumulateResult: to-animation does not accumulate
 238     if (!IsToAnimation() && GetAccumulate() && mRepeatIteration) {
 239       // If the target attribute type doesn't support addition Add will
 240       // fail leaving result = last
 241       result.Add(last, mRepeatIteration);
 242     }
 243
 244   } else {
 245     // Interpolation
 246     if (NS_FAILED(InterpolateResult(values, result, aResult))) return;
 247
 248     if (NS_FAILED(AccumulateResult(values, result))) return;
 249   }
 250
 251   // If additive animation isn't required or isn't supported, set the value.
 252   if (!isAdditive || NS_FAILED(aResult.SandwichAdd(result))) {
 253     aResult = std::move(result);
 254   }
 255 }
 256
 257 int8_t SMILAnimationFunction::CompareTo(
 258     const SMILAnimationFunction* aOther) const {
 259   NS_ENSURE_TRUE(aOther, 0);
 260
 261   NS_ASSERTION(aOther != this, "Trying to compare to self");
 262
 263   // Inactive animations sort first
 264   if (!IsActiveOrFrozen() && aOther->IsActiveOrFrozen()) return -1;
 265
 266   if (IsActiveOrFrozen() && !aOther->IsActiveOrFrozen()) return 1;
 267
 268   // Sort based on begin time
 269   if (mBeginTime != aOther->GetBeginTime())
 270     return mBeginTime > aOther->GetBeginTime() ? 1 : -1;
 271
 272   // Next sort based on syncbase dependencies: the dependent element sorts after
 273   // its syncbase
 274   const SMILTimedElement& thisTimedElement = mAnimationElement->TimedElement();
 275   const SMILTimedElement& otherTimedElement =
 276       aOther->mAnimationElement->TimedElement();
 277   if (thisTimedElement.IsTimeDependent(otherTimedElement)) return 1;
 278   if (otherTimedElement.IsTimeDependent(thisTimedElement)) return -1;
 279
 280   // Animations that appear later in the document sort after those earlier in
 281   // the document
 282   MOZ_ASSERT(mAnimationElement != aOther->mAnimationElement,
 283              "Two animations cannot have the same animation content element!");
 284
 285   return (nsContentUtils::PositionIsBefore(mAnimationElement,
 286                                            aOther->mAnimationElement))
 287              ? -1
 288              : 1;
 289 }
 290
 291 bool SMILAnimationFunction::WillReplace() const {
 292   /*
 293    * In IsAdditive() we don't consider to-animation to be additive as it is
 294    * a special case that is dealt with differently in the compositing method.
 295    * Here, however, we return FALSE for to-animation (i.e. it will NOT replace
 296    * the underlying value) as it builds on the underlying value.
 297    */
 298   return !mErrorFlags && !(IsAdditive() || IsToAnimation());
 299 }
 300
 301 bool SMILAnimationFunction::HasChanged() const {
 302   return mHasChanged || mValueNeedsReparsingEverySample;
 303 }
 304
 305 bool SMILAnimationFunction::UpdateCachedTarget(
 306     const SMILTargetIdentifier& aNewTarget) {
 307   if (!mLastTarget.Equals(aNewTarget)) {
 308     mLastTarget = aNewTarget;
 309     return true;
 310   }
 311   return false;
 312 }
 313
 314 //----------------------------------------------------------------------
 315 // Implementation helpers
 316
 317 nsresult SMILAnimationFunction::InterpolateResult(const SMILValueArray& aValues,
 318                                                   SMILValue& aResult,
 319                                                   SMILValue& aBaseValue) {
 320   // Sanity check animation values
 321   if ((!IsToAnimation() && aValues.Length() < 2) ||
 322       (IsToAnimation() && aValues.Length() != 1)) {
 323     NS_ERROR("Unexpected number of values");
 324     return NS_ERROR_FAILURE;
 325   }
 326
 327   if (IsToAnimation() && aBaseValue.IsNull()) {
 328     return NS_ERROR_FAILURE;
 329   }
 330
 331   // Get the normalised progress through the simple duration.
 332   //
 333   // If we have an indefinite simple duration, just set the progress to be
 334   // 0 which will give us the expected behaviour of the animation being fixed at
 335   // its starting point.
 336   double simpleProgress = 0.0;
 337
 338   if (mSimpleDuration.IsDefinite()) {
 339     SMILTime dur = mSimpleDuration.GetMillis();
 340
 341     MOZ_ASSERT(dur >= 0, "Simple duration should not be negative");
 342     MOZ_ASSERT(mSampleTime >= 0, "Sample time should not be negative");
 343
 344     if (mSampleTime >= dur || mSampleTime < 0) {
 345       NS_ERROR("Animation sampled outside interval");
 346       return NS_ERROR_FAILURE;
 347     }
 348
 349     if (dur > 0) {
 350       simpleProgress = (double)mSampleTime / dur;
 351     }  // else leave simpleProgress at 0.0 (e.g. if mSampleTime == dur == 0)
 352   }
 353
 354   nsresult rv = NS_OK;
 355   SMILCalcMode calcMode = GetCalcMode();
 356
 357   // Force discrete calcMode for visibility since StyleAnimationValue will
 358   // try to interpolate it using the special clamping behavior defined for
 359   // CSS.
 360   if (SMILCSSValueType::PropertyFromValue(aValues[0]) ==
 361       eCSSProperty_visibility) {
 362     calcMode = CALC_DISCRETE;
 363   }
 364
 365   if (calcMode != CALC_DISCRETE) {
 366     // Get the normalised progress between adjacent values
 367     const SMILValue* from = nullptr;
 368     const SMILValue* to = nullptr;
 369     // Init to -1 to make sure that if we ever forget to set this, the
 370     // MOZ_ASSERT that tests that intervalProgress is in range will fail.
 371     double intervalProgress = -1.f;
 372     if (IsToAnimation()) {
 373       from = &aBaseValue;
 374       to = &aValues[0];
 375       if (calcMode == CALC_PACED) {
 376         // Note: key[Times/Splines/Points] are ignored for calcMode="paced"
 377         intervalProgress = simpleProgress;
 378       } else {
 379         double scaledSimpleProgress =
 380             ScaleSimpleProgress(simpleProgress, calcMode);
 381         intervalProgress = ScaleIntervalProgress(scaledSimpleProgress, 0);
 382       }
 383     } else if (calcMode == CALC_PACED) {
 384       rv = ComputePacedPosition(aValues, simpleProgress, intervalProgress, from,
 385                                 to);
 386       // Note: If the above call fails, we'll skip the "from->Interpolate"
 387       // call below, and we'll drop into the CALC_DISCRETE section
 388       // instead. (as the spec says we should, because our failure was
 389       // presumably due to the values being non-additive)
 390     } else {  // calcMode == CALC_LINEAR or calcMode == CALC_SPLINE
 391       double scaledSimpleProgress =
 392           ScaleSimpleProgress(simpleProgress, calcMode);
 393       uint32_t index =
 394           (uint32_t)floor(scaledSimpleProgress * (aValues.Length() - 1));
 395       from = &aValues[index];
 396       to = &aValues[index + 1];
 397       intervalProgress = scaledSimpleProgress * (aValues.Length() - 1) - index;
 398       intervalProgress = ScaleIntervalProgress(intervalProgress, index);
 399     }
 400
 401     if (NS_SUCCEEDED(rv)) {
 402       MOZ_ASSERT(from, "NULL from-value during interpolation");
 403       MOZ_ASSERT(to, "NULL to-value during interpolation");
 404       MOZ_ASSERT(0.0f <= intervalProgress && intervalProgress < 1.0f,
 405                  "Interval progress should be in the range [0, 1)");
 406       rv = from->Interpolate(*to, intervalProgress, aResult);
 407     }
 408   }
 409
 410   // Discrete-CalcMode case
 411   // Note: If interpolation failed (isn't supported for this type), the SVG
 412   // spec says to force discrete mode.
 413   if (calcMode == CALC_DISCRETE || NS_FAILED(rv)) {
 414     double scaledSimpleProgress =
 415         ScaleSimpleProgress(simpleProgress, CALC_DISCRETE);
 416
 417     // Floating-point errors can mean that, for example, a sample time of 29s in
 418     // a 100s duration animation gives us a simple progress of 0.28999999999
 419     // instead of the 0.29 we'd expect. Normally this isn't a noticeable
 420     // problem, but when we have sudden jumps in animation values (such as is
 421     // the case here with discrete animation) we can get unexpected results.
 422     //
 423     // To counteract this, before we perform a floor() on the animation
 424     // progress, we add a tiny fudge factor to push us into the correct interval
 425     // in cases where floating-point errors might cause us to fall short.
 426     static const double kFloatingPointFudgeFactor = 1.0e-16;
 427     if (scaledSimpleProgress + kFloatingPointFudgeFactor <= 1.0) {
 428       scaledSimpleProgress += kFloatingPointFudgeFactor;
 429     }
 430
 431     if (IsToAnimation()) {
 432       // We don't follow SMIL 3, 12.6.4, where discrete to animations
 433       // are the same as <set> animations.  Instead, we treat it as a
 434       // discrete animation with two values (the underlying value and
 435       // the to="" value), and honor keyTimes="" as well.
 436       uint32_t index = (uint32_t)floor(scaledSimpleProgress * 2);
 437       aResult = index == 0 ? aBaseValue : aValues[0];
 438     } else {
 439       uint32_t index = (uint32_t)floor(scaledSimpleProgress * aValues.Length());
 440       aResult = aValues[index];
 441
 442       // For animation of CSS properties, normally when interpolating we perform
 443       // a zero-value fixup which means that empty values (values with type
 444       // SMILCSSValueType but a null pointer value) are converted into
 445       // a suitable zero value based on whatever they're being interpolated
 446       // with. For discrete animation, however, since we don't interpolate,
 447       // that never happens. In some rare cases, such as discrete non-additive
 448       // by-animation, we can arrive here with |aResult| being such an empty
 449       // value so we need to manually perform the fixup.
 450       //
 451       // We could define a generic method for this on SMILValue but its faster
 452       // and simpler to just special case SMILCSSValueType.
 453       if (aResult.mType == &SMILCSSValueType::sSingleton) {
 454         // We have currently only ever encountered this case for the first
 455         // value of a by-animation (which has two values) and since we have no
 456         // way of testing other cases we just skip them (but assert if we
 457         // ever do encounter them so that we can add code to handle them).
 458         if (index + 1 >= aValues.Length()) {
 459           MOZ_ASSERT(aResult.mU.mPtr, "The last value should not be empty");
 460         } else {
 461           // Base the type of the zero value on the next element in the series.
 462           SMILCSSValueType::FinalizeValue(aResult, aValues[index + 1]);
 463         }
 464       }
 465     }
 466     rv = NS_OK;
 467   }
 468   return rv;
 469 }
 470
 471 nsresult SMILAnimationFunction::AccumulateResult(const SMILValueArray& aValues,
 472                                                  SMILValue& aResult) {
 473   if (!IsToAnimation() && GetAccumulate() && mRepeatIteration) {
 474     // If the target attribute type doesn't support addition, Add will
 475     // fail and we leave aResult untouched.
 476     aResult.Add(aValues.LastElement(), mRepeatIteration);
 477   }
 478
 479   return NS_OK;
 480 }
 481
 482 /*
 483  * Given the simple progress for a paced animation, this method:
 484  *  - determines which two elements of the values array we're in between
 485  *    (returned as aFrom and aTo)
 486  *  - determines where we are between them
 487  *    (returned as aIntervalProgress)
 488  *
 489  * Returns NS_OK, or NS_ERROR_FAILURE if our values don't support distance
 490  * computation.
 491  */
 492 nsresult SMILAnimationFunction::ComputePacedPosition(
 493     const SMILValueArray& aValues, double aSimpleProgress,
 494     double& aIntervalProgress, const SMILValue*& aFrom, const SMILValue*& aTo) {
 495   NS_ASSERTION(0.0f <= aSimpleProgress && aSimpleProgress < 1.0f,
 496                "aSimpleProgress is out of bounds");
 497   NS_ASSERTION(GetCalcMode() == CALC_PACED,
 498                "Calling paced-specific function, but not in paced mode");
 499   MOZ_ASSERT(aValues.Length() >= 2, "Unexpected number of values");
 500
 501   // Trivial case: If we have just 2 values, then there's only one interval
 502   // for us to traverse, and our progress across that interval is the exact
 503   // same as our overall progress.
 504   if (aValues.Length() == 2) {
 505     aIntervalProgress = aSimpleProgress;
 506     aFrom = &aValues[0];
 507     aTo = &aValues[1];
 508     return NS_OK;
 509   }
 510
 511   double totalDistance = ComputePacedTotalDistance(aValues);
 512   if (totalDistance == COMPUTE_DISTANCE_ERROR) return NS_ERROR_FAILURE;
 513
 514   // If we have 0 total distance, then it's unclear where our "paced" position
 515   // should be.  We can just fail, which drops us into discrete animation mode.
 516   // (That's fine, since our values are apparently indistinguishable anyway.)
 517   if (totalDistance == 0.0) {
 518     return NS_ERROR_FAILURE;
 519   }
 520
 521   // total distance we should have moved at this point in time.
 522   // (called 'remainingDist' due to how it's used in loop below)
 523   double remainingDist = aSimpleProgress * totalDistance;
 524
 525   // Must be satisfied, because totalDistance is a sum of (non-negative)
 526   // distances, and aSimpleProgress is non-negative
 527   NS_ASSERTION(remainingDist >= 0, "distance values must be non-negative");
 528
 529   // Find where remainingDist puts us in the list of values
 530   // Note: We could optimize this next loop by caching the
 531   // interval-distances in an array, but maybe that's excessive.
 532   for (uint32_t i = 0; i < aValues.Length() - 1; i++) {
 533     // Note: The following assertion is valid because remainingDist should
 534     // start out non-negative, and this loop never shaves off more than its
 535     // current value.
 536     NS_ASSERTION(remainingDist >= 0, "distance values must be non-negative");
 537
 538     double curIntervalDist;
 539
 540     DebugOnly<nsresult> rv =
 541         aValues[i].ComputeDistance(aValues[i + 1], curIntervalDist);
 542     MOZ_ASSERT(NS_SUCCEEDED(rv),
 543                "If we got through ComputePacedTotalDistance, we should "
 544                "be able to recompute each sub-distance without errors");
 545
 546     NS_ASSERTION(curIntervalDist >= 0, "distance values must be non-negative");
 547     // Clamp distance value at 0, just in case ComputeDistance is evil.
 548     curIntervalDist = std::max(curIntervalDist, 0.0);
 549
 550     if (remainingDist >= curIntervalDist) {
 551       remainingDist -= curIntervalDist;
 552     } else {
 553       // NOTE: If we get here, then curIntervalDist necessarily is not 0. Why?
 554       // Because this clause is only hit when remainingDist < curIntervalDist,
 555       // and if curIntervalDist were 0, that would mean remainingDist would
 556       // have to be < 0.  But that can't happen, because remainingDist (as
 557       // a distance) is non-negative by definition.
 558       NS_ASSERTION(curIntervalDist != 0,
 559                    "We should never get here with this set to 0...");
 560
 561       // We found the right spot -- an interpolated position between
 562       // values i and i+1.
 563       aFrom = &aValues[i];
 564       aTo = &aValues[i + 1];
 565       aIntervalProgress = remainingDist / curIntervalDist;
 566       return NS_OK;
 567     }
 568   }
 569
 570   MOZ_ASSERT_UNREACHABLE(
 571       "shouldn't complete loop & get here -- if we do, "
 572       "then aSimpleProgress was probably out of bounds");
 573   return NS_ERROR_FAILURE;
 574 }
 575
 576 /*
 577  * Computes the total distance to be travelled by a paced animation.
 578  *
 579  * Returns the total distance, or returns COMPUTE_DISTANCE_ERROR if
 580  * our values don't support distance computation.
 581  */
 582 double SMILAnimationFunction::ComputePacedTotalDistance(
 583     const SMILValueArray& aValues) const {
 584   NS_ASSERTION(GetCalcMode() == CALC_PACED,
 585                "Calling paced-specific function, but not in paced mode");
 586
 587   double totalDistance = 0.0;
 588   for (uint32_t i = 0; i < aValues.Length() - 1; i++) {
 589     double tmpDist;
 590     nsresult rv = aValues[i].ComputeDistance(aValues[i + 1], tmpDist);
 591     if (NS_FAILED(rv)) {
 592       return COMPUTE_DISTANCE_ERROR;
 593     }
 594
 595     // Clamp distance value to 0, just in case we have an evil ComputeDistance
 596     // implementation somewhere
 597     MOZ_ASSERT(tmpDist >= 0.0f, "distance values must be non-negative");
 598     tmpDist = std::max(tmpDist, 0.0);
 599
 600     totalDistance += tmpDist;
 601   }
 602
 603   return totalDistance;
 604 }
 605
 606 double SMILAnimationFunction::ScaleSimpleProgress(double aProgress,
 607                                                   SMILCalcMode aCalcMode) {
 608   if (!HasAttr(nsGkAtoms::keyTimes)) return aProgress;
 609
 610   uint32_t numTimes = mKeyTimes.Length();
 611
 612   if (numTimes < 2) return aProgress;
 613
 614   uint32_t i = 0;
 615   for (; i < numTimes - 2 && aProgress >= mKeyTimes[i + 1]; ++i) {
 616   }
 617
 618   if (aCalcMode == CALC_DISCRETE) {
 619     // discrete calcMode behaviour differs in that each keyTime defines the time
 620     // from when the corresponding value is set, and therefore the last value
 621     // needn't be 1. So check if we're in the last 'interval', that is, the
 622     // space between the final value and 1.0.
 623     if (aProgress >= mKeyTimes[i + 1]) {
 624       MOZ_ASSERT(i == numTimes - 2,
 625                  "aProgress is not in range of the current interval, yet the "
 626                  "current interval is not the last bounded interval either.");
 627       ++i;
 628     }
 629     return (double)i / numTimes;
 630   }
 631
 632   double& intervalStart = mKeyTimes[i];
 633   double& intervalEnd = mKeyTimes[i + 1];
 634
 635   double intervalLength = intervalEnd - intervalStart;
 636   if (intervalLength <= 0.0) return intervalStart;
 637
 638   return (i + (aProgress - intervalStart) / intervalLength) /
 639          double(numTimes - 1);
 640 }
 641
 642 double SMILAnimationFunction::ScaleIntervalProgress(double aProgress,
 643                                                     uint32_t aIntervalIndex) {
 644   if (GetCalcMode() != CALC_SPLINE) return aProgress;
 645
 646   if (!HasAttr(nsGkAtoms::keySplines)) return aProgress;
 647
 648   MOZ_ASSERT(aIntervalIndex < mKeySplines.Length(), "Invalid interval index");
 649
 650   SMILKeySpline const& spline = mKeySplines[aIntervalIndex];
 651   return spline.GetSplineValue(aProgress);
 652 }
 653
 654 bool SMILAnimationFunction::HasAttr(nsAtom* aAttName) const {
 655   if (IsDisallowedAttribute(aAttName)) {
 656     return false;
 657   }
 658   return mAnimationElement->HasAttr(aAttName);
 659 }
 660
 661 const nsAttrValue* SMILAnimationFunction::GetAttr(nsAtom* aAttName) const {
 662   if (IsDisallowedAttribute(aAttName)) {
 663     return nullptr;
 664   }
 665   return mAnimationElement->GetParsedAttr(aAttName);
 666 }
 667
 668 bool SMILAnimationFunction::GetAttr(nsAtom* aAttName,
 669                                     nsAString& aResult) const {
 670   if (IsDisallowedAttribute(aAttName)) {
 671     return false;
 672   }
 673   return mAnimationElement->GetAttr(aAttName, aResult);
 674 }
 675
 676 /*
 677  * A utility function to make querying an attribute that corresponds to an
 678  * SMILValue a little neater.
 679  *
 680  * @param aAttName    The attribute name (in the global namespace).
 681  * @param aSMILAttr   The SMIL attribute to perform the parsing.
 682  * @param[out] aResult        The resulting SMILValue.
 683  * @param[out] aPreventCachingOfSandwich
 684  *                    If |aResult| contains dependencies on its context that
 685  *                    should prevent the result of the animation sandwich from
 686  *                    being cached and reused in future samples (as reported
 687  *                    by SMILAttr::ValueFromString), then this outparam
 688  *                    will be set to true. Otherwise it is left unmodified.
 689  *
 690  * Returns false if a parse error occurred, otherwise returns true.
 691  */
 692 bool SMILAnimationFunction::ParseAttr(nsAtom* aAttName,
 693                                       const SMILAttr& aSMILAttr,
 694                                       SMILValue& aResult,
 695                                       bool& aPreventCachingOfSandwich) const {
 696   nsAutoString attValue;
 697   if (GetAttr(aAttName, attValue)) {
 698     nsresult rv = aSMILAttr.ValueFromString(attValue, mAnimationElement,
 699                                             aResult, aPreventCachingOfSandwich);
 700     if (NS_FAILED(rv)) return false;
 701   }
 702   return true;
 703 }
 704
 705 /*
 706  * SMILANIM specifies the following rules for animation function values:
 707  *
 708  * (1) if values is set, it overrides everything
 709  * (2) for from/to/by animation at least to or by must be specified, from on its
 710  *     own (or nothing) is an error--which we will ignore
 711  * (3) if both by and to are specified only to will be used, by will be ignored
 712  * (4) if by is specified without from (by animation), forces additive behaviour
 713  * (5) if to is specified without from (to animation), special care needs to be
 714  *     taken when compositing animation as such animations are composited last.
 715  *
 716  * This helper method applies these rules to fill in the values list and to set
 717  * some internal state.
 718  */
 719 nsresult SMILAnimationFunction::GetValues(const SMILAttr& aSMILAttr,
 720                                           SMILValueArray& aResult) {
 721   if (!mAnimationElement) return NS_ERROR_FAILURE;
 722
 723   mValueNeedsReparsingEverySample = false;
 724   SMILValueArray result;
 725
 726   // If "values" is set, use it
 727   if (HasAttr(nsGkAtoms::values)) {
 728     nsAutoString attValue;
 729     GetAttr(nsGkAtoms::values, attValue);
 730     bool preventCachingOfSandwich = false;
 731     if (!SMILParserUtils::ParseValues(attValue, mAnimationElement, aSMILAttr,
 732                                       result, preventCachingOfSandwich)) {
 733       return NS_ERROR_FAILURE;
 734     }
 735
 736     if (preventCachingOfSandwich) {
 737       mValueNeedsReparsingEverySample = true;
 738     }
 739     // Else try to/from/by
 740   } else {
 741     bool preventCachingOfSandwich = false;
 742     bool parseOk = true;
 743     SMILValue to, from, by;
 744     parseOk &=
 745         ParseAttr(nsGkAtoms::to, aSMILAttr, to, preventCachingOfSandwich);
 746     parseOk &=
 747         ParseAttr(nsGkAtoms::from, aSMILAttr, from, preventCachingOfSandwich);
 748     parseOk &=
 749         ParseAttr(nsGkAtoms::by, aSMILAttr, by, preventCachingOfSandwich);
 750
 751     if (preventCachingOfSandwich) {
 752       mValueNeedsReparsingEverySample = true;
 753     }
 754
 755     if (!parseOk || !result.SetCapacity(2, fallible)) {
 756       return NS_ERROR_FAILURE;
 757     }
 758
 759     // AppendElement() below must succeed, because SetCapacity() succeeded.
 760     if (!to.IsNull()) {
 761       if (!from.IsNull()) {
 762         MOZ_ALWAYS_TRUE(result.AppendElement(from, fallible));
 763         MOZ_ALWAYS_TRUE(result.AppendElement(to, fallible));
 764       } else {
 765         MOZ_ALWAYS_TRUE(result.AppendElement(to, fallible));
 766       }
 767     } else if (!by.IsNull()) {
 768       SMILValue effectiveFrom(by.mType);
 769       if (!from.IsNull()) effectiveFrom = from;
 770       // Set values to 'from; from + by'
 771       MOZ_ALWAYS_TRUE(result.AppendElement(effectiveFrom, fallible));
 772       SMILValue effectiveTo(effectiveFrom);
 773       if (!effectiveTo.IsNull() && NS_SUCCEEDED(effectiveTo.Add(by))) {
 774         MOZ_ALWAYS_TRUE(result.AppendElement(effectiveTo, fallible));
 775       } else {
 776         // Using by-animation with non-additive type or bad base-value
 777         return NS_ERROR_FAILURE;
 778       }
 779     } else {
 780       // No values, no to, no by -- call it a day
 781       return NS_ERROR_FAILURE;
 782     }
 783   }
 784
 785   aResult = std::move(result);
 786
 787   return NS_OK;
 788 }
 789
 790 void SMILAnimationFunction::CheckValueListDependentAttrs(uint32_t aNumValues) {
 791   CheckKeyTimes(aNumValues);
 792   CheckKeySplines(aNumValues);
 793 }
 794
 795 /**
 796  * Performs checks for the keyTimes attribute required by the SMIL spec but
 797  * which depend on other attributes and therefore needs to be updated as
 798  * dependent attributes are set.
 799  */
 800 void SMILAnimationFunction::CheckKeyTimes(uint32_t aNumValues) {
 801   if (!HasAttr(nsGkAtoms::keyTimes)) return;
 802
 803   SMILCalcMode calcMode = GetCalcMode();
 804
 805   // attribute is ignored for calcMode = paced
 806   if (calcMode == CALC_PACED) {
 807     SetKeyTimesErrorFlag(false);
 808     return;
 809   }
 810
 811   uint32_t numKeyTimes = mKeyTimes.Length();
 812   if (numKeyTimes < 1) {
 813     // keyTimes isn't set or failed preliminary checks
 814     SetKeyTimesErrorFlag(true);
 815     return;
 816   }
 817
 818   // no. keyTimes == no. values
 819   // For to-animation the number of values is considered to be 2.
 820   bool matchingNumOfValues = numKeyTimes == (IsToAnimation() ? 2 : aNumValues);
 821   if (!matchingNumOfValues) {
 822     SetKeyTimesErrorFlag(true);
 823     return;
 824   }
 825
 826   // first value must be 0
 827   if (mKeyTimes[0] != 0.0) {
 828     SetKeyTimesErrorFlag(true);
 829     return;
 830   }
 831
 832   // last value must be 1 for linear or spline calcModes
 833   if (calcMode != CALC_DISCRETE && numKeyTimes > 1 &&
 834       mKeyTimes.LastElement() != 1.0) {
 835     SetKeyTimesErrorFlag(true);
 836     return;
 837   }
 838
 839   SetKeyTimesErrorFlag(false);
 840 }
 841
 842 void SMILAnimationFunction::CheckKeySplines(uint32_t aNumValues) {
 843   // attribute is ignored if calc mode is not spline
 844   if (GetCalcMode() != CALC_SPLINE) {
 845     SetKeySplinesErrorFlag(false);
 846     return;
 847   }
 848
 849   // calc mode is spline but the attribute is not set
 850   if (!HasAttr(nsGkAtoms::keySplines)) {
 851     SetKeySplinesErrorFlag(false);
 852     return;
 853   }
 854
 855   if (mKeySplines.Length() < 1) {
 856     // keyTimes isn't set or failed preliminary checks
 857     SetKeySplinesErrorFlag(true);
 858     return;
 859   }
 860
 861   // ignore splines if there's only one value
 862   if (aNumValues == 1 && !IsToAnimation()) {
 863     SetKeySplinesErrorFlag(false);
 864     return;
 865   }
 866
 867   // no. keySpline specs == no. values - 1
 868   uint32_t splineSpecs = mKeySplines.Length();
 869   if ((splineSpecs != aNumValues - 1 && !IsToAnimation()) ||
 870       (IsToAnimation() && splineSpecs != 1)) {
 871     SetKeySplinesErrorFlag(true);
 872     return;
 873   }
 874
 875   SetKeySplinesErrorFlag(false);
 876 }
 877
 878 bool SMILAnimationFunction::IsValueFixedForSimpleDuration() const {
 879   return mSimpleDuration.IsIndefinite() ||
 880          (!mHasChanged && mPrevSampleWasSingleValueAnimation);
 881 }
 882
 883 //----------------------------------------------------------------------
 884 // Property getters
 885
 886 bool SMILAnimationFunction::GetAccumulate() const {
 887   const nsAttrValue* value = GetAttr(nsGkAtoms::accumulate);
 888   if (!value) return false;
 889
 890   return value->GetEnumValue();
 891 }
 892
 893 bool SMILAnimationFunction::GetAdditive() const {
 894   const nsAttrValue* value = GetAttr(nsGkAtoms::additive);
 895   if (!value) return false;
 896
 897   return value->GetEnumValue();
 898 }
 899
 900 SMILAnimationFunction::SMILCalcMode SMILAnimationFunction::GetCalcMode() const {
 901   const nsAttrValue* value = GetAttr(nsGkAtoms::calcMode);
 902   if (!value) return CALC_LINEAR;
 903
 904   return SMILCalcMode(value->GetEnumValue());
 905 }
 906
 907 //----------------------------------------------------------------------
 908 // Property setters / un-setters:
 909
 910 nsresult SMILAnimationFunction::SetAccumulate(const nsAString& aAccumulate,
 911                                               nsAttrValue& aResult) {
 912   mHasChanged = true;
 913   bool parseResult =
 914       aResult.ParseEnumValue(aAccumulate, sAccumulateTable, true);
 915   SetAccumulateErrorFlag(!parseResult);
 916   return parseResult ? NS_OK : NS_ERROR_FAILURE;
 917 }
 918
 919 void SMILAnimationFunction::UnsetAccumulate() {
 920   SetAccumulateErrorFlag(false);
 921   mHasChanged = true;
 922 }
 923
 924 nsresult SMILAnimationFunction::SetAdditive(const nsAString& aAdditive,
 925                                             nsAttrValue& aResult) {
 926   mHasChanged = true;
 927   bool parseResult = aResult.ParseEnumValue(aAdditive, sAdditiveTable, true);
 928   SetAdditiveErrorFlag(!parseResult);
 929   return parseResult ? NS_OK : NS_ERROR_FAILURE;
 930 }
 931
 932 void SMILAnimationFunction::UnsetAdditive() {
 933   SetAdditiveErrorFlag(false);
 934   mHasChanged = true;
 935 }
 936
 937 nsresult SMILAnimationFunction::SetCalcMode(const nsAString& aCalcMode,
 938                                             nsAttrValue& aResult) {
 939   mHasChanged = true;
 940   bool parseResult = aResult.ParseEnumValue(aCalcMode, sCalcModeTable, true);
 941   SetCalcModeErrorFlag(!parseResult);
 942   return parseResult ? NS_OK : NS_ERROR_FAILURE;
 943 }
 944
 945 void SMILAnimationFunction::UnsetCalcMode() {
 946   SetCalcModeErrorFlag(false);
 947   mHasChanged = true;
 948 }
 949
 950 nsresult SMILAnimationFunction::SetKeySplines(const nsAString& aKeySplines,
 951                                               nsAttrValue& aResult) {
 952   mKeySplines.Clear();
 953   aResult.SetTo(aKeySplines);
 954
 955   mHasChanged = true;
 956
 957   if (!SMILParserUtils::ParseKeySplines(aKeySplines, mKeySplines)) {
 958     mKeySplines.Clear();
 959     return NS_ERROR_FAILURE;
 960   }
 961
 962   return NS_OK;
 963 }
 964
 965 void SMILAnimationFunction::UnsetKeySplines() {
 966   mKeySplines.Clear();
 967   SetKeySplinesErrorFlag(false);
 968   mHasChanged = true;
 969 }
 970
 971 nsresult SMILAnimationFunction::SetKeyTimes(const nsAString& aKeyTimes,
 972                                             nsAttrValue& aResult) {
 973   mKeyTimes.Clear();
 974   aResult.SetTo(aKeyTimes);
 975
 976   mHasChanged = true;
 977
 978   if (!SMILParserUtils::ParseSemicolonDelimitedProgressList(aKeyTimes, true,
 979                                                             mKeyTimes)) {
 980     mKeyTimes.Clear();
 981     return NS_ERROR_FAILURE;
 982   }
 983
 984   return NS_OK;
 985 }
 986
 987 void SMILAnimationFunction::UnsetKeyTimes() {
 988   mKeyTimes.Clear();
 989   SetKeyTimesErrorFlag(false);
 990   mHasChanged = true;
 991 }
 992
 993 }  // namespace mozilla