path: root/dom/smil/SMILParserUtils.cpp

/* -*- 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 "SMILParserUtils.h"

#include "mozilla/SMILAttr.h"
#include "mozilla/SMILKeySpline.h"
#include "mozilla/SMILRepeatCount.h"
#include "mozilla/SMILTimeValue.h"
#include "mozilla/SMILTimeValueSpecParams.h"
#include "mozilla/SMILTypes.h"
#include "mozilla/SMILValue.h"
#include "mozilla/SVGContentUtils.h"
#include "mozilla/TextUtils.h"
#include "nsContentUtils.h"
#include "nsCharSeparatedTokenizer.h"

using namespace mozilla::dom;
//------------------------------------------------------------------------------
// Helper functions and Constants

namespace {

using namespace mozilla;

const uint32_t MSEC_PER_SEC = 1000;
const uint32_t MSEC_PER_MIN = 1000 * 60;
const uint32_t MSEC_PER_HOUR = 1000 * 60 * 60;

#define ACCESSKEY_PREFIX_LC u"accesskey("_ns  // SMIL2+
#define ACCESSKEY_PREFIX_CC u"accessKey("_ns  // SVG/SMIL ANIM
#define REPEAT_PREFIX u"repeat("_ns
#define WALLCLOCK_PREFIX u"wallclock("_ns

inline bool SkipWhitespace(RangedPtr<const char16_t>& aIter,
                           const RangedPtr<const char16_t>& aEnd) {
  while (aIter != aEnd) {
    if (!nsContentUtils::IsHTMLWhitespace(*aIter)) {
      return true;
    }
    ++aIter;
  }
  return false;
}

inline bool ParseColon(RangedPtr<const char16_t>& aIter,
                       const RangedPtr<const char16_t>& aEnd) {
  if (aIter == aEnd || *aIter != ':') {
    return false;
  }
  ++aIter;
  return true;
}

/*
 * Exactly two digits in the range 00 - 59 are expected.
 */
bool ParseSecondsOrMinutes(RangedPtr<const char16_t>& aIter,
                           const RangedPtr<const char16_t>& aEnd,
                           uint32_t& aValue) {
  if (aIter == aEnd || !mozilla::IsAsciiDigit(*aIter)) {
    return false;
  }

  RangedPtr<const char16_t> iter(aIter);

  if (++iter == aEnd || !mozilla::IsAsciiDigit(*iter)) {
    return false;
  }

  uint32_t value = 10 * mozilla::AsciiAlphanumericToNumber(*aIter) +
                   mozilla::AsciiAlphanumericToNumber(*iter);
  if (value > 59) {
    return false;
  }
  if (++iter != aEnd && mozilla::IsAsciiDigit(*iter)) {
    return false;
  }

  aValue = value;
  aIter = iter;
  return true;
}

inline bool ParseClockMetric(RangedPtr<const char16_t>& aIter,
                             const RangedPtr<const char16_t>& aEnd,
                             uint32_t& aMultiplier) {
  if (aIter == aEnd) {
    aMultiplier = MSEC_PER_SEC;
    return true;
  }

  switch (*aIter) {
    case 'h':
      if (++aIter == aEnd) {
        aMultiplier = MSEC_PER_HOUR;
        return true;
      }
      return false;
    case 'm': {
      const nsAString& metric = Substring(aIter.get(), aEnd.get());
      if (metric.EqualsLiteral("min")) {
        aMultiplier = MSEC_PER_MIN;
        aIter = aEnd;
        return true;
      }
      if (metric.EqualsLiteral("ms")) {
        aMultiplier = 1;
        aIter = aEnd;
        return true;
      }
    }
      return false;
    case 's':
      if (++aIter == aEnd) {
        aMultiplier = MSEC_PER_SEC;
        return true;
      }
  }
  return false;
}

/**
 * See http://www.w3.org/TR/SVG/animate.html#ClockValueSyntax
 */
bool ParseClockValue(RangedPtr<const char16_t>& aIter,
                     const RangedPtr<const char16_t>& aEnd,
                     SMILTimeValue* aResult) {
  if (aIter == aEnd) {
    return false;
  }

  // TIMECOUNT_VALUE     ::= Timecount ("." Fraction)? (Metric)?
  // PARTIAL_CLOCK_VALUE ::= Minutes ":" Seconds ("." Fraction)?
  // FULL_CLOCK_VALUE    ::= Hours ":" Minutes ":" Seconds ("." Fraction)?
  enum ClockType { TIMECOUNT_VALUE, PARTIAL_CLOCK_VALUE, FULL_CLOCK_VALUE };

  int32_t clockType = TIMECOUNT_VALUE;

  RangedPtr<const char16_t> iter(aIter);

  // Determine which type of clock value we have by counting the number
  // of colons in the string.
  do {
    switch (*iter) {
      case ':':
        if (clockType == FULL_CLOCK_VALUE) {
          return false;
        }
        ++clockType;
        break;
      case 'e':
      case 'E':
      case '-':
      case '+':
        // Exclude anything invalid (for clock values)
        // that number parsing might otherwise allow.
        return false;
    }
    ++iter;
  } while (iter != aEnd);

  iter = aIter;

  int32_t hours = 0, timecount;
  double fraction = 0.0;
  uint32_t minutes, seconds, multiplier;

  switch (clockType) {
    case FULL_CLOCK_VALUE:
      if (!SVGContentUtils::ParseInteger(iter, aEnd, hours) ||
          !ParseColon(iter, aEnd)) {
        return false;
      }
      [[fallthrough]];
    case PARTIAL_CLOCK_VALUE:
      if (!ParseSecondsOrMinutes(iter, aEnd, minutes) ||
          !ParseColon(iter, aEnd) ||
          !ParseSecondsOrMinutes(iter, aEnd, seconds)) {
        return false;
      }
      if (iter != aEnd && (*iter != '.' || !SVGContentUtils::ParseNumber(
                                               iter, aEnd, fraction))) {
        return false;
      }
      aResult->SetMillis(SMILTime(hours) * MSEC_PER_HOUR +
                         minutes * MSEC_PER_MIN + seconds * MSEC_PER_SEC +
                         NS_round(fraction * MSEC_PER_SEC));
      aIter = iter;
      return true;
    case TIMECOUNT_VALUE:
      if (!SVGContentUtils::ParseInteger(iter, aEnd, timecount)) {
        return false;
      }
      if (iter != aEnd && *iter == '.' &&
          !SVGContentUtils::ParseNumber(iter, aEnd, fraction)) {
        return false;
      }
      if (!ParseClockMetric(iter, aEnd, multiplier)) {
        return false;
      }
      aResult->SetMillis(SMILTime(timecount) * multiplier +
                         NS_round(fraction * multiplier));
      aIter = iter;
      return true;
  }

  return false;
}

bool ParseOffsetValue(RangedPtr<const char16_t>& aIter,
                      const RangedPtr<const char16_t>& aEnd,
                      SMILTimeValue* aResult) {
  RangedPtr<const char16_t> iter(aIter);

  int32_t sign;
  if (!SVGContentUtils::ParseOptionalSign(iter, aEnd, sign) ||
      !SkipWhitespace(iter, aEnd) || !ParseClockValue(iter, aEnd, aResult)) {
    return false;
  }
  if (sign == -1) {
    aResult->SetMillis(-aResult->GetMillis());
  }
  aIter = iter;
  return true;
}

bool ParseOffsetValue(const nsAString& aSpec, SMILTimeValue* aResult) {
  RangedPtr<const char16_t> iter(SVGContentUtils::GetStartRangedPtr(aSpec));
  const RangedPtr<const char16_t> end(SVGContentUtils::GetEndRangedPtr(aSpec));

  return ParseOffsetValue(iter, end, aResult) && iter == end;
}

bool ParseOptionalOffset(RangedPtr<const char16_t>& aIter,
                         const RangedPtr<const char16_t>& aEnd,
                         SMILTimeValue* aResult) {
  if (aIter == aEnd) {
    aResult->SetMillis(0L);
    return true;
  }

  return SkipWhitespace(aIter, aEnd) && ParseOffsetValue(aIter, aEnd, aResult);
}

void MoveToNextToken(RangedPtr<const char16_t>& aIter,
                     const RangedPtr<const char16_t>& aEnd, bool aBreakOnDot,
                     bool& aIsAnyCharEscaped) {
  aIsAnyCharEscaped = false;

  bool isCurrentCharEscaped = false;

  while (aIter != aEnd && !nsContentUtils::IsHTMLWhitespace(*aIter)) {
    if (isCurrentCharEscaped) {
      isCurrentCharEscaped = false;
    } else {
      if (*aIter == '+' || *aIter == '-' || (aBreakOnDot && *aIter == '.')) {
        break;
      }
      if (*aIter == '\\') {
        isCurrentCharEscaped = true;
        aIsAnyCharEscaped = true;
      }
    }
    ++aIter;
  }
}

already_AddRefed<nsAtom> ConvertUnescapedTokenToAtom(const nsAString& aToken) {
  // Whether the token is an id-ref or event-symbol it should be a valid NCName
  if (aToken.IsEmpty() || NS_FAILED(nsContentUtils::CheckQName(aToken, false)))
    return nullptr;
  return NS_Atomize(aToken);
}

already_AddRefed<nsAtom> ConvertTokenToAtom(const nsAString& aToken,
                                            bool aUnescapeToken) {
  // Unescaping involves making a copy of the string which we'd like to avoid if
  // possible
  if (!aUnescapeToken) {
    return ConvertUnescapedTokenToAtom(aToken);
  }

  nsAutoString token(aToken);

  const char16_t* read = token.BeginReading();
  const char16_t* const end = token.EndReading();
  char16_t* write = token.BeginWriting();
  bool escape = false;

  while (read != end) {
    MOZ_ASSERT(write <= read, "Writing past where we've read");
    if (!escape && *read == '\\') {
      escape = true;
      ++read;
    } else {
      *write++ = *read++;
      escape = false;
    }
  }
  token.Truncate(write - token.BeginReading());

  return ConvertUnescapedTokenToAtom(token);
}

bool ParseElementBaseTimeValueSpec(const nsAString& aSpec,
                                   SMILTimeValueSpecParams& aResult) {
  SMILTimeValueSpecParams result;

  //
  // The spec will probably look something like one of these
  //
  // element-name.begin
  // element-name.event-name
  // event-name
  // element-name.repeat(3)
  // event\.name
  //
  // Technically `repeat(3)' is permitted but the behaviour in this case is not
  // defined (for SMIL Animation) so we don't support it here.
  //

  RangedPtr<const char16_t> start(SVGContentUtils::GetStartRangedPtr(aSpec));
  RangedPtr<const char16_t> end(SVGContentUtils::GetEndRangedPtr(aSpec));

  if (start == end) {
    return false;
  }

  RangedPtr<const char16_t> tokenEnd(start);

  bool requiresUnescaping;
  MoveToNextToken(tokenEnd, end, true, requiresUnescaping);

  RefPtr<nsAtom> atom = ConvertTokenToAtom(
      Substring(start.get(), tokenEnd.get()), requiresUnescaping);
  if (atom == nullptr) {
    return false;
  }

  // Parse the second token if there is one
  if (tokenEnd != end && *tokenEnd == '.') {
    result.mDependentElemID = atom;

    ++tokenEnd;
    start = tokenEnd;
    MoveToNextToken(tokenEnd, end, false, requiresUnescaping);

    const nsAString& token2 = Substring(start.get(), tokenEnd.get());

    // element-name.begin
    if (token2.EqualsLiteral("begin")) {
      result.mType = SMILTimeValueSpecParams::SYNCBASE;
      result.mSyncBegin = true;
      // element-name.end
    } else if (token2.EqualsLiteral("end")) {
      result.mType = SMILTimeValueSpecParams::SYNCBASE;
      result.mSyncBegin = false;
      // element-name.repeat(digit+)
    } else if (StringBeginsWith(token2, REPEAT_PREFIX)) {
      start += REPEAT_PREFIX.Length();
      int32_t repeatValue;
      if (start == tokenEnd || *start == '+' || *start == '-' ||
          !SVGContentUtils::ParseInteger(start, tokenEnd, repeatValue)) {
        return false;
      }
      if (start == tokenEnd || *start != ')') {
        return false;
      }
      result.mType = SMILTimeValueSpecParams::REPEAT;
      result.mRepeatIteration = repeatValue;
      // element-name.event-symbol
    } else {
      atom = ConvertTokenToAtom(token2, requiresUnescaping);
      if (atom == nullptr) {
        return false;
      }
      result.mType = SMILTimeValueSpecParams::EVENT;
      result.mEventSymbol = atom;
    }
  } else {
    // event-symbol
    result.mType = SMILTimeValueSpecParams::EVENT;
    result.mEventSymbol = atom;
  }

  // We've reached the end of the token, so we should now be either looking at
  // a '+', '-' (possibly with whitespace before it), or the end.
  if (!ParseOptionalOffset(tokenEnd, end, &result.mOffset) || tokenEnd != end) {
    return false;
  }
  aResult = result;
  return true;
}

}  // namespace

namespace mozilla {

//------------------------------------------------------------------------------
// Implementation

const nsDependentSubstring SMILParserUtils::TrimWhitespace(
    const nsAString& aString) {
  nsAString::const_iterator start, end;

  aString.BeginReading(start);
  aString.EndReading(end);

  // Skip whitespace characters at the beginning
  while (start != end && nsContentUtils::IsHTMLWhitespace(*start)) {
    ++start;
  }

  // Skip whitespace characters at the end.
  while (end != start) {
    --end;

    if (!nsContentUtils::IsHTMLWhitespace(*end)) {
      // Step back to the last non-whitespace character.
      ++end;

      break;
    }
  }

  return Substring(start, end);
}

bool SMILParserUtils::ParseKeySplines(
    const nsAString& aSpec, FallibleTArray<SMILKeySpline>& aKeySplines) {
  for (const auto& controlPoint :
       nsCharSeparatedTokenizerTemplate<nsContentUtils::IsHTMLWhitespace>(aSpec,
                                                                          ';')
           .ToRange()) {
    nsCharSeparatedTokenizerTemplate<nsContentUtils::IsHTMLWhitespace,
                                     nsTokenizerFlags::SeparatorOptional>
        tokenizer(controlPoint, ',');

    double values[4];
    for (auto& value : values) {
      if (!tokenizer.hasMoreTokens() ||
          !SVGContentUtils::ParseNumber(tokenizer.nextToken(), value) ||
          value > 1.0 || value < 0.0) {
        return false;
      }
    }
    if (tokenizer.hasMoreTokens() || tokenizer.separatorAfterCurrentToken() ||
        !aKeySplines.AppendElement(
            SMILKeySpline(values[0], values[1], values[2], values[3]),
            fallible)) {
      return false;
    }
  }

  return !aKeySplines.IsEmpty();
}

bool SMILParserUtils::ParseSemicolonDelimitedProgressList(
    const nsAString& aSpec, bool aNonDecreasing,
    FallibleTArray<double>& aArray) {
  nsCharSeparatedTokenizerTemplate<nsContentUtils::IsHTMLWhitespace> tokenizer(
      aSpec, ';');

  double previousValue = -1.0;

  while (tokenizer.hasMoreTokens()) {
    double value;
    if (!SVGContentUtils::ParseNumber(tokenizer.nextToken(), value)) {
      return false;
    }

    if (value > 1.0 || value < 0.0 ||
        (aNonDecreasing && value < previousValue)) {
      return false;
    }

    if (!aArray.AppendElement(value, fallible)) {
      return false;
    }
    previousValue = value;
  }

  return !aArray.IsEmpty();
}

// Helper class for ParseValues
class MOZ_STACK_CLASS SMILValueParser
    : public SMILParserUtils::GenericValueParser {
 public:
  SMILValueParser(const SVGAnimationElement* aSrcElement,
                  const SMILAttr* aSMILAttr,
                  FallibleTArray<SMILValue>* aValuesArray,
                  bool* aPreventCachingOfSandwich)
      : mSrcElement(aSrcElement),
        mSMILAttr(aSMILAttr),
        mValuesArray(aValuesArray),
        mPreventCachingOfSandwich(aPreventCachingOfSandwich) {}

  bool Parse(const nsAString& aValueStr) override {
    SMILValue newValue;
    bool tmpPreventCachingOfSandwich = false;
    if (NS_FAILED(mSMILAttr->ValueFromString(aValueStr, mSrcElement, newValue,
                                             tmpPreventCachingOfSandwich)))
      return false;

    if (!mValuesArray->AppendElement(newValue, fallible)) {
      return false;
    }
    if (tmpPreventCachingOfSandwich) {
      *mPreventCachingOfSandwich = true;
    }
    return true;
  }

 protected:
  const SVGAnimationElement* mSrcElement;
  const SMILAttr* mSMILAttr;
  FallibleTArray<SMILValue>* mValuesArray;
  bool* mPreventCachingOfSandwich;
};

bool SMILParserUtils::ParseValues(const nsAString& aSpec,
                                  const SVGAnimationElement* aSrcElement,
                                  const SMILAttr& aAttribute,
                                  FallibleTArray<SMILValue>& aValuesArray,
                                  bool& aPreventCachingOfSandwich) {
  // Assume all results can be cached, until we find one that can't.
  aPreventCachingOfSandwich = false;
  SMILValueParser valueParser(aSrcElement, &aAttribute, &aValuesArray,
                              &aPreventCachingOfSandwich);
  return ParseValuesGeneric(aSpec, valueParser);
}

bool SMILParserUtils::ParseValuesGeneric(const nsAString& aSpec,
                                         GenericValueParser& aParser) {
  nsCharSeparatedTokenizerTemplate<nsContentUtils::IsHTMLWhitespace> tokenizer(
      aSpec, ';');
  if (!tokenizer.hasMoreTokens()) {  // Empty list
    return false;
  }

  while (tokenizer.hasMoreTokens()) {
    if (!aParser.Parse(tokenizer.nextToken())) {
      return false;
    }
  }

  return true;
}

bool SMILParserUtils::ParseRepeatCount(const nsAString& aSpec,
                                       SMILRepeatCount& aResult) {
  const nsAString& spec = SMILParserUtils::TrimWhitespace(aSpec);

  if (spec.EqualsLiteral("indefinite")) {
    aResult.SetIndefinite();
    return true;
  }

  double value;
  if (!SVGContentUtils::ParseNumber(spec, value) || value <= 0.0) {
    return false;
  }
  aResult = value;
  return true;
}

bool SMILParserUtils::ParseTimeValueSpecParams(
    const nsAString& aSpec, SMILTimeValueSpecParams& aResult) {
  const nsAString& spec = TrimWhitespace(aSpec);

  if (spec.EqualsLiteral("indefinite")) {
    aResult.mType = SMILTimeValueSpecParams::INDEFINITE;
    return true;
  }

  // offset type
  if (ParseOffsetValue(spec, &aResult.mOffset)) {
    aResult.mType = SMILTimeValueSpecParams::OFFSET;
    return true;
  }

  // wallclock type
  if (StringBeginsWith(spec, WALLCLOCK_PREFIX)) {
    return false;  // Wallclock times not implemented
  }

  // accesskey type
  if (StringBeginsWith(spec, ACCESSKEY_PREFIX_LC) ||
      StringBeginsWith(spec, ACCESSKEY_PREFIX_CC)) {
    return false;  // accesskey is not supported
  }

  // event, syncbase, or repeat
  return ParseElementBaseTimeValueSpec(spec, aResult);
}

bool SMILParserUtils::ParseClockValue(const nsAString& aSpec,
                                      SMILTimeValue* aResult) {
  RangedPtr<const char16_t> iter(SVGContentUtils::GetStartRangedPtr(aSpec));
  RangedPtr<const char16_t> end(SVGContentUtils::GetEndRangedPtr(aSpec));

  return ::ParseClockValue(iter, end, aResult) && iter == end;
}

int32_t SMILParserUtils::CheckForNegativeNumber(const nsAString& aStr) {
  int32_t absValLocation = -1;

  RangedPtr<const char16_t> start(SVGContentUtils::GetStartRangedPtr(aStr));
  RangedPtr<const char16_t> iter = start;
  RangedPtr<const char16_t> end(SVGContentUtils::GetEndRangedPtr(aStr));

  // Skip initial whitespace
  while (iter != end && nsContentUtils::IsHTMLWhitespace(*iter)) {
    ++iter;
  }

  // Check for dash
  if (iter != end && *iter == '-') {
    ++iter;
    // Check for numeric character
    if (iter != end && mozilla::IsAsciiDigit(*iter)) {
      absValLocation = iter - start;
    }
  }
  return absValLocation;
}

}  // namespace mozilla