The Tor Browser: layout/style/CSSCalc.h@141e0f1194b1 (annotated)

layout/style/CSSCalc.h@141e0f1194b1 (annotated)

layout/style/CSSCalc.h

Wed, 31 Dec 2014 07:16:47 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 07:16:47 +0100
branch: TOR_BUG_9701
changeset 3: 141e0f1194b1
permissions: -rw-r--r--

Revert simplistic fix pending revisit of Mozilla integration attempt.

 /* vim: set shiftwidth=2 tabstop=8 autoindent cindent expandtab: */
 /* 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 CSSCalc_h_
 #define CSSCalc_h_
 #include "nsCSSValue.h"
 #include "nsStyleCoord.h"
 #include <math.h>
 namespace mozilla {
 namespace css {
 /**
  * ComputeCalc computes the result of a calc() expression tree.
  *
  * It is templatized over a CalcOps class that is expected to provide:
  *
  *   // input_type and input_array_type have a bunch of very specific
  *   // expectations (which happen to be met by two classes (nsCSSValue
  *   // and nsStyleCoord).  There must be methods (roughly):
  *   //   input_array_type* input_type::GetArrayValue();
  *   //   uint32_t input_array_type::Count() const;
  *   //   input_type& input_array_type::Item(uint32_t);
  *   typedef ... input_type;
  *   typedef ... input_array_type;
  *
  *   typedef ... result_type;
  *
  *   // GetUnit(avalue) must return the correct nsCSSUnit for any
  *   // value that represents a calc tree node (eCSSUnit_Calc*).  For
  *   // other nodes, it may return any non eCSSUnit_Calc* unit.
  *   static nsCSSUnit GetUnit(const input_type& aValue);
  *
  *   result_type
  *   MergeAdditive(nsCSSUnit aCalcFunction,
  *                 result_type aValue1, result_type aValue2);
  *
  *   result_type
  *   MergeMultiplicativeL(nsCSSUnit aCalcFunction,
  *                        float aValue1, result_type aValue2);
  *
  *   result_type
  *   MergeMultiplicativeR(nsCSSUnit aCalcFunction,
  *                        result_type aValue1, float aValue2);
  *
  *   result_type
  *   ComputeLeafValue(const input_type& aValue);
  *
  *   float
  *   ComputeNumber(const input_type& aValue);
  *
  * The CalcOps methods might compute the calc() expression down to a
  * number, reduce some parts of it to a number but replicate other
  * parts, or produce a tree with a different data structure (for
  * example, nsCSS* for specified values vs nsStyle* for computed
  * values).
  *
  * For each leaf in the calc() expression, ComputeCalc will call either
  * ComputeNumber (when the leaf is the left side of a Times_L or the
  * right side of a Times_R or Divided) or ComputeLeafValue (otherwise).
  * (The CalcOps in the CSS parser that reduces purely numeric
  * expressions in turn calls ComputeCalc on numbers; other ops can
  * presume that expressions in the number positions have already been
  * normalized to a single numeric value and derive from
  * NumbersAlreadyNormalizedCalcOps.)
  *
  * For non-leaves, one of the Merge functions will be called:
  *   MergeAdditive for Plus and Minus
  *   MergeMultiplicativeL for Times_L (number * value)
  *   MergeMultiplicativeR for Times_R (value * number) and Divided
  */
 template <class CalcOps>
 static typename CalcOps::result_type
 ComputeCalc(const typename CalcOps::input_type& aValue, CalcOps &aOps)
 {
   switch (CalcOps::GetUnit(aValue)) {
     case eCSSUnit_Calc: {
       typename CalcOps::input_array_type *arr = aValue.GetArrayValue();
       NS_ABORT_IF_FALSE(arr->Count() == 1, "unexpected length");
       return ComputeCalc(arr->Item(0), aOps);
     }
     case eCSSUnit_Calc_Plus:
     case eCSSUnit_Calc_Minus: {
       typename CalcOps::input_array_type *arr = aValue.GetArrayValue();
       NS_ABORT_IF_FALSE(arr->Count() == 2, "unexpected length");
       typename CalcOps::result_type lhs = ComputeCalc(arr->Item(0), aOps),
                                     rhs = ComputeCalc(arr->Item(1), aOps);
       return aOps.MergeAdditive(CalcOps::GetUnit(aValue), lhs, rhs);
     }
     case eCSSUnit_Calc_Times_L: {
       typename CalcOps::input_array_type *arr = aValue.GetArrayValue();
       NS_ABORT_IF_FALSE(arr->Count() == 2, "unexpected length");
       float lhs = aOps.ComputeNumber(arr->Item(0));
       typename CalcOps::result_type rhs = ComputeCalc(arr->Item(1), aOps);
       return aOps.MergeMultiplicativeL(CalcOps::GetUnit(aValue), lhs, rhs);
     }
     case eCSSUnit_Calc_Times_R:
     case eCSSUnit_Calc_Divided: {
       typename CalcOps::input_array_type *arr = aValue.GetArrayValue();
       NS_ABORT_IF_FALSE(arr->Count() == 2, "unexpected length");
       typename CalcOps::result_type lhs = ComputeCalc(arr->Item(0), aOps);
       float rhs = aOps.ComputeNumber(arr->Item(1));
       return aOps.MergeMultiplicativeR(CalcOps::GetUnit(aValue), lhs, rhs);
     }
     default: {
       return aOps.ComputeLeafValue(aValue);
     }
   }
 }
 /**
  * The input unit operation for input_type being nsCSSValue.
  */
 struct CSSValueInputCalcOps
 {
   typedef nsCSSValue input_type;
   typedef nsCSSValue::Array input_array_type;
   static nsCSSUnit GetUnit(const nsCSSValue& aValue)
   {
     return aValue.GetUnit();
   }
 };
 /**
  * Basic*CalcOps provide a partial implementation of the CalcOps
  * template parameter to ComputeCalc, for those callers whose merging
  * just consists of mathematics (rather than tree construction).
  */
 struct BasicCoordCalcOps
 {
   typedef nscoord result_type;
   result_type
   MergeAdditive(nsCSSUnit aCalcFunction,
                 result_type aValue1, result_type aValue2)
   {
     if (aCalcFunction == eCSSUnit_Calc_Plus) {
       return NSCoordSaturatingAdd(aValue1, aValue2);
     }
     NS_ABORT_IF_FALSE(aCalcFunction == eCSSUnit_Calc_Minus,
                       "unexpected unit");
     return NSCoordSaturatingSubtract(aValue1, aValue2, 0);
   }
   result_type
   MergeMultiplicativeL(nsCSSUnit aCalcFunction,
                        float aValue1, result_type aValue2)
   {
     NS_ABORT_IF_FALSE(aCalcFunction == eCSSUnit_Calc_Times_L,
                       "unexpected unit");
     return NSCoordSaturatingMultiply(aValue2, aValue1);
   }
   result_type
   MergeMultiplicativeR(nsCSSUnit aCalcFunction,
                        result_type aValue1, float aValue2)
   {
     NS_ABORT_IF_FALSE(aCalcFunction == eCSSUnit_Calc_Times_R ||
                       aCalcFunction == eCSSUnit_Calc_Divided,
                       "unexpected unit");
     if (aCalcFunction == eCSSUnit_Calc_Divided) {
       aValue2 = 1.0f / aValue2;
     }
     return NSCoordSaturatingMultiply(aValue1, aValue2);
   }
 };
 struct BasicFloatCalcOps
 {
   typedef float result_type;
   result_type
   MergeAdditive(nsCSSUnit aCalcFunction,
                 result_type aValue1, result_type aValue2)
   {
     if (aCalcFunction == eCSSUnit_Calc_Plus) {
       return aValue1 + aValue2;
     }
     NS_ABORT_IF_FALSE(aCalcFunction == eCSSUnit_Calc_Minus,
                       "unexpected unit");
     return aValue1 - aValue2;
   }
   result_type
   MergeMultiplicativeL(nsCSSUnit aCalcFunction,
                        float aValue1, result_type aValue2)
   {
     NS_ABORT_IF_FALSE(aCalcFunction == eCSSUnit_Calc_Times_L,
                       "unexpected unit");
     return aValue1 * aValue2;
   }
   result_type
   MergeMultiplicativeR(nsCSSUnit aCalcFunction,
                        result_type aValue1, float aValue2)
   {
     if (aCalcFunction == eCSSUnit_Calc_Times_R) {
       return aValue1 * aValue2;
     }
     NS_ABORT_IF_FALSE(aCalcFunction == eCSSUnit_Calc_Divided,
                       "unexpected unit");
     return aValue1 / aValue2;
   }
 };
 /**
  * A ComputeNumber implementation for callers that can assume numbers
  * are already normalized (i.e., anything past the parser).
  */
 struct NumbersAlreadyNormalizedOps : public CSSValueInputCalcOps
 {
   float ComputeNumber(const nsCSSValue& aValue)
   {
     NS_ABORT_IF_FALSE(aValue.GetUnit() == eCSSUnit_Number, "unexpected unit");
     return aValue.GetFloatValue();
   }
 };
 /**
  * SerializeCalc appends the serialization of aValue to a string.
  *
  * It is templatized over a CalcOps class that is expected to provide:
  *
  *   // input_type and input_array_type have a bunch of very specific
  *   // expectations (which happen to be met by two classes (nsCSSValue
  *   // and nsStyleCoord).  There must be methods (roughly):
  *   //   input_array_type* input_type::GetArrayValue();
  *   //   uint32_t input_array_type::Count() const;
  *   //   input_type& input_array_type::Item(uint32_t);
  *   typedef ... input_type;
  *   typedef ... input_array_type;
  *
  *   static nsCSSUnit GetUnit(const input_type& aValue);
  *
  *   void Append(const char* aString);
  *   void AppendLeafValue(const input_type& aValue);
  *   void AppendNumber(const input_type& aValue);
  *
  * Data structures given may or may not have a toplevel eCSSUnit_Calc
  * node representing a calc whose toplevel is not min() or max().
  */
 template <class CalcOps>
 static void
 SerializeCalcInternal(const typename CalcOps::input_type& aValue, CalcOps &aOps);
 // Serialize the toplevel value in a calc() tree.  See big comment
 // above.
 template <class CalcOps>
 static void
 SerializeCalc(const typename CalcOps::input_type& aValue, CalcOps &aOps)
 {
   aOps.Append("calc(");
   nsCSSUnit unit = CalcOps::GetUnit(aValue);
   if (unit == eCSSUnit_Calc) {
     const typename CalcOps::input_array_type *array = aValue.GetArrayValue();
     NS_ABORT_IF_FALSE(array->Count() == 1, "unexpected length");
     SerializeCalcInternal(array->Item(0), aOps);
   } else {
     SerializeCalcInternal(aValue, aOps);
   }
   aOps.Append(")");
 }
 static inline bool
 IsCalcAdditiveUnit(nsCSSUnit aUnit)
 {
   return aUnit == eCSSUnit_Calc_Plus ||
          aUnit == eCSSUnit_Calc_Minus;
 }
 static inline bool
 IsCalcMultiplicativeUnit(nsCSSUnit aUnit)
 {
   return aUnit == eCSSUnit_Calc_Times_L ||
          aUnit == eCSSUnit_Calc_Times_R ||
          aUnit == eCSSUnit_Calc_Divided;
 }
 // Serialize a non-toplevel value in a calc() tree.  See big comment
 // above.
 template <class CalcOps>
 /* static */ void
 SerializeCalcInternal(const typename CalcOps::input_type& aValue, CalcOps &aOps)
 {
   nsCSSUnit unit = CalcOps::GetUnit(aValue);
   if (IsCalcAdditiveUnit(unit)) {
     const typename CalcOps::input_array_type *array = aValue.GetArrayValue();
     NS_ABORT_IF_FALSE(array->Count() == 2, "unexpected length");
     SerializeCalcInternal(array->Item(0), aOps);
     if (eCSSUnit_Calc_Plus == unit) {
       aOps.Append(" + ");
     } else {
       NS_ABORT_IF_FALSE(eCSSUnit_Calc_Minus == unit, "unexpected unit");
       aOps.Append(" - ");
     }
     bool needParens = IsCalcAdditiveUnit(CalcOps::GetUnit(array->Item(1)));
     if (needParens) {
       aOps.Append("(");
     }
     SerializeCalcInternal(array->Item(1), aOps);
     if (needParens) {
       aOps.Append(")");
     }
   } else if (IsCalcMultiplicativeUnit(unit)) {
     const typename CalcOps::input_array_type *array = aValue.GetArrayValue();
     NS_ABORT_IF_FALSE(array->Count() == 2, "unexpected length");
     bool needParens = IsCalcAdditiveUnit(CalcOps::GetUnit(array->Item(0)));
     if (needParens) {
       aOps.Append("(");
     }
     if (unit == eCSSUnit_Calc_Times_L) {
       aOps.AppendNumber(array->Item(0));
     } else {
       SerializeCalcInternal(array->Item(0), aOps);
     }
     if (needParens) {
       aOps.Append(")");
     }
     if (eCSSUnit_Calc_Times_L == unit || eCSSUnit_Calc_Times_R == unit) {
       aOps.Append(" * ");
     } else {
       NS_ABORT_IF_FALSE(eCSSUnit_Calc_Divided == unit, "unexpected unit");
       aOps.Append(" / ");
     }
     nsCSSUnit subUnit = CalcOps::GetUnit(array->Item(1));
     needParens = IsCalcAdditiveUnit(subUnit) ||
                  IsCalcMultiplicativeUnit(subUnit);
     if (needParens) {
       aOps.Append("(");
     }
     if (unit == eCSSUnit_Calc_Times_L) {
       SerializeCalcInternal(array->Item(1), aOps);
     } else {
       aOps.AppendNumber(array->Item(1));
     }
     if (needParens) {
       aOps.Append(")");
     }
   } else {
     aOps.AppendLeafValue(aValue);
   }
 }
 }
 }
 #endif /* !defined(CSSCalc_h_) */

The Tor Browser / annotate

layout/style/CSSCalc.h@141e0f1194b1 (annotated)

layout/style/CSSCalc.h