dom/base/nsAttrValue.h

   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 /*
   8  * A struct that represents the value (type and actual data) of an
   9  * attribute.
  10  */
  11
  12 #ifndef nsAttrValue_h___
  13 #define nsAttrValue_h___
  14
  15 #include <type_traits>
  16
  17 #include "nscore.h"
  18 #include "nsString.h"
  19 #include "nsStringBuffer.h"
  20 #include "nsColor.h"
  21 #include "nsCaseTreatment.h"
  22 #include "nsMargin.h"
  23 #include "nsStringFwd.h"
  24 #include "nsTArrayForwardDeclare.h"
  25 #include "mozilla/AtomArray.h"
  26 #include "mozilla/EnumTypeTraits.h"
  27 #include "mozilla/MemoryReporting.h"
  28
  29 class nsAtom;
  30 class nsIPrincipal;
  31 class nsIURI;
  32 class nsStyledElement;
  33 struct MiscContainer;
  34
  35 namespace mozilla {
  36 class DeclarationBlock;
  37 class ShadowParts;
  38 class SVGAnimatedIntegerPair;
  39 class SVGAnimatedLength;
  40 class SVGAnimatedNumberPair;
  41 class SVGAnimatedOrient;
  42 class SVGAnimatedPreserveAspectRatio;
  43 class SVGAnimatedViewBox;
  44 class SVGLengthList;
  45 class SVGNumberList;
  46 class SVGPathData;
  47 class SVGPointList;
  48 class SVGStringList;
  49 class SVGTransformList;
  50
  51 namespace dom {
  52 class DOMString;
  53 }
  54 }  // namespace mozilla
  55
  56 #define NS_ATTRVALUE_MAX_STRINGLENGTH_ATOM 12
  57
  58 const uintptr_t NS_ATTRVALUE_BASETYPE_MASK = 3;
  59 #define NS_ATTRVALUE_POINTERVALUE_MASK (~NS_ATTRVALUE_BASETYPE_MASK)
  60
  61 #define NS_ATTRVALUE_INTEGERTYPE_BITS 4
  62 #define NS_ATTRVALUE_INTEGERTYPE_MASK \
  63   (uintptr_t((1 << NS_ATTRVALUE_INTEGERTYPE_BITS) - 1))
  64 #define NS_ATTRVALUE_INTEGERTYPE_MULTIPLIER (1 << NS_ATTRVALUE_INTEGERTYPE_BITS)
  65 #define NS_ATTRVALUE_INTEGERTYPE_MAXVALUE \
  66   ((1 << (31 - NS_ATTRVALUE_INTEGERTYPE_BITS)) - 1)
  67 #define NS_ATTRVALUE_INTEGERTYPE_MINVALUE \
  68   (-NS_ATTRVALUE_INTEGERTYPE_MAXVALUE - 1)
  69
  70 #define NS_ATTRVALUE_ENUMTABLEINDEX_BITS \
  71   (32 - 16 - NS_ATTRVALUE_INTEGERTYPE_BITS)
  72 #define NS_ATTRVALUE_ENUMTABLE_VALUE_NEEDS_TO_UPPER \
  73   (1 << (NS_ATTRVALUE_ENUMTABLEINDEX_BITS - 1))
  74 #define NS_ATTRVALUE_ENUMTABLEINDEX_MAXVALUE \
  75   (NS_ATTRVALUE_ENUMTABLE_VALUE_NEEDS_TO_UPPER - 1)
  76 #define NS_ATTRVALUE_ENUMTABLEINDEX_MASK                      \
  77   (uintptr_t((((1 << NS_ATTRVALUE_ENUMTABLEINDEX_BITS) - 1) & \
  78               ~NS_ATTRVALUE_ENUMTABLE_VALUE_NEEDS_TO_UPPER)))
  79
  80 /**
  81  * A class used to construct a nsString from a nsStringBuffer (we might
  82  * want to move this to nsString at some point).
  83  *
  84  * WARNING: Note that nsCheapString doesn't take an explicit length -- it
  85  * assumes the string is maximally large, given the nsStringBuffer's storage
  86  * size.  This means the given string buffer *must* be sized exactly correctly
  87  * for the string it contains (including one byte for a null terminator).  If
  88  * it has any unused storage space, then that will result in bogus characters
  89  * at the end of our nsCheapString.
  90  */
  91 class nsCheapString : public nsString {
  92  public:
  93   explicit nsCheapString(nsStringBuffer* aBuf) {
  94     if (aBuf) aBuf->ToString(aBuf->StorageSize() / sizeof(char16_t) - 1, *this);
  95   }
  96 };
  97
  98 class nsAttrValue {
  99   friend struct MiscContainer;
 100
 101  public:
 102   // This has to be the same as in ValueBaseType
 103   enum ValueType {
 104     eString = 0x00,   //   00
 105                       //   01  this value indicates a 'misc' struct
 106     eAtom = 0x02,     //   10
 107     eInteger = 0x03,  // 0011
 108     eColor = 0x07,    // 0111
 109     eEnum = 0x0B,     // 1011  This should eventually die
 110     ePercent = 0x0F,  // 1111
 111     // Values below here won't matter, they'll be always stored in the 'misc'
 112     // struct.
 113     eCSSDeclaration = 0x10,
 114     eURL,
 115     eImage,
 116     eAtomArray,
 117     eDoubleValue,
 118     eIntMarginValue,
 119     // eShadowParts is refcounted in the misc container, as we do copy attribute
 120     // values quite a bit (for example to process style invalidation), and the
 121     // underlying value could get expensive to copy.
 122     eShadowParts,
 123     eSVGIntegerPair,
 124     eSVGTypesBegin = eSVGIntegerPair,
 125     eSVGOrient,
 126     eSVGLength,
 127     eSVGLengthList,
 128     eSVGNumberList,
 129     eSVGNumberPair,
 130     eSVGPathData,
 131     eSVGPointList,
 132     eSVGPreserveAspectRatio,
 133     eSVGStringList,
 134     eSVGTransformList,
 135     eSVGViewBox,
 136     eSVGTypesEnd = eSVGViewBox,
 137   };
 138
 139   nsAttrValue();
 140   nsAttrValue(const nsAttrValue& aOther);
 141   explicit nsAttrValue(const nsAString& aValue);
 142   explicit nsAttrValue(nsAtom* aValue);
 143   nsAttrValue(already_AddRefed<mozilla::DeclarationBlock> aValue,
 144               const nsAString* aSerialized);
 145   explicit nsAttrValue(const nsIntMargin& aValue);
 146   ~nsAttrValue();
 147
 148   inline const nsAttrValue& operator=(const nsAttrValue& aOther);
 149
 150   static void Init();
 151   static void Shutdown();
 152
 153   inline ValueType Type() const;
 154   // Returns true when this value is self-contained and does not depend on
 155   // the state of its associated element.
 156   // Returns false when this value depends on the state of its associated
 157   // element and may be invalid if that state has been changed by changes to
 158   // that element state outside of attribute setting.
 159   inline bool StoresOwnData() const;
 160
 161   void Reset();
 162
 163   void SetTo(const nsAttrValue& aOther);
 164   void SetTo(const nsAString& aValue);
 165   void SetTo(nsAtom* aValue);
 166   void SetTo(int16_t aInt);
 167   void SetTo(int32_t aInt, const nsAString* aSerialized);
 168   void SetTo(double aValue, const nsAString* aSerialized);
 169   void SetTo(already_AddRefed<mozilla::DeclarationBlock> aValue,
 170              const nsAString* aSerialized);
 171   void SetTo(nsIURI* aValue, const nsAString* aSerialized);
 172   void SetTo(const nsIntMargin& aValue);
 173   void SetTo(const mozilla::SVGAnimatedIntegerPair& aValue,
 174              const nsAString* aSerialized);
 175   void SetTo(const mozilla::SVGAnimatedLength& aValue,
 176              const nsAString* aSerialized);
 177   void SetTo(const mozilla::SVGAnimatedNumberPair& aValue,
 178              const nsAString* aSerialized);
 179   void SetTo(const mozilla::SVGAnimatedOrient& aValue,
 180              const nsAString* aSerialized);
 181   void SetTo(const mozilla::SVGAnimatedPreserveAspectRatio& aValue,
 182              const nsAString* aSerialized);
 183   void SetTo(const mozilla::SVGAnimatedViewBox& aValue,
 184              const nsAString* aSerialized);
 185   void SetTo(const mozilla::SVGLengthList& aValue,
 186              const nsAString* aSerialized);
 187   void SetTo(const mozilla::SVGNumberList& aValue,
 188              const nsAString* aSerialized);
 189   void SetTo(const mozilla::SVGPathData& aValue, const nsAString* aSerialized);
 190   void SetTo(const mozilla::SVGPointList& aValue, const nsAString* aSerialized);
 191   void SetTo(const mozilla::SVGStringList& aValue,
 192              const nsAString* aSerialized);
 193   void SetTo(const mozilla::SVGTransformList& aValue,
 194              const nsAString* aSerialized);
 195
 196   /**
 197    * Sets this object with the string or atom representation of aValue.
 198    *
 199    * After calling this method, this object will have type eString unless the
 200    * type of aValue is eAtom, in which case this object will also have type
 201    * eAtom.
 202    */
 203   void SetToSerialized(const nsAttrValue& aValue);
 204
 205   void SwapValueWith(nsAttrValue& aOther);
 206
 207   void ToString(nsAString& aResult) const;
 208   inline void ToString(mozilla::dom::DOMString& aResult) const;
 209
 210   /**
 211    * Returns the value of this object as an atom. If necessary, the value will
 212    * first be serialised using ToString before converting to an atom.
 213    */
 214   already_AddRefed<nsAtom> GetAsAtom() const;
 215
 216   // Methods to get value. These methods do not convert so only use them
 217   // to retrieve the datatype that this nsAttrValue has.
 218   inline bool IsEmptyString() const;
 219   const nsCheapString GetStringValue() const;
 220   inline nsAtom* GetAtomValue() const;
 221   inline int32_t GetIntegerValue() const;
 222   bool GetColorValue(nscolor& aColor) const;
 223   inline int16_t GetEnumValue() const;
 224   inline double GetPercentValue() const;
 225   inline mozilla::AtomArray* GetAtomArrayValue() const;
 226   inline mozilla::DeclarationBlock* GetCSSDeclarationValue() const;
 227   inline nsIURI* GetURLValue() const;
 228   inline double GetDoubleValue() const;
 229   bool GetIntMarginValue(nsIntMargin& aMargin) const;
 230   inline const mozilla::ShadowParts& GetShadowPartsValue() const;
 231
 232   /**
 233    * Returns the string corresponding to the stored enum value.
 234    *
 235    * @param aResult   the string representing the enum tag
 236    * @param aRealTag  wheter we want to have the real tag or the saved one
 237    */
 238   void GetEnumString(nsAString& aResult, bool aRealTag) const;
 239
 240   // Methods to get access to atoms we may have
 241   // Returns the number of atoms we have; 0 if we have none.  It's OK
 242   // to call this without checking the type first; it handles that.
 243   uint32_t GetAtomCount() const;
 244   // Returns the atom at aIndex (0-based).  Do not call this with
 245   // aIndex >= GetAtomCount().
 246   nsAtom* AtomAt(int32_t aIndex) const;
 247
 248   uint32_t HashValue() const;
 249   bool Equals(const nsAttrValue& aOther) const;
 250   // aCaseSensitive == eIgnoreCase means ASCII case-insenstive matching
 251   bool Equals(const nsAString& aValue, nsCaseTreatment aCaseSensitive) const;
 252   bool Equals(const nsAtom* aValue, nsCaseTreatment aCaseSensitive) const;
 253   bool HasPrefix(const nsAString& aValue, nsCaseTreatment aCaseSensitive) const;
 254   bool HasSuffix(const nsAString& aValue, nsCaseTreatment aCaseSensitive) const;
 255   bool HasSubstring(const nsAString& aValue,
 256                     nsCaseTreatment aCaseSensitive) const;
 257
 258   /**
 259    * Compares this object with aOther according to their string representation.
 260    *
 261    * For example, when called on an object with type eInteger and value 4, and
 262    * given aOther of type eString and value "4", EqualsAsStrings will return
 263    * true (while Equals will return false).
 264    */
 265   bool EqualsAsStrings(const nsAttrValue& aOther) const;
 266
 267   /**
 268    * Returns true if this AttrValue is equal to the given atom, or is an
 269    * array which contains the given atom.
 270    */
 271   bool Contains(nsAtom* aValue, nsCaseTreatment aCaseSensitive) const;
 272   /**
 273    * Returns true if this AttrValue is an atom equal to the given
 274    * string, or is an array of atoms which contains the given string.
 275    * This always does a case-sensitive comparison.
 276    */
 277   bool Contains(const nsAString& aValue) const;
 278
 279   void ParseAtom(const nsAString& aValue);
 280   void ParseAtomArray(const nsAString& aValue);
 281   void ParseStringOrAtom(const nsAString& aValue);
 282
 283   /**
 284    * Parses an exportparts attribute.
 285    *
 286    * https://drafts.csswg.org/css-shadow-parts/#parsing-mapping-list
 287    */
 288   void ParsePartMapping(const nsAString&);
 289
 290   /**
 291    * Structure for a mapping from int (enum) values to strings.  When you use
 292    * it you generally create an array of them.
 293    * Instantiate like this:
 294    * EnumTable myTable[] = {
 295    *   { "string1", 1 },
 296    *   { "string2", 2 },
 297    *   { nullptr, 0 }
 298    * }
 299    */
 300   struct EnumTable {
 301     // EnumTable can be initialized either with an int16_t value
 302     // or a value of an enumeration type that can fit within an int16_t.
 303
 304     constexpr EnumTable(const char* aTag, int16_t aValue)
 305         : tag(aTag), value(aValue) {}
 306
 307     template <typename T,
 308               typename = typename std::enable_if<std::is_enum<T>::value>::type>
 309     constexpr EnumTable(const char* aTag, T aValue)
 310         : tag(aTag), value(static_cast<int16_t>(aValue)) {
 311       static_assert(mozilla::EnumTypeFitsWithin<T, int16_t>::value,
 312                     "aValue must be an enum that fits within int16_t");
 313     }
 314
 315     /** The string the value maps to */
 316     const char* tag;
 317     /** The enum value that maps to this string */
 318     int16_t value;
 319   };
 320
 321   /**
 322    * Parse into an enum value.
 323    *
 324    * @param aValue the string to find the value for
 325    * @param aTable the enumeration to map with
 326    * @param aCaseSensitive specify if the parsing has to be case sensitive
 327    * @param aDefaultValue if non-null, this function will always return true.
 328    *        Failure to parse aValue as one of the values in aTable will just
 329    *        cause aDefaultValue->value to be stored as the enumeration value.
 330    * @return whether the enum value was found or not
 331    */
 332   bool ParseEnumValue(const nsAString& aValue, const EnumTable* aTable,
 333                       bool aCaseSensitive,
 334                       const EnumTable* aDefaultValue = nullptr);
 335
 336   /**
 337    * Parse a string into a dimension value.  This is similar to
 338    * https://html.spec.whatwg.org/multipage/#rules-for-parsing-dimension-values
 339    * but drops the fractional part of the value for now, until we figure out how
 340    * to store that in our nsAttrValue.
 341    *
 342    * The resulting value (if the parse succeeds) is one of eInteger,
 343    * eDoubleValue, or ePercent, depending on whether we found a fractional part
 344    * and whether we found '%' at the end of the value.
 345    *
 346    * @param aInput the string to parse
 347    * @return whether the value could be parsed
 348    */
 349   bool ParseHTMLDimension(const nsAString& aInput) {
 350     return DoParseHTMLDimension(aInput, false);
 351   }
 352
 353   /**
 354    * Parse a string into a nonzero dimension value.  This implements
 355    * https://html.spec.whatwg.org/multipage/#rules-for-parsing-non-zero-dimension-values
 356    * subject to the same constraints as ParseHTMLDimension above.
 357    *
 358    * @param aInput the string to parse
 359    * @return whether the value could be parsed
 360    */
 361   bool ParseNonzeroHTMLDimension(const nsAString& aInput) {
 362     return DoParseHTMLDimension(aInput, true);
 363   }
 364
 365   /**
 366    * Parse a string value into an integer.
 367    *
 368    * @param aString the string to parse
 369    * @return whether the value could be parsed
 370    */
 371   bool ParseIntValue(const nsAString& aString) {
 372     return ParseIntWithBounds(aString, INT32_MIN, INT32_MAX);
 373   }
 374
 375   /**
 376    * Parse a string value into an integer with minimum value and maximum value.
 377    *
 378    * @param aString the string to parse
 379    * @param aMin the minimum value (if value is less it will be bumped up)
 380    * @param aMax the maximum value (if value is greater it will be chopped down)
 381    * @return whether the value could be parsed
 382    */
 383   bool ParseIntWithBounds(const nsAString& aString, int32_t aMin,
 384                           int32_t aMax = INT32_MAX);
 385
 386   /**
 387    * Parse a string value into an integer with a fallback for invalid values.
 388    * Also allows clamping to a maximum value to support col/colgroup.span (this
 389    * is not per spec right now).
 390    *
 391    * @param aString the string to parse
 392    * @param aDefault the default value
 393    * @param aMax the maximum value (if value is greater it will be clamped)
 394    */
 395   void ParseIntWithFallback(const nsAString& aString, int32_t aDefault,
 396                             int32_t aMax = INT32_MAX);
 397
 398   /**
 399    * Parse a string value into a non-negative integer.
 400    * This method follows the rules for parsing non-negative integer from:
 401    * http://dev.w3.org/html5/spec/infrastructure.html#rules-for-parsing-non-negative-integers
 402    *
 403    * @param  aString the string to parse
 404    * @return whether the value is valid
 405    */
 406   bool ParseNonNegativeIntValue(const nsAString& aString);
 407
 408   /**
 409    * Parse a string value into a clamped non-negative integer.
 410    * This method follows the rules for parsing non-negative integer from:
 411    * https://html.spec.whatwg.org/multipage/infrastructure.html#clamped-to-the-range
 412    *
 413    * @param aString the string to parse
 414    * @param aDefault value to return for negative or invalid values
 415    * @param aMin minimum value
 416    * @param aMax maximum value
 417    */
 418   void ParseClampedNonNegativeInt(const nsAString& aString, int32_t aDefault,
 419                                   int32_t aMin, int32_t aMax);
 420
 421   /**
 422    * Parse a string value into a positive integer.
 423    * This method follows the rules for parsing non-negative integer from:
 424    * http://dev.w3.org/html5/spec/infrastructure.html#rules-for-parsing-non-negative-integers
 425    * In addition of these rules, the value has to be greater than zero.
 426    *
 427    * This is generally used for parsing content attributes which reflecting IDL
 428    * attributes are limited to only non-negative numbers greater than zero, see:
 429    * http://dev.w3.org/html5/spec/common-dom-interfaces.html#limited-to-only-non-negative-numbers-greater-than-zero
 430    *
 431    * @param aString       the string to parse
 432    * @return              whether the value was valid
 433    */
 434   bool ParsePositiveIntValue(const nsAString& aString);
 435
 436   /**
 437    * Parse a string into a color.  This implements what HTML5 calls the
 438    * "rules for parsing a legacy color value".
 439    *
 440    * @param aString the string to parse
 441    * @return whether the value could be parsed
 442    */
 443   bool ParseColor(const nsAString& aString);
 444
 445   /**
 446    * Parse a string value into a double-precision floating point value.
 447    *
 448    * @param aString the string to parse
 449    * @return whether the value could be parsed
 450    */
 451   bool ParseDoubleValue(const nsAString& aString);
 452
 453   /**
 454    * Parse a margin string of format 'top, right, bottom, left' into
 455    * an nsIntMargin.
 456    *
 457    * @param aString the string to parse
 458    * @return whether the value could be parsed
 459    */
 460   bool ParseIntMarginValue(const nsAString& aString);
 461
 462   /**
 463    * Parse a string into a CSS style rule.
 464    *
 465    * @param aString the style attribute value to be parsed.
 466    * @param aElement the element the attribute is set on.
 467    * @param aMaybeScriptedPrincipal if available, the scripted principal
 468    *        responsible for this attribute value, as passed to
 469    *        Element::ParseAttribute.
 470    */
 471   bool ParseStyleAttribute(const nsAString& aString,
 472                            nsIPrincipal* aMaybeScriptedPrincipal,
 473                            nsStyledElement* aElement);
 474
 475   size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
 476
 477  private:
 478   // These have to be the same as in ValueType
 479   enum ValueBaseType {
 480     eStringBase = eString,  // 00
 481     eOtherBase = 0x01,      // 01
 482     eAtomBase = eAtom,      // 10
 483     eIntegerBase = 0x03     // 11
 484   };
 485
 486   inline ValueBaseType BaseType() const;
 487   inline bool IsSVGType(ValueType aType) const;
 488
 489   /**
 490    * Get the index of an EnumTable in the sEnumTableArray.
 491    * If the EnumTable is not in the sEnumTableArray, it is added.
 492    *
 493    * @param aTable   the EnumTable to get the index of.
 494    * @return         the index of the EnumTable.
 495    */
 496   int16_t GetEnumTableIndex(const EnumTable* aTable);
 497
 498   inline void SetPtrValueAndType(void* aValue, ValueBaseType aType);
 499   void SetIntValueAndType(int32_t aValue, ValueType aType,
 500                           const nsAString* aStringValue);
 501   // aType can be ePercent or eDoubleValue.
 502   void SetDoubleValueAndType(double aValue, ValueType aType,
 503                              const nsAString* aStringValue);
 504   void SetColorValue(nscolor aColor, const nsAString& aString);
 505   void SetMiscAtomOrString(const nsAString* aValue);
 506   void ResetMiscAtomOrString();
 507   void SetSVGType(ValueType aType, const void* aValue,
 508                   const nsAString* aSerialized);
 509   inline void ResetIfSet();
 510
 511   inline void* GetPtr() const;
 512   inline MiscContainer* GetMiscContainer() const;
 513   inline int32_t GetIntInternal() const;
 514
 515   // Clears the current MiscContainer.  This will return null if there is no
 516   // existing container.
 517   MiscContainer* ClearMiscContainer();
 518   // Like ClearMiscContainer, except allocates a new container if one does not
 519   // exist already.
 520   MiscContainer* EnsureEmptyMiscContainer();
 521   bool EnsureEmptyAtomArray();
 522   already_AddRefed<nsStringBuffer> GetStringBuffer(
 523       const nsAString& aValue) const;
 524   // Given an enum table and a particular entry in that table, return
 525   // the actual integer value we should store.
 526   int32_t EnumTableEntryToValue(const EnumTable* aEnumTable,
 527                                 const EnumTable* aTableEntry);
 528
 529   template <typename F>
 530   bool SubstringCheck(const nsAString& aValue,
 531                       nsCaseTreatment aCaseSensitive) const;
 532
 533   static MiscContainer* AllocMiscContainer();
 534   static void DeallocMiscContainer(MiscContainer* aCont);
 535
 536   static nsTArray<const EnumTable*>* sEnumTableArray;
 537   static MiscContainer* sMiscContainerCache;
 538
 539   /**
 540    * Helper for ParseHTMLDimension and ParseNonzeroHTMLDimension.
 541    *
 542    * @param aInput the string to parse
 543    * @param aEnsureNonzero whether to fail the parse if the value is 0
 544    * @return whether the value could be parsed
 545    */
 546   bool DoParseHTMLDimension(const nsAString& aInput, bool aEnsureNonzero);
 547
 548   uintptr_t mBits;
 549 };
 550
 551 inline const nsAttrValue& nsAttrValue::operator=(const nsAttrValue& aOther) {
 552   SetTo(aOther);
 553   return *this;
 554 }
 555
 556 inline nsAttrValue::ValueBaseType nsAttrValue::BaseType() const {
 557   return static_cast<ValueBaseType>(mBits & NS_ATTRVALUE_BASETYPE_MASK);
 558 }
 559
 560 inline void* nsAttrValue::GetPtr() const {
 561   NS_ASSERTION(BaseType() != eIntegerBase, "getting pointer from non-pointer");
 562   return reinterpret_cast<void*>(mBits & NS_ATTRVALUE_POINTERVALUE_MASK);
 563 }
 564
 565 inline bool nsAttrValue::IsEmptyString() const { return !mBits; }
 566
 567 #endif