layout/style/nsRuleData.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 /*
   7  * temporary (expanded) representation of property-value pairs used to
   8  * hold data from matched rules during style data computation.
   9  */
  10
  11 #ifndef nsRuleData_h_
  12 #define nsRuleData_h_
  13
  14 #include "mozilla/CSSVariableDeclarations.h"
  15 #include "nsCSSProps.h"
  16 #include "nsCSSValue.h"
  17 #include "nsStyleStructFwd.h"
  18
  19 class nsPresContext;
  20 class nsStyleContext;
  21 struct nsRuleData;
  22
  23 typedef void (*nsPostResolveFunc)(void* aStyleStruct, nsRuleData* aData);
  24
  25 struct nsRuleData
  26 {
  27   const uint32_t mSIDs;
  28   bool mCanStoreInRuleTree;
  29   bool mIsImportantRule;
  30   uint16_t mLevel; // an nsStyleSet::sheetType
  31   nsPresContext* const mPresContext;
  32   nsStyleContext* const mStyleContext;
  33
  34   // We store nsCSSValues needed to compute the data for one or more
  35   // style structs (specified by the bitfield mSIDs).  These are stored
  36   // in a single array allocation (which our caller allocates; see
  37   // AutoCSSValueArray)   The offset of each property |prop| in
  38   // mValueStorage is the sum of
  39   // mValueOffsets[nsCSSProps::kSIDTable[prop]] and
  40   // nsCSSProps::PropertyIndexInStruct(prop).  The only place we gather
  41   // more than one style struct's data at a time is
  42   // nsRuleNode::HasAuthorSpecifiedRules; therefore some code that we
  43   // know is not called from HasAuthorSpecifiedRules assumes that the
  44   // mValueOffsets for the one struct in mSIDs is zero.
  45   nsCSSValue* const mValueStorage; // our user owns this array
  46   size_t mValueOffsets[nsStyleStructID_Length];
  47
  48   nsAutoPtr<mozilla::CSSVariableDeclarations> mVariables;
  49
  50   nsRuleData(uint32_t aSIDs, nsCSSValue* aValueStorage,
  51              nsPresContext* aContext, nsStyleContext* aStyleContext);
  52
  53 #ifdef DEBUG
  54   ~nsRuleData();
  55 #else
  56   ~nsRuleData() {}
  57 #endif
  58
  59   /**
  60    * Return a pointer to the value object within |this| corresponding
  61    * to property |aProperty|.
  62    *
  63    * This function must only be called if the given property is in
  64    * mSIDs.
  65    */
  66   nsCSSValue* ValueFor(nsCSSProperty aProperty)
  67   {
  68     NS_ABORT_IF_FALSE(aProperty < eCSSProperty_COUNT_no_shorthands,
  69                       "invalid or shorthand property");
  70
  71     nsStyleStructID sid = nsCSSProps::kSIDTable[aProperty];
  72     size_t indexInStruct = nsCSSProps::PropertyIndexInStruct(aProperty);
  73
  74     // This should really be nsCachedStyleData::GetBitForSID, but we can't
  75     // include that here since it includes us.
  76     NS_ABORT_IF_FALSE(mSIDs & (1 << sid),
  77                       "calling nsRuleData::ValueFor on property not in mSIDs");
  78     NS_ABORT_IF_FALSE(sid != eStyleStruct_BackendOnly &&
  79                       indexInStruct != size_t(-1),
  80                       "backend-only property");
  81
  82     return mValueStorage + mValueOffsets[sid] + indexInStruct;
  83   }
  84
  85   const nsCSSValue* ValueFor(nsCSSProperty aProperty) const {
  86     return const_cast<nsRuleData*>(this)->ValueFor(aProperty);
  87   }
  88
  89   /**
  90    * Getters like ValueFor(aProperty), but for each property by name
  91    * (ValueForBackgroundColor, etc.), and more efficient than ValueFor.
  92    * These use the names used for the property on DOM interfaces (the
  93    * 'method' field in nsCSSPropList.h).
  94    *
  95    * Like ValueFor(), the caller must check that the property is within
  96    * mSIDs.
  97    */
  98   #define CSS_PROP_PUBLIC_OR_PRIVATE(publicname_, privatename_) privatename_
  99   #define CSS_PROP(name_, id_, method_, flags_, pref_, parsevariant_,        \
 100                    kwtable_, stylestruct_, stylestructoffset_, animtype_)    \
 101     nsCSSValue* ValueFor##method_() {                                        \
 102       NS_ABORT_IF_FALSE(mSIDs & NS_STYLE_INHERIT_BIT(stylestruct_),          \
 103                         "Calling nsRuleData::ValueFor" #method_ " without "  \
 104                         "NS_STYLE_INHERIT_BIT(" #stylestruct_ " in mSIDs."); \
 105       nsStyleStructID sid = eStyleStruct_##stylestruct_;                     \
 106       size_t indexInStruct =                                                 \
 107         nsCSSProps::PropertyIndexInStruct(eCSSProperty_##id_);               \
 108       NS_ABORT_IF_FALSE(sid != eStyleStruct_BackendOnly &&                   \
 109                         indexInStruct != size_t(-1),                         \
 110                         "backend-only property");                            \
 111       return mValueStorage + mValueOffsets[sid] + indexInStruct;             \
 112     }                                                                        \
 113     const nsCSSValue* ValueFor##method_() const {                            \
 114       return const_cast<nsRuleData*>(this)->ValueFor##method_();             \
 115     }
 116   #define CSS_PROP_BACKENDONLY(name_, id_, method_, flags_, pref_,           \
 117                              parsevariant_, kwtable_)                        \
 118     /* empty; backend-only structs are not in nsRuleData  */
 119   #include "nsCSSPropList.h"
 120   #undef CSS_PROP
 121   #undef CSS_PROP_PUBLIC_OR_PRIVATE
 122   #undef CSS_PROP_BACKENDONLY
 123
 124 private:
 125   inline size_t GetPoisonOffset();
 126
 127 };
 128
 129 #endif