layout/style/nsCSSProps.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 /*
   8  * methods for dealing with CSS properties and tables of the keyword
   9  * values they accept
  10  */
  11
  12 #include "nsCSSProps.h"
  13
  14 #include "mozilla/ArrayUtils.h"
  15 #include "mozilla/Casting.h"
  16
  17 #include "gfxPlatform.h"
  18 #include "nsLayoutUtils.h"
  19 #include "nsIWidget.h"
  20 #include "nsStyleConsts.h"  // For system widget appearance types
  21
  22 #include "mozilla/dom/Animation.h"
  23 #include "mozilla/dom/AnimationEffectBinding.h"  // for PlaybackDirection
  24 #include "mozilla/gfx/gfxVars.h"                 // for UseWebRender
  25 #include "mozilla/gfx/gfxVarReceiver.h"
  26 #include "mozilla/LookAndFeel.h"  // for system colors
  27
  28 #include "nsString.h"
  29 #include "nsStaticNameTable.h"
  30
  31 #include "mozilla/Preferences.h"
  32 #include "mozilla/StaticPrefs_layout.h"
  33
  34 using namespace mozilla;
  35
  36 static int32_t gPropertyTableRefCount;
  37 static nsStaticCaseInsensitiveNameTable* gFontDescTable;
  38 static nsStaticCaseInsensitiveNameTable* gCounterDescTable;
  39 static nsTHashMap<nsCStringHashKey, nsCSSPropertyID>* gPropertyIDLNameTable;
  40
  41 static const char* const kCSSRawFontDescs[] = {
  42 #define CSS_FONT_DESC(name_, method_) #name_,
  43 #include "nsCSSFontDescList.h"
  44 #undef CSS_FONT_DESC
  45 };
  46
  47 static const char* const kCSSRawCounterDescs[] = {
  48 #define CSS_COUNTER_DESC(name_, method_) #name_,
  49 #include "nsCSSCounterDescList.h"
  50 #undef CSS_COUNTER_DESC
  51 };
  52
  53 static nsStaticCaseInsensitiveNameTable* CreateStaticTable(
  54     const char* const aRawTable[], int32_t aLength) {
  55   auto table = new nsStaticCaseInsensitiveNameTable(aRawTable, aLength);
  56 #ifdef DEBUG
  57   // Partially verify the entries.
  58   for (int32_t index = 0; index < aLength; ++index) {
  59     nsAutoCString temp(aRawTable[index]);
  60     MOZ_ASSERT(-1 == temp.FindChar('_'),
  61                "underscore char in case insensitive name table");
  62   }
  63 #endif
  64   return table;
  65 }
  66
  67 void nsCSSProps::RecomputeEnabledState(const char* aPref, void*) {
  68   MOZ_RELEASE_ASSERT(NS_IsMainThread());
  69   DebugOnly<bool> foundPref = false;
  70   for (const PropertyPref* pref = kPropertyPrefTable;
  71        pref->mPropID != eCSSProperty_UNKNOWN; pref++) {
  72     if (!aPref || !strcmp(aPref, pref->mPref)) {
  73       foundPref = true;
  74 #ifdef FUZZING
  75       gPropertyEnabled[pref->mPropID] = true;
  76 #else
  77       gPropertyEnabled[pref->mPropID] = Preferences::GetBool(pref->mPref);
  78 #endif
  79       if (pref->mPropID == eCSSProperty_backdrop_filter) {
  80         gPropertyEnabled[pref->mPropID] &=
  81             gfx::gfxVars::GetUseWebRenderOrDefault();
  82       }
  83     }
  84   }
  85   MOZ_ASSERT(foundPref);
  86 }
  87
  88 void nsCSSProps::AddRefTable(void) {
  89   if (0 == gPropertyTableRefCount++) {
  90     MOZ_ASSERT(!gFontDescTable, "pre existing array!");
  91     MOZ_ASSERT(!gCounterDescTable, "pre existing array!");
  92     MOZ_ASSERT(!gPropertyIDLNameTable, "pre existing array!");
  93
  94     gFontDescTable = CreateStaticTable(kCSSRawFontDescs, eCSSFontDesc_COUNT);
  95     gCounterDescTable =
  96         CreateStaticTable(kCSSRawCounterDescs, eCSSCounterDesc_COUNT);
  97
  98     gPropertyIDLNameTable = new nsTHashMap<nsCStringHashKey, nsCSSPropertyID>;
  99     for (nsCSSPropertyID p = nsCSSPropertyID(0);
 100          size_t(p) < ArrayLength(kIDLNameTable); p = nsCSSPropertyID(p + 1)) {
 101       if (kIDLNameTable[p]) {
 102         gPropertyIDLNameTable->InsertOrUpdate(
 103             nsDependentCString(kIDLNameTable[p]), p);
 104       }
 105     }
 106
 107     static bool prefObserversInited = false;
 108     if (!prefObserversInited) {
 109       prefObserversInited = true;
 110       for (const PropertyPref* pref = kPropertyPrefTable;
 111            pref->mPropID != eCSSProperty_UNKNOWN; pref++) {
 112         // https://bugzilla.mozilla.org/show_bug.cgi?id=1472523
 113         // We need to use nsCString instead of substring because the preference
 114         // callback code stores them. Using AssignLiteral prevents any
 115         // unnecessary allocations.
 116         nsCString prefName;
 117         prefName.AssignLiteral(pref->mPref, strlen(pref->mPref));
 118         Preferences::RegisterCallback(nsCSSProps::RecomputeEnabledState,
 119                                       prefName);
 120       }
 121       RecomputeEnabledState(/* aPrefName = */ nullptr);
 122     }
 123   }
 124 }
 125
 126 void nsCSSProps::ReleaseTable(void) {
 127   if (0 == --gPropertyTableRefCount) {
 128     delete gFontDescTable;
 129     gFontDescTable = nullptr;
 130
 131     delete gCounterDescTable;
 132     gCounterDescTable = nullptr;
 133
 134     delete gPropertyIDLNameTable;
 135     gPropertyIDLNameTable = nullptr;
 136   }
 137 }
 138
 139 /* static */
 140 bool nsCSSProps::IsCustomPropertyName(const nsACString& aProperty) {
 141   return aProperty.Length() >= CSS_CUSTOM_NAME_PREFIX_LENGTH &&
 142          StringBeginsWith(aProperty, "--"_ns);
 143 }
 144
 145 nsCSSPropertyID nsCSSProps::LookupPropertyByIDLName(
 146     const nsACString& aPropertyIDLName, EnabledState aEnabled) {
 147   MOZ_ASSERT(gPropertyIDLNameTable, "no lookup table, needs addref");
 148   nsCSSPropertyID res;
 149   if (!gPropertyIDLNameTable->Get(aPropertyIDLName, &res)) {
 150     return eCSSProperty_UNKNOWN;
 151   }
 152   MOZ_ASSERT(res < eCSSProperty_COUNT);
 153   if (!IsEnabled(res, aEnabled)) {
 154     return eCSSProperty_UNKNOWN;
 155   }
 156   return res;
 157 }
 158
 159 nsCSSFontDesc nsCSSProps::LookupFontDesc(const nsACString& aFontDesc) {
 160   MOZ_ASSERT(gFontDescTable, "no lookup table, needs addref");
 161   nsCSSFontDesc which = nsCSSFontDesc(gFontDescTable->Lookup(aFontDesc));
 162
 163   if (which == eCSSFontDesc_Display &&
 164       !StaticPrefs::layout_css_font_display_enabled()) {
 165     which = eCSSFontDesc_UNKNOWN;
 166   }
 167   return which;
 168 }
 169
 170 const nsCString& nsCSSProps::GetStringValue(nsCSSFontDesc aFontDescID) {
 171   MOZ_ASSERT(gFontDescTable, "no lookup table, needs addref");
 172   if (gFontDescTable) {
 173     return gFontDescTable->GetStringValue(int32_t(aFontDescID));
 174   } else {
 175     static nsDependentCString sNullStr("");
 176     return sNullStr;
 177   }
 178 }
 179
 180 const nsCString& nsCSSProps::GetStringValue(nsCSSCounterDesc aCounterDesc) {
 181   MOZ_ASSERT(gCounterDescTable, "no lookup table, needs addref");
 182   if (gCounterDescTable) {
 183     return gCounterDescTable->GetStringValue(int32_t(aCounterDesc));
 184   } else {
 185     static nsDependentCString sNullStr("");
 186     return sNullStr;
 187   }
 188 }
 189 const CSSPropFlags nsCSSProps::kFlagsTable[eCSSProperty_COUNT] = {
 190 #define CSS_PROP_LONGHAND(name_, id_, method_, flags_, ...) flags_,
 191 #define CSS_PROP_SHORTHAND(name_, id_, method_, flags_, ...) flags_,
 192 #include "mozilla/ServoCSSPropList.h"
 193 #undef CSS_PROP_SHORTHAND
 194 #undef CSS_PROP_LONGHAND
 195 };
 196
 197 /* static */
 198 bool nsCSSProps::gPropertyEnabled[eCSSProperty_COUNT_with_aliases] = {
 199 // If the property has any "ENABLED_IN" flag set, it is disabled by
 200 // default. Note that, if a property has pref, whatever its default
 201 // value is, it will later be changed in nsCSSProps::AddRefTable().
 202 // If the property has "ENABLED_IN" flags but doesn't have a pref,
 203 // it is an internal property which is disabled elsewhere.
 204 #define IS_ENABLED_BY_DEFAULT(flags_) \
 205   (!((flags_) & (CSSPropFlags::EnabledMask | CSSPropFlags::Inaccessible)))
 206
 207 #define CSS_PROP_LONGHAND(name_, id_, method_, flags_, ...) \
 208   IS_ENABLED_BY_DEFAULT(flags_),
 209 #define CSS_PROP_SHORTHAND(name_, id_, method_, flags_, ...) \
 210   IS_ENABLED_BY_DEFAULT(flags_),
 211 #define CSS_PROP_ALIAS(...) true,
 212 #include "mozilla/ServoCSSPropList.h"
 213 #undef CSS_PROP_ALIAS
 214 #undef CSS_PROP_SHORTHAND
 215 #undef CSS_PROP_LONGHAND
 216
 217 #undef IS_ENABLED_BY_DEFAULT
 218 };
 219
 220 /**
 221  * A singleton class to register as a receiver for gfxVars.
 222  * Updates the state of backdrop-filter's pref if the gfx
 223  * WebRender var changes state.
 224  */
 225 class nsCSSPropsGfxVarReceiver final : public gfx::gfxVarReceiver {
 226   constexpr nsCSSPropsGfxVarReceiver() = default;
 227
 228   // WebRender's last known enabled state.
 229   static bool sLastKnownUseWebRender;
 230   static nsCSSPropsGfxVarReceiver sInstance;
 231
 232  public:
 233   static gfx::gfxVarReceiver& GetInstance() { return sInstance; }
 234
 235   void OnVarChanged(const gfx::GfxVarUpdate&) override {
 236     bool enabled = gfxVars::UseWebRender();
 237     if (sLastKnownUseWebRender != enabled) {
 238       sLastKnownUseWebRender = enabled;
 239       nsCSSProps::RecomputeEnabledState("layout.css.backdrop-filter.enabled");
 240     }
 241   }
 242 };
 243
 244 /* static */
 245 nsCSSPropsGfxVarReceiver nsCSSPropsGfxVarReceiver::sInstance =
 246     nsCSSPropsGfxVarReceiver();
 247
 248 /* static */
 249 bool nsCSSPropsGfxVarReceiver::sLastKnownUseWebRender = false;
 250
 251 /* static */
 252 gfx::gfxVarReceiver& nsCSSProps::GfxVarReceiver() {
 253   return nsCSSPropsGfxVarReceiver::GetInstance();
 254 }
 255
 256 #include "nsCSSPropsGenerated.inc"