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