layout/style/ComputedStyleInlines.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  * Inlined methods for ComputedStyle. Will just redirect to
   9  * GeckoComputedStyle methods when compiled without stylo, but will do
  10  * virtual dispatch (by checking which kind of container it is)
  11  * in stylo mode.
  12  */
  13
  14 #ifndef ComputedStyleInlines_h
  15 #define ComputedStyleInlines_h
  16
  17 #include "mozilla/ComputedStyle.h"
  18
  19 #include "MainThreadUtils.h"
  20 #include "mozilla/Assertions.h"
  21 #include "mozilla/Unused.h"
  22 #include "nsStyleStructInlines.h"
  23
  24 namespace mozilla {
  25
  26 namespace detail {
  27
  28 template <typename T, typename Enable = void>
  29 struct HasTriggerImageLoads : public std::false_type {};
  30
  31 template <typename T>
  32 struct HasTriggerImageLoads<T, decltype(std::declval<T&>().TriggerImageLoads(
  33                                    std::declval<dom::Document&>(), nullptr))>
  34     : public std::true_type {};
  35
  36 template <typename T, const T* (ComputedStyle::*Method)() const>
  37 void TriggerImageLoads(dom::Document& aDocument, const ComputedStyle* aOldStyle,
  38                        ComputedStyle* aStyle) {
  39   if constexpr (HasTriggerImageLoads<T>::value) {
  40     auto* old = aOldStyle ? (aOldStyle->*Method)() : nullptr;
  41     auto* current = const_cast<T*>((aStyle->*Method)());
  42     current->TriggerImageLoads(aDocument, old);
  43   } else {
  44     Unused << aOldStyle;
  45     Unused << aStyle;
  46   }
  47 }
  48
  49 }  // namespace detail
  50
  51 void ComputedStyle::StartImageLoads(dom::Document& aDocument,
  52                                     const ComputedStyle* aOldStyle) {
  53   MOZ_ASSERT(NS_IsMainThread());
  54
  55 #define STYLE_STRUCT(name_)                                                \
  56   detail::TriggerImageLoads<nsStyle##name_, &ComputedStyle::Style##name_>( \
  57       aDocument, aOldStyle, this);
  58 #include "nsStyleStructList.h"
  59 #undef STYLE_STRUCT
  60 }
  61
  62 StylePointerEvents ComputedStyle::PointerEvents() const {
  63   if (IsRootElementStyle()) {
  64     // The root frame is not allowed to have pointer-events: none, or else no
  65     // frames could be hit test against and scrolling the viewport would not
  66     // work.
  67     return StylePointerEvents::Auto;
  68   }
  69   const auto& ui = *StyleUI();
  70   if (ui.IsInert()) {
  71     return StylePointerEvents::None;
  72   }
  73   return ui.ComputedPointerEvents();
  74 }
  75
  76 StyleUserSelect ComputedStyle::UserSelect() const {
  77   return StyleUI()->IsInert() ? StyleUserSelect::None
  78                               : StyleUIReset()->ComputedUserSelect();
  79 }
  80
  81 bool ComputedStyle::IsFixedPosContainingBlockForNonSVGTextFrames() const {
  82   // NOTE: Any CSS properties that influence the output of this function
  83   // should return FIXPOS_CB_NON_SVG for will-change.
  84   if (IsRootElementStyle()) {
  85     return false;
  86   }
  87
  88   const auto& disp = *StyleDisplay();
  89   if (disp.mWillChange.bits & mozilla::StyleWillChangeBits::FIXPOS_CB_NON_SVG) {
  90     return true;
  91   }
  92
  93   const auto& effects = *StyleEffects();
  94   return effects.HasFilters() || effects.HasBackdropFilters();
  95 }
  96
  97 bool ComputedStyle::IsFixedPosContainingBlock(
  98     const nsIFrame* aContextFrame) const {
  99   // NOTE: Any CSS properties that influence the output of this function
 100   // should also handle will-change appropriately.
 101   if (aContextFrame->IsInSVGTextSubtree()) {
 102     return false;
 103   }
 104   if (IsFixedPosContainingBlockForNonSVGTextFrames()) {
 105     return true;
 106   }
 107   const auto& disp = *StyleDisplay();
 108   if (disp.IsFixedPosContainingBlockForContainLayoutAndPaintSupportingFrames() &&
 109       aContextFrame->SupportsContainLayoutAndPaint()) {
 110     return true;
 111   }
 112   if (disp.IsFixedPosContainingBlockForTransformSupportingFrames() &&
 113       aContextFrame->SupportsCSSTransforms()) {
 114     return true;
 115   }
 116   return false;
 117 }
 118
 119 bool ComputedStyle::IsAbsPosContainingBlock(
 120     const nsIFrame* aContextFrame) const {
 121   if (IsFixedPosContainingBlock(aContextFrame)) {
 122     return true;
 123   }
 124   // NOTE: Any CSS properties that influence the output of this function
 125   // should also handle will-change appropriately.
 126   return StyleDisplay()->IsPositionedStyle() &&
 127          !aContextFrame->IsInSVGTextSubtree();
 128 }
 129
 130 }  // namespace mozilla
 131
 132 #endif  // ComputedStyleInlines_h