layout/style/GroupRule.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  * internal interface representing CSS style rules that contain other
   9  * rules, such as @media rules
  10  */
  11
  12 #include "mozilla/css/GroupRule.h"
  13
  14 #include "mozilla/dom/CSSRuleList.h"
  15
  16 #include "nsPrintfCString.h"
  17
  18 using namespace mozilla::dom;
  19
  20 namespace mozilla::css {
  21
  22 GroupRule::GroupRule(StyleSheet* aSheet, Rule* aParentRule,
  23                      uint32_t aLineNumber, uint32_t aColumnNumber)
  24     : Rule(aSheet, aParentRule, aLineNumber, aColumnNumber) {}
  25
  26 GroupRule::~GroupRule() {
  27   MOZ_ASSERT(!mSheet, "SetStyleSheet should have been called");
  28   if (mRuleList) {
  29     mRuleList->DropReferences();
  30   }
  31 }
  32
  33 NS_IMPL_ADDREF_INHERITED(GroupRule, Rule)
  34 NS_IMPL_RELEASE_INHERITED(GroupRule, Rule)
  35
  36 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(GroupRule)
  37 NS_INTERFACE_MAP_END_INHERITING(Rule)
  38
  39 bool GroupRule::IsCCLeaf() const {
  40   if (!Rule::IsCCLeaf()) {
  41     return false;
  42   }
  43   return !mRuleList;
  44 }
  45
  46 ServoCSSRuleList* GroupRule::CssRules() {
  47   if (!mRuleList) {
  48     // Lazily create the rule list since most style rules won't have child
  49     // rules.
  50     mRuleList =
  51         new ServoCSSRuleList(GetOrCreateRawRules(), GetStyleSheet(), this);
  52   }
  53   return mRuleList;
  54 }
  55
  56 NS_IMPL_CYCLE_COLLECTION_CLASS(GroupRule)
  57
  58 NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(GroupRule, Rule)
  59   if (tmp->mRuleList) {
  60     // If tmp has a style sheet (which can happen if it gets unlinked
  61     // earlier than its owning style sheet), then we need to null out the
  62     // style sheet pointer on descendants now, before we clear mRuleList.
  63     tmp->mRuleList->DropReferences();
  64     tmp->mRuleList = nullptr;
  65   }
  66 NS_IMPL_CYCLE_COLLECTION_UNLINK_END
  67
  68 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(GroupRule, Rule)
  69   ImplCycleCollectionTraverse(cb, tmp->mRuleList, "mRuleList");
  70 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
  71
  72 #ifdef DEBUG
  73 void GroupRule::List(FILE* out, int32_t aIndent) const {
  74   // TODO list something reasonable?
  75 }
  76 #endif
  77
  78 /* virtual */
  79 void GroupRule::DropSheetReference() {
  80   if (mRuleList) {
  81     mRuleList->DropSheetReference();
  82   }
  83   Rule::DropSheetReference();
  84 }
  85
  86 uint32_t GroupRule::InsertRule(const nsACString& aRule, uint32_t aIndex,
  87                                ErrorResult& aRv) {
  88   if (IsReadOnly()) {
  89     return 0;
  90   }
  91
  92   StyleSheet* sheet = GetStyleSheet();
  93   if (NS_WARN_IF(!sheet)) {
  94     aRv.Throw(NS_ERROR_FAILURE);
  95     return 0;
  96   }
  97
  98   uint32_t count = StyleRuleCount();
  99   if (aIndex > count) {
 100     aRv.ThrowIndexSizeError(nsPrintfCString(
 101         "Can't insert rule at index %u because rule list length is %u", aIndex,
 102         count));
 103     return 0;
 104   }
 105
 106   NS_ASSERTION(count <= INT32_MAX, "Too many style rules!");
 107
 108   nsresult rv = sheet->InsertRuleIntoGroup(aRule, this, aIndex);
 109   if (NS_FAILED(rv)) {
 110     aRv.Throw(rv);
 111     return 0;
 112   }
 113   return aIndex;
 114 }
 115
 116 void GroupRule::DeleteRule(uint32_t aIndex, ErrorResult& aRv) {
 117   if (IsReadOnly()) {
 118     return;
 119   }
 120
 121   StyleSheet* sheet = GetStyleSheet();
 122   if (NS_WARN_IF(!sheet)) {
 123     aRv.Throw(NS_ERROR_FAILURE);
 124     return;
 125   }
 126
 127   uint32_t count = StyleRuleCount();
 128   if (aIndex >= count) {
 129     aRv.ThrowIndexSizeError(nsPrintfCString(
 130         "Index %u is too large for list of length %u", aIndex, count));
 131     return;
 132   }
 133
 134   NS_ASSERTION(count <= INT32_MAX, "Too many style rules!");
 135
 136   nsresult rv = sheet->DeleteRuleFromGroup(this, aIndex);
 137   if (NS_FAILED(rv)) {
 138     aRv.Throw(rv);
 139   }
 140 }
 141
 142 size_t GroupRule::SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const {
 143   // TODO how to implement?
 144   return 0;
 145 }
 146
 147 }  // namespace mozilla::css