Implement custom 'range' values for @counter-style

Bug: 687225
Change-Id: I57449229bf443ce33613a41b21e47f3fe52ca4f0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2586096
Commit-Queue: Xiaocheng Hu <xiaochengh@chromium.org>
Reviewed-by: Anders Hartvoll Ruud <andruud@chromium.org>
Cr-Commit-Position: refs/heads/master@{#836883}

third_party/blink/renderer/core/css/counter_style.cc

@@ -87,6 +87,27 @@ String SymbolToString(const CSSValue& value) {
   return To<CSSCustomIdentValue>(value).Value();
 }
 
+std::pair<int, int> BoundsToIntegerPair(const CSSValuePair& bounds) {
+  int lower_bound, upper_bound;
+  if (bounds.First().IsIdentifierValue()) {
+    DCHECK_EQ(CSSValueID::kInfinite,
+              To<CSSIdentifierValue>(bounds.First()).GetValueID());
+    lower_bound = std::numeric_limits<int>::min();
+  } else {
+    DCHECK(bounds.First().IsPrimitiveValue());
+    lower_bound = To<CSSPrimitiveValue>(bounds.First()).GetIntValue();
+  }
+  if (bounds.Second().IsIdentifierValue()) {
+    DCHECK_EQ(CSSValueID::kInfinite,
+              To<CSSIdentifierValue>(bounds.Second()).GetValueID());
+    upper_bound = std::numeric_limits<int>::max();
+  } else {
+    DCHECK(bounds.Second().IsPrimitiveValue());
+    upper_bound = To<CSSPrimitiveValue>(bounds.Second()).GetIntValue();
+  }
+  return std::make_pair(lower_bound, upper_bound);
+}
+
 // https://drafts.csswg.org/css-counter-styles/#cyclic-system
 Vector<wtf_size_t> CyclicAlgorithm(int value, wtf_size_t num_symbols) {
   DCHECK(num_symbols);
@@ -253,6 +274,16 @@ CounterStyle::CounterStyle(const StyleRuleCounterStyle& rule)
     pad_symbol_ = SymbolToString(pair.Second());
   }
 
+  if (const CSSValue* range = rule.GetRange()) {
+    if (range->IsIdentifierValue()) {
+      DCHECK_EQ(CSSValueID::kAuto, To<CSSIdentifierValue>(range)->GetValueID());
+      // Empty |range_| already means 'auto'.
+    } else {
+      for (const CSSValue* bounds : To<CSSValueList>(*range))
+        range_.push_back(BoundsToIntegerPair(To<CSSValuePair>(*bounds)));
+    }
+  }
+
   // TODO(crbug.com/687225): Implement and populate other fields.
 }
 
@@ -281,6 +312,9 @@ void CounterStyle::ResolveExtends(const CounterStyle& extended) {
     pad_symbol_ = extended.pad_symbol_;
   }
 
+  if (!style_rule_->GetRange())
+    range_ = extended.range_;
+
   // TODO(crbug.com/687225): Implement and populate other fields.
 }
 
@@ -299,7 +333,13 @@ void CounterStyle::ResetFallback() {
 }
 
 bool CounterStyle::RangeContains(int value) const {
-  // TODO(crbug.com/687225): Implement non-auto values of 'range'
+  if (range_.size()) {
+    for (const auto& bounds : range_) {
+      if (value >= bounds.first && value <= bounds.second)
+        return true;
+    }
+    return false;
+  }
 
   // 'range' value is auto
   switch (system_) {

third_party/blink/renderer/core/css/counter_style.h

@@ -101,6 +101,9 @@ class CORE_EXPORT CounterStyle final : public GarbageCollected<CounterStyle> {
   // Additive weights, for the 'additive' system only.
   Vector<wtf_size_t> additive_weights_;
 
+  // Value of 'range' descriptor. Empty vector means 'auto'.
+  Vector<std::pair<int, int>> range_;
+
   String negative_prefix_ = "-";
   String negative_suffix_;
 

third_party/blink/renderer/core/css/counter_style_test.cc

@@ -252,4 +252,78 @@ TEST_F(CounterStyleTest, PadLengthLimit) {
   EXPECT_EQ("0", foo.GenerateRepresentation(0));
 }
 
+TEST_F(CounterStyleTest, SymbolicWithExtendedRange) {
+  InsertStyleElement(R"CSS(
+    @counter-style base {
+      system: symbolic;
+      symbols: A B;
+    }
+
+    @counter-style custom {
+      system: extends base;
+      range: infinite -2, 0 infinite;
+    }
+
+    @counter-style extended {
+      system: extends custom;
+    }
+  )CSS");
+  UpdateAllLifecyclePhasesForTest();
+
+  // Getting custom 'range' directly from descriptor value.
+  const CounterStyle& custom = GetCounterStyle("custom");
+  EXPECT_EQ("-AA", custom.GenerateRepresentation(-3));
+  EXPECT_EQ("-B", custom.GenerateRepresentation(-2));
+  // -1 is out of 'range' value. Fallback to 'decimal'
+  EXPECT_EQ("-1", custom.GenerateRepresentation(-1));
+  // 0 is within 'range' but not representable. Fallback to 'decimal'.
+  EXPECT_EQ("0", custom.GenerateRepresentation(0));
+  EXPECT_EQ("A", custom.GenerateRepresentation(1));
+
+  // Getting custom 'range' indirectly by extending a counter style.
+  const CounterStyle& extended = GetCounterStyle("extended");
+  EXPECT_EQ("-AA", extended.GenerateRepresentation(-3));
+  EXPECT_EQ("-B", extended.GenerateRepresentation(-2));
+  EXPECT_EQ("-1", extended.GenerateRepresentation(-1));
+  EXPECT_EQ("0", extended.GenerateRepresentation(0));
+  EXPECT_EQ("A", extended.GenerateRepresentation(1));
+}
+
+TEST_F(CounterStyleTest, AdditiveWithExtendedRange) {
+  InsertStyleElement(R"CSS(
+    @counter-style base {
+      system: additive;
+      additive-symbols: 2 B, 1 A;
+    }
+
+    @counter-style custom {
+      system: extends base;
+      range: infinite -2, 0 infinite;
+    }
+
+    @counter-style extended {
+      system: extends custom;
+    }
+  )CSS");
+  UpdateAllLifecyclePhasesForTest();
+
+  // Getting custom 'range' directly from descriptor value.
+  const CounterStyle& custom = GetCounterStyle("custom");
+  EXPECT_EQ("-BA", custom.GenerateRepresentation(-3));
+  EXPECT_EQ("-B", custom.GenerateRepresentation(-2));
+  // -1 is out of 'range' value. Fallback to 'decimal'.
+  EXPECT_EQ("-1", custom.GenerateRepresentation(-1));
+  // 0 is within 'range' but not representable. Fallback to 'decimal'.
+  EXPECT_EQ("0", custom.GenerateRepresentation(0));
+  EXPECT_EQ("A", custom.GenerateRepresentation(1));
+
+  // Getting custom 'range' indirectly by extending a counter style.
+  const CounterStyle& extended = GetCounterStyle("extended");
+  EXPECT_EQ("-BA", extended.GenerateRepresentation(-3));
+  EXPECT_EQ("-B", extended.GenerateRepresentation(-2));
+  EXPECT_EQ("-1", extended.GenerateRepresentation(-1));
+  EXPECT_EQ("0", extended.GenerateRepresentation(0));
+  EXPECT_EQ("A", extended.GenerateRepresentation(1));
+}
+
 }  // namespace blink