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LibWeb: Handle reference cycles in SVG gradient linking

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Since SVG gradients can reference each other, we have to keep track of
visited gradients when traversing the link chain, or we will recurse
infinitely when there's a reference cycle.
This commit is contained in:
Andreas Kling 2024-03-10 12:18:09 +01:00
parent 1b8d8c7bbc
commit 2e0297d703
Notes: sideshowbarker 2024-07-17 02:14:39 +09:00
8 changed files with 155 additions and 36 deletions
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1
Tests/LibWeb/Text/expected/SVG/gradient-with-reference-cycle.txt Normal file
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@ -0,0 +1 @@
PASS (didn't hang or crash)

13
Tests/LibWeb/Text/input/SVG/gradient-with-reference-cycle.html Normal file
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@ -0,0 +1,13 @@
<!doctype html>
<script src="../include.js"></script>
<svg>
<linearGradient id="lol" href="#lmao"/>
<linearGradient id="lmao" href="#even"/>
<linearGradient id="even" href="#lol"/>
<rect fill="url(#lol)" />
</svg>
<script>
test(() => {
println("PASS (didn't hang or crash)");
});
</script>

36
Userland/Libraries/LibWeb/SVG/SVGGradientElement.cpp
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@ -34,29 +34,47 @@ void SVGGradientElement::attribute_changed(FlyString const& name, Optional<Strin
}
GradientUnits SVGGradientElement::gradient_units() const
{
HashTable<SVGGradientElement const*> seen_gradients;
return gradient_units_impl(seen_gradients);
}
GradientUnits SVGGradientElement::gradient_units_impl(HashTable<SVGGradientElement const*>& seen_gradients) const
{
if (m_gradient_units.has_value())
return *m_gradient_units;
if (auto gradient = linked_gradient())
return gradient->gradient_units();
if (auto gradient = linked_gradient(seen_gradients))
return gradient->gradient_units_impl(seen_gradients);
return GradientUnits::ObjectBoundingBox;
}
SpreadMethod SVGGradientElement::spread_method() const
{
HashTable<SVGGradientElement const*> seen_gradients;
return spread_method_impl(seen_gradients);
}
SpreadMethod SVGGradientElement::spread_method_impl(HashTable<SVGGradientElement const*>& seen_gradients) const
{
if (m_spread_method.has_value())
return *m_spread_method;
if (auto gradient = linked_gradient())
return gradient->spread_method();
if (auto gradient = linked_gradient(seen_gradients))
return gradient->spread_method_impl(seen_gradients);
return SpreadMethod::Pad;
}
Optional<Gfx::AffineTransform> SVGGradientElement::gradient_transform() const
{
HashTable<SVGGradientElement const*> seen_gradients;
return gradient_transform_impl(seen_gradients);
}
Optional<Gfx::AffineTransform> SVGGradientElement::gradient_transform_impl(HashTable<SVGGradientElement const*>& seen_gradients) const
{
if (m_gradient_transform.has_value())
return m_gradient_transform;
if (auto gradient = linked_gradient())
return gradient->gradient_transform();
if (auto gradient = linked_gradient(seen_gradients))
return gradient->gradient_transform_impl(seen_gradients);
return {};
}
@ -89,7 +107,7 @@ void SVGGradientElement::add_color_stops(Gfx::SVGGradientPaintStyle& paint_style
});
}
JS::GCPtr<SVGGradientElement const> SVGGradientElement::linked_gradient() const
JS::GCPtr<SVGGradientElement const> SVGGradientElement::linked_gradient(HashTable<SVGGradientElement const*>& seen_gradients) const
{
// FIXME: This entire function is an ad-hoc hack!
// It can only resolve #<ids> in the same document.
@ -103,8 +121,12 @@ JS::GCPtr<SVGGradientElement const> SVGGradientElement::linked_gradient() const
auto element = document().get_element_by_id(id.value());
if (!element)
return {};
if (element == this)
return {};
if (!is<SVGGradientElement>(*element))
return {};
if (seen_gradients.set(&verify_cast<SVGGradientElement>(*element)) != AK::HashSetResult::InsertedNewEntry)
return {};
return &verify_cast<SVGGradientElement>(*element);
}
return {};

21
Userland/Libraries/LibWeb/SVG/SVGGradientElement.h
View file

@ -55,12 +55,22 @@ protected:
virtual void initialize(JS::Realm&) override;
JS::GCPtr<SVGGradientElement const> linked_gradient() const;
JS::GCPtr<SVGGradientElement const> linked_gradient(HashTable<SVGGradientElement const*>& seen_gradients) const;
Gfx::AffineTransform gradient_paint_transform(SVGPaintContext const&) const;
template<VoidFunction<SVGStopElement> Callback>
void for_each_color_stop(Callback const& callback) const
{
HashTable<SVGGradientElement const*> seen_gradients;
return for_each_color_stop_impl(callback, seen_gradients);
}
void add_color_stops(Gfx::SVGGradientPaintStyle&) const;
private:
template<VoidFunction<SVGStopElement> Callback>
void for_each_color_stop_impl(Callback const& callback, HashTable<SVGGradientElement const*>& seen_gradients) const
{
bool color_stops_found = false;
for_each_child_of_type<SVG::SVGStopElement>([&](auto& stop) {
@ -68,14 +78,15 @@ protected:
callback(stop);
});
if (!color_stops_found) {
if (auto gradient = linked_gradient())
gradient->for_each_color_stop(callback);
if (auto gradient = linked_gradient(seen_gradients))
gradient->for_each_color_stop_impl(callback, seen_gradients);
}
}
void add_color_stops(Gfx::SVGGradientPaintStyle&) const;
GradientUnits gradient_units_impl(HashTable<SVGGradientElement const*>& seen_gradients) const;
SpreadMethod spread_method_impl(HashTable<SVGGradientElement const*>& seen_gradients) const;
Optional<Gfx::AffineTransform> gradient_transform_impl(HashTable<SVGGradientElement const*>& seen_gradients) const;
private:
Optional<GradientUnits> m_gradient_units = {};
Optional<SpreadMethod> m_spread_method = {};
Optional<Gfx::AffineTransform> m_gradient_transform = {};

40
Userland/Libraries/LibWeb/SVG/SVGLinearGradientElement.cpp
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@ -48,44 +48,68 @@ void SVGLinearGradientElement::attribute_changed(FlyString const& name, Optional
// https://www.w3.org/TR/SVG11/pservers.html#LinearGradientElementX1Attribute
NumberPercentage SVGLinearGradientElement::start_x() const
{
HashTable<SVGGradientElement const*> seen_gradients;
return start_x_impl(seen_gradients);
}
NumberPercentage SVGLinearGradientElement::start_x_impl(HashTable<SVGGradientElement const*>& seen_gradients) const
{
if (m_x1.has_value())
return *m_x1;
if (auto gradient = linked_linear_gradient())
return gradient->start_x();
if (auto gradient = linked_linear_gradient(seen_gradients))
return gradient->start_x_impl(seen_gradients);
// If the attribute is not specified, the effect is as if a value of '0%' were specified.
return NumberPercentage::create_percentage(0);
}
// https://www.w3.org/TR/SVG11/pservers.html#LinearGradientElementY1Attribute
NumberPercentage SVGLinearGradientElement::start_y() const
{
HashTable<SVGGradientElement const*> seen_gradients;
return start_y_impl(seen_gradients);
}
NumberPercentage SVGLinearGradientElement::start_y_impl(HashTable<SVGGradientElement const*>& seen_gradients) const
{
if (m_y1.has_value())
return *m_y1;
if (auto gradient = linked_linear_gradient())
return gradient->start_x();
if (auto gradient = linked_linear_gradient(seen_gradients))
return gradient->start_y_impl(seen_gradients);
// If the attribute is not specified, the effect is as if a value of '0%' were specified.
return NumberPercentage::create_percentage(0);
}
// https://www.w3.org/TR/SVG11/pservers.html#LinearGradientElementX2Attribute
NumberPercentage SVGLinearGradientElement::end_x() const
{
HashTable<SVGGradientElement const*> seen_gradients;
return end_x_impl(seen_gradients);
}
NumberPercentage SVGLinearGradientElement::end_x_impl(HashTable<SVGGradientElement const*>& seen_gradients) const
{
if (m_x2.has_value())
return *m_x2;
if (auto gradient = linked_linear_gradient())
return gradient->start_x();
if (auto gradient = linked_linear_gradient(seen_gradients))
return gradient->end_x_impl(seen_gradients);
// If the attribute is not specified, the effect is as if a value of '100%' were specified.
return NumberPercentage::create_percentage(100);
}
// https://www.w3.org/TR/SVG11/pservers.html#LinearGradientElementY2Attribute
NumberPercentage SVGLinearGradientElement::end_y() const
{
HashTable<SVGGradientElement const*> seen_gradients;
return end_y_impl(seen_gradients);
}
NumberPercentage SVGLinearGradientElement::end_y_impl(HashTable<SVGGradientElement const*>& seen_gradients) const
{
if (m_y2.has_value())
return *m_y2;
if (auto gradient = linked_linear_gradient())
return gradient->start_x();
if (auto gradient = linked_linear_gradient(seen_gradients))
return gradient->end_y_impl(seen_gradients);
// If the attribute is not specified, the effect is as if a value of '0%' were specified.
return NumberPercentage::create_percentage(0);
}

9
Userland/Libraries/LibWeb/SVG/SVGLinearGradientElement.h
View file

@ -34,9 +34,9 @@ protected:
virtual void initialize(JS::Realm&) override;
private:
JS::GCPtr<SVGLinearGradientElement const> linked_linear_gradient() const
JS::GCPtr<SVGLinearGradientElement const> linked_linear_gradient(HashTable<SVGGradientElement const*>& seen_gradients) const
{
if (auto gradient = linked_gradient(); gradient && is<SVGLinearGradientElement>(*gradient))
if (auto gradient = linked_gradient(seen_gradients); gradient && is<SVGLinearGradientElement>(*gradient))
return &verify_cast<SVGLinearGradientElement>(*gradient);
return {};
}
@ -46,6 +46,11 @@ private:
NumberPercentage end_x() const;
NumberPercentage end_y() const;
NumberPercentage start_x_impl(HashTable<SVGGradientElement const*>& seen_gradients) const;
NumberPercentage start_y_impl(HashTable<SVGGradientElement const*>& seen_gradients) const;
NumberPercentage end_x_impl(HashTable<SVGGradientElement const*>& seen_gradients) const;
NumberPercentage end_y_impl(HashTable<SVGGradientElement const*>& seen_gradients) const;
Optional<NumberPercentage> m_x1;
Optional<NumberPercentage> m_y1;
Optional<NumberPercentage> m_x2;

60
Userland/Libraries/LibWeb/SVG/SVGRadialGradientElement.cpp
View file

@ -52,13 +52,19 @@ void SVGRadialGradientElement::attribute_changed(FlyString const& name, Optional
// https://svgwg.org/svg2-draft/pservers.html#RadialGradientElementFXAttribute
NumberPercentage SVGRadialGradientElement::start_circle_x() const
{
HashTable<SVGGradientElement const*> seen_gradients;
return start_circle_x_impl(seen_gradients);
}
NumberPercentage SVGRadialGradientElement::start_circle_x_impl(HashTable<SVGGradientElement const*>& seen_gradients) const
{
if (m_fx.has_value())
return *m_fx;
// If the element references an element that specifies a value for 'fx', then the value of 'fx' is
// inherited from the referenced element.
if (auto gradient = linked_radial_gradient())
return gradient->start_circle_x();
if (auto gradient = linked_radial_gradient(seen_gradients))
return gradient->start_circle_x_impl(seen_gradients);
// If attribute ‘fx’ is not specified, ‘fx’ will coincide with the presentational value of ‘cx’ for
// the element whether the value for 'cx' was inherited or not.
return end_circle_x();
@ -66,13 +72,19 @@ NumberPercentage SVGRadialGradientElement::start_circle_x() const
// https://svgwg.org/svg2-draft/pservers.html#RadialGradientElementFYAttribute
NumberPercentage SVGRadialGradientElement::start_circle_y() const
{
HashTable<SVGGradientElement const*> seen_gradients;
return start_circle_y_impl(seen_gradients);
}
NumberPercentage SVGRadialGradientElement::start_circle_y_impl(HashTable<SVGGradientElement const*>& seen_gradients) const
{
if (m_fy.has_value())
return *m_fy;
// If the element references an element that specifies a value for 'fy', then the value of 'fy' is
// inherited from the referenced element.
if (auto gradient = linked_radial_gradient())
return gradient->start_circle_y();
if (auto gradient = linked_radial_gradient(seen_gradients))
return gradient->start_circle_y_impl(seen_gradients);
// If attribute ‘fy’ is not specified, ‘fy’ will coincide with the presentational value of ‘cy’ for
// the element whether the value for 'cy' was inherited or not.
return end_circle_y();
@ -80,46 +92,70 @@ NumberPercentage SVGRadialGradientElement::start_circle_y() const
// https://svgwg.org/svg2-draft/pservers.html#RadialGradientElementFRAttribute
NumberPercentage SVGRadialGradientElement::start_circle_radius() const
{
HashTable<SVGGradientElement const*> seen_gradients;
return start_circle_radius_impl(seen_gradients);
}
NumberPercentage SVGRadialGradientElement::start_circle_radius_impl(HashTable<SVGGradientElement const*>& seen_gradients) const
{
// Note: A negative value is an error.
if (m_fr.has_value() && m_fr->value() >= 0)
return *m_fr;
// if the element references an element that specifies a value for 'fr', then the value of
// 'fr' is inherited from the referenced element.
if (auto gradient = linked_radial_gradient())
return gradient->start_circle_radius();
if (auto gradient = linked_radial_gradient(seen_gradients))
return gradient->start_circle_radius_impl(seen_gradients);
// If the attribute is not specified, the effect is as if a value of '0%' were specified.
return NumberPercentage::create_percentage(0);
}
// https://svgwg.org/svg2-draft/pservers.html#RadialGradientElementCXAttribute
NumberPercentage SVGRadialGradientElement::end_circle_x() const
{
HashTable<SVGGradientElement const*> seen_gradients;
return end_circle_x_impl(seen_gradients);
}
NumberPercentage SVGRadialGradientElement::end_circle_x_impl(HashTable<SVGGradientElement const*>& seen_gradients) const
{
if (m_cx.has_value())
return *m_cx;
if (auto gradient = linked_radial_gradient())
return gradient->end_circle_x();
if (auto gradient = linked_radial_gradient(seen_gradients))
return gradient->end_circle_x_impl(seen_gradients);
return NumberPercentage::create_percentage(50);
}
// https://svgwg.org/svg2-draft/pservers.html#RadialGradientElementCYAttribute
NumberPercentage SVGRadialGradientElement::end_circle_y() const
{
HashTable<SVGGradientElement const*> seen_gradients;
return end_circle_y_impl(seen_gradients);
}
NumberPercentage SVGRadialGradientElement::end_circle_y_impl(HashTable<SVGGradientElement const*>& seen_gradients) const
{
if (m_cy.has_value())
return *m_cy;
if (auto gradient = linked_radial_gradient())
return gradient->end_circle_y();
if (auto gradient = linked_radial_gradient(seen_gradients))
return gradient->end_circle_y_impl(seen_gradients);
return NumberPercentage::create_percentage(50);
}
// https://svgwg.org/svg2-draft/pservers.html#RadialGradientElementRAttribute
NumberPercentage SVGRadialGradientElement::end_circle_radius() const
{
HashTable<SVGGradientElement const*> seen_gradients;
return end_circle_radius_impl(seen_gradients);
}
NumberPercentage SVGRadialGradientElement::end_circle_radius_impl(HashTable<SVGGradientElement const*>& seen_gradients) const
{
// Note: A negative value is an error.
if (m_r.has_value() && m_r->value() >= 0)
return *m_r;
if (auto gradient = linked_radial_gradient())
return gradient->end_circle_radius();
if (auto gradient = linked_radial_gradient(seen_gradients))
return gradient->end_circle_radius_impl(seen_gradients);
return NumberPercentage::create_percentage(50);
}

11
Userland/Libraries/LibWeb/SVG/SVGRadialGradientElement.h
View file

@ -36,9 +36,9 @@ protected:
virtual void initialize(JS::Realm&) override;
private:
JS::GCPtr<SVGRadialGradientElement const> linked_radial_gradient() const
JS::GCPtr<SVGRadialGradientElement const> linked_radial_gradient(HashTable<SVGGradientElement const*>& seen_gradients) const
{
if (auto gradient = linked_gradient(); gradient && is<SVGRadialGradientElement>(*gradient))
if (auto gradient = linked_gradient(seen_gradients); gradient && is<SVGRadialGradientElement>(*gradient))
return &verify_cast<SVGRadialGradientElement>(*gradient);
return {};
}
@ -50,6 +50,13 @@ private:
NumberPercentage end_circle_y() const;
NumberPercentage end_circle_radius() const;
NumberPercentage start_circle_x_impl(HashTable<SVGGradientElement const*>& seen_gradients) const;
NumberPercentage start_circle_y_impl(HashTable<SVGGradientElement const*>& seen_gradients) const;
NumberPercentage start_circle_radius_impl(HashTable<SVGGradientElement const*>& seen_gradients) const;
NumberPercentage end_circle_x_impl(HashTable<SVGGradientElement const*>& seen_gradients) const;
NumberPercentage end_circle_y_impl(HashTable<SVGGradientElement const*>& seen_gradients) const;
NumberPercentage end_circle_radius_impl(HashTable<SVGGradientElement const*>& seen_gradients) const;
Optional<NumberPercentage> m_cx;
Optional<NumberPercentage> m_cy;
Optional<NumberPercentage> m_fx;