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/*
* Copyright (C) Research In Motion Limited 2010. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_LAYOUT_SVG_SVG_RESOURCES_CYCLE_SOLVER_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_LAYOUT_SVG_SVG_RESOURCES_CYCLE_SOLVER_H_
#include "third_party/blink/renderer/core/layout/svg/layout_svg_resource_container.h"
#include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"
#include "third_party/blink/renderer/platform/wtf/hash_set.h"
namespace blink {
// This class traverses the graph formed by SVGResources of
// LayoutObjects, maintaining the active path as LayoutObjects are
// visited. It also maintains a cache of sub-graphs that has already
// been visited and that does not contain any cycles.
class SVGResourcesCycleSolver {
STACK_ALLOCATED();
public:
SVGResourcesCycleSolver();
SVGResourcesCycleSolver(const SVGResourcesCycleSolver&) = delete;
SVGResourcesCycleSolver& operator=(const SVGResourcesCycleSolver&) = delete;
~SVGResourcesCycleSolver();
bool IsKnownAcyclic(const LayoutSVGResourceContainer*) const;
void AddAcyclicSubgraph(const LayoutSVGResourceContainer*);
class Scope {
STACK_ALLOCATED();
public:
Scope(SVGResourcesCycleSolver& solver)
: solver_(solver), resource_(nullptr) {}
~Scope() {
if (resource_)
solver_.LeaveResource(resource_);
}
bool Enter(const LayoutSVGResourceContainer* resource) {
if (!solver_.EnterResource(resource))
return false;
resource_ = resource;
return true;
}
private:
SVGResourcesCycleSolver& solver_;
const LayoutSVGResourceContainer* resource_;
};
private:
bool EnterResource(const LayoutSVGResourceContainer*);
void LeaveResource(const LayoutSVGResourceContainer*);
using ResourceSet = HashSet<const LayoutSVGResourceContainer*>;
ResourceSet active_resources_;
ResourceSet dag_cache_;
};
} // namespace blink
#endif
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