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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.
*/
#include "config.h"
#include "SVGResourcesCycleSolver.h"
#include "Logging.h"
#include "RenderAncestorIterator.h"
#include "RenderSVGResourceClipper.h"
#include "RenderSVGResourceFilter.h"
#include "RenderSVGResourceMarker.h"
#include "RenderSVGResourceMasker.h"
#include "SVGGradientElement.h"
#include "SVGPatternElement.h"
#include "SVGResources.h"
#include "SVGResourcesCache.h"
// Set to truthy value to debug the resource cache.
#define DEBUG_CYCLE_DETECTION 0
#if DEBUG_CYCLE_DETECTION
#define LOG_DEBUG_CYCLE(...) LOG(SVG, __VA_ARGS__)
#else
#define LOG_DEBUG_CYCLE(...) ((void)0)
#endif
namespace WebCore {
SVGResourcesCycleSolver::SVGResourcesCycleSolver(RenderElement& renderer, SVGResources& resources)
: m_renderer(renderer)
, m_resources(resources)
{
}
SVGResourcesCycleSolver::~SVGResourcesCycleSolver()
{
}
bool SVGResourcesCycleSolver::resourceContainsCycles(RenderElement& renderer) const
{
LOG_DEBUG_CYCLE("\n(%p) Check for cycles\n", &renderer);
// First operate on the resources of the given renderer.
// <marker id="a"> <path marker-start="url(#b)"/> ...
// <marker id="b" marker-start="url(#a)"/>
if (auto* resources = SVGResourcesCache::cachedResourcesForRenderer(renderer)) {
HashSet<RenderSVGResourceContainer*> resourceSet;
resources->buildSetOfResources(resourceSet);
LOG_DEBUG_CYCLE("(%p) Examine our cached resources\n", &renderer);
// Walk all resources and check whether they reference any resource contained in the resources set.
for (auto* resource : resourceSet) {
LOG_DEBUG_CYCLE("(%p) Check %p\n", &renderer, resource);
if (m_allResources.contains(resource))
return true;
// Now check if the resources themselves contain cycles.
if (resourceContainsCycles(*resource))
return true;
}
}
LOG_DEBUG_CYCLE("(%p) Now the children renderers\n", &renderer);
// Then operate on the child resources of the given renderer.
// <marker id="a"> <path marker-start="url(#b)"/> ...
// <marker id="b"> <path marker-start="url(#a)"/> ...
for (auto& child : childrenOfType<RenderElement>(renderer)) {
LOG_DEBUG_CYCLE("(%p) Checking child %p\n", &renderer, &child);
if (auto* childResources = SVGResourcesCache::cachedResourcesForRenderer(child)) {
LOG_DEBUG_CYCLE("(%p) Child %p had cached resources. Check them.\n", &renderer, &child);
// A child of the given 'resource' contains resources.
HashSet<RenderSVGResourceContainer*> childResourceSet;
childResources->buildSetOfResources(childResourceSet);
// Walk all child resources and check whether they reference any resource contained in the resources set.
for (auto* resource : childResourceSet) {
LOG_DEBUG_CYCLE("(%p) Child %p had resource %p\n", &renderer, &child, resource);
if (m_allResources.contains(resource))
return true;
}
}
LOG_DEBUG_CYCLE("(%p) Recurse into child %p\n", &renderer, &child);
// Walk children recursively, stop immediately if we found a cycle
if (resourceContainsCycles(child))
return true;
LOG_DEBUG_CYCLE("\n(%p) Child %p was ok\n", &renderer, &child);
}
LOG_DEBUG_CYCLE("\n(%p) No cycles found\n", &renderer);
return false;
}
void SVGResourcesCycleSolver::resolveCycles()
{
ASSERT(m_allResources.isEmpty());
#if DEBUG_CYCLE_DETECTION
LOG_DEBUG_CYCLE("\nBefore cycle detection:\n");
m_resources.dump(&m_renderer);
#endif
// Stash all resources into a HashSet for the ease of traversing.
HashSet<RenderSVGResourceContainer*> localResources;
m_resources.buildSetOfResources(localResources);
ASSERT(!localResources.isEmpty());
// Add all parent resource containers to the HashSet.
HashSet<RenderSVGResourceContainer*> ancestorResources;
for (auto& resource : ancestorsOfType<RenderSVGResourceContainer>(m_renderer))
ancestorResources.add(&resource);
#if DEBUG_CYCLE_DETECTION
LOG_DEBUG_CYCLE("\nDetecting whether any resources references any of following objects:\n");
{
LOG_DEBUG_CYCLE("Local resources:\n");
for (RenderObject* resource : localResources)
LOG_DEBUG_CYCLE("|> %s : %p (node %p)\n", resource->renderName(), resource, resource->node());
fprintf(stderr, "Parent resources:\n");
for (RenderObject* resource : ancestorResources)
LOG_DEBUG_CYCLE("|> %s : %p (node %p)\n", resource->renderName(), resource, resource->node());
}
#endif
// Build combined set of local and parent resources.
m_allResources = localResources;
for (auto* resource : ancestorResources)
m_allResources.add(resource);
// If we're a resource, add ourselves to the HashSet.
if (is<RenderSVGResourceContainer>(m_renderer))
m_allResources.add(&downcast<RenderSVGResourceContainer>(m_renderer));
ASSERT(!m_allResources.isEmpty());
#if DEBUG_CYCLE_DETECTION
LOG_DEBUG_CYCLE("\nAll resources:\n");
for (auto* resource : m_allResources)
LOG_DEBUG_CYCLE("- %p\n", resource);
#endif
// The job of this function is to determine wheter any of the 'resources' associated with the given 'renderer'
// references us (or whether any of its kids references us) -> that's a cycle, we need to find and break it.
for (auto* resource : localResources) {
if (ancestorResources.contains(resource) || resourceContainsCycles(*resource)) {
LOG_DEBUG_CYCLE("\n**** Detected a cycle (see the last test in the output above) ****\n");
breakCycle(*resource);
}
}
#if DEBUG_CYCLE_DETECTION
LOG_DEBUG_CYCLE("\nAfter cycle detection:\n");
m_resources.dump(&m_renderer);
#endif
m_allResources.clear();
}
void SVGResourcesCycleSolver::breakCycle(RenderSVGResourceContainer& resourceLeadingToCycle)
{
if (&resourceLeadingToCycle == m_resources.linkedResource()) {
m_resources.resetLinkedResource();
return;
}
switch (resourceLeadingToCycle.resourceType()) {
case MaskerResourceType:
ASSERT(&resourceLeadingToCycle == m_resources.masker());
m_resources.resetMasker();
break;
case MarkerResourceType:
ASSERT(&resourceLeadingToCycle == m_resources.markerStart() || &resourceLeadingToCycle == m_resources.markerMid() || &resourceLeadingToCycle == m_resources.markerEnd());
if (m_resources.markerStart() == &resourceLeadingToCycle)
m_resources.resetMarkerStart();
if (m_resources.markerMid() == &resourceLeadingToCycle)
m_resources.resetMarkerMid();
if (m_resources.markerEnd() == &resourceLeadingToCycle)
m_resources.resetMarkerEnd();
break;
case PatternResourceType:
case LinearGradientResourceType:
case RadialGradientResourceType:
ASSERT(&resourceLeadingToCycle == m_resources.fill() || &resourceLeadingToCycle == m_resources.stroke());
if (m_resources.fill() == &resourceLeadingToCycle)
m_resources.resetFill();
if (m_resources.stroke() == &resourceLeadingToCycle)
m_resources.resetStroke();
break;
case FilterResourceType:
ASSERT(&resourceLeadingToCycle == m_resources.filter());
m_resources.resetFilter();
break;
case ClipperResourceType:
ASSERT(&resourceLeadingToCycle == m_resources.clipper());
m_resources.resetClipper();
break;
case SolidColorResourceType:
ASSERT_NOT_REACHED();
break;
}
}
}
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