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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"
// Set to a value > 0, to debug the resource cache.
#define DEBUG_CYCLE_DETECTION 0
#if ENABLE(SVG)
#include "RenderSVGResourceClipper.h"
#include "RenderSVGResourceFilter.h"
#include "RenderSVGResourceMarker.h"
#include "RenderSVGResourceMasker.h"
#include "SVGFilterElement.h"
#include "SVGGradientElement.h"
#include "SVGPatternElement.h"
#include "SVGResources.h"
#include "SVGResourcesCache.h"
namespace WebCore {
SVGResourcesCycleSolver::SVGResourcesCycleSolver(RenderObject* renderer, SVGResources* resources)
: m_renderer(renderer)
, m_resources(resources)
{
ASSERT(m_renderer);
ASSERT(m_resources);
}
SVGResourcesCycleSolver::~SVGResourcesCycleSolver()
{
}
bool SVGResourcesCycleSolver::resourceContainsCycles(RenderObject* renderer) const
{
ASSERT(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 (SVGResources* resources = SVGResourcesCache::cachedResourcesForRenderObject(renderer)) {
HashSet<RenderSVGResourceContainer*> resourceSet;
resources->buildSetOfResources(resourceSet);
// Walk all resources and check wheter they reference any resource contained in the resources set.
HashSet<RenderSVGResourceContainer*>::iterator end = resourceSet.end();
for (HashSet<RenderSVGResourceContainer*>::iterator it = resourceSet.begin(); it != end; ++it) {
if (m_allResources.contains(*it))
return true;
}
}
// 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 (RenderObject* child = renderer->firstChild(); child; child = child->nextSibling()) {
SVGResources* childResources = SVGResourcesCache::cachedResourcesForRenderObject(child);
if (!childResources)
continue;
// A child of the given 'resource' contains resources.
HashSet<RenderSVGResourceContainer*> childSet;
childResources->buildSetOfResources(childSet);
// Walk all child resources and check wheter they reference any resource contained in the resources set.
HashSet<RenderSVGResourceContainer*>::iterator end = childSet.end();
for (HashSet<RenderSVGResourceContainer*>::iterator it = childSet.begin(); it != end; ++it) {
if (m_allResources.contains(*it))
return true;
}
// Walk children recursively, stop immediately if we found a cycle
if (resourceContainsCycles(child))
return true;
}
return false;
}
void SVGResourcesCycleSolver::resolveCycles()
{
ASSERT(m_allResources.isEmpty());
#if DEBUG_CYCLE_DETECTION > 0
fprintf(stderr, "\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*> parentResources;
RenderObject* parent = m_renderer->parent();
while (parent) {
if (parent->isSVGResourceContainer())
parentResources.add(parent->toRenderSVGResourceContainer());
parent = parent->parent();
}
#if DEBUG_CYCLE_DETECTION > 0
fprintf(stderr, "\nDetecting wheter any resources references any of following objects:\n");
{
fprintf(stderr, "Local resources:\n");
HashSet<RenderSVGResourceContainer*>::iterator end = localResources.end();
for (HashSet<RenderSVGResourceContainer*>::iterator it = localResources.begin(); it != end; ++it)
fprintf(stderr, "|> %s: object=%p (node=%p)\n", (*it)->renderName(), *it, (*it)->node());
fprintf(stderr, "Parent resources:\n");
end = parentResources.end();
for (HashSet<RenderSVGResourceContainer*>::iterator it = parentResources.begin(); it != end; ++it)
fprintf(stderr, "|> %s: object=%p (node=%p)\n", (*it)->renderName(), *it, (*it)->node());
}
#endif
// Build combined set of local and parent resources.
m_allResources = localResources;
HashSet<RenderSVGResourceContainer*>::iterator end = parentResources.end();
for (HashSet<RenderSVGResourceContainer*>::iterator it = parentResources.begin(); it != end; ++it)
m_allResources.add(*it);
// If we're a resource, add ourselves to the HashSet.
if (m_renderer->isSVGResourceContainer())
m_allResources.add(m_renderer->toRenderSVGResourceContainer());
ASSERT(!m_allResources.isEmpty());
// The job of this function is to determine wheter any of the 'resources' associated with the given 'renderer'
// references us (or wheter any of its kids references us) -> that's a cycle, we need to find and break it.
end = localResources.end();
for (HashSet<RenderSVGResourceContainer*>::iterator it = localResources.begin(); it != end; ++it) {
RenderSVGResourceContainer* resource = *it;
if (parentResources.contains(resource) || resourceContainsCycles(resource))
breakCycle(resource);
}
#if DEBUG_CYCLE_DETECTION > 0
fprintf(stderr, "\nAfter cycle detection:\n");
m_resources->dump(m_renderer);
#endif
m_allResources.clear();
}
void SVGResourcesCycleSolver::breakCycle(RenderSVGResourceContainer* resourceLeadingToCycle)
{
ASSERT(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:
#if ENABLE(FILTERS)
ASSERT(resourceLeadingToCycle == m_resources->filter());
m_resources->resetFilter();
#endif
break;
case ClipperResourceType:
ASSERT(resourceLeadingToCycle == m_resources->clipper());
m_resources->resetClipper();
break;
case SolidColorResourceType:
ASSERT_NOT_REACHED();
break;
}
}
}
#endif
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