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Diffstat (limited to 'Source/WebCore/rendering/SVGResourcesCycleSolver.cpp')
| -rw-r--r-- | Source/WebCore/rendering/SVGResourcesCycleSolver.cpp | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/Source/WebCore/rendering/SVGResourcesCycleSolver.cpp b/Source/WebCore/rendering/SVGResourcesCycleSolver.cpp new file mode 100644 index 0000000..8cd2e80 --- /dev/null +++ b/Source/WebCore/rendering/SVGResourcesCycleSolver.cpp @@ -0,0 +1,213 @@ +/* + 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 + aint 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 |