Extract the SVG Filter Reference implementation out of the FilterEffectRenderer into its own type

Source/core/rendering/svg/ReferenceFilterBuilder.cpp

Index: Source/core/rendering/svg/ReferenceFilterBuilder.cpp
diff --git a/Source/core/rendering/svg/ReferenceFilterBuilder.cpp b/Source/core/rendering/svg/ReferenceFilterBuilder.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..494e4063af6f1c55b6aacda79cb1f72ef73a5abd
--- /dev/null
+++ b/Source/core/rendering/svg/ReferenceFilterBuilder.cpp
@@ -0,0 +1,152 @@
+/*
+ * Copyright (C) 2013 Adobe Systems Inc. All rights reserved.
+ * Copyright (C) 2013 Google Inc.  All rights reserved.
+ * Copyright (C) 2011 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+
+#include "core/rendering/svg/ReferenceFilterBuilder.h"
+
+#include "core/css/CSSPrimitiveValue.h"
+#include "core/css/CSSPrimitiveValueMappings.h"
+#include "core/dom/Element.h"
+#include "core/loader/cache/CachedDocument.h"
+#include "core/loader/cache/CachedSVGDocumentReference.h"
+#include "core/platform/graphics/filters/FilterEffect.h"
+#include "core/platform/graphics/filters/SourceAlpha.h"
+#include "core/svg/SVGDocumentExtensions.h"
+#include "core/svg/SVGFilterPrimitiveStandardAttributes.h"
+#include "core/svg/graphics/filters/SVGFilterBuilder.h"
+
+namespace WebCore {
+
+// Returns whether or not the SVGStyledElement object contains a valid color-interpolation-filters attribute
+static bool getSVGStyledElementColorSpace(SVGStyledElement* svgStyledElement, ColorSpace& cs)
+{
+    if (!svgStyledElement)
+        return false;
+
+    const RenderObject* renderer = svgStyledElement->renderer();
+    const RenderStyle* style = renderer ? renderer->style() : 0;
+    const SVGRenderStyle* svgStyle = style ? style->svgStyle() : 0;
+    EColorInterpolation eColorInterpolation = CI_AUTO;
+    if (svgStyle) {
+        // If a layout has been performed, then we can use the fast path to get this attribute
+        eColorInterpolation = svgStyle->colorInterpolationFilters();
+    } else {
+        // Otherwise, use the slow path by using string comparison (used by external svg files)
+        RefPtr<CSSValue> cssValue = svgStyledElement->getPresentationAttribute(
+            SVGNames::color_interpolation_filtersAttr.toString());
+        if (cssValue.get() && cssValue->isPrimitiveValue()) {
+            const CSSPrimitiveValue& primitiveValue = *((CSSPrimitiveValue*)cssValue.get());
+            eColorInterpolation = (EColorInterpolation)primitiveValue;
+        } else {
+            return false;
+        }
+    }
+
+    switch (eColorInterpolation) {
+    case CI_AUTO:
+    case CI_SRGB:
+        cs = ColorSpaceDeviceRGB;
+        break;
+    case CI_LINEARRGB:
+        cs = ColorSpaceLinearRGB;
+        break;
+    default:
+        return false;
+    }
+
+    return true;
+}
+
+PassRefPtr<FilterEffect> ReferenceFilterBuilder::build(Filter* parentFilter, RenderObject* renderer, FilterEffect* previousEffect, const ReferenceFilterOperation* filterOperation)
+{
+    if (!renderer)
+        return 0;
+
+    Document* document = renderer->document();
+    ASSERT(document);
+
+    CachedSVGDocumentReference* cachedSVGDocumentReference = filterOperation->cachedSVGDocumentReference();
+    CachedDocument* cachedSVGDocument = cachedSVGDocumentReference ? cachedSVGDocumentReference->document() : 0;
+
+    // If we have an SVG document, this is an external reference. Otherwise
+    // we look up the referenced node in the current document.
+    if (cachedSVGDocument)
+        document = cachedSVGDocument->document();
+
+    if (!document)
+        return 0;
+
+    Element* filter = document->getElementById(filterOperation->fragment());
+
+    if (!filter) {
+        // Although we did not find the referenced filter, it might exist later
+        // in the document
+        document->accessSVGExtensions()->addPendingResource(filterOperation->fragment(), toElement(renderer->node()));
+        return 0;
+    }
+
+    if (!filter->isSVGElement() || !filter->hasTagName(SVGNames::filterTag))
+        return 0;
+
+    SVGFilterElement* filterElement = toSVGFilterElement(toSVGElement(filter));
+
+    // FIXME: Figure out what to do with SourceAlpha. Right now, we're
+    // using the alpha of the original input layer, which is obviously
+    // wrong. We should probably be extracting the alpha from the
+    // previousEffect, but this requires some more processing.
+    // This may need a spec clarification.
+    RefPtr<SVGFilterBuilder> builder = SVGFilterBuilder::create(previousEffect, SourceAlpha::create(parentFilter));
+
+    ColorSpace filterColorSpace = ColorSpaceDeviceRGB;
+    bool useFilterColorSpace = getSVGStyledElementColorSpace(filterElement, filterColorSpace);
+
+    for (Node* node = filterElement->firstChild(); node; node = node->nextSibling()) {
+        if (!node->isSVGElement())
+            continue;
+
+        SVGElement* element = toSVGElement(node);
+        if (!element->isFilterEffect())
+            continue;
+
+        SVGFilterPrimitiveStandardAttributes* effectElement = static_cast<SVGFilterPrimitiveStandardAttributes*>(element);
+
+        RefPtr<FilterEffect> effect = effectElement->build(builder.get(), parentFilter);
+        if (!effect)
+            continue;
+
+        effectElement->setStandardAttributes(effect.get());
+        effect->setEffectBoundaries(SVGLengthContext::resolveRectangle<SVGFilterPrimitiveStandardAttributes>(effectElement, filterElement->primitiveUnits(), parentFilter->sourceImageRect()));
+        ColorSpace colorSpace = filterColorSpace;
+        if (useFilterColorSpace || getSVGStyledElementColorSpace(effectElement, colorSpace))
+            effect->setOperatingColorSpace(colorSpace);
+        builder->add(effectElement->result(), effect);
+    }
+    return builder->lastEffect();
+}
+
+} // namespace WebCore