Move transient/temporary RenderSVGResource state out of SVGInlineTextBox

The SVGInlineTextBox member variable |m_paintingResource| is only set
temporarily within paintTextWithShadows and paintDecorationWithStyle, and
is only accessed from the methods that do setup and teardown of it. This
makes it possible to remove it from SVGInlineTextBox and instead manage it
in through a variable on the stack.
The lifetime management is kept manual/the same as previously. The
interaction with TextRun::RenderingContext is changed to be passed as a
parameter to the added "scope" object in order to simplify the interface
a bit.

Review URL: https://codereview.chromium.org/568723002

git-svn-id: svn://svn.chromium.org/blink/trunk@181904 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/core/rendering/svg/SVGInlineTextBox.cpp

@@ -48,7 +48,6 @@ namespace blink {
 struct ExpectedSVGInlineTextBoxSize : public InlineTextBox {
     float float1;
     uint32_t bitfields : 1;
-    void* pointer;
     Vector<SVGTextFragment> vector;
 };
 
@@ -58,7 +57,6 @@ SVGInlineTextBox::SVGInlineTextBox(RenderObject& object)
     : InlineTextBox(object)
     , m_logicalHeight(0)
     , m_startsNewTextChunk(false)
-    , m_paintingResource(0)
 {
 }
 
@@ -221,7 +219,6 @@ void SVGInlineTextBox::paintSelectionBackground(PaintInfo& paintInfo)
     unsigned textFragmentsSize = m_textFragments.size();
     for (unsigned i = 0; i < textFragmentsSize; ++i) {
         SVGTextFragment& fragment = m_textFragments.at(i);
-        ASSERT(!m_paintingResource);
 
         fragmentStartPosition = startPosition;
         fragmentEndPosition = endPosition;
@@ -236,8 +233,6 @@ void SVGInlineTextBox::paintSelectionBackground(PaintInfo& paintInfo)
         paintInfo.context->setFillColor(backgroundColor);
         paintInfo.context->fillRect(selectionRectForTextFragment(fragment, fragmentStartPosition, fragmentEndPosition, style), backgroundColor);
     }
-
-    ASSERT(!m_paintingResource);
 }
 
 void SVGInlineTextBox::paint(PaintInfo& paintInfo, const LayoutPoint& paintOffset, LayoutUnit, LayoutUnit)
@@ -297,7 +292,6 @@ void SVGInlineTextBox::paint(PaintInfo& paintInfo, const LayoutPoint& paintOffse
     unsigned textFragmentsSize = m_textFragments.size();
     for (unsigned i = 0; i < textFragmentsSize; ++i) {
         SVGTextFragment& fragment = m_textFragments.at(i);
-        ASSERT(!m_paintingResource);
 
         GraphicsContextStateSaver stateSaver(*paintInfo.context, false);
         fragment.buildFragmentTransform(fragmentTransform);
@@ -346,24 +340,40 @@ void SVGInlineTextBox::paint(PaintInfo& paintInfo, const LayoutPoint& paintOffse
     // finally, paint the outline if any
     if (style->hasOutline() && parentRenderer.isRenderInline())
         toRenderInline(parentRenderer).paintOutline(paintInfo, paintOffset);
-
-    ASSERT(!m_paintingResource);
 }
 
-bool SVGInlineTextBox::acquirePaintingResource(GraphicsContext*& context, float scalingFactor,
-    RenderObject* renderer, RenderStyle* style, RenderSVGResourceModeFlags resourceMode)
+class PaintingResourceScope {
+public:
+    PaintingResourceScope(RenderObject& renderer, TextRun::RenderingContext* renderingContext = 0)
+        : m_renderer(renderer)
+        , m_renderingContext(renderingContext)
+        , m_paintingResource(0)
+    {
+    }
+    ~PaintingResourceScope() { ASSERT(!m_paintingResource); }
+
+    bool acquirePaintingResource(GraphicsContext*&, float scalingFactor, RenderStyle*, RenderSVGResourceModeFlags);
+    void releasePaintingResource(GraphicsContext*&, const Path*, RenderSVGResourceModeFlags);
+
+private:
+    RenderObject& m_renderer;
+    TextRun::RenderingContext* m_renderingContext;
+    RenderSVGResource* m_paintingResource;
+};
+
+bool PaintingResourceScope::acquirePaintingResource(GraphicsContext*& context, float scalingFactor,
+    RenderStyle* style, RenderSVGResourceModeFlags resourceMode)
 {
     // Callers must save the context state before calling when scalingFactor is not 1.
     ASSERT(scalingFactor);
-    ASSERT(renderer);
     ASSERT(style);
     ASSERT(resourceMode != ApplyToDefaultMode);
 
     bool hasFallback = false;
     if (resourceMode & ApplyToFillMode)
-        m_paintingResource = RenderSVGResource::fillPaintingResource(renderer, style, hasFallback);
+        m_paintingResource = RenderSVGResource::fillPaintingResource(&m_renderer, style, hasFallback);
     else if (resourceMode & ApplyToStrokeMode)
-        m_paintingResource = RenderSVGResource::strokePaintingResource(renderer, style, hasFallback);
+        m_paintingResource = RenderSVGResource::strokePaintingResource(&m_renderer, style, hasFallback);
     else {
         // We're either called for stroking or filling.
         ASSERT_NOT_REACHED();
@@ -372,54 +382,36 @@ bool SVGInlineTextBox::acquirePaintingResource(GraphicsContext*& context, float
     if (!m_paintingResource)
         return false;
 
-    if (!m_paintingResource->applyResource(renderer, style, context, resourceMode)) {
+    if (!m_paintingResource->applyResource(&m_renderer, style, context, resourceMode)) {
         if (hasFallback) {
             m_paintingResource = RenderSVGResource::sharedSolidPaintingResource();
-            m_paintingResource->applyResource(renderer, style, context, resourceMode);
+            m_paintingResource->applyResource(&m_renderer, style, context, resourceMode);
         }
     }
 
     if (scalingFactor != 1 && resourceMode & ApplyToStrokeMode)
         context->setStrokeThickness(context->strokeThickness() * scalingFactor);
 
-    return true;
-}
-
-void SVGInlineTextBox::releasePaintingResource(GraphicsContext*& context, const Path* path,
-    RenderSVGResourceModeFlags resourceMode)
-{
-    ASSERT(m_paintingResource);
-
-    m_paintingResource->postApplyResource(&parent()->renderer(), context, resourceMode, path, 0);
-    m_paintingResource = 0;
-}
-
-bool SVGInlineTextBox::prepareGraphicsContextForTextPainting(GraphicsContext*& context,
-    float scalingFactor, TextRun& textRun, RenderStyle* style, RenderSVGResourceModeFlags resourceMode)
-{
-    bool acquiredResource = acquirePaintingResource(context, scalingFactor, &parent()->renderer(), style, resourceMode);
-    if (!acquiredResource)
-        return false;
-
 #if ENABLE(SVG_FONTS)
     // SVG Fonts need access to the painting resource used to draw the current text chunk.
-    TextRun::RenderingContext* renderingContext = textRun.renderingContext();
-    if (renderingContext)
-        static_cast<SVGTextRunRenderingContext*>(renderingContext)->setActivePaintingResource(m_paintingResource);
+    if (m_renderingContext)
+        static_cast<SVGTextRunRenderingContext*>(m_renderingContext)->setActivePaintingResource(m_paintingResource);
 #endif
 
     return true;
 }
 
-void SVGInlineTextBox::restoreGraphicsContextAfterTextPainting(GraphicsContext*& context,
-    TextRun& textRun, RenderSVGResourceModeFlags resourceMode)
+void PaintingResourceScope::releasePaintingResource(GraphicsContext*& context, const Path* path,
+    RenderSVGResourceModeFlags resourceMode)
 {
-    releasePaintingResource(context, 0, resourceMode);
+    ASSERT(m_paintingResource);
+
+    m_paintingResource->postApplyResource(&m_renderer, context, resourceMode, path, 0);
+    m_paintingResource = 0;
 
 #if ENABLE(SVG_FONTS)
-    TextRun::RenderingContext* renderingContext = textRun.renderingContext();
-    if (renderingContext)
-        static_cast<SVGTextRunRenderingContext*>(renderingContext)->setActivePaintingResource(0);
+    if (m_renderingContext)
+        static_cast<SVGTextRunRenderingContext*>(m_renderingContext)->setActivePaintingResource(0);
 #endif
 }
 
@@ -562,7 +554,6 @@ void SVGInlineTextBox::paintDecoration(GraphicsContext* context, TextDecoration
 void SVGInlineTextBox::paintDecorationWithStyle(GraphicsContext* context, TextDecoration decoration,
     const SVGTextFragment& fragment, RenderObject* decorationRenderer, RenderSVGResourceModeFlags resourceMode)
 {
-    ASSERT(!m_paintingResource);
     ASSERT(resourceMode != ApplyToDefaultMode);
 
     RenderStyle* decorationStyle = decorationRenderer->style();
@@ -598,8 +589,9 @@ void SVGInlineTextBox::paintDecorationWithStyle(GraphicsContext* context, TextDe
 
     // acquirePaintingResource also modifies state if the scalingFactor is non-identity.
     // Above we have saved the state for this case.
-    if (acquirePaintingResource(context, scalingFactor, decorationRenderer, decorationStyle, resourceMode))
-        releasePaintingResource(context, &path, resourceMode);
+    PaintingResourceScope resourceScope(*decorationRenderer);
+    if (resourceScope.acquirePaintingResource(context, scalingFactor, decorationStyle, resourceMode))
+        resourceScope.releasePaintingResource(context, &path, resourceMode);
 }
 
 void SVGInlineTextBox::paintTextWithShadows(GraphicsContext* context, RenderStyle* style,
@@ -630,7 +622,8 @@ void SVGInlineTextBox::paintTextWithShadows(GraphicsContext* context, RenderStyl
     if (hasShadow)
         context->setDrawLooper(shadowList->createDrawLooper(DrawLooperBuilder::ShadowRespectsAlpha));
 
-    if (prepareGraphicsContextForTextPainting(context, scalingFactor, textRun, style, resourceMode)) {
+    PaintingResourceScope resourceScope(parent()->renderer(), textRun.renderingContext());
+    if (resourceScope.acquirePaintingResource(context, scalingFactor, style, resourceMode)) {
         TextRunPaintInfo textRunPaintInfo(textRun);
         textRunPaintInfo.from = startPosition;
         textRunPaintInfo.to = endPosition;
@@ -640,7 +633,7 @@ void SVGInlineTextBox::paintTextWithShadows(GraphicsContext* context, RenderStyl
             textSize.width(), textSize.height());
 
         scaledFont.drawText(context, textRunPaintInfo, textOrigin);
-        restoreGraphicsContextAfterTextPainting(context, textRun, resourceMode);
+        resourceScope.releasePaintingResource(context, 0, resourceMode);
     }
 
     if (scalingFactor != 1)

third_party/WebKit/Source/core/rendering/svg/SVGInlineTextBox.h

@@ -65,14 +65,6 @@ public:
 private:
     TextRun constructTextRun(RenderStyle*, const SVGTextFragment&) const;
 
-    bool acquirePaintingResource(GraphicsContext*&, float scalingFactor, RenderObject*,
-        RenderStyle*, RenderSVGResourceModeFlags);
-    void releasePaintingResource(GraphicsContext*&, const Path*, RenderSVGResourceModeFlags);
-
-    bool prepareGraphicsContextForTextPainting(GraphicsContext*&, float scalingFactor, TextRun&,
-        RenderStyle*, RenderSVGResourceModeFlags);
-    void restoreGraphicsContextAfterTextPainting(GraphicsContext*&, TextRun&, RenderSVGResourceModeFlags);
-
     void paintDecoration(GraphicsContext*, TextDecoration, const SVGTextFragment&);
     void paintDecorationWithStyle(GraphicsContext*, TextDecoration, const SVGTextFragment&,
         RenderObject* decorationRenderer, RenderSVGResourceModeFlags);
@@ -89,7 +81,6 @@ private:
 private:
     float m_logicalHeight;
     bool m_startsNewTextChunk : 1;
-    RenderSVGResource* m_paintingResource;
     Vector<SVGTextFragment> m_textFragments;
 };