Adding cache for security origin validations in 2D/WebGL canvases

Source/core/html/canvas/CanvasRenderingContext.cpp

 /*
  * Copyright (C) 2009 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 COMPUTER, 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/html/canvas/CanvasRenderingContext.h"
 
+#include "core/html/canvas/CanvasImageSource.h"
 #include "platform/weborigin/SecurityOrigin.h"
 
 namespace WebCore {
 
 CanvasRenderingContext::CanvasRenderingContext(HTMLCanvasElement* canvas)
     : m_canvas(canvas)
 {
 
 }
 
+bool CanvasRenderingContext::wouldTaintOrigin(CanvasImageSource* imageSource)
+{
+    const KURL& sourceURL = imageSource->sourceURL();
+    bool hasURL = (sourceURL.isValid() && !sourceURL.isAboutBlankURL());
+
+    if (hasURL) {
+        if (sourceURL.protocolIsData() || m_cleanURLs.contains(sourceURL.string()))
+            return false;
+        if (m_dirtyURLs.contains(sourceURL.string()))
+            return true;
+    }
+
+    bool taintOrigin = imageSource->wouldTaintOrigin(canvas()->securityOrigin());
+
+    if (hasURL) {
+        if (taintOrigin)
+            m_dirtyURLs.add(sourceURL.string());
+        else
+            m_cleanURLs.add(sourceURL.string());
+    }
+    return taintOrigin;
+}
+
 } // namespace WebCore