Merge 92430 - [chromium] Implement a global resource limit for DrawingBuffer to limit the amount ...

Source/WebCore/platform/graphics/gpu/DrawingBuffer.cpp

 /*
  * Copyright (c) 2010, Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 20 matching lines @@
 #include "config.h"
 
 #if ENABLE(ACCELERATED_2D_CANVAS) || ENABLE(WEBGL)
 
 #include "DrawingBuffer.h"
 
 #include "Extensions3D.h"
 
 namespace WebCore {
 
+// Global resource ceiling (expressed in terms of pixels) for DrawingBuffer creation and resize.
+// When this limit is set, DrawingBuffer::create() and DrawingBuffer::reset() calls that would
+// exceed the global cap will instead clear the buffer.
+#if PLATFORM(CHROMIUM) // Currently, this cap only exists for chromium.
+static int s_maximumResourceUsePixels = 16 * 1024 * 1024;
+#else
+static int s_maximumResourceUsePixels = 0;
+#endif
+static int s_currentResourceUsePixels = 0;
+
 PassRefPtr<DrawingBuffer> DrawingBuffer::create(GraphicsContext3D* context, const IntSize& size)
 {
     Extensions3D* extensions = context->getExtensions();
     bool multisampleSupported = extensions->supports("GL_ANGLE_framebuffer_blit") && extensions->supports("GL_ANGLE_framebuffer_multisample") && extensions->supports("GL_OES_rgb8_rgba8");
     if (multisampleSupported) {
         extensions->ensureEnabled("GL_ANGLE_framebuffer_blit");
         extensions->ensureEnabled("GL_ANGLE_framebuffer_multisample");
         extensions->ensureEnabled("GL_OES_rgb8_rgba8");
     }
     bool packedDepthStencilSupported = extensions->supports("GL_OES_packed_depth_stencil");
     if (packedDepthStencilSupported)
         extensions->ensureEnabled("GL_OES_packed_depth_stencil");
     RefPtr<DrawingBuffer> drawingBuffer = adoptRef(new DrawingBuffer(context, size, multisampleSupported, packedDepthStencilSupported));
     return (drawingBuffer->m_context) ? drawingBuffer.release() : 0;
 }
 
 void DrawingBuffer::clear()
 {
     if (!m_context)
         return;
 
     m_context->makeContextCurrent();
+    if (!m_size.isEmpty())
+        s_currentResourceUsePixels -= m_size.width() * m_size.height();
 
     if (m_colorBuffer) {
         m_context->deleteTexture(m_colorBuffer);
         m_colorBuffer = 0;
     }
 
     if (m_multisampleColorBuffer) {
         m_context->deleteRenderbuffer(m_multisampleColorBuffer);
         m_multisampleColorBuffer = 0;
     }
@@ skipping 122 matching lines @@
 bool DrawingBuffer::reset(const IntSize& newSize)
 {
     if (!m_context)
         return false;
 
     m_context->makeContextCurrent();
 
     int maxTextureSize = 0;
     m_context->getIntegerv(GraphicsContext3D::MAX_TEXTURE_SIZE, &maxTextureSize);
     if (newSize.height() > maxTextureSize || newSize.width() > maxTextureSize) {
-      clear();
-      return false;
+        clear();
+        return false;
     }
 
+    int pixelDelta = newSize.width() * newSize.height();
+    if (!m_size.isEmpty())
+        pixelDelta -= m_size.width() * m_size.height();
+
+    if (s_maximumResourceUsePixels && (s_currentResourceUsePixels + pixelDelta) > s_maximumResourceUsePixels) {
+        clear();
+        return false;
+    }
+    s_currentResourceUsePixels += pixelDelta;
+
     const GraphicsContext3D::Attributes& attributes = m_context->getContextAttributes();
 
     if (newSize != m_size) {
         m_size = newSize;
 
         unsigned long internalColorFormat, colorFormat, internalRenderbufferFormat;
         if (attributes.alpha) {
             internalColorFormat = GraphicsContext3D::RGBA;
             colorFormat = GraphicsContext3D::RGBA;
             internalRenderbufferFormat = Extensions3D::RGBA8_OES;
@@ skipping 76 matching lines @@
     if (!m_context)
         return;
         
     m_context->bindFramebuffer(GraphicsContext3D::FRAMEBUFFER, m_multisampleFBO ? m_multisampleFBO : m_fbo);
     m_context->viewport(0, 0, m_size.width(), m_size.height());
 }
 
 } // namespace WebCore
 
 #endif