Defend against NULL pointer dereferences in buggy OpenGL drivers.

gpu/command_buffer/service/gles2_cmd_decoder.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "gpu/command_buffer/service/gles2_cmd_decoder.h"
 
 #include <stdio.h>
 
 #include <algorithm>
 #include <list>
@@ skipping 1519 matching lines @@
   MsgCallback msg_callback_;
 
   StreamTextureManager* stream_texture_manager_;
 
   // The format of the back buffer_
   GLenum back_buffer_color_format_;
   bool back_buffer_has_depth_;
   bool back_buffer_has_stencil_;
 
   bool teximage2d_faster_than_texsubimage2d_;
-  bool bufferdata_faster_than_buffersubdata_;
 
   // The last error message set.
   std::string last_error_;
 
   int log_message_count_;
 
   // The current decoder error.
   error::Error current_decoder_error_;
 
   DebugMarkerManager debug_marker_manager_;
@@ skipping 433 matching lines @@
       offscreen_target_depth_format_(0),
       offscreen_target_stencil_format_(0),
       offscreen_target_samples_(0),
       offscreen_target_buffer_preserved_(true),
       offscreen_saved_color_format_(0),
       stream_texture_manager_(NULL),
       back_buffer_color_format_(0),
       back_buffer_has_depth_(false),
       back_buffer_has_stencil_(false),
       teximage2d_faster_than_texsubimage2d_(true),
-      bufferdata_faster_than_buffersubdata_(true),
       log_message_count_(0),
       current_decoder_error_(error::kNoError),
       use_shader_translator_(true),
       validators_(group_->feature_info()->validators()),
       feature_info_(group_->feature_info()),
       tex_image_2d_failed_(false),
       frame_number_(0),
       has_robustness_extension_(false),
       reset_status_(GL_NO_ERROR),
       needs_mac_nvidia_driver_workaround_(false),
@@ skipping 27 matching lines @@
   // TODO(apatrick): fix this test.
   if ((gfx::GetGLImplementation() == gfx::kGLImplementationEGLGLES2 &&
        !feature_info_->feature_flags().chromium_webglsl &&
        !force_webgl_glsl_validation_) ||
       gfx::GetGLImplementation() == gfx::kGLImplementationMockGL ||
       CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kDisableGLSLTranslator)) {
     use_shader_translator_ = false;
   }
 
-  // TODO(gman): Consider setting these based on GPU and/or driver.
+  // TODO(gman): Consider setting this based on GPU and/or driver.
   if (IsAngle()) {
     teximage2d_faster_than_texsubimage2d_ = false;
-    bufferdata_faster_than_buffersubdata_ = false;
   }
 }
 
 GLES2DecoderImpl::~GLES2DecoderImpl() {
 }
 
 bool GLES2DecoderImpl::Initialize(
     const scoped_refptr<gfx::GLSurface>& surface,
     const scoped_refptr<gfx::GLContext>& context,
     bool offscreen,
@@ skipping 4797 matching lines @@
     return;
   }
   // Clear the buffer to 0 if no initial data was passed in.
   scoped_array<int8> zero;
   if (!data) {
     zero.reset(new int8[size]);
     memset(zero.get(), 0, size);
     data = zero.get();
   }
 
-  if (!bufferdata_faster_than_buffersubdata_ &&
-      size == info->size() && usage == info->usage()) {
-    glBufferSubData(target, 0, size, data);
-    info->SetRange(0, size, data);
-    return;
-  }
-
   CopyRealGLErrorsToWrapper();
   glBufferData(target, size, data, usage);
   GLenum error = PeekGLError();
   if (error == GL_NO_ERROR) {
     buffer_manager()->SetInfo(info, size, usage);
     info->SetRange(0, size, data);
+  } else {
+    buffer_manager()->SetInfo(info, 0, usage);
   }
 }
 
 error::Error GLES2DecoderImpl::HandleBufferData(
     uint32 immediate_data_size, const gles2::BufferData& c) {
   GLenum target = static_cast<GLenum>(c.target);
   GLsizeiptr size = static_cast<GLsizeiptr>(c.size);
   uint32 data_shm_id = static_cast<uint32>(c.data_shm_id);
   uint32 data_shm_offset = static_cast<uint32>(c.data_shm_offset);
   GLenum usage = static_cast<GLenum>(c.usage);
@@ skipping 26 matching lines @@
   GLenum target, GLintptr offset, GLsizeiptr size, const GLvoid * data) {
   BufferManager::BufferInfo* info = GetBufferInfoForTarget(target);
   if (!info) {
     SetGLError(GL_INVALID_VALUE, "glBufferSubData", "unknown buffer");
     return;
   }
   if (!info->SetRange(offset, size, data)) {
     SetGLError(GL_INVALID_VALUE, "glBufferSubData", "out of range");
     return;
   }
-  if (bufferdata_faster_than_buffersubdata_ &&
-      offset == 0 && size == info->size()) {
-    glBufferData(target, size, data, info->usage());
-    return;
-  }
   glBufferSubData(target, offset, size, data);
 }
 
 bool GLES2DecoderImpl::ClearLevel(
     unsigned service_id,
     unsigned bind_target,
     unsigned target,
     int level,
     unsigned format,
     unsigned type,
@@ skipping 2339 matching lines @@
 }
 
 
 // Include the auto-generated part of this file. We split this because it means
 // we can easily edit the non-auto generated parts right here in this file
 // instead of having to edit some template or the code generator.
 #include "gpu/command_buffer/service/gles2_cmd_decoder_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu