Initialize destinations variables before calling GL functions...

gpu/command_buffer/client/gles2_c_lib.cc

 // Copyright (c) 2009 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.
 
 // These functions emluate GLES2 over command buffers for C.
 
+#include <assert.h>
 #include "../client/gles2_lib.h"
 
+// Check that destination pointers point to initialized memory.
+// When the context is lost, calling GL function has no effect so if destination
+// pointers point to initialized memory it can often lead to crash bugs. eg.
+//
+// GLsizei len;
+// glGetShaderSource(shader, max_size, &len, buffer);
+// std::string src(buffer, buffer + len);  // len can be uninitialized here!!!
+//
+// Because this is check is not official GL this check happens only on Chrome

[apatrick, 2010/11/24 18:13:04]

this is check -> this check

+// code, not Pepper.
+//
+// If it was up to us we'd just always write to the destination but the OpenGL
+// spec defines the behavior of OpenGL function, not us. :-(
+#if defined(GPU_DCHECK)
+#define GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION(ptr) \
+  GPU_DCHECK(ptr && (ptr[0] == 0 || ptr[0] == -1));
+#elif defined(DCHECK)
+#define GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION(ptr) \
+  DCHECK(ptr && (ptr[0] == 0 || ptr[0] == -1));
+#elif !defined(__native_client__)
+#define GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION(ptr) \
+  assert(ptr && (ptr[0] == 0 || ptr[0] == -1));
+#else
+#define GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION(ptr)
+#endif
+
 extern "C" {
 // 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 "../client/gles2_c_lib_autogen.h"
 }  // extern "C"