mesa: Enable true refcounting for NullBufferObj.

This object can be shared with another context, so we cannot just
delete it when the owning context is being destroyed.

Ensuring that buffer objects are properly refcounted guarantees
NullBufferObj is destroyed when all references to it are removed.

src/mesa/main/arrayobj.c

@@ -95,6 +95,10 @@ unbind_array_object_vbos(GLcontext *ctx, struct gl_array_object *obj)
 
    for (i = 0; i < Elements(obj->VertexAttrib); i++)
       _mesa_reference_buffer_object(ctx, &obj->VertexAttrib[i].BufferObj,NULL);
+
+#if FEATURE_point_size_array
+   _mesa_reference_buffer_object(ctx, &obj->PointSize.BufferObj, NULL);
+#endif
 }
 
 

src/mesa/main/bufferobj.c

@@ -556,6 +556,17 @@ _mesa_init_buffer_objects( GLcontext *ctx )
 }
 
 
+void
+_mesa_free_buffer_objects( GLcontext *ctx )
+{
+   _mesa_reference_buffer_object(ctx, &ctx->Array.ArrayBufferObj, NULL);
+   _mesa_reference_buffer_object(ctx, &ctx->Array.ElementArrayBufferObj, NULL);
+
+   _mesa_reference_buffer_object(ctx, &ctx->CopyReadBuffer, NULL);
+   _mesa_reference_buffer_object(ctx, &ctx->CopyWriteBuffer, NULL);
+}
+
+
 /**
  * Bind the specified target to buffer for the specified context.
  * Called by glBindBuffer() and other functions.

src/mesa/main/bufferobj.h

@@ -59,6 +59,9 @@ _mesa_is_bufferobj(const struct gl_buffer_object *obj)
 extern void
 _mesa_init_buffer_objects( GLcontext *ctx );
 
+extern void
+_mesa_free_buffer_objects( GLcontext *ctx );
+
 extern void
 _mesa_update_default_objects_buffer_objects(GLcontext *ctx);
 

src/mesa/main/context.c

@@ -955,6 +955,7 @@ _mesa_free_context_data( GLcontext *ctx )
    _mesa_reference_fragprog(ctx, &ctx->FragmentProgram._TexEnvProgram, NULL);
 
    _mesa_free_attrib_data(ctx);
+   _mesa_free_buffer_objects(ctx);
    _mesa_free_lighting_data( ctx );
    _mesa_free_eval_data( ctx );
    _mesa_free_texture_data( ctx );
@@ -974,6 +975,7 @@ _mesa_free_context_data( GLcontext *ctx )
 #if FEATURE_ARB_pixel_buffer_object
    _mesa_reference_buffer_object(ctx, &ctx->Pack.BufferObj, NULL);
    _mesa_reference_buffer_object(ctx, &ctx->Unpack.BufferObj, NULL);
+   _mesa_reference_buffer_object(ctx, &ctx->DefaultPacking.BufferObj, NULL);
 #endif
 
 #if FEATURE_ARB_vertex_buffer_object

src/mesa/main/pixel.c

@@ -150,13 +150,17 @@ validate_pbo_access(GLcontext *ctx, struct gl_pixelstore_attrib *pack,
    GLboolean ok;
 
    /* Note, need to use DefaultPacking and Unpack's buffer object */
-   ctx->DefaultPacking.BufferObj = pack->BufferObj;
+   _mesa_reference_buffer_object(ctx,
+                                 &ctx->DefaultPacking.BufferObj,
+                                 pack->BufferObj);
 
    ok = _mesa_validate_pbo_access(1, &ctx->DefaultPacking, mapsize, 1, 1,
                                   format, type, ptr);
 
    /* restore */
-   ctx->DefaultPacking.BufferObj = ctx->Shared->NullBufferObj;
+   _mesa_reference_buffer_object(ctx,
+                                 &ctx->DefaultPacking.BufferObj,
+                                 ctx->Shared->NullBufferObj);
 
    if (!ok) {
       _mesa_error(ctx, GL_INVALID_OPERATION,

src/mesa/main/shared.c

@@ -95,12 +95,6 @@ _mesa_alloc_shared_state(GLcontext *ctx)
 
    /* Allocate the default buffer object */
    shared->NullBufferObj = ctx->Driver.NewBufferObject(ctx, 0, 0);
-#ifndef DEBUG
-   /* Set refcount so high that it never gets deleted.
-    * XXX with recent/improved refcounting this should be no longer be needed.
-    */
-   shared->NullBufferObj->RefCount = 1000 * 1000 * 1000;
-#endif
 
    /* Create default texture objects */
    for (i = 0; i < NUM_TEXTURE_TARGETS; i++) {

src/mesa/vbo/vbo_context.c

@@ -249,17 +249,25 @@ void _vbo_InvalidateState( GLcontext *ctx, GLuint new_state )
 
 void _vbo_DestroyContext( GLcontext *ctx )
 {
+   struct vbo_context *vbo = vbo_context(ctx);
+
    if (ctx->aelt_context) {
       _ae_destroy_context( ctx );
       ctx->aelt_context = NULL;
    }
 
-   if (vbo_context(ctx)) {
+   if (vbo) {
+      GLuint i;
+
+      for (i = 0; i < VBO_ATTRIB_MAX; i++) {
+         _mesa_reference_buffer_object(ctx, &vbo->currval[i].BufferObj, NULL);
+      }
+
       vbo_exec_destroy(ctx);
 #if FEATURE_dlist
       vbo_save_destroy(ctx);
 #endif
-      FREE(vbo_context(ctx));
+      FREE(vbo);
       ctx->swtnl_im = NULL;
    }
 }

src/mesa/vbo/vbo_exec_api.c

@@ -759,6 +759,7 @@ void vbo_use_buffer_objects(GLcontext *ctx)
    }
 
    /* Allocate a real buffer object now */
+   _mesa_reference_buffer_object(ctx, &exec->vtx.bufferobj, NULL);
    exec->vtx.bufferobj = ctx->Driver.NewBufferObject(ctx, bufName, target);
    ctx->Driver.BufferData(ctx, target, size, NULL, usage, exec->vtx.bufferobj);
 }
@@ -803,8 +804,19 @@ void vbo_exec_vtx_init( struct vbo_exec_context *exec )
    
    {
       struct gl_client_array *arrays = exec->vtx.arrays;
+      unsigned i;
+
       memcpy(arrays,      vbo->legacy_currval,  16 * sizeof(arrays[0]));
       memcpy(arrays + 16, vbo->generic_currval, 16 * sizeof(arrays[0]));
+
+      for (i = 0; i < 16; ++i) {
+         arrays[i     ].BufferObj = NULL;
+         arrays[i + 16].BufferObj = NULL;
+         _mesa_reference_buffer_object(ctx, &arrays[i     ].BufferObj,
+                                       vbo->legacy_currval[i].BufferObj);
+         _mesa_reference_buffer_object(ctx, &arrays[i + 16].BufferObj,
+                                       vbo->generic_currval[i].BufferObj);
+      }
    }
 
    exec->vtx.vertex_size = 0;