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.

6 files changed, 26 insertions, 8 deletions

diff --git a/src/mesa/main/arrayobj.c b/src/mesa/main/arrayobj.c
index fd35d4e38c..e36137d378 100644
--- a/src/mesa/main/arrayobj.c
+++ b/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
 }
 
 
diff --git a/src/mesa/main/bufferobj.c b/src/mesa/main/bufferobj.c
index 2271550efe..dabb1386ca 100644
--- a/src/mesa/main/bufferobj.c
+++ b/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.
diff --git a/src/mesa/main/bufferobj.h b/src/mesa/main/bufferobj.h
index 2931962ac0..f8bca5ff71 100644
--- a/src/mesa/main/bufferobj.h
+++ b/src/mesa/main/bufferobj.h
@@ -60,6 +60,9 @@ 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);
 
 
diff --git a/src/mesa/main/context.c b/src/mesa/main/context.c
index fccce51e85..591aa1121d 100644
--- a/src/mesa/main/context.c
+++ b/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
diff --git a/src/mesa/main/pixel.c b/src/mesa/main/pixel.c
index f6f9c1173a..ca6ecd7bfb 100644
--- a/src/mesa/main/pixel.c
+++ b/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,
diff --git a/src/mesa/main/shared.c b/src/mesa/main/shared.c
index a7cf623c47..b889364f0d 100644
--- a/src/mesa/main/shared.c
+++ b/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++) {