mesa: create _mesa_attach_renderbuffer_without_ref() helper

This will be used to take ownership of freashly created renderbuffers,
avoiding the need to call the reference function which requires
locking.

V2: dereference any existing fb attachments and actually attach the
    new rb.

v3: split out validation and attachment type/complete setting into
    a shared static function.

Reviewed-by: Emil Velikov <[email protected]>
Tested-by: Bartosz Tomczyk <[email protected]>

2 files changed, 40 insertions, 8 deletions

diff --git a/src/mesa/main/renderbuffer.c b/src/mesa/main/renderbuffer.c
index 4375b5b882c..627bdca66c5 100644
--- a/src/mesa/main/renderbuffer.c
+++ b/src/mesa/main/renderbuffer.c
@@ -106,14 +106,10 @@ _mesa_delete_renderbuffer(struct gl_context *ctx, struct gl_renderbuffer *rb)
    free(rb);
 }
 
-
-/**
- * Attach a renderbuffer to a framebuffer.
- * \param bufferName  one of the BUFFER_x tokens
- */
-void
-_mesa_add_renderbuffer(struct gl_framebuffer *fb,
-                       gl_buffer_index bufferName, struct gl_renderbuffer *rb)
+static void
+validate_and_init_renderbuffer_attachment(struct gl_framebuffer *fb,
+                                          gl_buffer_index bufferName,
+                                          struct gl_renderbuffer *rb)
 {
    assert(fb);
    assert(rb);
@@ -137,6 +133,37 @@ _mesa_add_renderbuffer(struct gl_framebuffer *fb,
 
    fb->Attachment[bufferName].Type = GL_RENDERBUFFER_EXT;
    fb->Attachment[bufferName].Complete = GL_TRUE;
+}
+
+
+/**
+ * Attach a renderbuffer to a framebuffer.
+ * \param bufferName  one of the BUFFER_x tokens
+ *
+ * This function avoids adding a reference and is therefore intended to be
+ * used with a freashly created renderbuffer.
+ */
+void
+_mesa_add_renderbuffer_without_ref(struct gl_framebuffer *fb,
+                                   gl_buffer_index bufferName,
+                                   struct gl_renderbuffer *rb)
+{
+   validate_and_init_renderbuffer_attachment(fb, bufferName, rb);
+
+   _mesa_reference_renderbuffer(&fb->Attachment[bufferName].Renderbuffer,
+                                NULL);
+   fb->Attachment[bufferName].Renderbuffer = rb;
+}
+
+/**
+ * Attach a renderbuffer to a framebuffer.
+ * \param bufferName  one of the BUFFER_x tokens
+ */
+void
+_mesa_add_renderbuffer(struct gl_framebuffer *fb,
+                       gl_buffer_index bufferName, struct gl_renderbuffer *rb)
+{
+   validate_and_init_renderbuffer_attachment(fb, bufferName, rb);
    _mesa_reference_renderbuffer(&fb->Attachment[bufferName].Renderbuffer, rb);
 }
 
diff --git a/src/mesa/main/renderbuffer.h b/src/mesa/main/renderbuffer.h
index aa83120c1e4..a6f14394982 100644
--- a/src/mesa/main/renderbuffer.h
+++ b/src/mesa/main/renderbuffer.h
@@ -47,6 +47,11 @@ extern void
 _mesa_delete_renderbuffer(struct gl_context *ctx, struct gl_renderbuffer *rb);
 
 extern void
+_mesa_add_renderbuffer_without_ref(struct gl_framebuffer *fb,
+                                   gl_buffer_index bufferName,
+                                   struct gl_renderbuffer *rb);
+
+extern void
 _mesa_add_renderbuffer(struct gl_framebuffer *fb,
                        gl_buffer_index bufferName, struct gl_renderbuffer *rb);