til_setup: introduce til_setup_t

Preparatory commit for providing a res_setup type to replace
void*.

The impetus for this isn't just pursuit of less void*, but
primarily implementing setup freeing by embedding this struct
into the private setup types.

An alternative method of adding setup freeing would have been to
introduce something like til_module_t.free_setup().  But that
would require having the til_module_t on hand, and the whole
setup machinery is more generalized than til_module_t anyways.
This way anything can simply embed the struct in their private
setup instance and return the pointer to that in *res_setup.
They should always be able to find their containing struct's
offset from the til_setup_t* they returned.  Either by using
container_of(), or simply placing it at the start of the private
setup struct.

1 files changed, 10 insertions, 0 deletions

diff --git a/src/til_setup.h b/src/til_setup.h
new file mode 100644
index 0000000..7984dd1
--- /dev/null
+++ b/src/til_setup.h
@@ -0,0 +1,10 @@
+#ifndef _TIL_SETUP_H
+#define _TIL_SETUP_H
+
+typedef struct til_setup_t til_setup_t;
+
+struct til_setup_t {
+	void (*free)(til_setup_t *setup);
+};
+
+#endif