[Libguestfs] [libnbd PATCH] generator: Add support for namespace constants

[Martin Kletzander]

This just defines the namespace, its contexts and related constants and the only
supported one is currently base:allocation.  The names of the constants are not
very future-proof, but shorter than LIBNBD_META_NS_CONTEXT_BASE_ALLOCATION or
similar.

Currently the output looks like this:

/* "base" namespace */

/* "base" namespace contexts */

/* "base:allocation" context related constants */

Separated by two empty lines from unrelated parts of the header file above and
below.

Signed-off-by: Martin Kletzander <mkletzan at redhat.com>
---

Notes:
    Everything is up for a debate:
    
    - the names might need to be different so that they do not clash with other
      constants in the scope later on,
    
    - the fact that "base" and "base:allocation" are even defined, which might be
      useless, since listing contexts of a namespace is not exposed,
    
    - whether this should live in a separate (still included in libnbd.h) file,
    
    - and more...

 generator/generator | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/generator/generator b/generator/generator
index 684fb44ac918..9d8d257fd2f1 100755
--- a/generator/generator
+++ b/generator/generator
@@ -2066,6 +2066,13 @@ let constants = [
   "READ_ERROR",          3;
 ]
 
+let metadata_namespaces = [
+  "base", [ "allocation", [
+    "STATE_HOLE", 1 lsl 0;
+    "STATE_ZERO", 1 lsl 1;
+  ] ];
+]
+
 (*----------------------------------------------------------------------*)
 
 (* Helper functions. *)
@@ -2908,6 +2915,25 @@ let print_extern_and_define name args ret =
   pr "#define LIBNBD_HAVE_NBD_%s 1\n" name_upper;
   pr "\n"
 
+let print_ns_ctxt ns ns_upper ctxt consts =
+  let ctxt_upper = String.uppercase_ascii ctxt in
+  pr "#define LIBNBD_CONTEXT_%s_%s \"%s:%s\"\n"
+    ns_upper ctxt_upper ns ctxt;
+  pr "\n";
+  pr "/* \"%s:%s\" context related constants */\n" ns ctxt;
+  List.iter (fun (n, i) -> pr "#define LIBNBD_%-30s %d\n" n i) consts
+
+let print_ns ns ctxts =
+  let ns_upper = String.uppercase_ascii ns in
+  pr "/* \"%s\" namespace */\n" ns;
+  pr "#define LIBNBD_NAMESPACE_%s \"%s\"\n" ns_upper ns;
+  pr "\n";
+  pr "/* \"%s\" namespace contexts */\n" ns;
+  List.iter (
+    fun (ctxt, consts) -> print_ns_ctxt ns ns_upper ctxt consts
+  ) ctxts;
+  pr "\n"
+
 let generate_include_libnbd_h () =
   generate_header CStyle;
 
@@ -2944,6 +2970,10 @@ let generate_include_libnbd_h () =
     fun (name, { args; ret }) -> print_extern_and_define name args ret
   ) handle_calls;
   pr "\n";
+  List.iter (
+    fun (ns, ctxts) -> print_ns ns ctxts
+  ) metadata_namespaces;
+  pr "\n";
   pr "#endif /* LIBNBD_H */\n"
 
 let generate_lib_unlocked_h () =
-- 
2.22.0