[PATCH v2 02/30] libxl: idl: allow KeyedUnion members to be empty

[Rob Hoes <rob.hoes@citrix.com>]

This is useful when the key enum has an "invalid" option and avoids
the need to declare a dummy struct. Use this for domain_build_info
resulting in the generated API changing like so:
    --- tools/libxl/_libxl_BACKUP_types.h
    +++ tools/libxl/_libxl_types.h
    @@ -377,8 +377,6 @@ typedef struct libxl_domain_build_info {
                 const char * features;
                 libxl_defbool e820_host;
             } pv;
    -        struct {
    -        } invalid;
         } u;
     } libxl_domain_build_info;
     void libxl_domain_build_info_dispose(libxl_domain_build_info *p);

+ a related change to the JSON generation.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Rob Hoes <rob.hoes@citrix.com>
---
 tools/libxl/gentest.py      |    3 ++-
 tools/libxl/gentypes.py     |   11 ++++++++---
 tools/libxl/libxl_types.idl |    2 +-
 3 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/tools/libxl/gentest.py b/tools/libxl/gentest.py
index 84b4fd7..6fab493 100644
--- a/tools/libxl/gentest.py
+++ b/tools/libxl/gentest.py
@@ -46,7 +46,8 @@ def gen_rand_init(ty, v, indent = "    ", parent = None):
         for f in ty.fields:
             (nparent,fexpr) = ty.member(v, f, parent is None)
             s += "case %s:\n" % f.enumname
-            s += gen_rand_init(f.type, fexpr, indent + "    ", nparent)
+            if f.type is not None:
+                s += gen_rand_init(f.type, fexpr, indent + "    ", nparent)
             s += "    break;\n"
         s += "}\n"
     elif isinstance(ty, idl.Struct) \
diff --git a/tools/libxl/gentypes.py b/tools/libxl/gentypes.py
index 30f29ba..be06257 100644
--- a/tools/libxl/gentypes.py
+++ b/tools/libxl/gentypes.py
@@ -45,6 +45,8 @@ def libxl_C_type_define(ty, indent = ""):
             s += "typedef %s %s {\n" % (ty.kind, ty.typename)
 
         for f in ty.fields:
+            if isinstance(ty, idl.KeyedUnion) and f.type is None: continue
+            
             x = libxl_C_instance_of(f.type, f.name)
             if f.const:
                 x = "const " + x
@@ -67,7 +69,8 @@ def libxl_C_type_dispose(ty, v, indent = "    ", parent = None):
         for f in ty.fields:
             (nparent,fexpr) = ty.member(v, f, parent is None)
             s += "case %s:\n" % f.enumname
-            s += libxl_C_type_dispose(f.type, fexpr, indent + "    ", nparent)
+            if f.type is not None:
+                s += libxl_C_type_dispose(f.type, fexpr, indent + "    ", nparent)
             s += "    break;\n"
         s += "}\n"
     elif isinstance(ty, idl.Array):
@@ -115,7 +118,8 @@ def _libxl_C_type_init(ty, v, indent = "    ", parent = None, subinit=False):
             for f in ty.fields:
                 (nparent,fexpr) = ty.member(v, f, parent is None)
                 s += "case %s:\n" % f.enumname
-                s += _libxl_C_type_init(f.type, fexpr, "    ", nparent)
+                if f.type is not None:
+                    s += _libxl_C_type_init(f.type, fexpr, "    ", nparent)
                 s += "    break;\n"
             s += "}\n"
         else:
@@ -214,7 +218,8 @@ def libxl_C_type_gen_json(ty, v, indent = "    ", parent = None):
         for f in ty.fields:
             (nparent,fexpr) = ty.member(v, f, parent is None)
             s += "case %s:\n" % f.enumname
-            s += libxl_C_type_gen_json(f.type, fexpr, indent + "    ", nparent)
+            if f.type is not None:
+                s += libxl_C_type_gen_json(f.type, fexpr, indent + "    ", nparent)
             s += "    break;\n"
         s += "}\n"
     elif isinstance(ty, idl.Struct) and (parent is None or ty.json_fn is None):
diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
index a22569f..81fb25a 100644
--- a/tools/libxl/libxl_types.idl
+++ b/tools/libxl/libxl_types.idl
@@ -344,7 +344,7 @@ libxl_domain_build_info = Struct("domain_build_info",[
                                       # Use host's E820 for PCI passthrough.
                                       ("e820_host", libxl_defbool),
                                       ])),
-                 ("invalid", Struct(None, [])),
+                 ("invalid", None),
                  ], keyvar_init_val = "LIBXL_DOMAIN_TYPE_INVALID")),
     ], dir=DIR_IN
 )
-- 
1.7.10.4