layer: Add utility template for sType init

Add utility function to auto populate sType field based on typename
given to autogen of typemap helper. Return value optimization (copy
elision) should make this perfomance neutral vs. inline init.

Change-Id: I231cf92d5063c19f9ad5b14189dd162fdac76a43

1 files changed, 27 insertions, 6 deletions

diff --git a/scripts/helper_file_generator.py b/scripts/helper_file_generator.py
index 114f47f8..f47857a8 100644
--- a/scripts/helper_file_generator.py
+++ b/scripts/helper_file_generator.py
@@ -1103,6 +1103,7 @@ class HelperFileOutputGenerator(OutputGenerator):
         typename_func = fprefix + 'typename'
         idname_func = fprefix + 'stype_name'
         find_func = fprefix + 'find_in_chain'
+        init_func = fprefix + 'init_struct'
 
         explanatory_comment = '\n'.join((
                 '// These empty generic templates are specialized for each type with sType',
@@ -1142,22 +1143,35 @@ class HelperFileOutputGenerator(OutputGenerator):
             '    }}',
             '    return found;',
             '}}',
+            '',
+            '// Init the header of an sType struct with pNext',
+            'template <typename T> T {init_func}(void *p_next) {{',
+            '    T out = {{}};',
+            '    out.sType = {type_map}<T>::kSType;',
+            '    out.pNext = p_next;',
+            '    return out;',
+            '}}',
+                        '',
+            '// Init the header of an sType struct',
+            'template <typename T> T {init_func}() {{',
+            '    T out = {{}};',
+            '    out.sType = {type_map}<T>::kSType;',
+            '    return out;',
+            '}}',
+
             ''))
 
         code = []
+
+        # Generate header
         code.append('\n'.join((
             '#pragma once',
             '#include <vulkan/vulkan.h>\n',
             explanatory_comment, '',
             empty_idmap,
-            empty_typemap, '',
-            utilities_format.format(id_member=id_member, id_map=idmap, type_map=typemap,
-                type_member=type_member, header=generic_header, typename_func=typename_func, idname_func=idname_func,
-                find_func=find_func), ''
-            )))
+            empty_typemap, '')))
 
         # Generate the specializations for each type and stype
-
         for item in self.structMembers:
             typename = item.name
             info = self.structTypes.get(typename)
@@ -1175,6 +1189,13 @@ class HelperFileOutputGenerator(OutputGenerator):
             if item.ifdef_protect != None:
                 code.append('#endif // %s' % item.ifdef_protect)
 
+        # Generate utilities for all types
+        code.append('\n'.join((
+            utilities_format.format(id_member=id_member, id_map=idmap, type_map=typemap,
+                type_member=type_member, header=generic_header, typename_func=typename_func, idname_func=idname_func,
+                find_func=find_func, init_func=init_func), ''
+            )))
+
         return "\n".join(code)
 
     #