qapi: Better separate the different kinds of helpers

Insert comments to separate sections dealing with parsing, semantic
analysis, code generation, and so forth.

Move helpers to their proper section.

Backports commit 00e4b285a31d19dcd88bd46729c9e09bfc9cc7fd from qemu

qemu/scripts/qapi.py

@@ -65,6 +65,10 @@ union_types = []
 events = []
 all_names = {}
 
+#
+# Parsing the schema into expressions
+#
+
 def error_path(parent):
     res = ""
     while parent:
@@ -296,6 +300,10 @@ class QAPISchema:
             raise QAPISchemaError(self, 'Expected "{", "[" or string')
         return expr
 
+#
+# Semantic analysis of schema expressions
+#
+
 def find_base_fields(base):
     base_struct_define = find_struct(base)
     if not base_struct_define:
@@ -356,6 +364,60 @@ def check_name(expr_info, source, name, allow_optional = False,
         raise QAPIExprError(expr_info,
                             "%s uses invalid name '%s'" % (source, name))
 
+def add_name(name, info, meta, implicit = False):
+    global all_names
+    check_name(info, "'%s'" % meta, name)
+    if name in all_names:
+        raise QAPIExprError(info,
+                            "%s '%s' is already defined"
+                            % (all_names[name], name))
+    if not implicit and name[-4:] == 'Kind':
+        raise QAPIExprError(info,
+                            "%s '%s' should not end in 'Kind'"
+                            % (meta, name))
+    all_names[name] = meta
+
+def add_struct(definition, info):
+    global struct_types
+    name = definition['struct']
+    add_name(name, info, 'struct')
+    struct_types.append(definition)
+
+def find_struct(name):
+    global struct_types
+    for struct in struct_types:
+        if struct['struct'] == name:
+            return struct
+    return None
+
+def add_union(definition, info):
+    global union_types
+    name = definition['union']
+    add_name(name, info, 'union')
+    union_types.append(definition)
+
+def find_union(name):
+    global union_types
+    for union in union_types:
+        if union['union'] == name:
+            return union
+    return None
+
+def add_enum(name, info, enum_values = None, implicit = False):
+    global enum_types
+    add_name(name, info, 'enum', implicit)
+    enum_types.append({"enum_name": name, "enum_values": enum_values})
+
+def find_enum(name):
+    global enum_types
+    for enum in enum_types:
+        if enum['enum_name'] == name:
+            return enum
+    return None
+
+def is_enum(name):
+    return find_enum(name) != None
+
 def check_type(expr_info, source, value, allow_array = False,
                allow_dict = False, allow_optional = False,
                allow_star = False, allow_metas = []):
@@ -699,6 +761,10 @@ def parse_schema(fname):
         print >>sys.stderr, e
         exit(1)
 
+#
+# Code generation helpers
+#
+
 def parse_args(typeinfo):
     if isinstance(typeinfo, str):
         struct = find_struct(typeinfo)
@@ -816,60 +882,6 @@ def type_name(value):
         return value
     return c_name(value)
 
-def add_name(name, info, meta, implicit = False):
-    global all_names
-    check_name(info, "'%s'" % meta, name)
-    if name in all_names:
-        raise QAPIExprError(info,
-                            "%s '%s' is already defined"
-                            % (all_names[name], name))
-    if not implicit and name[-4:] == 'Kind':
-        raise QAPIExprError(info,
-                            "%s '%s' should not end in 'Kind'"
-                            % (meta, name))
-    all_names[name] = meta
-
-def add_struct(definition, info):
-    global struct_types
-    name = definition['struct']
-    add_name(name, info, 'struct')
-    struct_types.append(definition)
-
-def find_struct(name):
-    global struct_types
-    for struct in struct_types:
-        if struct['struct'] == name:
-            return struct
-    return None
-
-def add_union(definition, info):
-    global union_types
-    name = definition['union']
-    add_name(name, info, 'union')
-    union_types.append(definition)
-
-def find_union(name):
-    global union_types
-    for union in union_types:
-        if union['union'] == name:
-            return union
-    return None
-
-def add_enum(name, info, enum_values = None, implicit = False):
-    global enum_types
-    add_name(name, info, 'enum', implicit)
-    enum_types.append({"enum_name": name, "enum_values": enum_values})
-
-def find_enum(name):
-    global enum_types
-    for enum in enum_types:
-        if enum['enum_name'] == name:
-            return enum
-    return None
-
-def is_enum(name):
-    return find_enum(name) != None
-
 eatspace = '\033EATSPACE.'
 pointer_suffix = ' *' + eatspace
 
@@ -966,6 +978,10 @@ def guardend(name):
 ''',
                  name=guardname(name))
 
+#
+# Common command line parsing
+#
+
 def parse_command_line(extra_options = "", extra_long_options = []):
 
     try:
@@ -1007,6 +1023,10 @@ def parse_command_line(extra_options = "", extra_long_options = []):
 
     return (fname, output_dir, do_c, do_h, prefix, extra_opts)
 
+#
+# Generate output files with boilerplate
+#
+
 def open_output(output_dir, do_c, do_h, prefix, c_file, h_file,
                 c_comment, h_comment):
     c_file = output_dir + prefix + c_file