qapi: Make c_type() consistently convert qapi names

Continuing the string of cleanups for supporting downstream names
containing '.', this patch focuses on ensuring c_type() can
handle a downstream name. This patch alone does not fix the
places where generator output should be calling this function
but was open-coding things instead, but it gets us a step closer.

In particular, the changes to c_list_type() and type_name() mean
that type_name(FOO) now handles the case when FOO contains '.',
'-', or is a ticklish identifier other than a builtin (builtins
are exempted because ['int'] must remain mapped to 'intList' and
not 'q_intList'). Meanwhile, ['unix'] now maps to 'q_unixList'
rather than 'unixList', to match the fact that 'unix' is ticklish;
however, our naming conventions state that complex types should
start with a capital, so no type name following conventions will
ever have the 'q_' prepended.

Likewise, changes to c_type() mean that c_type(FOO) properly
handles an enum or complex type FOO with '.' or '-' in the
name, or is a ticklish identifier (again, a ticklish identifier
as a type name violates conventions).

Backports commit c6405b54b7b09a876f2f2fba2aa6f8ac87189cb9 from qemu

qemu/scripts/qapi.py

@@ -779,6 +779,15 @@ def c_enum_const(type_name, const_name):
 
 c_name_trans = string.maketrans('.-', '__')
 
+# Map @name to a valid C identifier.
+# If @protect, avoid returning certain ticklish identifiers (like
+# C keywords) by prepending "q_".
+#
+# Used for converting 'name' from a 'name':'type' qapi definition
+# into a generated struct member, as well as converting type names
+# into substrings of a generated C function name.
+# '__a.b_c' -> '__a_b_c', 'x-foo' -> 'x_foo'
+# protect=True: 'int' -> 'q_int'; protect=False: 'int' -> 'int'
 def c_name(name, protect=True):
     # ANSI X3J11/88-090, 3.1.1
     c89_words = set(['auto', 'break', 'case', 'char', 'const', 'continue',
@@ -810,13 +819,25 @@ def c_name(name, protect=True):
         return "q_" + name
     return name.translate(c_name_trans)
 
+# Map type @name to the C typedef name for the list form.
+#
+# ['Name'] -> 'NameList', ['x-Foo'] -> 'x_FooList', ['int'] -> 'intList'
 def c_list_type(name):
     return name + 'List'
 
+# Map type @value to the C typedef form.
+#
+# Used for converting 'type' from a 'member':'type' qapi definition
+# into the alphanumeric portion of the type for a generated C parameter,
+# as well as generated C function names.  See c_type() for the rest of
+# the conversion such as adding '*' on pointer types.
+# 'int' -> 'int', '[x-Foo]' -> 'x_FooList', '__a.b_c' -> '__a_b_c'
 def type_name(value):
     if type(value) == list:
         return c_list_type(value[0])
+    if value in builtin_types.keys():
         return value
+    return c_name(value)
 
 def add_name(name, info, meta, implicit = False):
     global all_names
@@ -875,6 +896,10 @@ def is_enum(name):
 eatspace = '\033EATSPACE.'
 pointer_suffix = ' *' + eatspace
 
+# Map type @name to its C type expression.
+# If @is_param, const-qualify the string type.
+#
+# This function is used for computing the full C type of 'member':'name'.
 # A special suffix is added in c_type() for pointer types, and it's
 # stripped in mcgen(). So please notice this when you check the return
 # value of c_type() outside mcgen().
@@ -899,7 +924,7 @@ def c_type(value, is_param=False):
     elif type(value) == list:
         return c_list_type(value[0]) + pointer_suffix
     elif is_enum(value):
-        return value
+        return c_name(value)
     elif value == None:
         return 'void'
     elif value in events:
@@ -907,7 +932,7 @@ def c_type(value, is_param=False):
     else:
         # complex type name
         assert isinstance(value, str) and value != ""
-        return value + pointer_suffix
+        return c_name(value) + pointer_suffix
 
 def is_c_ptr(value):
     return c_type(value).endswith(pointer_suffix)