tools: add ability to wrap wire messages with ifs

Makes it possible to hide wire messages behind EXPERIMENTAL_FEATURES
flag.

tools/gen/header_template

@@ -85,12 +85,18 @@ void fromwire_${subtype.name}(const u8 **cursor, size_t *plen, ${subtype.type_na
 % endfor
 % endif
 % for msg in messages:
+    % if msg.if_token:
+#if ${msg.if_token}
+    % endif
 /* WIRE: ${msg.name.upper()} */
     % for c in msg.msg_comments:
 /* ${c} */
     % endfor
 u8 *towire_${msg.name}(const tal_t *ctx${''.join([f.arg_desc_to() for f in msg.fields.values()])});
 bool fromwire_${msg.name}(${'const tal_t *ctx, ' if msg.needs_context() else ''}const void *p${''.join([f.arg_desc_from() for f in msg.fields.values()])});
+    % if msg.if_token:
+#endif /* ${msg.if_token} */
+    % endif
 
 % endfor
 

tools/gen/impl_template

@@ -210,6 +210,9 @@ ${static}const struct tlv_record_type tlvs_${tlv.name}[] = {
 % endfor ##  END TLV's
 % for msg in messages: ## START Wire Messages
 
+    % if msg.if_token:
+#if ${msg.if_token}
+    % endif
 /* WIRE: ${msg.name.upper()} */
     % for c in msg.msg_comments:
 /*${c} */
@@ -322,4 +325,7 @@ bool fromwire_${msg.name}(${'const tal_t *ctx, ' if msg.needs_context() else ''}
 	% endfor
 	return cursor != NULL;
 }
+    % if msg.if_token:
+#endif /* ${msg.if_token} */
+    % endif
 % endfor ## END Wire Messages

tools/generate-wire.py

@@ -356,6 +356,7 @@ class Message(FieldSet):
         self.struct_prefix = struct_prefix
         self.enumname = None
         self.msg_comments = comments
+        self.if_token = None
 
     def has_option(self):
         return self.option is not None
@@ -369,6 +370,9 @@ class Message(FieldSet):
             return self.struct_prefix + "_" + self.name
         return self.name
 
+    def add_if(self, if_token):
+        self.if_token = if_token
+
 
 class Tlv(object):
     def __init__(self, name):
@@ -518,6 +522,7 @@ def main(options, args=None, output=sys.stdout, lines=None):
     genline = next_line(args, lines)
 
     comment_set = []
+    token_name = None
 
     # Create a new 'master' that serves as the coordinator for the file generation
     master = Master()
@@ -530,8 +535,12 @@ def main(options, args=None, output=sys.stdout, lines=None):
             if not bool(line):
                 master.add_comments(comment_set)
                 comment_set = []
+                token_name = None
                 continue
 
+            if len(tokens) > 2:
+                token_name = tokens[1]
+
             if token_type == 'subtype':
                 subtype, _, _ = master.add_type(tokens[1])
 
@@ -632,6 +641,11 @@ def main(options, args=None, output=sys.stdout, lines=None):
                 comment_set = []
             elif token_type.startswith('#include'):
                 master.add_include(token_type)
+            elif token_type.startswith('#if'):
+                msg = master.find_message(token_name)
+                if (msg):
+                    if_token = token_type[token_type.index(' ') + 1:]
+                    msg.add_if(if_token)
             elif token_type.startswith('#'):
                 comment_set.append(token_type[1:])
             else:

tools/test/enum.h

@@ -3,6 +3,8 @@
 #include <ccan/short_types/short_types.h>
 #include <stdlib.h>
 
+#define TEST_IFDEF 0
+
 enum test_enum {
 	TEST_ONE,
 	TEST_TWO,

tools/test/test_cases

@@ -47,6 +47,10 @@ msgdata,test_msg,test_sbt_arrays,subtype_arrays,
 msgdata,test_msg,extension_1,test_features,,option_short_id
 msgdata,test_msg,extension_2,test_short_id,,option_one,option_two
 
+msgtype,test_ifdef,100
+#ifdef TEST_IFDEF
+msgdata,test_ifdef,is_def,u32,
+
 msgtype,test_tlv1,2
 msgdata,test_tlv1,test_struct,test_short_id,
 msgdata,test_tlv1,tlv,test_n1,