From 39f63eb27f8b2d62b98339e7fbab8a87e83701eb Mon Sep 17 00:00:00 2001
From: Aditya Sharma <aditya.sharma.met19@itbhu.ac.in>
Date: Fri, 21 Feb 2025 00:19:18 +0530
Subject: [PATCH] tools/gen: Enable Subtypes to have TLVStreams

This change will allow subtypes in wiregen files to have tlvstreams.
Shifting tlv structs above subtypes in header_template is done to prevent
forward declaration.

Since generate-wire prepends 'tlv_' in tlvname, we
have to modify fromwire_subtype_field and towire_subtype_field in
impl_template to accommodate this.

Changelog-Added: This PR would turn our peers into watchtower and enable SCB to create penalty txn.
---
 tools/gen/header_template | 45 ++++++++++++++++++++-------------------
 tools/gen/impl_template   |  4 ++++
 tools/generate-wire.py    |  3 +++
 3 files changed, 30 insertions(+), 22 deletions(-)

diff --git a/tools/gen/header_template b/tools/gen/header_template
index 4b7188555..bbfe0df97 100644
--- a/tools/gen/header_template
+++ b/tools/gen/header_template
@@ -37,28 +37,6 @@ const char *${enum_set['name']}_name(int e);
 bool ${enum_set['name']}_is_defined(u16 type);
 % endfor
 
-## Structs for subtypes + tlv messages
-% for struct in structs:
-struct ${struct.struct_name()} {
-        % for f in struct.fields.values():
-            % for c in f.field_comments:
-        /* ${c} */
-            % endfor
-        % if bool(f.len_field_of):
-<% continue %>
-        % endif
-            % if f.is_varlen() and f.type_obj.is_varsize():
-        ${f.type_obj.type_name()} **${f.name};
-            % elif f.is_varlen() or f.type_obj.is_varsize():
-        ${f.type_obj.type_name()} *${f.name};
-            % elif f.is_array():
-        ${f.type_obj.type_name()} ${f.name}[${f.count}];
-            % else:
-        ${f.type_obj.type_name()} ${f.name};
-            % endif
-        % endfor
-};
-% endfor
 ## Structs for TLVs
 % for tlv in tlvs.values():
 struct ${tlv.struct_name()} {
@@ -82,6 +60,29 @@ struct ${tlv.struct_name()} {
 };
 % endfor
 
+## Structs for subtypes + tlv messages
+% for struct in structs:
+struct ${struct.struct_name()} {
+        % for f in struct.fields.values():
+            % for c in f.field_comments:
+        /* ${c} */
+            % endfor
+        % if bool(f.len_field_of):
+<% continue %>
+        % endif
+            % if f.is_varlen() and f.type_obj.is_varsize():
+        ${f.type_obj.type_name()} **${f.name};
+            % elif f.is_varlen() or f.type_obj.is_varsize():
+        ${f.type_obj.type_name()} *${f.name};
+            % elif f.is_array():
+        ${f.type_obj.type_name()} ${f.name}[${f.count}];
+            % else:
+        ${f.type_obj.type_name()} ${f.name};
+            % endif
+        % endfor
+};
+% endfor
+
 % for tlv in tlvs.values():
 struct ${tlv.struct_name()} *${tlv.struct_name()}_new(const tal_t *ctx);
 
diff --git a/tools/gen/impl_template b/tools/gen/impl_template
index 4ce2dcb37..7b9011e1d 100644
--- a/tools/gen/impl_template
+++ b/tools/gen/impl_template
@@ -66,6 +66,8 @@ towire_${type_obj.name}_array(${ptr}, ${fieldname}, ${f.size('tal_count(' + fiel
 towire_${type_obj.name}(${ptr}, ${f.name});
 % elif is_single_ptr:
 towire_${type_obj.name}(${ptr}, ${'*' if type_obj.is_assignable() else ''}${fieldname});
+%elif f.type_obj.is_tlv():
+towire_tlv_${type_obj.name}(${ptr}, ${'' if type_obj.is_assignable() or type_obj.is_varsize() else '&'}${fieldname});
 % else:
 towire_${type_obj.name}(${ptr}, ${'' if type_obj.is_assignable() or type_obj.is_varsize() else '&'}${fieldname});
 % endif
@@ -74,6 +76,8 @@ towire_${type_obj.name}(${ptr}, ${'' if type_obj.is_assignable() or type_obj.is_
 <%def name="fromwire_subtype_field(fieldname, f, ctx, is_ptr)">\
 <%
     type_ = f.type_obj.name
+    if f.type_obj.is_tlv():
+	type_ = 'tlv_' + type_
     typename = f.type_obj.type_name()
     if f.type_obj.is_varsize():
 	typename += ' *'
diff --git a/tools/generate-wire.py b/tools/generate-wire.py
index ebf7614d5..dfd3b11a4 100755
--- a/tools/generate-wire.py
+++ b/tools/generate-wire.py
@@ -590,6 +590,9 @@ def main(options, args=None, output=sys.stdout, lines=None):
                 else:
                     count = tokens[4]
 
+                if tokens[3] in master.tlvs:
+                    type_obj.tlv = master.tlvs[tokens[3]]
+
                 subtype.add_data_field(tokens[2], type_obj, count, comments=list(comment_set),
                                        optional=optional)
                 comment_set = []