subtypes: add some parsing for subtypes, so that it passes

this probably could be consolidated, as it splits
out all the print_to/fromwire method stuff for the Subtype class

tools/generate-wire.py

@@ -55,6 +55,9 @@ class FieldType(object):
     def is_assignable(self):
         return self.name in ['u8', 'u16', 'u32', 'u64', 'bool', 'struct amount_msat', 'struct amount_sat', 'var_int'] or self.name.startswith('enum ')
 
+    def needs_ptr(self):
+        return not self.is_assignable()
+
     # We only accelerate the u8 case: it's common and trivial.
     def has_array_helper(self):
         return self.name in ['u8']
@@ -69,6 +72,12 @@ class FieldType(object):
             return 'u64'
         return basetype
 
+    def is_subtype(self):
+        for subtype in subtypes:
+            if subtype.name == self.base():
+                return True
+        return False
+
     # Returns base size
     @staticmethod
     def _typesize(typename):
@@ -144,6 +153,7 @@ class Field(object):
         self.num_elems = 1
         self.optional = False
         self.is_tlv = False
+        self.is_subtype = False
 
         if name.endswith('_tlv'):
             self.is_tlv = True
@@ -169,9 +179,15 @@ class Field(object):
 
         # Bolts use just a number: Guess type based on size.
         if options.bolt:
-            if size == '$':  # this is a subtype
+            if size.startswith('$'):  # this is a subtype
                 self.fieldtype = FieldType('struct {}'.format(name))
-            elif size == 'var_int':
+                self.is_subtype = True
+                if size[1:] == prevname:
+                    self.lenvar = size[1:]
+                else:
+                    raise ValueError('Expected size field for subtype field {}'.format(name))
+            else:
+                if size == 'var_int':
                     base_size = 8
                     self.fieldtype = FieldType(size)
                 else:
@@ -255,6 +271,15 @@ fromwire_tlv_impl_templ = """static bool fromwire_{tlv_name}_{name}({ctx}{args})
 }}
 """
 
+fromwire_subtype_impl_templ = """static bool fromwire_{name}({ctx}{args})
+{{
+
+{fields}
+{subcalls}
+\treturn cursor != NULL;
+}}
+"""
+
 fromwire_header_templ = """bool fromwire_{name}({ctx}const void *p{args});
 """
 
@@ -408,8 +433,9 @@ class Message(object):
                 subcalls.append('({})[i] = fromwire_{}({}, {}cursor, {}plen);'
                                 .format(name, basetype, ctx, p_ref, p_ref))
             else:
-                subcalls.append('fromwire_{}({}cursor, {}plen, {} + i);'
+                ctx_arg = ctx + ', ' if f.fieldtype.is_subtype() else ''
-                                .format(basetype, p_ref, p_ref, name))
+                subcalls.append('fromwire_{}({}{}cursor, {}plen, {} + i);'
+                                .format(basetype, ctx_arg, p_ref, p_ref, name))
 
     def print_fromwire(self, is_header):
         ctx_arg = 'const tal_t *ctx, ' if self.has_variable_fields else ''
@@ -859,6 +885,99 @@ class Subtype(Message):
     def print_struct(self):
         return TlvMessage._inner_print_struct(self.name, self.fields)
 
+    def print_towire(self):
+        """ prints towire function definition for a subtype"""
+        field_decls = []
+        for f in self.fields:
+            if f.optional:
+                raise TypeError("Optional fields on subtypes not currently supported. {}".format(f.name))
+            if f.is_len_var:
+                field_decls.append('\t{0} {1} = tal_count({2}->{3});'.format(
+                    f.fieldtype.name, f.name, self.name, f.lenvar_for.name
+                ))
+
+        subcalls = CCode()
+        for f in self.fields:
+            basetype = f.fieldtype.base()
+            for c in f.comments:
+                subcalls.append('/*{} */'.format(c))
+
+            if f.is_padding():
+                subcalls.append('towire_pad(p, {});'.format(f.num_elems))
+            elif f.is_array():
+                self.print_towire_array(subcalls, basetype, f, f.num_elems,
+                                        is_tlv=True)
+            elif f.is_variable_size():
+                self.print_towire_array(subcalls, basetype, f, f.lenvar,
+                                        is_tlv=True)
+            elif f.is_len_var:
+                subcalls.append('towire_{}(p, {});'.format(basetype, f.name))
+            else:
+                ref = '&' if f.fieldtype.needs_ptr() else ''
+                subcalls.append('towire_{}(p, {}{}->{});'.format(basetype, ref, self.name, f.name))
+        return subtype_towire_stub.format(
+            name=self.name,
+            field_decls='\n'.join(field_decls),
+            subcalls=str(subcalls))
+
+    def print_fromwire(self):
+        """ prints fromwire function definition for a subtype.
+        these are significantly different in that they take in a struct
+        to populate, instead of fields.
+        """
+        ctx_arg = 'const tal_t *ctx, ' if self.has_variable_fields else ''
+        args = 'const u8 **cursor, size_t *plen, struct {name} *{name}'.format(name=self.name)
+        fields = ['\t{} {};\n'.format(f.fieldtype.name, f.name) for f in self.fields if f.is_len_var]
+        subcalls = CCode()
+        for f in self.fields:
+            basetype = f.fieldtype.base()
+            if f.optional:
+                raise TypeError('Optional fields on subtypes not currently supported')
+
+            for c in f.comments:
+                subcalls.append('/*{} */'.format(c))
+
+            if f.is_padding():
+                subcalls.append('fromwire_pad(cursor, plen, {});'
+                                .format(f.num_elems))
+            elif f.is_array():
+                name = '*{}->{}'.format(self.name, f.name)
+                self.print_fromwire_array('ctx', subcalls, basetype, f, name,
+                                          f.num_elems, is_tlv=True)
+            elif f.is_variable_size():
+                subcalls.append("// 2nd case {name}".format(name=f.name))
+                typename = f.fieldtype.name
+                # If structs are varlen, need array of ptrs to them.
+                if basetype in varlen_structs:
+                    typename += ' *'
+                subcalls.append('{}->{} = {} ? tal_arr(ctx, {}, {}) : NULL;'
+                                .format(self.name, f.name, f.lenvar, typename, f.lenvar))
+
+                name = '{}->{}'.format(self.name, f.name)
+                # Allocate these off the array itself, if they need alloc.
+                self.print_fromwire_array('*' + f.name, subcalls, basetype, f,
+                                          name, f.lenvar, is_tlv=True)
+            else:
+                if f.is_assignable():
+                    if f.is_len_var:
+                        s = '{} = fromwire_{}(cursor, plen);'.format(f.name, basetype)
+                    else:
+                        s = '{}->{} = fromwire_{}(cursor, plen);'.format(
+                            self.name, f.name, basetype)
+                else:
+                    ref = '&' if f.fieldtype.needs_ptr() else ''
+                    s = 'fromwire_{}(cursor, plen, {}{}->{});'.format(
+                        basetype, ref, self.name, f.name)
+                subcalls.append(s)
+
+        return fromwire_subtype_impl_templ.format(
+            name=self.name,
+            ctx=ctx_arg,
+            args=''.join(args),
+            fields=''.join(fields),
+            subcalls=str(subcalls)
+        )
+
 
 tlv_message_towire_stub = """static void towire_{tlv_name}_{name}(u8 **p, struct tlv_msg_{name} *{name}) {{
 {field_decls}
@@ -866,6 +985,12 @@ tlv_message_towire_stub = """static void towire_{tlv_name}_{name}(u8 **p, struct
 }}
 """
 
+subtype_towire_stub = """static void towire_{name}(u8 **p, const struct {name} *{name}) {{
+{field_decls}
+{subcalls}
+}}
+"""
+
 tlv_struct_template = """
 struct {tlv_name} {{
 {msg_type_structs}
@@ -1345,6 +1470,9 @@ else:
     if not options.header:
         towire_decls += build_tlv_towires(tlv_fields)
         fromwire_decls += build_tlv_fromwires(tlv_fields)
+        for subtype in subtypes:
+            towire_decls.append(subtype.print_towire())
+            fromwire_decls.append(subtype.print_fromwire())
 
     towire_decls += [m.print_towire(options.header) for m in toplevel_messages + messages_with_option]
     fromwire_decls += [m.print_fromwire(options.header) for m in toplevel_messages + messages_with_option]