Introduce `init_and_read_tlv_fields` macro

We introduce a new macro that inits and reads tlv fields and DRY up
`impl_writeable_tlv_based` and other macros.

diff --git a/lightning/src/util/ser_macros.rs b/lightning/src/util/ser_macros.rs
index 74b206d3a5774ca8885a7693f2562c05187348be..6c9b618dad4a281f0609c1301cb290025881aaf1 100644 (file)
--- a/lightning/src/util/ser_macros.rs
+++ b/lightning/src/util/ser_macros.rs
@@ -391,6 +391,18 @@ macro_rules! init_tlv_field_var {
        };
 }
 
+macro_rules! init_and_read_tlv_fields {
+       ($reader: ident, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}) => {
+               $(
+                       init_tlv_field_var!($field, $fieldty);
+               )*
+
+               read_tlv_fields!($reader, {
+                       $(($type, $field, $fieldty)),*
+               });
+       }
+}
+
 /// Implements Readable/Writeable for a struct storing it as a set of TLVs
 /// If $fieldty is `required`, then $field is a required field that is not an Option nor a Vec.
 /// If $fieldty is `option`, then $field is optional field.
@@ -425,10 +437,7 @@ macro_rules! impl_writeable_tlv_based {
 
                impl $crate::util::ser::Readable for $st {
                        fn read<R: $crate::io::Read>(reader: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
-                               $(
-                                       init_tlv_field_var!($field, $fieldty);
-                               )*
-                               read_tlv_fields!(reader, {
+                               init_and_read_tlv_fields!(reader, {
                                        $(($type, $field, $fieldty)),*
                                });
                                Ok(Self {
@@ -493,10 +502,7 @@ macro_rules! impl_writeable_tlv_based_enum_upgradable {
                                                // Because read_tlv_fields creates a labeled loop, we cannot call it twice
                                                // in the same function body. Instead, we define a closure and call it.
                                                let f = || {
-                                                       $(
-                                                               init_tlv_field_var!($field, $fieldty);
-                                                       )*
-                                                       read_tlv_fields!(reader, {
+                                                       init_and_read_tlv_fields!(reader, {
                                                                $(($type, $field, $fieldty)),*
                                                        });
                                                        Ok(Some($st::$variant_name {
@@ -546,10 +552,7 @@ macro_rules! impl_writeable_tlv_based_enum {
                                                // Because read_tlv_fields creates a labeled loop, we cannot call it twice
                                                // in the same function body. Instead, we define a closure and call it.
                                                let f = || {
-                                                       $(
-                                                               init_tlv_field_var!($field, $fieldty);
-                                                       )*
-                                                       read_tlv_fields!(reader, {
+                                                       init_and_read_tlv_fields!(reader, {
                                                                $(($type, $field, $fieldty)),*
                                                        });
                                                        Ok($st::$variant_name {