Merge pull request #2677 from Evanfeenstra/public-onion-utils
[rust-lightning] / lightning / src / util / ser_macros.rs
index 742ea25714dafb4d291f249e30376366cfeebbaa..247fdf60074dc4ff0bad148bef3c89ae374f26d6 100644 (file)
 //! [`Readable`]: crate::util::ser::Readable
 //! [`Writeable`]: crate::util::ser::Writeable
 
+// There are quite a few TLV serialization "types" which behave differently. We currently only
+// publicly document the `optional` and `required` types, not supporting anything else publicly and
+// changing them at will.
+//
+// Some of the other types include:
+//  * (default_value, $default) - reads optionally, reading $default if no TLV is present
+//  * (static_value, $value) - ignores any TLVs, always using $value
+//  * required_vec - reads into a Vec without a length prefix, failing if no TLV is present.
+//  * optional_vec - reads into an Option<Vec> without a length prefix, continuing if no TLV is
+//                   present. Writes from a Vec directly, only if any elements are present. Note
+//                   that the struct deserialization macros return a Vec, not an Option.
+//  * upgradable_option - reads via MaybeReadable.
+//  * upgradable_required - reads via MaybeReadable, requiring a TLV be present but may return None
+//                          if MaybeReadable::read() returns None.
+
 /// Implements serialization for a single TLV record.
 /// This is exported for use by other exported macros, do not use directly.
 #[doc(hidden)]
@@ -29,7 +44,7 @@ macro_rules! _encode_tlv {
                BigSize($field.serialized_length() as u64).write($stream)?;
                $field.write($stream)?;
        };
-       ($stream: expr, $type: expr, $field: expr, vec_type) => {
+       ($stream: expr, $type: expr, $field: expr, required_vec) => {
                $crate::_encode_tlv!($stream, $type, $crate::util::ser::WithoutLength(&$field), required);
        };
        ($stream: expr, $optional_type: expr, $optional_field: expr, option) => {
@@ -41,7 +56,7 @@ macro_rules! _encode_tlv {
        };
        ($stream: expr, $type: expr, $field: expr, optional_vec) => {
                if !$field.is_empty() {
-                       $crate::_encode_tlv!($stream, $type, $field, vec_type);
+                       $crate::_encode_tlv!($stream, $type, $field, required_vec);
                }
        };
        ($stream: expr, $type: expr, $field: expr, upgradable_required) => {
@@ -117,7 +132,20 @@ macro_rules! _check_encoded_tlv_order {
 /// [`Writer`]: crate::util::ser::Writer
 #[macro_export]
 macro_rules! encode_tlv_stream {
+       ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),* $(,)*}) => {
+               $crate::_encode_tlv_stream!($stream, {$(($type, $field, $fieldty)),*})
+       }
+}
+
+/// Implementation of [`encode_tlv_stream`].
+/// This is exported for use by other exported macros, do not use directly.
+#[doc(hidden)]
+#[macro_export]
+macro_rules! _encode_tlv_stream {
        ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),* $(,)*}) => { {
+               $crate::_encode_tlv_stream!($stream, { $(($type, $field, $fieldty)),* }, &[])
+       } };
+       ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),* $(,)*}, $extra_tlvs: expr) => { {
                #[allow(unused_imports)]
                use $crate::{
                        ln::msgs::DecodeError,
@@ -129,6 +157,10 @@ macro_rules! encode_tlv_stream {
                $(
                        $crate::_encode_tlv!($stream, $type, $field, $fieldty);
                )*
+               for tlv in $extra_tlvs {
+                       let (typ, value): &(u64, Vec<u8>) = tlv;
+                       $crate::_encode_tlv!($stream, *typ, *value, required_vec);
+               }
 
                #[allow(unused_mut, unused_variables, unused_assignments)]
                #[cfg(debug_assertions)]
@@ -137,8 +169,12 @@ macro_rules! encode_tlv_stream {
                        $(
                                $crate::_check_encoded_tlv_order!(last_seen, $type, $fieldty);
                        )*
+                       for tlv in $extra_tlvs {
+                               let (typ, _): &(u64, Vec<u8>) = tlv;
+                               $crate::_check_encoded_tlv_order!(last_seen, *typ, required_vec);
+                       }
                }
-       } }
+       } };
 }
 
 /// Adds the length of the serialized field to a [`LengthCalculatingWriter`].
@@ -159,7 +195,7 @@ macro_rules! _get_varint_length_prefixed_tlv_length {
                BigSize(field_len as u64).write(&mut $len).expect("No in-memory data may fail to serialize");
                $len.0 += field_len;
        };
-       ($len: expr, $type: expr, $field: expr, vec_type) => {
+       ($len: expr, $type: expr, $field: expr, required_vec) => {
                $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $crate::util::ser::WithoutLength(&$field), required);
        };
        ($len: expr, $optional_type: expr, $optional_field: expr, option) => {
@@ -172,7 +208,7 @@ macro_rules! _get_varint_length_prefixed_tlv_length {
        };
        ($len: expr, $type: expr, $field: expr, optional_vec) => {
                if !$field.is_empty() {
-                       $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field, vec_type);
+                       $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field, required_vec);
                }
        };
        ($len: expr, $type: expr, $field: expr, (option: $trait: ident $(, $read_arg: expr)?)) => {
@@ -195,18 +231,27 @@ macro_rules! _get_varint_length_prefixed_tlv_length {
 #[macro_export]
 macro_rules! _encode_varint_length_prefixed_tlv {
        ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),*}) => { {
+               $crate::_encode_varint_length_prefixed_tlv!($stream, {$(($type, $field, $fieldty)),*}, &[])
+       } };
+       ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),*}, $extra_tlvs: expr) => { {
+               extern crate alloc;
                use $crate::util::ser::BigSize;
+               use alloc::vec::Vec;
                let len = {
                        #[allow(unused_mut)]
                        let mut len = $crate::util::ser::LengthCalculatingWriter(0);
                        $(
                                $crate::_get_varint_length_prefixed_tlv_length!(len, $type, $field, $fieldty);
                        )*
+                       for tlv in $extra_tlvs {
+                               let (typ, value): &(u64, Vec<u8>) = tlv;
+                               $crate::_get_varint_length_prefixed_tlv_length!(len, *typ, *value, required_vec);
+                       }
                        len.0
                };
                BigSize(len as u64).write($stream)?;
-               $crate::encode_tlv_stream!($stream, { $(($type, $field, $fieldty)),* });
-       } }
+               $crate::_encode_tlv_stream!($stream, { $(($type, $field, $fieldty)),* }, $extra_tlvs);
+       } };
 }
 
 /// Errors if there are missing required TLV types between the last seen type and the type currently being processed.
@@ -236,8 +281,8 @@ macro_rules! _check_decoded_tlv_order {
        ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, option) => {{
                // no-op
        }};
-       ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, vec_type) => {{
-               // no-op
+       ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, required_vec) => {{
+               $crate::_check_decoded_tlv_order!($last_seen_type, $typ, $type, $field, required);
        }};
        ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, optional_vec) => {{
                // no-op
@@ -281,8 +326,8 @@ macro_rules! _check_missing_tlv {
        ($last_seen_type: expr, $type: expr, $field: ident, (required: $trait: ident $(, $read_arg: expr)?)) => {{
                $crate::_check_missing_tlv!($last_seen_type, $type, $field, required);
        }};
-       ($last_seen_type: expr, $type: expr, $field: ident, vec_type) => {{
-               // no-op
+       ($last_seen_type: expr, $type: expr, $field: ident, required_vec) => {{
+               $crate::_check_missing_tlv!($last_seen_type, $type, $field, required);
        }};
        ($last_seen_type: expr, $type: expr, $field: ident, option) => {{
                // no-op
@@ -320,15 +365,16 @@ macro_rules! _decode_tlv {
        ($reader: expr, $field: ident, (required: $trait: ident $(, $read_arg: expr)?)) => {{
                $field = $trait::read(&mut $reader $(, $read_arg)*)?;
        }};
-       ($reader: expr, $field: ident, vec_type) => {{
+       ($reader: expr, $field: ident, required_vec) => {{
                let f: $crate::util::ser::WithoutLength<Vec<_>> = $crate::util::ser::Readable::read(&mut $reader)?;
-               $field = Some(f.0);
+               $field = f.0;
        }};
        ($reader: expr, $field: ident, option) => {{
                $field = Some($crate::util::ser::Readable::read(&mut $reader)?);
        }};
        ($reader: expr, $field: ident, optional_vec) => {{
-               $crate::_decode_tlv!($reader, $field, vec_type);
+               let f: $crate::util::ser::WithoutLength<Vec<_>> = $crate::util::ser::Readable::read(&mut $reader)?;
+               $field = Some(f.0);
        }};
        // `upgradable_required` indicates we're reading a required TLV that may have been upgraded
        // without backwards compat. We'll error if the field is missing, and return `Ok(None)` if the
@@ -694,8 +740,8 @@ macro_rules! _init_tlv_based_struct_field {
        ($field: ident, required) => {
                $field.0.unwrap()
        };
-       ($field: ident, vec_type) => {
-               $field.unwrap()
+       ($field: ident, required_vec) => {
+               $field
        };
        ($field: ident, optional_vec) => {
                $field.unwrap()
@@ -720,8 +766,8 @@ macro_rules! _init_tlv_field_var {
        ($field: ident, (required: $trait: ident $(, $read_arg: expr)?)) => {
                $crate::_init_tlv_field_var!($field, required);
        };
-       ($field: ident, vec_type) => {
-               let mut $field = Some(Vec::new());
+       ($field: ident, required_vec) => {
+               let mut $field = Vec::new();
        };
        ($field: ident, option) => {
                let mut $field = None;
@@ -745,10 +791,13 @@ macro_rules! _init_tlv_field_var {
 
 /// Equivalent to running [`_init_tlv_field_var`] then [`read_tlv_fields`].
 ///
+/// If any unused values are read, their type MUST be specified or else `rustc` will read them as an
+/// `i64`.
+///
 /// This is exported for use by other exported macros, do not use directly.
 #[doc(hidden)]
 #[macro_export]
-macro_rules! _init_and_read_tlv_fields {
+macro_rules! _init_and_read_len_prefixed_tlv_fields {
        ($reader: ident, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}) => {
                $(
                        $crate::_init_tlv_field_var!($field, $fieldty);
@@ -760,6 +809,22 @@ macro_rules! _init_and_read_tlv_fields {
        }
 }
 
+/// Equivalent to running [`_init_tlv_field_var`] then [`decode_tlv_stream`].
+///
+/// If any unused values are read, their type MUST be specified or else `rustc` will read them as an
+/// `i64`.
+macro_rules! _init_and_read_tlv_stream {
+       ($reader: ident, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}) => {
+               $(
+                       $crate::_init_tlv_field_var!($field, $fieldty);
+               )*
+
+               $crate::decode_tlv_stream!($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 `(default_value, $default)`, then `$field` will be set to `$default` if not present.
@@ -817,7 +882,7 @@ 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> {
-                               $crate::_init_and_read_tlv_fields!(reader, {
+                               $crate::_init_and_read_len_prefixed_tlv_fields!(reader, {
                                        $(($type, $field, $fieldty)),*
                                });
                                Ok(Self {
@@ -969,7 +1034,7 @@ 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 = || {
-                                                       $crate::_init_and_read_tlv_fields!(reader, {
+                                                       $crate::_init_and_read_len_prefixed_tlv_fields!(reader, {
                                                                $(($type, $field, $fieldty)),*
                                                        });
                                                        Ok($st::$variant_name {
@@ -1023,7 +1088,7 @@ 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 = || {
-                                                       $crate::_init_and_read_tlv_fields!(reader, {
+                                                       $crate::_init_and_read_len_prefixed_tlv_fields!(reader, {
                                                                $(($type, $field, $fieldty)),*
                                                        });
                                                        Ok(Some($st::$variant_name {