Invoice serialization in iterative style

Author: optout21

fuzz/src/bolt11_deser.rs

@@ -12,7 +12,6 @@ use bech32::Fe32;
 use bitcoin::secp256k1::{Secp256k1, SecretKey};
 use lightning_invoice::{
 	Bolt11Invoice, FromBase32, RawBolt11Invoice, RawDataPart, RawHrp, RawTaggedField, TaggedField,
-	ToBase32,
 };
 use std::str::FromStr;
 

lightning-invoice/src/de.rs

@@ -40,22 +40,21 @@ impl FromBase32 for Vec<u8> {
 impl FromBase32 for PaymentSecret {
 	type Err = CheckedHrpstringError;
 
-	fn from_base32(field_data: &[Fe32]) -> Result<PaymentSecret, CheckedHrpstringError> {
+	fn from_base32(field_data: &[Fe32]) -> Result<Self, Self::Err> {
 		if field_data.len() != 52 {
 			return Err(CheckedHrpstringError::Checksum(ChecksumError::InvalidLength)) // TODO(bech32): not entirely accurate
-		} else {
-			let data_bytes = Vec::<u8>::from_base32(field_data)?;
-			let mut payment_secret = [0; 32];
-			payment_secret.copy_from_slice(&data_bytes);
-			Ok(PaymentSecret(payment_secret))
 		}
+		let data_bytes = Vec::<u8>::from_base32(field_data)?;
+		let mut payment_secret = [0; 32];
+		payment_secret.copy_from_slice(&data_bytes);
+		Ok(PaymentSecret(payment_secret))
 	}
 }
 
 impl FromBase32 for Bolt11InvoiceFeatures {
 	type Err = CheckedHrpstringError;
 
-	fn from_base32(field_data: &[Fe32]) -> Result<Bolt11InvoiceFeatures, CheckedHrpstringError> {
+	fn from_base32(field_data: &[Fe32]) -> Result<Self, Self::Err> {
 		// Explanation for the "7": the normal way to round up when dividing is to add the divisor
 		// minus one before dividing
 		let length_bytes = (field_data.len() * 5 + 7) / 8 as usize;

lightning-invoice/src/lib.rs

@@ -77,44 +77,7 @@ mod prelude {
 
 use crate::prelude::*;
 
-/// Interface to write `Fe32`s into a sink
-pub trait WriteBase32 {
-	/// Write error
-	type Err: fmt::Debug;
-
-	/// Write a `Fe32` slice
-	fn write(&mut self, data: &Vec<Fe32>) -> Result<(), Self::Err> {
-		for b in data {
-			self.write_fe32(*b)?;
-		}
-		Ok(())
-	}
-
-	/// Write a single `Fe32`
-	fn write_fe32(&mut self, data: Fe32) -> Result<(), Self::Err>;
-}
-
-/// A trait for converting a value to a type `T` that represents a `Fe32` slice.
-pub trait ToBase32 {
-	/// Convert `Self` to base32 vector
-	fn to_base32(&self) -> Vec<Fe32> {
-		let mut vec = Vec::new();
-		self.write_base32(&mut vec).unwrap();
-		vec
-	}
-
-	/// Encode as base32 and write it to the supplied writer
-	/// Implementations shouldn't allocate.
-	fn write_base32<W: WriteBase32>(&self, writer: &mut W) -> Result<(), <W as WriteBase32>::Err>;
-}
-
-/// Interface to calculate the length of the base32 representation before actually serializing
-pub trait Base32Len: ToBase32 {
-	/// Calculate the base32 serialized length
-	fn base32_len(&self) -> usize;
-}
-
-/// Trait for paring/converting base32 slice. It is the reciprocal of `ToBase32`.
+/// Trait for paring/converting base32 slice.
 pub trait FromBase32: Sized {
 	/// The associated error which can be returned from parsing (e.g. because of bad padding).
 	type Err;
@@ -347,6 +310,15 @@ pub struct RawHrp {
 	pub si_prefix: Option<SiPrefix>,
 }
 
+impl RawHrp {
+	/// Convert to bech32::Hrp
+	pub fn to_hrp(&self) -> bech32::Hrp {
+		let hrp_str = self.to_string();
+		let s = core::str::from_utf8(&hrp_str.as_bytes()).expect("asserted to be ASCII");
+		bech32::Hrp::parse_unchecked(s)
+	}
+}
+
 /// Data of the [`RawBolt11Invoice`] that is encoded in the data part
 #[derive(Eq, PartialEq, Debug, Clone, Hash, Ord, PartialOrd)]
 pub struct RawDataPart {
@@ -1048,9 +1020,11 @@ impl RawBolt11Invoice {
 
 	/// Calculate the hash of the encoded `RawBolt11Invoice` which should be signed.
 	pub fn signable_hash(&self) -> [u8; 32] {
+		use crate::ser::Base32Iterable;
+
 		RawBolt11Invoice::hash_from_parts(
 			self.hrp.to_string().as_bytes(),
-			&self.data.to_base32()
+			&self.data.fe_iter().collect::<Vec<Fe32>>(),
 		)
 	}