Simplify api commits (#3423)

* simplify api with unspent by commitment

* fix chain tests

chain/src/chain.rs

@@ -568,11 +568,14 @@ impl Chain {
 		}
 	}
 
-	/// Returns Ok(Some(pos)) if output is unspent.
+	/// Returns Ok(Some((out, pos))) if output is unspent.
 	/// Returns Ok(None) if output is spent.
 	/// Returns Err if something went wrong beyond not finding the output.
-	pub fn get_unspent(&self, output_ref: &OutputIdentifier) -> Result<Option<CommitPos>, Error> {
-		self.txhashset.read().get_unspent(output_ref)
+	pub fn get_unspent(
+		&self,
+		commit: Commitment,
+	) -> Result<Option<(OutputIdentifier, CommitPos)>, Error> {
+		self.txhashset.read().get_unspent(commit)
 	}
 
 	/// Retrieves an unspent output using its PMMR position
@@ -1387,17 +1390,14 @@ impl Chain {
 	}
 
 	/// Gets the block header in which a given output appears in the txhashset.
-	pub fn get_header_for_output(
-		&self,
-		output_ref: &OutputIdentifier,
-	) -> Result<BlockHeader, Error> {
+	pub fn get_header_for_output(&self, commit: Commitment) -> Result<BlockHeader, Error> {
 		let header_pmmr = self.header_pmmr.read();
 		let txhashset = self.txhashset.read();
-		let output_pos = match txhashset.get_unspent(output_ref)? {
+		let (_, pos) = match txhashset.get_unspent(commit)? {
 			Some(o) => o,
 			None => return Err(ErrorKind::OutputNotFound.into()),
 		};
-		let hash = header_pmmr.get_header_hash_by_height(output_pos.height)?;
+		let hash = header_pmmr.get_header_hash_by_height(pos.height)?;
 		Ok(self.get_block_header(&hash)?)
 	}
 

chain/src/txhashset/txhashset.rs

@@ -255,15 +255,17 @@ impl TxHashSet {
 	/// Check if an output is unspent.
 	/// We look in the index to find the output MMR pos.
 	/// Then we check the entry in the output MMR and confirm the hash matches.
-	pub fn get_unspent(&self, output_id: &OutputIdentifier) -> Result<Option<CommitPos>, Error> {
-		let commit = output_id.commit;
+	pub fn get_unspent(
+		&self,
+		commit: Commitment,
+	) -> Result<Option<(OutputIdentifier, CommitPos)>, Error> {
 		match self.commit_index.get_output_pos_height(&commit) {
 			Ok(Some(pos)) => {
 				let output_pmmr: ReadonlyPMMR<'_, Output, _> =
 					ReadonlyPMMR::at(&self.output_pmmr_h.backend, self.output_pmmr_h.last_pos);
 				if let Some(out) = output_pmmr.get_data(pos.pos) {
-					if out == *output_id {
-						Ok(Some(pos))
+					if out.commitment() == commit {
+						Ok(Some((out, pos)))
 					} else {
 						Ok(None)
 					}