Some simple Option / Result / iterator pattern simplifications (#3205)

api/src/handlers/chain_api.rs

@@ -463,10 +463,7 @@ impl KernelHandler {
 				height,
 				mmr_index,
 			});
-		match kernel {
-			Some(kernel) => Ok(kernel),
-			None => Err(ErrorKind::NotFound.into()),
-		}
+		kernel.ok_or_else(|| ErrorKind::NotFound.into())
 	}
 }
 

api/src/types.rs

@@ -334,10 +334,10 @@ impl OutputPrintable {
 	}
 
 	pub fn range_proof(&self) -> Result<pedersen::RangeProof, ser::Error> {
-		let proof_str = match self.proof.clone() {
-			Some(p) => p,
-			None => return Err(ser::Error::HexError(format!("output range_proof missing"))),
-		};
+		let proof_str = self
+			.proof
+			.clone()
+			.ok_or_else(|| ser::Error::HexError(format!("output range_proof missing")))?;
 
 		let p_vec = util::from_hex(proof_str)
 			.map_err(|_| ser::Error::HexError(format!("invalid output range_proof")))?;

api/src/web.rs

@@ -105,10 +105,7 @@ impl QueryParams {
 	}
 
 	pub fn get(&self, name: &str) -> Option<&String> {
-		match self.params.get(name) {
-			None => None,
-			Some(v) => v.first(),
-		}
+		self.params.get(name).and_then(|v| v.first())
 	}
 }
 

core/src/libtx/proof.rs

@@ -65,10 +65,7 @@ pub fn verify(
 	extra_data: Option<Vec<u8>>,
 ) -> Result<(), secp::Error> {
 	let result = secp.verify_bullet_proof(commit, proof, extra_data);
-	match result {
-		Ok(_) => Ok(()),
-		Err(e) => Err(e),
-	}
+	result.map(|_| ())
 }
 
 /// Rewind a rangeproof to retrieve the amount, derivation path and switch commitment type
@@ -228,9 +225,10 @@ where
 		let id = Identifier::from_serialized_path(depth, &msg[4..]);
 
 		let commit_exp = self.keychain.commit(amount, &id, &switch)?;
-		match commit == &commit_exp {
-			true => Ok(Some((id, switch))),
-			false => Ok(None),
+		if commit == &commit_exp {
+			Ok(Some((id, switch)))
+		} else {
+			Ok(None)
 		}
 	}
 }
@@ -338,9 +336,10 @@ where
 		let commit_exp = self
 			.keychain
 			.commit(amount, &id, &SwitchCommitmentType::Regular)?;
-		match commit == &commit_exp {
-			true => Ok(Some((id, SwitchCommitmentType::Regular))),
-			false => Ok(None),
+		if commit == &commit_exp {
+			Ok(Some((id, SwitchCommitmentType::Regular)))
+		} else {
+			Ok(None)
 		}
 	}
 }

keychain/src/extkey_bip32.rs

@@ -107,15 +107,17 @@ impl BIP32GrinHasher {
 
 impl BIP32Hasher for BIP32GrinHasher {
 	fn network_priv(&self) -> [u8; 4] {
-		match self.is_floo {
-			true => [0x03, 0x27, 0x3A, 0x10],  // fprv
-			false => [0x03, 0x3C, 0x04, 0xA4], // gprv
+		if self.is_floo {
+			[0x03, 0x27, 0x3A, 0x10]
+		} else {
+			[0x03, 0x3C, 0x04, 0xA4]
 		}
 	}
 	fn network_pub(&self) -> [u8; 4] {
-		match self.is_floo {
-			true => [0x03, 0x27, 0x3E, 0x4B],  // fpub
-			false => [0x03, 0x3C, 0x08, 0xDF], // gpub
+		if self.is_floo {
+			[0x03, 0x27, 0x3E, 0x4B]
+		} else {
+			[0x03, 0x3C, 0x08, 0xDF]
 		}
 	}
 	fn master_seed() -> [u8; 12] {
@@ -380,10 +382,7 @@ impl ExtendedPrivKey {
 		passphrase: &str,
 		is_floo: bool,
 	) -> Result<ExtendedPrivKey, Error> {
-		let seed = match mnemonic::to_seed(mnemonic, passphrase) {
-			Ok(s) => s,
-			Err(e) => return Err(Error::MnemonicError(e)),
-		};
+		let seed = mnemonic::to_seed(mnemonic, passphrase).map_err(|e| Error::MnemonicError(e))?;
 		let mut hasher = BIP32GrinHasher::new(is_floo);
 		let key = ExtendedPrivKey::new_master(secp, &mut hasher, &seed)?;
 		Ok(key)

pool/src/pool.rs

@@ -403,11 +403,7 @@ impl Pool {
 		// Oldest (based on pool insertion time) will then be prioritized.
 		tx_buckets.sort_unstable_by_key(|x| (Reverse(x.fee_to_weight), x.age_idx));
 
-		tx_buckets
-			.into_iter()
-			.map(|x| x.raw_txs)
-			.flatten()
-			.collect()
+		tx_buckets.into_iter().flat_map(|x| x.raw_txs).collect()
 	}
 
 	pub fn find_matching_transactions(&self, kernels: &[TxKernel]) -> Vec<Transaction> {

src/bin/tui/mining.rs

@@ -130,9 +130,10 @@ impl TableViewItem<DiffColumn> for DiffBlock {
 	fn to_column(&self, column: DiffColumn) -> String {
 		let naive_datetime = NaiveDateTime::from_timestamp(self.time as i64, 0);
 		let datetime: DateTime<Utc> = DateTime::from_utc(naive_datetime, Utc);
-		let pow_type = match self.is_secondary {
-			true => String::from("Secondary"),
-			false => String::from("Primary"),
+		let pow_type = if self.is_secondary {
+			String::from("Secondary")
+		} else {
+			String::from("Primary")
 		};
 
 		match column {

store/src/leaf_set.rs

@@ -96,8 +96,7 @@ impl LeafSet {
 	/// Only applicable for the output MMR.
 	fn unpruned_pre_cutoff(&self, cutoff_pos: u64, prune_list: &PruneList) -> Bitmap {
 		(1..=cutoff_pos)
-			.filter(|&x| pmmr::is_leaf(x))
-			.filter(|&x| !prune_list.is_pruned(x))
+			.filter(|&x| pmmr::is_leaf(x) && !prune_list.is_pruned(x))
 			.map(|x| x as u32)
 			.collect()
 	}

store/src/types.rs

@@ -107,10 +107,7 @@ where
 	/// Elements can be of variable size (handled internally in the append-only file impl).
 	///
 	pub fn read(&self, position: u64) -> Option<T> {
-		match self.file.read_as_elmt(position - 1) {
-			Ok(x) => Some(x),
-			Err(_) => None,
-		}
+		self.file.read_as_elmt(position - 1).ok()
 	}
 
 	/// Rewind the backend file to the specified position.

util/src/file.rs

@@ -70,15 +70,12 @@ fn copy_to(src: &Path, src_type: &fs::FileType, dst: &Path) -> io::Result<u64> {
 
 /// Retrieve first line from file
 pub fn get_first_line(file_path: Option<String>) -> Option<String> {
-	match file_path {
-		Some(path) => match fs::File::open(path) {
+	file_path.and_then(|path| match fs::File::open(path) {
 		Ok(file) => {
 			let buf_reader = io::BufReader::new(file);
 			let mut lines_iter = buf_reader.lines().map(|l| l.unwrap());
 			lines_iter.next()
 		}
 		Err(_) => None,
-		},
-		None => None,
-	}
+	})
 }