style: improve use of std api

- replace get(0) by first()
lint message: accessing first element with `objs.get(0)`
help: for further information visit https://rust-lang.github.io/rust-clippy/rust-1.92.0/index.html#get_first
- use io::Error::other method available since Rust 1.87
lint message: this can be `std::io::Error::other(_)`
help: for further information visit https://rust-lang.github.io/rust-clippy/rust-1.92.0/index.html#io_other_error
- implement From<_> instead of Into<_>
lint message: an implementation of `From` is preferred since it gives you `Into<_>` for free where the reverse isn't true
help: `impl From<Local> for Foreign` is allowed by the orphan rules, for more information see
            https://doc.rust-lang.org/reference/items/implementations.html#trait-implementation-coherence
help: for further information visit https://rust-lang.github.io/rust-clippy/rust-1.92.0/index.html#from_over_into
- use next_back instead of rev + next
lint message: manual backwards iteration
help: for further information visit https://rust-lang.github.io/rust-clippy/rust-1.92.0/index.html#manual_next_back
- use saturating_sub instead of manual implement it
lint message: manual arithmetic check found
help: for further information visit https://rust-lang.github.io/rust-clippy/rust-1.92.0/index.html#implicit_saturating_sub
- add Default implementation for Checksummer
use derived Default ans use it in new, as new set all value to None
lint message: you should consider adding a `Default` implementation for `Checksummer`
help: for further information visit https://rust-lang.github.io/rust-clippy/rust-1.92.0/index.html#new_without_default
- use `any` instead of `find` + `is_some`
lint message: called `is_some()` after searching an `Iterator` with `find`
help: for further information visit https://rust-lang.github.io/rust-clippy/rust-1.92.0/index.html#search_is_some
- replace `and_then` + `Some(_)` with `map`
lint message: using `Option.and_then(|x| Some(y))`, which is more succinctly expressed as `map(|x| y)`
help: for further information visit https://rust-lang.github.io/rust-clippy/rust-1.92.0/index.html#bind_instead_of_map
- replace `skip_while` + `next` with `find`
lint message: called `skip_while(<p>).next()` on an `Iterator`
help: this is more succinctly expressed by calling `.find(!<p>)` instead
help: for further information visit https://rust-lang.github.io/rust-clippy/rust-1.92.0/index.html#skip_while_next
- use `matches!` instead of manual implementation
lint message: match expression looks like `matches!` macro
help: for further information visit https://rust-lang.github.io/rust-clippy/rust-1.92.0/index.html#match_like_matches_macro
- use `keys` and `values methods insteads of iterating and ignoring either the keys or values.
help: for further information visit https://rust-lang.github.io/rust-clippy/rust-1.92.0/index.html#iter_kv_map

src/api/admin/layout.rs

@@ -380,9 +380,9 @@ impl From<layout::ZoneRedundancy> for ZoneRedundancy {
 	}
 }
 
-impl Into<layout::ZoneRedundancy> for ZoneRedundancy {
-	fn into(self) -> layout::ZoneRedundancy {
-		match self {
+impl From<ZoneRedundancy> for layout::ZoneRedundancy {
+	fn from(val: ZoneRedundancy) -> Self {
+		match val {
 			ZoneRedundancy::Maximum => layout::ZoneRedundancy::Maximum,
 			ZoneRedundancy::AtLeast(x) => layout::ZoneRedundancy::AtLeast(x),
 		}
@@ -397,10 +397,10 @@ impl From<layout::LayoutParameters> for LayoutParameters {
 	}
 }
 
-impl Into<layout::LayoutParameters> for LayoutParameters {
-	fn into(self) -> layout::LayoutParameters {
+impl From<LayoutParameters> for layout::LayoutParameters {
+	fn from(val: LayoutParameters) -> Self {
 		layout::LayoutParameters {
-			zone_redundancy: self.zone_redundancy.into(),
+			zone_redundancy: val.zone_redundancy.into(),
 		}
 	}
 }

src/api/common/signature/checksum.rs

@@ -63,6 +63,7 @@ pub struct ExpectedChecksums {
 	pub extra: Option<ChecksumValue>,
 }
 
+#[derive(Default)]
 pub struct Checksummer {
 	pub crc32: Option<CrcDigest>,
 	pub crc32c: Option<CrcDigest>,
@@ -84,14 +85,7 @@ pub struct Checksums {
 
 impl Checksummer {
 	pub fn new() -> Self {
-		Self {
-			crc32: None,
-			crc32c: None,
-			crc64nvme: None,
-			md5: None,
-			sha1: None,
-			sha256: None,
-		}
+		Default::default()
 	}
 
 	pub fn init(expected: &ExpectedChecksums, add_md5: bool) -> Self {

src/api/s3/delete.rs

@@ -29,7 +29,7 @@ async fn handle_delete_internal(ctx: &ReqCtx, key: &str) -> Result<(Uuid, Uuid),
 		.iter()
 		.rev()
 		.find(|v| !matches!(&v.state, ObjectVersionState::Aborted))
-		.or_else(|| object.versions().iter().rev().next());
+		.or_else(|| object.versions().iter().next_back());
 	let deleted_version = match deleted_version {
 		Some(dv) => dv.uuid,
 		None => {

src/api/s3/encryption.rs

@@ -94,10 +94,7 @@ impl EncryptionParams {
 		// data blocks are reused as-is. Since Garage v2, we are using
 		// object-specific encryption keys, so we know that if both source
 		// and destination are encrypted, it can't be with the same key.
-		match (a, b) {
-			(Self::Plaintext, Self::Plaintext) => true,
-			_ => false,
-		}
+		matches!((a, b), (Self::Plaintext, Self::Plaintext))
 	}
 
 	pub fn new_from_headers(
@@ -587,8 +584,7 @@ impl Stream for DecryptStream {
 
 		if matches!(this.state, DecryptStreamState::Done) {
 			if !this.buf.is_empty() {
-				return Poll::Ready(Some(Err(std::io::Error::new(
-					std::io::ErrorKind::Other,
+				return Poll::Ready(Some(Err(std::io::Error::other(
 					"Decrypt: unexpected bytes after last encrypted chunk",
 				))));
 			}
@@ -622,10 +618,7 @@ impl Stream for DecryptStream {
 		match res {
 			Ok(bytes) if bytes.is_empty() => Poll::Ready(None),
 			Ok(bytes) => Poll::Ready(Some(Ok(bytes.into()))),
-			Err(_) => Poll::Ready(Some(Err(std::io::Error::new(
-				std::io::ErrorKind::Other,
-				"Decryption failed",
-			)))),
+			Err(_) => Poll::Ready(Some(Err(std::io::Error::other("Decryption failed")))),
 		}
 	}
 }

src/api/s3/get.rs

@@ -400,15 +400,10 @@ async fn handle_get_full(
 	overrides: GetObjectOverrides,
 	checksum_mode: ChecksumMode,
 ) -> Result<Response<ResBody>, Error> {
-	let mut resp_builder = object_headers(
-		version,
-		version_meta,
-		meta_inner,
-		encryption,
-		checksum_mode,
-	)
-	.header(CONTENT_LENGTH, format!("{}", version_meta.size))
-	.status(StatusCode::OK);
+	let mut resp_builder =
+		object_headers(version, version_meta, meta_inner, encryption, checksum_mode)
+			.header(CONTENT_LENGTH, format!("{}", version_meta.size))
+			.status(StatusCode::OK);
 	getobject_override_headers(overrides, &mut resp_builder)?;
 
 	let stream = full_object_byte_stream(garage, version, version_data, encryption);
@@ -708,11 +703,7 @@ fn body_from_blocks_range(
 									Some(None)
 								} else {
 									// The chunk has an intersection with the requested range
-									let start_in_chunk = if *chunk_offset > begin {
-										0
-									} else {
-										begin - *chunk_offset
-									};
+									let start_in_chunk = begin.saturating_sub(*chunk_offset);
 									let end_in_chunk = if *chunk_offset + chunk_len < end {
 										chunk_len
 									} else {
@@ -773,10 +764,7 @@ fn error_stream_item<E: std::fmt::Display>(e: E) -> ByteStream {
 }
 
 fn std_error_from_read_error<E: std::fmt::Display>(e: E) -> std::io::Error {
-	std::io::Error::new(
-		std::io::ErrorKind::Other,
-		format!("Error while reading object data: {}", e),
-	)
+	std::io::Error::other(format!("Error while reading object data: {}", e))
 }
 
 // ----

src/api/s3/list.rs

@@ -1014,12 +1014,12 @@ mod tests {
 
 		query.common.prefix = "a/".to_string();
 		assert_eq!(
-			common_prefix(objs.get(0).unwrap(), &query.common),
+			common_prefix(objs.first().unwrap(), &query.common),
 			Some("a/b/")
 		);
 
 		query.common.prefix = "a/b/".to_string();
-		assert_eq!(common_prefix(objs.get(0).unwrap(), &query.common), None);
+		assert_eq!(common_prefix(objs.first().unwrap(), &query.common), None);
 	}
 
 	#[test]