Replace unnecessary exchange util.

Signed-off-by: Jason Volk <jason@zemos.net>

src/core/info/rustc.rs

@@ -5,11 +5,10 @@
 
 use std::{
 	collections::BTreeMap,
+	mem::replace,
 	sync::{Mutex, OnceLock},
 };
 
-use crate::utils::exchange;
-
 // Capture rustc version during compilation.
 tuwunel_macros::rustc_version! {}
 
@@ -54,7 +53,7 @@ fn append_features(features: &mut Vec<&'static str>, flags: &[&'static str]) {
 	for flag in flags {
 		let is_cfg = *flag == "--cfg";
 		let is_feature = flag.starts_with("feature=");
-		if exchange(&mut next_is_cfg, is_cfg) && is_feature {
+		if replace(&mut next_is_cfg, is_cfg) && is_feature {
 			if let Some(feature) = flag
 				.split_once('=')
 				.map(|(_, feature)| feature.trim_matches('"'))

src/core/utils/mod.rs

@@ -42,9 +42,6 @@
 	},
 };
 
-#[inline]
-pub fn exchange<T>(state: &mut T, source: T) -> T { std::mem::replace(state, source) }
-
 #[macro_export]
 macro_rules! extract_variant {
 	( $e:expr_2021, $( $variant:path )|* ) => {

src/core/utils/string.rs

@@ -4,8 +4,10 @@
 mod unquote;
 mod unquoted;
 
+use std::mem::replace;
+
 pub use self::{between::Between, split::SplitInfallible, unquote::Unquote, unquoted::Unquoted};
-use crate::{Result, smallstr::SmallString, utils::exchange};
+use crate::{Result, smallstr::SmallString};
 
 pub const EMPTY: &str = "";
 
@@ -76,7 +78,7 @@ pub fn camel_to_snake_case<I, O>(output: &mut O, input: I) -> Result
 		.map(char::from)
 		.try_for_each(|ch| {
 			let m = ch.is_ascii_uppercase();
-			let s = exchange(&mut state, !m);
+			let s = replace(&mut state, !m);
 			if m && s {
 				output.write_char('_')?;
 			}

src/database/ser.rs

@@ -1,7 +1,7 @@
-use std::io::Write;
+use std::{io::Write, mem::replace};
 
 use serde::{Deserialize, Serialize, ser};
-use tuwunel_core::{Error, Result, debug::type_name, err, result::DebugInspect, utils::exchange};
+use tuwunel_core::{Error, Result, debug::type_name, err, result::DebugInspect};
 
 use crate::util::unhandled;
 
@@ -97,7 +97,7 @@ fn sequence_end(&mut self) -> Result {
 
 	fn record_start(&mut self) -> Result {
 		debug_assert!(!self.is_finalized(), "Starting a record after serialization finalized");
-		exchange(&mut self.sep, true)
+		replace(&mut self.sep, true)
 			.then(|| self.separator())
 			.unwrap_or(Ok(()))
 	}

src/database/stream.rs

@@ -3,10 +3,10 @@
 mod keys;
 mod keys_rev;
 
-use std::sync::Arc;
+use std::{mem::replace, sync::Arc};
 
 use rocksdb::{DBRawIteratorWithThreadMode, ReadOptions};
-use tuwunel_core::{Result, utils::exchange};
+use tuwunel_core::Result;
 
 pub(crate) use self::{items::Items, items_rev::ItemsRev, keys::Keys, keys_rev::KeysRev};
 use crate::{
@@ -94,7 +94,7 @@ pub(super) fn init_rev(mut self, from: From<'_>) -> Self {
 	#[inline]
 	#[cfg_attr(unabridged, tracing::instrument(level = "trace", skip_all))]
 	pub(super) fn seek_fwd(&mut self) {
-		if !exchange(&mut self.init, false) {
+		if !replace(&mut self.init, false) {
 			self.inner.next();
 		} else if !self.seek {
 			self.inner.seek_to_first();
@@ -104,7 +104,7 @@ pub(super) fn seek_fwd(&mut self) {
 	#[inline]
 	#[cfg_attr(unabridged, tracing::instrument(level = "trace", skip_all))]
 	pub(super) fn seek_rev(&mut self) {
-		if !exchange(&mut self.init, false) {
+		if !replace(&mut self.init, false) {
 			self.inner.prev();
 		} else if !self.seek {
 			self.inner.seek_to_last();