From be949fb12298d203edfa9679dab5a625e788d203 Mon Sep 17 00:00:00 2001
From: Sander <hey@sandydoo.me>
Date: Thu, 20 Mar 2025 19:40:14 +0000
Subject: [PATCH] refactor(snix/glue): reduce string allocations in the flake
 ref parser

Change-Id: Id6818976b651b6d6ffa51cf7e2066cce0cb01055
Reviewed-on: https://cl.snix.dev/c/snix/+/30203
Reviewed-by: Florian Klink <flokli@flokli.de>
Autosubmit: Sander Melnikov <hey@sandydoo.me>
Tested-by: besadii
---
 snix/eval/src/value/string/mod.rs  |  5 +++++
 snix/glue/src/builtins/fetchers.rs | 24 +++++++++++-------------
 2 files changed, 16 insertions(+), 13 deletions(-)

diff --git a/snix/eval/src/value/string/mod.rs b/snix/eval/src/value/string/mod.rs
index 4419da777..003b2bf2e 100644
--- a/snix/eval/src/value/string/mod.rs
+++ b/snix/eval/src/value/string/mod.rs
@@ -633,6 +633,11 @@ impl NixString {
         unsafe { NixStringInner::data_slice(self.0) }
     }
 
+    /// Returns a &str if the NixString is a valid UTF-8 string.
+    pub fn as_str(&self) -> Result<&str, std::str::Utf8Error> {
+        std::str::from_utf8(self.as_bytes())
+    }
+
     pub fn into_bstring(self) -> BString {
         self.as_bstr().to_owned()
     }
diff --git a/snix/glue/src/builtins/fetchers.rs b/snix/glue/src/builtins/fetchers.rs
index 613618d52..8db10a462 100644
--- a/snix/glue/src/builtins/fetchers.rs
+++ b/snix/glue/src/builtins/fetchers.rs
@@ -202,20 +202,18 @@ pub(crate) mod fetcher_builtins {
         co: GenCo,
         value: Value,
     ) -> Result<Value, ErrorKind> {
-        let flake_ref_str = value.to_str()?.into_bstring().as_bstr().to_string();
+        let flake_ref = value.to_str()?;
+        let flake_ref_str = flake_ref.to_str()?;
 
-        let fetch_args = match flake_ref_str.parse() {
-            Ok(args) => args,
-            Err(err) => {
-                return Err(ErrorKind::SnixError(Rc::new(err)));
-            }
-        };
+        let fetch_args = flake_ref_str
+            .parse()
+            .map_err(|err| ErrorKind::SnixError(Rc::new(err)))?;
 
         // Convert the FlakeRef to our Value format
         let mut attrs = BTreeMap::new();
 
         // Extract type and url based on the variant
-        match &fetch_args {
+        match fetch_args {
             flakeref::FlakeRef::Git { url, .. } => {
                 attrs.insert("type".into(), Value::from("git"));
                 attrs.insert("url".into(), Value::from(url.to_string()));
@@ -224,16 +222,16 @@ pub(crate) mod fetcher_builtins {
                 owner, repo, r#ref, ..
             } => {
                 attrs.insert("type".into(), Value::from("github"));
-                attrs.insert("owner".into(), Value::from(owner.clone()));
-                attrs.insert("repo".into(), Value::from(repo.clone()));
+                attrs.insert("owner".into(), Value::from(owner));
+                attrs.insert("repo".into(), Value::from(repo));
                 if let Some(ref_name) = r#ref {
-                    attrs.insert("ref".into(), Value::from(ref_name.clone()));
+                    attrs.insert("ref".into(), Value::from(ref_name));
                 }
             }
             flakeref::FlakeRef::GitLab { owner, repo, .. } => {
                 attrs.insert("type".into(), Value::from("gitlab"));
-                attrs.insert("owner".into(), Value::from(owner.clone()));
-                attrs.insert("repo".into(), Value::from(repo.clone()));
+                attrs.insert("owner".into(), Value::from(owner));
+                attrs.insert("repo".into(), Value::from(repo));
             }
             flakeref::FlakeRef::File { url, .. } => {
                 attrs.insert("type".into(), Value::from("file"));