refactor(source): Pull out git ref logic

Author: epage

src/cargo/core/source_id.rs

@@ -188,17 +188,7 @@ impl SourceId {
         match kind {
             "git" => {
                 let mut url = url.into_url()?;
-                let mut reference = GitReference::DefaultBranch;
-                for (k, v) in url.query_pairs() {
-                    match &k[..] {
-                        // Map older 'ref' to branch.
-                        "branch" | "ref" => reference = GitReference::Branch(v.into_owned()),
-
-                        "rev" => reference = GitReference::Rev(v.into_owned()),
-                        "tag" => reference = GitReference::Tag(v.into_owned()),
-                        _ => {}
-                    }
-                }
+                let reference = GitReference::from_query(url.query_pairs());
                 let precise = url.fragment().map(|s| s.to_owned());
                 url.set_fragment(None);
                 url.set_query(None);
@@ -884,6 +874,24 @@ impl<'a> fmt::Display for SourceIdAsUrl<'a> {
 }
 
 impl GitReference {
+    pub fn from_query(
+        query_pairs: impl Iterator<Item = (impl AsRef<str>, impl AsRef<str>)>,
+    ) -> Self {
+        let mut reference = GitReference::DefaultBranch;
+        for (k, v) in query_pairs {
+            let v = v.as_ref();
+            match k.as_ref() {
+                // Map older 'ref' to branch.
+                "branch" | "ref" => reference = GitReference::Branch(v.to_owned()),
+
+                "rev" => reference = GitReference::Rev(v.to_owned()),
+                "tag" => reference = GitReference::Tag(v.to_owned()),
+                _ => {}
+            }
+        }
+        reference
+    }
+
     /// Returns a `Display`able view of this git reference, or None if using
     /// the head of the default branch
     pub fn pretty_ref(&self, url_encoded: bool) -> Option<PrettyRef<'_>> {