fixup! fixup! rustdoc font links only emit crossorigin when needed

Author: MingweiSamuel

src/librustdoc/html/layout.rs

@@ -8,6 +8,8 @@ use super::static_files::{STATIC_FILES, StaticFiles};
 use crate::externalfiles::ExternalHtml;
 use crate::html::render::{StylePath, ensure_trailing_slash};
 
+#[cfg(test)]
+mod tests;
 pub(crate) struct Layout {
     pub(crate) logo: String,
     pub(crate) favicon: String,
@@ -69,24 +71,9 @@ struct PageLayout<'a> {
 }
 
 impl PageLayout<'_> {
-    /// Conservatively determines if [`Self::static_root_path`] is relative to the current origin,
-    /// so that `crossorigin` may be safely removed from `<link>` elements.
+    /// See [`may_remove_crossorigin`].
     fn static_root_path_may_remove_crossorigin(&self) -> bool {
-        let href = &*self.static_root_path;
-        // Reject scheme-relative URLs (`//example.com/`).
-        if href.starts_with("//") {
-            return false;
-        }
-        // URL is interpreted as having a scheme iff: it starts with an ascii alpha, and only
-        // contains ascii alphanumeric or `+` `-` `.` up to the `:`.
-        // https://url.spec.whatwg.org/#url-parsing
-        let has_scheme = href.split_once(':').is_some_and(|(scheme, _rest)| {
-            let mut chars = scheme.chars();
-            chars.next().is_some_and(|c| c.is_ascii_alphabetic())
-                && chars.all(|c| c.is_ascii_alphanumeric() || c == '+' || c == '-' || c == '.')
-        });
-        // Reject anything with a scheme (`http:`, etc.).
-        !has_scheme
+        may_remove_crossorigin(&self.static_root_path)
     }
 }
 
@@ -156,3 +143,22 @@ pub(crate) fn redirect(url: &str) -> String {
 </html>"##,
     )
 }
+
+/// Conservatively determines if `href` is relative to the current origin,
+/// so that `crossorigin` may be safely removed from `<link>` elements.
+pub(crate) fn may_remove_crossorigin(href: &str) -> bool {
+    // Reject scheme-relative URLs (`//example.com/`).
+    if href.starts_with("//") {
+        return false;
+    }
+    // URL is interpreted as having a scheme iff: it starts with an ascii alpha, and only
+    // contains ascii alphanumeric or `+` `-` `.` up to the `:`.
+    // https://url.spec.whatwg.org/#url-parsing
+    let has_scheme = href.split_once(':').is_some_and(|(scheme, _rest)| {
+        let mut chars = scheme.chars();
+        chars.next().is_some_and(|c| c.is_ascii_alphabetic())
+            && chars.all(|c| c.is_ascii_alphanumeric() || c == '+' || c == '-' || c == '.')
+    });
+    // Reject anything with a scheme (`http:`, etc.).
+    !has_scheme
+}

src/librustdoc/html/layout/tests.rs

@@ -0,0 +1,24 @@
+#[test]
+fn test_may_remove_crossorigin() {
+    use super::may_remove_crossorigin;
+
+    assert!(may_remove_crossorigin("font.woff2"));
+    assert!(may_remove_crossorigin("/font.woff2"));
+    assert!(may_remove_crossorigin("./font.woff2"));
+    assert!(may_remove_crossorigin(":D/font.woff2"));
+    assert!(may_remove_crossorigin("../font.woff2"));
+
+    assert!(!may_remove_crossorigin("//example.com/static.files"));
+    assert!(!may_remove_crossorigin("http://example.com/static.files"));
+    assert!(!may_remove_crossorigin("https://example.com/static.files"));
+    assert!(!may_remove_crossorigin("https://example.com:8080/static.files"));
+
+    assert!(!may_remove_crossorigin("ftp://example.com/static.files"));
+    assert!(!may_remove_crossorigin("blob:http://example.com/static.files"));
+    assert!(!may_remove_crossorigin("javascript:alert('Hello, world!')"));
+    assert!(!may_remove_crossorigin("//./C:"));
+    assert!(!may_remove_crossorigin("file:////C:"));
+    assert!(!may_remove_crossorigin("file:///./C:"));
+    assert!(!may_remove_crossorigin("data:,Hello%2C%20World%21"));
+    assert!(!may_remove_crossorigin("hi...:hello"));
+}