Sync with FRID protocol v5. Improved direct content id search

src/share.rs

@@ -22,15 +22,30 @@ pub fn track_share_link(track: &TrackItem) -> Option<String> {
     Some(track_share_link_for_content_id(track, &content_id))
 }
 
-pub fn parse_frid_content_id(value: &str) -> Option<String> {
+/// A parsed `frid://` share link.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct FridLink {
+    /// Canonical content id (`b3:<64 hex>`).
+    pub content_id: String,
+    /// Human-readable "artists-title" label from the `t` query parameter.
+    pub label: Option<String>,
+}
+
+pub fn parse_frid_link(value: &str) -> Option<FridLink> {
     let value = value.trim();
     let rest = value.strip_prefix("frid://")?;
-    let content_id = rest
-        .split(['?', '#'])
-        .next()
-        .unwrap_or_default()
-        .trim_end_matches('/');
-    music_dht::normalize_content_id(content_id)
+    let mut parts = rest.splitn(2, ['?', '#']);
+    let content_id =
+        music_dht::normalize_content_id(parts.next().unwrap_or_default().trim_end_matches('/'))?;
+    let label = parts.next().and_then(|query| {
+        query.split('&').find_map(|pair| {
+            let value = pair.strip_prefix("t=")?;
+            let decoded = percent_decode(value);
+            let decoded = decoded.trim();
+            (!decoded.is_empty()).then(|| decoded.to_string())
+        })
+    });
+    Some(FridLink { content_id, label })
 }
 
 pub fn cached_track_share_link(track: &TrackItem) -> Option<String> {
@@ -71,6 +86,41 @@ fn percent_encode(value: &str) -> String {
     out
 }
 
+fn percent_decode(value: &str) -> String {
+    let bytes = value.as_bytes();
+    let mut out = Vec::with_capacity(bytes.len());
+    let mut index = 0;
+    while index < bytes.len() {
+        match bytes[index] {
+            b'%' if index + 3 <= bytes.len() => {
+                let hex = std::str::from_utf8(&bytes[index + 1..index + 3])
+                    .ok()
+                    .and_then(|hex| u8::from_str_radix(hex, 16).ok());
+                match hex {
+                    Some(byte) => {
+                        out.push(byte);
+                        index += 3;
+                    }
+                    None => {
+                        out.push(b'%');
+                        index += 1;
+                    }
+                }
+            }
+            // Liberal form-encoding acceptance; our encoder never emits '+'.
+            b'+' => {
+                out.push(b' ');
+                index += 1;
+            }
+            byte => {
+                out.push(byte);
+                index += 1;
+            }
+        }
+    }
+    String::from_utf8_lossy(&out).into_owned()
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -116,13 +166,78 @@ mod tests {
 
     #[test]
     fn parses_frid_content_link() {
+        let link = parse_frid_link(
+            "frid://b3:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef?t=Artist-Track"
+        )
+        .expect("valid link");
         assert_eq!(
-            parse_frid_content_id(
-                "frid://b3:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef?t=Artist-Track"
-            )
-            .as_deref(),
-            Some("b3:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef")
+            link.content_id,
+            "b3:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
         );
-        assert!(parse_frid_content_id("https://example.com").is_none());
+        assert_eq!(link.label.as_deref(), Some("Artist-Track"));
+        assert!(parse_frid_link("https://example.com").is_none());
+    }
+
+    #[test]
+    fn parses_percent_encoded_label() {
+        let link = parse_frid_link(
+            "frid://B3:0123456789ABCDEF0123456789abcdef0123456789abcdef0123456789abcdef?t=Rammstein-Du%20Riechst%20So%20Gut"
+        )
+        .expect("valid link");
+        assert_eq!(
+            link.content_id,
+            "b3:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
+        );
+        assert_eq!(link.label.as_deref(), Some("Rammstein-Du Riechst So Gut"));
+
+        // Cyrillic labels and a missing label both survive.
+        let link = parse_frid_link(
+            "frid://b3:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef?t=%D0%90%D1%80%D1%82%D0%B8%D1%81%D1%82"
+        )
+        .expect("valid link");
+        assert_eq!(link.label.as_deref(), Some("Артист"));
+        let link = parse_frid_link(
+            "frid://b3:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
+        )
+        .expect("valid link");
+        assert_eq!(link.label, None);
+    }
+
+    #[test]
+    fn share_link_round_trips_through_parse() {
+        let track = TrackItem {
+            id: 1,
+            title: "Du Riechst So Gut".into(),
+            track_number: None,
+            disc_number: None,
+            duration_seconds: 1.0,
+            artists: vec![ArtistRef {
+                id: 1,
+                name: "Rammstein".into(),
+            }],
+            featured_artists: Vec::new(),
+            release_id: 1,
+            release_title: "Herzeleid".into(),
+            release_year: None,
+            file_path: String::new(),
+            content_id: Some(
+                "b3:5ebd9e61e1154a64470e6ee4dd1225550f380dd575d01fd4ffba6a5bd1b34104".into(),
+            ),
+            cover_path: None,
+            audio_format: None,
+            audio_bitrate: None,
+            audio_sample_rate: None,
+            audio_bit_depth: None,
+            file_size_bytes: None,
+            play_count: 0,
+            fed: None,
+        };
+        let link = track_share_link(&track).expect("link");
+        let parsed = parse_frid_link(&link).expect("parses back");
+        assert_eq!(
+            parsed.content_id,
+            "b3:5ebd9e61e1154a64470e6ee4dd1225550f380dd575d01fd4ffba6a5bd1b34104"
+        );
+        assert_eq!(parsed.label.as_deref(), Some("Rammstein-Du Riechst So Gut"));
     }
 }