gff/record: Parse phase

noodles-gff/CHANGELOG.md

@@ -36,6 +36,8 @@
 
     This splits the line into its key-optional value components.
 
+  * gff/record: Parse phase (`Record::phase`).
+
 ### Removed
 
   * gff: Remove `lazy` module.

noodles-gff/src/record.rs

@@ -10,7 +10,7 @@ use noodles_core::Position;
 
 pub use self::attributes::Attributes;
 use self::fields::Fields;
-use crate::record_buf::Strand;
+use crate::record_buf::{Phase, Strand};
 
 /// An immutable, lazily-evalulated GFF record.
 #[derive(Clone, Eq, PartialEq)]
@@ -57,8 +57,8 @@ impl<'l> Record<'l> {
     }
 
     /// Returns the phase.
-    pub fn phase(&self) -> &str {
-        self.0.phase()
+    pub fn phase(&self) -> Option<io::Result<Phase>> {
+        parse_phase(self.0.phase())
     }
 
     /// Returns the attributes.
@@ -87,3 +87,35 @@ fn parse_strand(s: &str) -> io::Result<Strand> {
     s.parse()
         .map_err(|e| io::Error::new(io::ErrorKind::InvalidData, e))
 }
+
+fn parse_phase(s: &str) -> Option<io::Result<Phase>> {
+    const MISSING: &str = ".";
+
+    match s {
+        MISSING => None,
+        _ => Some(
+            s.parse()
+                .map_err(|e| io::Error::new(io::ErrorKind::InvalidData, e)),
+        ),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_parse_phase() -> io::Result<()> {
+        assert!(parse_phase(".").is_none());
+        assert_eq!(parse_phase("0").transpose()?, Some(Phase::Zero));
+        assert_eq!(parse_phase("1").transpose()?, Some(Phase::One));
+        assert_eq!(parse_phase("2").transpose()?, Some(Phase::Two));
+
+        assert!(matches!(
+            parse_phase(""),
+            Some(Err(e)) if e.kind() == io::ErrorKind::InvalidData
+        ));
+
+        Ok(())
+    }
+}

noodles-gff/src/record_buf/convert.rs

@@ -27,12 +27,7 @@ impl<'l> TryFrom<Record<'l>> for RecordBuf {
 
         builder = builder.set_strand(record.strand()?);
 
-        if record.phase() != MISSING_FIELD {
-            let phase = record
-                .phase()
-                .parse()
-                .map_err(|e| io::Error::new(io::ErrorKind::InvalidData, e))?;
-
+        if let Some(phase) = record.phase().transpose()? {
             builder = builder.set_phase(phase);
         }