surf: expose BlobRef

The current `blob` function is limited to always associating a Blob
with a Commit.

Expose `BlobRef` through a `blob_ref` method, and add useful methods
and serialization to it.

Signed-off-by: Fintan Halpenny <fintan.halpenny@gmail.com>
X-Clacks-Overhead: GNU Terry Pratchett

radicle-surf/src/blob.rs

@@ -95,7 +95,13 @@ impl<'a> Blob<BlobRef<'a>> {
 
 /// Represents a blob with borrowed content bytes.
 pub struct BlobRef<'a> {
-    inner: git2::Blob<'a>,
+    pub(crate) inner: git2::Blob<'a>,
+}
+
+impl<'a> BlobRef<'a> {
+    pub fn id(&self) -> Oid {
+        self.inner.id().into()
+    }
 }
 
 impl AsRef<[u8]> for BlobRef<'_> {
@@ -138,3 +144,26 @@ where
         state.end()
     }
 }
+
+#[cfg(feature = "serde")]
+impl<'a> Serialize for BlobRef<'a> {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        const FIELDS: usize = 3;
+        let mut state = serializer.serialize_struct("BlobRef", FIELDS)?;
+        state.serialize_field("id", &self.id())?;
+        state.serialize_field("binary", &self.inner.is_binary())?;
+
+        let bytes = self.as_ref();
+        match std::str::from_utf8(bytes) {
+            Ok(s) => state.serialize_field("content", s)?,
+            Err(_) => {
+                let encoded = base64::encode(bytes);
+                state.serialize_field("content", &encoded)?
+            },
+        };
+        state.end()
+    }
+}

radicle-surf/src/repo.rs

@@ -301,6 +301,12 @@ impl Repository {
         Ok(Blob::<BlobRef<'a>>::new(file.id(), git2_blob, last_commit))
     }
 
+    pub fn blob_ref(&self, oid: Oid) -> Result<BlobRef<'_>, Error> {
+        Ok(BlobRef {
+            inner: self.find_blob(oid)?,
+        })
+    }
+
     /// Returns the last commit, if exists, for a `path` in the history of
     /// `rev`.
     pub fn last_commit<P, C>(&self, path: &P, rev: C) -> Result<Option<Commit>, Error>