Add `ReadStorage::contains` method

radicle/src/storage.rs

@@ -254,6 +254,8 @@ pub trait ReadStorage {
         remote: &RemoteId,
         rid: Id,
     ) -> Result<Option<identity::Doc<Verified>>, ProjectError>;
+    /// Check whether storage contains a repository.
+    fn contains(&self, rid: &Id) -> Result<bool, ProjectError>;
     /// Get the inventory of repositories hosted under this storage.
     fn inventory(&self) -> Result<Inventory, Error>;
 }
@@ -357,6 +359,10 @@ where
         self.deref().path()
     }
 
+    fn contains(&self, rid: &Id) -> Result<bool, ProjectError> {
+        self.deref().contains(rid)
+    }
+
     fn inventory(&self) -> Result<Inventory, Error> {
         self.deref().inventory()
     }

radicle/src/storage/git.rs

@@ -99,6 +99,14 @@ impl ReadStorage for Storage {
         self.path.as_path()
     }
 
+    fn contains(&self, rid: &Id) -> Result<bool, ProjectError> {
+        if paths::repository(&self, rid).exists() {
+            let _ = self.repository(*rid)?.head()?;
+            return Ok(true);
+        }
+        Ok(false)
+    }
+
     fn get(&self, remote: &RemoteId, proj: Id) -> Result<Option<Doc<Verified>>, ProjectError> {
         // TODO: Don't create a repo here if it doesn't exist?
         // Perhaps for checking we could have a `contains` method?

radicle/src/test/storage.rs

@@ -36,6 +36,10 @@ impl ReadStorage for MockStorage {
         self.path.as_path()
     }
 
+    fn contains(&self, rid: &Id) -> Result<bool, ProjectError> {
+        Ok(self.inventory.contains_key(rid))
+    }
+
     fn get(
         &self,
         _remote: &RemoteId,