RUST-1421 Implement FromStr for Namespace (#889)

* RUST-1421 Implement FromStr for Namespace

src/coll/mod.rs

@@ -1,6 +1,6 @@
 pub mod options;
 
-use std::{borrow::Borrow, collections::HashSet, fmt, fmt::Debug, sync::Arc};
+use std::{borrow::Borrow, collections::HashSet, fmt, fmt::Debug, str::FromStr, sync::Arc};
 
 use futures_util::{
     future,
@@ -1501,3 +1501,23 @@ impl Serialize for Namespace {
         serializer.serialize_str(&(self.db.clone() + "." + &self.coll))
     }
 }
+
+impl FromStr for Namespace {
+    type Err = Error;
+    fn from_str(s: &str) -> Result<Self> {
+        let mut parts = s.split('.');
+
+        let db = parts.next();
+        let coll = parts.collect::<Vec<_>>().join(".");
+
+        match (db, coll) {
+            (Some(db), coll) if !coll.is_empty() => Ok(Self {
+                db: db.to_string(),
+                coll,
+            }),
+            _ => Err(Self::Err::invalid_argument(
+                "Missing one or more fields in namespace",
+            )),
+        }
+    }
+}

src/test/coll.rs

@@ -1,5 +1,6 @@
 use std::{fmt::Debug, time::Duration};
 
+use crate::Namespace;
 use futures::stream::{StreamExt, TryStreamExt};
 use lazy_static::lazy_static;
 use semver::VersionReq;
@@ -1201,3 +1202,15 @@ fn assert_duplicate_key_error_with_utf8_replacement(error: &ErrorKind) {
         ),
     }
 }
+
+#[test]
+fn test_namespace_fromstr() {
+    let t: Namespace = "something.somethingelse".parse().unwrap();
+    assert_eq!(t.db, "something");
+    assert_eq!(t.coll, "somethingelse");
+    let t2: Result<Namespace> = "blahblah".parse();
+    assert!(t2.is_err());
+    let t: Namespace = "something.something.else".parse().unwrap();
+    assert_eq!(t.db, "something");
+    assert_eq!(t.coll, "something.else");
+}