support a different source db than dest for transfer command

src/main.rs

@@ -21,13 +21,14 @@ Usage:
   foil set [--namespace=<ns>] [--db=<db>]
   foil get [--namespace=<ns>] [--db=<db>]
   foil list [--namespace=<ns>] [--db=<db>]
-  foil transfer [--namespace=<ns>] [--db=<db>]
+  foil transfer [--namespace=<ns>] [--db=<db>] [--src=<db>]
   foil dump [--db=<db>]
   foil generate <spec>
   foil (-h | --help)
 
 Options:
   --db=<db>                The path to the sqlite database [default: db.sqlite3].
+  --src=<db>               The path to the old sqlite database [default: db.sqlite3].
   -n DB, --namespace=<db>  An identifier for a group of secrets [default: main]
   -h, --help               Show this screen.
   --version                Show version.
@@ -42,6 +43,7 @@ struct Args {
     cmd_transfer: bool,
     cmd_dump: bool,
     flag_db: Option<String>,
+    flag_src: Option<String>,
     flag_namespace: String,
     arg_spec: Option<String>,
 }
@@ -156,8 +158,14 @@ fn dump(mut db_conn: db::DbHandle, master_key: [u8; 32]) {
     }
 }
 
-fn transfer(mut db_conn: db::DbHandle, master_key: [u8; 32], namespace: &str) {
+fn transfer(
-    for account in db_conn.list_accounts(master_key).into_iter() {
+    mut db_conn_src: db::DbHandle,
+    mut db_conn_dest: db::DbHandle,
+    master_key_src: [u8; 32],
+    master_key_dest: [u8; 32],
+    namespace: &str,
+) {
+    for account in db_conn_src.list_accounts(master_key_src).into_iter() {
         let new_note = db::Note {
             id: 0,
             namespace: namespace.to_string(),
@@ -168,7 +176,7 @@ fn transfer(mut db_conn: db::DbHandle, master_key: [u8; 32], namespace: &str) {
                 account.user, account.password
             ),
         };
-        db_conn.write_note(master_key, new_note);
+        db_conn_dest.write_note(master_key_dest, new_note);
     }
 }
 
@@ -195,7 +203,15 @@ fn main() -> Result<(), Box<dyn Error>> {
     } else if args.cmd_list {
         list(db_conn, master_key, &args.flag_namespace);
     } else if args.cmd_transfer {
-        transfer(db_conn, master_key, &args.flag_namespace);
+        let mut db_conn_src: db::DbHandle = db::DbHandle::new(&args.flag_src);
+        let master_key_src: [u8; 32] = get_master_key(&mut db_conn_src);
+        transfer(
+            db_conn_src,
+            db_conn,
+            master_key_src,
+            master_key,
+            &args.flag_namespace,
+        );
     } else if args.cmd_dump {
         dump(db_conn, master_key);
     }