Identify read-only files from permission records

You are given a list of file metadata records. Each record contains:

• owner (string): the username who owns the file
• permission (string): a Unix-like permission string of length 9, representing owner/group/others permissions in order, e.g. rwxr-xr--
• filename (string)

A file is considered read-only if no user category has write permission, i.e., the permission string contains no w character anywhere.

Task

Return the list of filenames that are read-only.

Input format (one possible representation)

• An array/list of records, where each record is a tuple/object: { owner, permission, filename } .

Output

• An array/list of filenames (strings) that are read-only.

Notes / assumptions

• permission is always exactly 9 characters and consists only of r , w , x , and - .
• Filenames are unique.

Example

Input records:

1. {owner: "alice", permission: "r--r--r--", filename: "a.txt"}
2. {owner: "bob", permission: "rw-r--r--", filename: "b.txt"}
3. {owner: "carl", permission: "r-xr-xr-x", filename: "c.sh"}

Output:

• ["a.txt", "c.sh"]