Another feature of the MutexProtected implementation in SerenityOS is the ability to either obtain an exclusive lock (writable) or a shared lock (read-only). A

Another feature of the MutexProtected implementation in SerenityOS is the ability to either obtain an exclusive lock (writable) or a shared lock (read-only). A shared lock provides a const reference to the protected value and therefore enforces read-only access semantics at compile-time by leveraging the C++ type system (specifically, const-correctness). The initial PR introducing the ancestor to MutexProtected has some details on the motivation behind it and also unearthed a bunch of incorrect locking that the C++ compiler caught when introducing it: https://github.com/SerenityOS/serenity/pull/8851 https://github.com/SerenityOS/serenity/pull/8851