1 // SPDX-License-Identifier: GPL-2.0 2 // Copyright (C) 2025 Google LLC. 3 4 //! Traits for rendering or updating values exported to DebugFS. 5 6 use crate::sync::Mutex; 7 use core::fmt::{self, Debug, Formatter}; 8 9 /// A trait for types that can be written into a string. 10 /// 11 /// This works very similarly to `Debug`, and is automatically implemented if `Debug` is 12 /// implemented for a type. It is also implemented for any writable type inside a `Mutex`. 13 /// 14 /// The derived implementation of `Debug` [may 15 /// change](https://doc.rust-lang.org/std/fmt/trait.Debug.html#stability) 16 /// between Rust versions, so if stability is key for your use case, please implement `Writer` 17 /// explicitly instead. 18 pub trait Writer { 19 /// Formats the value using the given formatter. 20 fn write(&self, f: &mut Formatter<'_>) -> fmt::Result; 21 } 22 23 impl<T: Writer> Writer for Mutex<T> { 24 fn write(&self, f: &mut Formatter<'_>) -> fmt::Result { 25 self.lock().write(f) 26 } 27 } 28 29 impl<T: Debug> Writer for T { 30 fn write(&self, f: &mut Formatter<'_>) -> fmt::Result { 31 writeln!(f, "{self:?}") 32 } 33 } 34