Remove `impl Display for CStr` in preparation for replacing `CStr` with `core::ffi::CStr` which doesn't impl `Display`. Add `CStr::display` returning a helper struct to replace the lost functionality; this matches the APIs exposed by `std::ffi::OSstr` and `std::path::Path` for printing non-Unicode data.
Signed-off-by: Tamir Duberstein tamird@gmail.com --- rust/kernel/kunit.rs | 9 +++++--- rust/kernel/str.rs | 63 ++++++++++++++++++++++++++++++++++++++++++---------- 2 files changed, 57 insertions(+), 15 deletions(-)
diff --git a/rust/kernel/kunit.rs b/rust/kernel/kunit.rs index 824da0e9738a..630b947c708c 100644 --- a/rust/kernel/kunit.rs +++ b/rust/kernel/kunit.rs @@ -56,6 +56,7 @@ macro_rules! kunit_assert { break 'out; }
+ static NAME: &'static $crate::str::CStr = $crate::c_str!($name); static FILE: &'static $crate::str::CStr = $crate::c_str!($file); static LINE: i32 = core::line!() as i32 - $diff; static CONDITION: &'static $crate::str::CStr = $crate::c_str!(stringify!($condition)); @@ -71,11 +72,13 @@ macro_rules! kunit_assert { // // This mimics KUnit's failed assertion format. $crate::kunit::err(format_args!( - " # {}: ASSERTION FAILED at {FILE}:{LINE}\n", - $name + " # {NAME}: ASSERTION FAILED at {FILE}:{LINE}\n", + NAME = NAME.display(), + FILE = FILE.display(), )); $crate::kunit::err(format_args!( - " Expected {CONDITION} to be true, but is false\n" + " Expected {CONDITION} to be true, but is false\n", + CONDITION = CONDITION.display(), )); $crate::kunit::err(format_args!( " Failure not reported to KUnit since this is a non-KUnit task\n" diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs index 28e2201604d6..50eb4266047a 100644 --- a/rust/kernel/str.rs +++ b/rust/kernel/str.rs @@ -376,27 +376,66 @@ pub fn to_ascii_uppercase(&self) -> Result<CString, AllocError> {
Ok(s) } -}
-impl fmt::Display for CStr { - /// Formats printable ASCII characters, escaping the rest. + /// Returns an object that implements [`Display`] for safely printing a [`CStr`] that may + /// contain non-Unicode data. If you would like an implementation which escapes the [`CStr`] + /// please use [`Debug`] instead. + /// + /// [`Display`]: fmt::Display + /// [`Debug`]: fmt::Debug + /// + /// # Examples /// /// ``` /// # use kernel::c_str; /// # use kernel::fmt; - /// # use kernel::str::CStr; /// # use kernel::str::CString; /// let penguin = c_str!("🐧"); - /// let s = CString::try_from_fmt(fmt!("{}", penguin))?; + /// let s = CString::try_from_fmt(fmt!("{}", penguin.display()))?; /// assert_eq!(s.as_bytes_with_nul(), "\xf0\x9f\x90\xa7\0".as_bytes()); /// /// let ascii = c_str!("so "cool""); - /// let s = CString::try_from_fmt(fmt!("{}", ascii))?; + /// let s = CString::try_from_fmt(fmt!("{}", ascii.display()))?; /// assert_eq!(s.as_bytes_with_nul(), "so "cool"\0".as_bytes()); /// # Ok::<(), kernel::error::Error>(()) /// ``` + #[inline] + pub fn display(&self) -> Display<'_> { + Display { inner: self } + } +} + +/// Helper struct for safely printing a [`CStr`] with [`fmt!`] and `{}`. +/// +/// A [`CStr`] might contain non-Unicode data. This `struct` implements the [`Display`] trait in a +/// way that mitigates that. It is created by the [`display`](CStr::display) method on [`CStr`]. +/// +/// If you would like an implementation which escapes the string please use [`Debug`] instead. +/// +/// # Examples +/// +/// ``` +/// # use kernel::{fmt, c_str, str::CString}; +/// let ascii = c_str!("Hello, CStr!"); +/// let s = CString::try_from_fmt(fmt!("{}", ascii.display()))?; +/// assert_eq!(s.as_bytes(), "Hello, CStr!".as_bytes()); +/// +/// let non_ascii = c_str!("🦀"); +/// let s = CString::try_from_fmt(fmt!("{}", non_ascii.display()))?; +/// assert_eq!(s.as_bytes(), "\xf0\x9f\xa6\x80".as_bytes()); +/// # Ok::<(), kernel::error::Error>(()) +/// ``` +/// +/// [`fmt!`]: crate::fmt +/// [`Debug`]: fmt::Debug +/// [`Display`]: fmt::Display +pub struct Display<'a> { + inner: &'a CStr, +} + +impl fmt::Display for Display<'_> { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - for &c in self.as_bytes() { + for &c in self.inner.as_bytes() { if (0x20..0x7f).contains(&c) { // Printable character. f.write_char(c as char)?; @@ -595,13 +634,13 @@ fn test_cstr_as_str_unchecked() { #[test] fn test_cstr_display() { let hello_world = CStr::from_bytes_with_nul(b"hello, world!\0").unwrap(); - assert_eq!(format!("{}", hello_world), "hello, world!"); + assert_eq!(format!("{}", hello_world.display()), "hello, world!"); let non_printables = CStr::from_bytes_with_nul(b"\x01\x09\x0a\0").unwrap(); - assert_eq!(format!("{}", non_printables), "\x01\x09\x0a"); + assert_eq!(format!("{}", non_printables.display()), "\x01\x09\x0a"); let non_ascii = CStr::from_bytes_with_nul(b"d\xe9j\xe0 vu\0").unwrap(); - assert_eq!(format!("{}", non_ascii), "d\xe9j\xe0 vu"); + assert_eq!(format!("{}", non_ascii.display()), "d\xe9j\xe0 vu"); let good_bytes = CStr::from_bytes_with_nul(b"\xf0\x9f\xa6\x80\0").unwrap(); - assert_eq!(format!("{}", good_bytes), "\xf0\x9f\xa6\x80"); + assert_eq!(format!("{}", good_bytes.display()), "\xf0\x9f\xa6\x80"); }
#[test] @@ -612,7 +651,7 @@ fn test_cstr_display_all_bytes() { bytes[i as usize] = i.wrapping_add(1); } let cstr = CStr::from_bytes_with_nul(&bytes).unwrap(); - assert_eq!(format!("{}", cstr), ALL_ASCII_CHARS); + assert_eq!(format!("{}", cstr.display()), ALL_ASCII_CHARS); }
#[test]