API: Proper error types instead of String #1424
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,39 +1,102 @@ | ||
| use std::ffi::{CString, NulError}; | ||
| use std::{error, fmt, io}; | ||
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| #[derive(Debug)] | ||
| pub struct SdlError { | ||
| msg: String, | ||
| } | ||
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| impl SdlError { | ||
| pub fn from_last_error() -> Self { | ||
| let msg = crate::get_error(); | ||
| Self { msg } | ||
| } | ||
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| pub(crate) fn from_string(msg: String) -> Self { | ||
| Self { msg } | ||
| } | ||
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| pub fn message(&self) -> &str { | ||
| &self.msg | ||
| } | ||
| } | ||
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| impl fmt::Display for SdlError { | ||
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | ||
| write!(f, "{}", self.msg) | ||
| } | ||
| } | ||
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| impl error::Error for SdlError {} | ||
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| #[derive(Debug)] | ||
| pub enum Error { | ||
| Sdl(SdlError), | ||
| Io(io::Error), | ||
| /// An integer was larger than [`i32::MAX`] in a parameter, and it can't be converted to a C int | ||
| IntOverflow(&'static str, u32), | ||
| /// A null byte was found within a parameter, and it can't be sent to SDL | ||
| InvalidString(NulError, &'static str), | ||
| } | ||
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| impl Error { | ||
| pub fn from_sdl_error() -> Self { | ||
| Self::Sdl(SdlError::from_last_error()) | ||
| } | ||
| } | ||
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| impl fmt::Display for Error { | ||
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | ||
| match self { | ||
| Self::Sdl(msg) => write!(f, "SDL error: {msg}"), | ||
| Self::Io(err) => write!(f, "IO error: {err}"), | ||
| Self::IntOverflow(name, value) => write!(f, "Integer '{name}' overflows: {value}"), | ||
| Self::InvalidString(name, nul) => write!(f, "Invalid string '{name}': {nul}"), | ||
| } | ||
| } | ||
| } | ||
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| impl error::Error for Error { | ||
| fn source(&self) -> Option<&(dyn error::Error + 'static)> { | ||
| match self { | ||
| Self::Sdl(..) | Self::IntOverflow(..) => None, | ||
|
There was a problem hiding this comment. The source may also be returned for |
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| Self::Io(err) => Some(err), | ||
| Self::InvalidString(nul, _) => Some(nul), | ||
| } | ||
| } | ||
| } | ||
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| impl From<SdlError> for Error { | ||
| fn from(value: SdlError) -> Self { | ||
| Self::Sdl(value) | ||
| } | ||
| } | ||
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| impl From<io::Error> for Error { | ||
| fn from(value: io::Error) -> Self { | ||
| Self::Io(value) | ||
| } | ||
| } | ||
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| pub fn validate_string(str: impl Into<Vec<u8>>, name: &'static str) -> Result<CString, Error> { | ||
| match CString::new(str) { | ||
| Ok(c) => Ok(c), | ||
| Err(nul) => Err(Error::InvalidString(nul, name)), | ||
| } | ||
| } | ||
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| /// Validates and converts the given u32 to a positive C integer. | ||
| pub fn validate_int(value: u32, name: &'static str) -> Result<libc::c_int, Error> { | ||
| // Many SDL functions will accept `int` values, even if it doesn't make sense | ||
| // for the values to be negative. | ||
| // In the cases that SDL doesn't check negativity, passing negative values | ||
| // could be unsafe. | ||
| // For example, `SDL_JoystickGetButton` uses the index argument to access an | ||
| // array without checking if it's negative, which could potentially lead to | ||
| // segmentation faults. | ||
| if value > libc::c_int::MAX as u32 { | ||
| Err(Error::IntOverflow(name, value)) | ||
| } else { | ||
| Ok(value as libc::c_int) | ||
| } | ||
| } | ||
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In the definition the first field is the
NulError, not the name.To prevent these bugs (in this crate but also user code using this crate) I advise to use a struct like variant instead of a tuple like one. This also adds context to the context-less
&'static strfield. I suggest to change the definition toInvalidString { nul_err: NulError, var_name: &'static str }(or something like this) and roughly the same forIntOverflow.