lix/nix-rust/src/error.rs
Eelco Dolstra bbe97dff8b Make the Store API more type-safe
Most functions now take a StorePath argument rather than a Path (which
is just an alias for std::string). The StorePath constructor ensures
that the path is syntactically correct (i.e. it looks like
<store-dir>/<base32-hash>-<name>). Similarly, functions like
buildPaths() now take a StorePathWithOutputs, rather than abusing Path
by adding a '!<outputs>' suffix.

Note that the StorePath type is implemented in Rust. This involves
some hackery to allow Rust values to be used directly in C++, via a
helper type whose destructor calls the Rust type's drop()
function. The main issue is the dynamic nature of C++ move semantics:
after we have moved a Rust value, we should not call the drop function
on the original value. So when we move a value, we set the original
value to bitwise zero, and the destructor only calls drop() if the
value is not bitwise zero. This should be sufficient for most types.

Also lots of minor cleanups to the C++ API to make it more modern
(e.g. using std::optional and std::string_view in some places).
2019-12-10 22:06:05 +01:00

88 lines
2.9 KiB
Rust

use std::fmt;
#[derive(Debug)]
pub enum Error {
InvalidPath(crate::store::StorePath),
BadStorePath(std::path::PathBuf),
BadNarInfo,
BadBase32,
StorePathNameEmpty,
StorePathNameTooLong,
BadStorePathName,
NarSizeFieldTooBig,
BadNarString,
BadNarPadding,
BadNarVersionMagic,
MissingNarOpenTag,
MissingNarCloseTag,
MissingNarField,
BadNarField(String),
BadExecutableField,
IOError(std::io::Error),
#[cfg(unused)]
HttpError(hyper::error::Error),
Misc(String),
Foreign(CppException),
}
impl From<std::io::Error> for Error {
fn from(err: std::io::Error) -> Self {
Error::IOError(err)
}
}
#[cfg(unused)]
impl From<hyper::error::Error> for Error {
fn from(err: hyper::error::Error) -> Self {
Error::HttpError(err)
}
}
impl fmt::Display for Error {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
Error::InvalidPath(_) => write!(f, "invalid path"),
Error::BadNarInfo => write!(f, ".narinfo file is corrupt"),
Error::BadStorePath(path) => write!(f, "path '{}' is not a store path", path.display()),
Error::BadBase32 => write!(f, "invalid base32 string"),
Error::StorePathNameEmpty => write!(f, "store path name is empty"),
Error::StorePathNameTooLong => {
write!(f, "store path name is longer than 211 characters")
}
Error::BadStorePathName => write!(f, "store path name contains forbidden character"),
Error::NarSizeFieldTooBig => write!(f, "size field in NAR is too big"),
Error::BadNarString => write!(f, "NAR string is not valid UTF-8"),
Error::BadNarPadding => write!(f, "NAR padding is not zero"),
Error::BadNarVersionMagic => write!(f, "unsupported NAR version"),
Error::MissingNarOpenTag => write!(f, "NAR open tag is missing"),
Error::MissingNarCloseTag => write!(f, "NAR close tag is missing"),
Error::MissingNarField => write!(f, "expected NAR field is missing"),
Error::BadNarField(s) => write!(f, "unrecognized NAR field '{}'", s),
Error::BadExecutableField => write!(f, "bad 'executable' field in NAR"),
Error::IOError(err) => write!(f, "I/O error: {}", err),
#[cfg(unused)]
Error::HttpError(err) => write!(f, "HTTP error: {}", err),
Error::Foreign(_) => write!(f, "<C++ exception>"), // FIXME
Error::Misc(s) => write!(f, "{}", s),
}
}
}
impl From<Error> for CppException {
fn from(err: Error) -> Self {
match err {
Error::Foreign(ex) => ex,
_ => unsafe { make_error(&err.to_string()) },
}
}
}
#[repr(C)]
#[derive(Debug)]
pub struct CppException(*const libc::c_void); // == std::exception_ptr*
extern "C" {
#[allow(improper_ctypes)] // YOLO
fn make_error(s: &str) -> CppException;
}