98 lines
3.8 KiB
Rust
98 lines
3.8 KiB
Rust
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use nix;
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use std::error;
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use std::fmt;
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/// This module implements a simple error type to match the errors that can be thrown from the C
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/// functions as well as some extra errors resulting from internal validations.
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///
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/// As this crate exposes an opinionated API to the POSIX queues certain errors have been
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/// ignored:
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///
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/// * ETIMEDOUT: The low-level timed functions are not exported and this error can not occur.
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/// * EAGAIN: Non-blocking queue calls are not supported.
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/// * EINVAL: Same reason as ETIMEDOUT
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/// * EMSGSIZE: The message size is immutable after queue creation and this crate checks it.
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/// * ENAMETOOLONG: This crate performs name validation
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///
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/// If an unexpected error is encountered it will be wrapped appropriately and should be reported
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/// as a bug on https://github.com/aprilabank/posix_mq.rs
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#[derive(Debug)]
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pub enum Error {
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// These errors match what is described in the man pages (from mq_overview(7) onwards).
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PermissionDenied(),
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InvalidQueueDescriptor(),
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QueueCallInterrupted(),
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QueueAlreadyExists(),
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QueueNotFound(),
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InsufficientMemory(),
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InsufficientSpace(),
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// These two are (hopefully) unlikely in modern systems
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ProcessFileDescriptorLimitReached(),
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SystemFileDescriptorLimitReached(),
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// If an unhandled / unknown / unexpected error occurs this error will be used.
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// In those cases bug reports would be welcome!
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UnknownForeignError(nix::Errno),
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// Some other unexpected / unknown error occured. This is probably an error from
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// the nix crate. Bug reports also welcome for this!
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UnknownInternalError(Option<nix::Error>),
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}
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impl error::Error for Error {
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fn description(&self) -> &str {
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use Error::*;
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match *self {
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PermissionDenied() => "permission to the specified queue was denied",
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InvalidQueueDescriptor() => "the internal queue descriptor was invalid",
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QueueCallInterrupted() => "queue method interrupted by signal",
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QueueAlreadyExists() => "the specified queue already exists",
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QueueNotFound() => "the specified queue could not be found",
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InsufficientMemory() => "insufficient memory to call queue method",
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InsufficientSpace() => "insufficient space to call queue method",
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ProcessFileDescriptorLimitReached() => "max. number of process file descriptors reached",
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SystemFileDescriptorLimitReached() => "max. number of system file descriptors reached",
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UnknownForeignError(_) => "unknown foreign error occured: please report a bug!",
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UnknownInternalError(_) => "unknown internal error occured: please report a bug!",
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}
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}
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}
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impl fmt::Display for Error {
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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// Explicitly import this to gain access to Error::description()
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use std::error::Error;
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f.write_str(self.description())
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}
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}
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/// This from implementation is used to translate errors from the lower-level
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/// C-calls into sensible Rust errors.
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impl From<nix::Error> for Error {
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fn from(e: nix::Error) -> Self {
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match e {
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nix::Error::Sys(e) => match_errno(e),
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_ => Error::UnknownInternalError(Some(e)),
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}
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}
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}
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fn match_errno(err: nix::Errno) -> Error {
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use nix::errno::*;
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match err {
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EACCES => Error::PermissionDenied(),
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EBADF => Error::InvalidQueueDescriptor(),
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EINTR => Error::QueueCallInterrupted(),
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EEXIST => Error::QueueAlreadyExists(),
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EMFILE => Error::ProcessFileDescriptorLimitReached(),
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ENFILE => Error::SystemFileDescriptorLimitReached(),
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ENOENT => Error::QueueNotFound(),
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ENOMEM => Error::InsufficientMemory(),
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ENOSPC => Error::InsufficientSpace(),
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_ => Error::UnknownForeignError(err),
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}
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}
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