214 lines
8 KiB
Rust
214 lines
8 KiB
Rust
use std::fmt;
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use std::sync::Arc;
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use std::result::Result as StdResult;
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use failure;
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/// Error type returned by `rlua` methods.
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#[derive(Debug, Clone)]
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pub enum Error {
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/// Syntax error while parsing Lua source code.
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SyntaxError {
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/// The error message as returned by Lua.
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message: String,
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/// `true` if the error can likely be fixed by appending more input to the source code.
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///
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/// This is useful for implementing REPLs as they can query the user for more input if this
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/// is set.
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incomplete_input: bool,
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},
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/// Lua runtime error, aka `LUA_ERRRUN`.
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///
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/// The Lua VM returns this error when a builtin operation is performed on incompatible types.
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/// Among other things, this includes invoking operators on wrong types (such as calling or
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/// indexing a `nil` value).
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RuntimeError(String),
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/// Lua garbage collector error, aka `LUA_ERRGCMM`.
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///
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/// The Lua VM returns this error when there is an error running a `__gc` metamethod.
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GarbageCollectorError(String),
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/// A callback has triggered Lua code that has called the same callback again.
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///
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/// This is an error because `rlua` callbacks are FnMut and thus can only be mutably borrowed
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/// once.
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RecursiveCallbackError,
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/// Lua code has accessed a [`UserData`] value that was already garbage collected
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///
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/// This can happen when a [`UserData`] has a custom `__gc` metamethod, this method resurrects
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/// the [`UserData`], and then the [`UserData`] is subsequently accessed.
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/// [`UserData`]: trait.UserData.html
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ExpiredUserData,
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/// A Rust value could not be converted to a Lua value.
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ToLuaConversionError {
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/// Name of the Rust type that could not be converted.
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from: &'static str,
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/// Name of the Lua type that could not be created.
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to: &'static str,
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/// A message indicating why the conversion failed in more detail.
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message: Option<String>,
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},
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/// A Lua value could not be converted to the expected Rust type.
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FromLuaConversionError {
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/// Name of the Lua type that could not be converted.
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from: &'static str,
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/// Name of the Rust type that could not be created.
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to: &'static str,
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/// A string containing more detailed error information.
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message: Option<String>,
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},
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/// [`Thread::resume`] was called on an inactive coroutine.
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///
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/// A coroutine is inactive if its main function has returned or if an error has occured inside
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/// the coroutine.
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///
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/// [`Thread::status`] can be used to check if the coroutine can be resumed without causing this
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/// error.
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///
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/// [`Thread::resume`]: struct.Thread.html#method.resume
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/// [`Thread::status`]: struct.Thread.html#method.status
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CoroutineInactive,
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/// An [`AnyUserData`] is not the expected type in a borrow.
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///
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/// This error can only happen when manually using [`AnyUserData`], or when implementing
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/// metamethods for binary operators. Refer to the documentation of [`UserDataMethods`] for
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/// details.
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///
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/// [`AnyUserData`]: struct.AnyUserData.html
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/// [`UserDataMethods`]: struct.UserDataMethods.html
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UserDataTypeMismatch,
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/// An [`AnyUserData`] immutable borrow failed because it is already borrowed mutably.
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///
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/// This error can occur when a method on a [`UserData`] type calls back into Lua, which then
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/// tries to call a method on the same [`UserData`] type. Consider restructuring your API to
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/// prevent these errors.
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///
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/// [`AnyUserData`]: struct.AnyUserData.html
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/// [`UserData`]: trait.UserData.html
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UserDataBorrowError,
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/// An [`AnyUserData`] mutable borrow failed because it is already borrowed.
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///
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/// This error can occur when a method on a [`UserData`] type calls back into Lua, which then
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/// tries to call a method on the same [`UserData`] type. Consider restructuring your API to
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/// prevent these errors.
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///
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/// [`AnyUserData`]: struct.AnyUserData.html
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/// [`UserData`]: trait.UserData.html
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UserDataBorrowMutError,
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/// A Rust callback returned `Err`, raising the contained `Error` as a Lua error.
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CallbackError {
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/// Lua call stack backtrace.
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traceback: String,
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/// Original error returned by the Rust code.
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cause: Arc<Error>,
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},
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/// A custom error.
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///
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/// This can be used for returning user-defined errors from callbacks.
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///
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/// Returning `Err(ExternalError(...))` from a Rust callback will raise the error as a Lua
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/// error. The Rust code that originally invoked the Lua code then receives a `CallbackError`,
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/// from which the original error (and a stack traceback) can be recovered.
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ExternalError(Arc<failure::Error>),
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}
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/// A specialized `Result` type used by `rlua`'s API.
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pub type Result<T> = StdResult<T, Error>;
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impl fmt::Display for Error {
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fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
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match *self {
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Error::SyntaxError { ref message, .. } => write!(fmt, "syntax error: {}", message),
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Error::RuntimeError(ref msg) => write!(fmt, "runtime error: {}", msg),
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Error::GarbageCollectorError(ref msg) => {
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write!(fmt, "garbage collector error: {}", msg)
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}
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Error::RecursiveCallbackError => write!(fmt, "callback called recursively"),
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Error::ExpiredUserData => write!(
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fmt,
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"access of userdata which has already been garbage collected"
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),
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Error::ToLuaConversionError {
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from,
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to,
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ref message,
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} => {
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write!(fmt, "error converting {} to Lua {}", from, to)?;
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match *message {
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None => Ok(()),
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Some(ref message) => write!(fmt, " ({})", message),
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}
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}
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Error::FromLuaConversionError {
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from,
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to,
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ref message,
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} => {
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write!(fmt, "error converting Lua {} to {}", from, to)?;
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match *message {
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None => Ok(()),
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Some(ref message) => write!(fmt, " ({})", message),
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}
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}
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Error::CoroutineInactive => write!(fmt, "cannot resume inactive coroutine"),
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Error::UserDataTypeMismatch => write!(fmt, "userdata is not expected type"),
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Error::UserDataBorrowError => write!(fmt, "userdata already mutably borrowed"),
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Error::UserDataBorrowMutError => write!(fmt, "userdata already borrowed"),
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Error::CallbackError { ref traceback, .. } => {
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write!(fmt, "callback error: {}", traceback)
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}
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Error::ExternalError(ref err) => err.fmt(fmt),
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}
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}
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}
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impl failure::Fail for Error {
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fn cause(&self) -> Option<&failure::Fail> {
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match *self {
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Error::CallbackError { ref cause, .. } => Some(cause.as_ref()),
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// Error::cause simply returns the contained Fail type, which we are already displaying
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// and returning the backtrace for, no need to repeat it as the cause.
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Error::ExternalError(ref err) => err.cause().cause(),
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_ => None,
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}
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}
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fn backtrace(&self) -> Option<&failure::Backtrace> {
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match *self {
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Error::ExternalError(ref err) => Some(err.backtrace()),
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_ => None,
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}
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}
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}
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impl Error {
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pub fn external<T: Into<failure::Error>>(err: T) -> Error {
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Error::ExternalError(Arc::new(err.into()))
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}
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}
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pub trait ExternalError {
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fn to_lua_err(self) -> Error;
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}
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impl<E> ExternalError for E
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where
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E: Into<failure::Error>,
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{
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fn to_lua_err(self) -> Error {
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Error::external(self)
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}
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}
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pub trait ExternalResult<T> {
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fn to_lua_err(self) -> Result<T>;
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}
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impl<T, E> ExternalResult<T> for StdResult<T, E>
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where
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E: ExternalError,
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{
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fn to_lua_err(self) -> Result<T> {
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self.map_err(|e| e.to_lua_err())
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}
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}
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