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/// Create a shim error type between [`human_errors::Error`] and other error types.
///
/// # Examples
/// ```
/// human_errors::error_shim!(MyError);
///
/// impl From<std::num::ParseIntError> for MyError {
/// fn from(err: std::num::ParseIntError) -> Self {
/// user_with_internal(
/// "We could not parse the number you provided.",
/// "Make sure that you're providing a number in the form 12345 or -12345.",
/// err,
/// )
/// }
/// }
/// ```
#[macro_export]
macro_rules! error_shim {
($type:ident) => {
/// A basic error triggered by something the user has done.
///
/// Constructs a new [Error] describing a failure which was the result of an
/// action that the user has taken. This error includes a description of what
/// occurred, as well as some advice for the user to try to mitigate the problem.
///
/// # Examples
/// ```
/// use human_errors;
///
/// human_errors::user(
/// "We could not open the config file you provided.",
/// "Make sure that the file exists and is readable by the application.",
/// );
/// ```
#[allow(dead_code)]
pub fn user(description: &str, advice: &str) -> $type {
$crate::user(description, advice).into()
}
/// An error triggered by something the user has done, with a deeper cause.
///
/// Constructs a new [Error] describing a failure which was the result of an
/// action that the user has taken. This error includes a description of what
/// occurred, as well as some advice for the user to try to mitigate the problem.
/// It also includes the details of another error which resulted in this failure,
/// as well as any advice that error may provide.
///
/// # Examples
/// ```
/// use human_errors;
///
/// human_errors::user_with_cause(
/// "We could not open the config file you provided.",
/// "Make sure that you've specified a valid config file with the --config option.",
/// human_errors::user(
/// "We could not find a file at /home/user/.config/demo.yml",
/// "Make sure that the file exists and is readable by the application."
/// )
/// );
/// ```
#[allow(dead_code)]
pub fn user_with_cause(description: &str, advice: &str, cause: $type) -> $type {
$crate::user_with_cause(description, advice, cause.into()).into()
}
/// An error triggered by something the user has done, with a deeper cause.
///
/// Constructs a new [Error] describing a failure which was the result of an
/// action that the user has taken. This error includes a description of what
/// occurred, as well as some advice for the user to try to mitigate the problem.
/// It also includes the details of another error which resulted in this failure.
///
/// **NOTE**: The internal error may be any type which may be converted into a [Box<std::error::Error>].
///
/// # Examples
/// ```
/// use human_errors;
///
/// human_errors::user_with_internal(
/// "We could not open the config file you provided.",
/// "Make sure that the file exists and is readable by the application.",
/// human_errors::detailed_message("ENOENT 2: No such file or directory")
/// );
/// ```
#[allow(dead_code)]
pub fn user_with_internal<T>(description: &str, advice: &str, internal: T) -> $type
where
T: Into<Box<dyn std::error::Error + Send + Sync>>,
{
$crate::user_with_internal(description, advice, internal).into()
}
/// An error triggered by the system rather than the user.
///
/// Constructs a new [Error] describing a failure which was the result of a failure
/// in the system, rather than a user's action. This error includes a description of what
/// occurred, as well as some advice for the user to try to mitigate the problem.
///
/// # Examples
/// ```
/// use human_errors;
///
/// human_errors::system(
/// "We could not open the config file you provided.",
/// "Make sure that the file exists and is readable by the application."
/// );
/// ```
#[allow(dead_code)]
pub fn system(description: &str, advice: &str) -> $type {
$crate::system(description, advice).into()
}
/// An error triggered by the system rather than the user, with a deeper cause.
///
/// Constructs a new [Error] describing a failure which was the result of a failure
/// in the system, rather than a user's action. This error includes a description of what
/// occurred, as well as some advice for the user to try to mitigate the problem.
/// It also includes the details of another error which resulted in this failure,
/// as well as any advice that error may provide.
///
/// # Examples
/// ```
/// use human_errors;
///
/// human_errors::system_with_cause(
/// "We could not open the config file you provided.",
/// "Make sure that you've specified a valid config file with the --config option.",
/// human_errors::system(
/// "We could not find a file at /home/user/.config/demo.yml",
/// "Make sure that the file exists and is readable by the application."
/// )
/// );
/// ```
#[allow(dead_code)]
pub fn system_with_cause(description: &str, advice: &str, cause: $type) -> $type {
$crate::system_with_cause(description, advice, cause.into()).into()
}
/// An error triggered by the system rather than the user, with a deeper cause.
///
/// Constructs a new [Error] describing a failure which was the result of a failure
/// in the system, rather than a user's action. This error includes a description of what
/// occurred, as well as some advice for the user to try to mitigate the problem.
/// It also includes the details of another error which resulted in this failure.
///
/// **NOTE**: The internal error may be any type which may be converted into a [Box<std::error::Error>].
///
/// # Examples
/// ```
/// use human_errors;
///
/// human_errors::system_with_internal(
/// "We could not open the config file you provided.",
/// "Make sure that the file exists and is readable by the application.",
/// human_errors::detailed_message("ENOENT 2: No such file or directory")
/// );
/// ```
#[allow(dead_code)]
pub fn system_with_internal<T>(description: &str, advice: &str, internal: T) -> $type
where
T: Into<Box<dyn std::error::Error + Send + Sync>>,
{
$crate::system_with_internal(description, advice, internal).into()
}
/// The fundamental error type used by this library.
///
/// An error type which encapsulates information about whether an error
/// is the result of something the user did, or a system failure outside
/// of their control. These errors include a description of what occurred,
/// advice on how to proceed and references to the causal chain which led
/// to this failure.
///
/// # Examples
/// ```
/// let err = user(
/// "We could not open the config file you provided.",
/// "Make sure that the file exists and is readable by the application.",
/// );
///
/// // Prints the error and any advice for the user.
/// println!("{}", err)
/// ```
#[derive(Debug)]
pub struct $type($crate::Error);
impl From<$crate::Error> for $type {
fn from(err: $crate::Error) -> Self {
Self(err)
}
}
impl Into<$crate::Error> for $type {
fn into(self) -> $crate::Error {
self.0
}
}
#[allow(dead_code)]
impl $type {
/// Gets the description message from this error.
///
/// Gets the description which was provided as the first argument when constructing
/// this error.
///
/// # Examples
/// ```
/// use human_errors;
///
/// let err = human_errors::user(
/// "We could not open the config file you provided.",
/// "Make sure that the file exists and is readable by the application.",
/// );
///
/// // Prints: "We could not open the config file you provided."
/// println!("{}", err.description())
/// ```
pub fn description(&self) -> String {
self.0.description()
}
/// Gets the formatted error and its advice.
///
/// Generates a string containing the description of the error and any causes,
/// as well as a list of suggestions for how a user should
/// deal with this error. The "deepest" error's advice is presented first, with
/// successively higher errors appearing lower in the list. This is done because
/// the most specific error is the one most likely to have the best advice on how
/// to resolve the problem.
///
/// # Examples
/// ```
/// use human_errors;
///
/// let err = human_errors::user_with_cause(
/// "We could not open the config file you provided.",
/// "Make sure that you've specified a valid config file with the --config option.",
/// human_errors::user(
/// "We could not find a file at /home/user/.config/demo.yml",
/// "Make sure that the file exists and is readable by the application."
/// )
/// );
///
/// // Prints a message like the following:
/// // Oh no! We could not open the config file you provided.
/// //
/// // This was caused by:
/// // We could not find a file at /home/user/.config/demo.yml
/// //
/// // To try and fix this, you can:
/// // - Make sure that the file exists and is readable by the application.
/// // - Make sure that you've specified a valid config file with the --config option.
/// println!("{}", err.message());
/// ```
pub fn message(&self) -> String {
self.0.message()
}
/// Checks if this error is a user error.
///
/// Returns `true` if this error is a [Error::UserError],
/// otherwise `false`.
///
/// # Examples
/// ```
/// use human_errors;
///
/// let err = human_errors::user(
/// "We could not open the config file you provided.",
/// "Make sure that the file exists and is readable by the application.",
/// );
///
/// // Prints "is_user?: true"
/// println!("is_user?: {}", err.is_user());
/// ```
pub fn is_user(&self) -> bool {
self.0.is_user()
}
/// Checks if this error is a system error.
///
/// Returns `true` if this error is a [Error::SystemError],
/// otherwise `false`.
///
/// # Examples
/// ```
/// use human_errors;
///
/// let err = human_errors::system(
/// "Failed to generate config file.",
/// "Please file an error report on GitHub."
/// );
///
/// // Prints "is_system?: true"
/// println!("is_system?: {}", err.is_system());
/// ```
pub fn is_system(&self) -> bool {
self.0.is_system()
}
}
impl std::error::Error for $type {
fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
self.0.source()
}
}
impl std::fmt::Display for $type {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
self.0.fmt(f)
}
}
}
}
#[cfg(test)]
mod tests {
error_shim!(MyError);
impl From<std::num::ParseIntError> for MyError {
fn from(err: std::num::ParseIntError) -> Self {
user_with_internal(
"We could not parse the number you provided.",
"Make sure that you're providing a number in the form 12345 or -12345.",
err,
)
}
}
#[test]
fn test_error_conversion() {
let err = user(
"Something exploded.",
"Don't blow it up in future."
);
assert_eq!(err.description(), "Something exploded.");
}
}