Enum Outcome

pub enum Outcome<S, E, F> {
    Success(S),
    Error(E),
    Forward(F),
}

An enum representing success (Success), error (Error), or forwarding (Forward).

See the top level documentation for detailed information.

Variants

Success(S)

Contains the success value.

Error(E)

Contains the error error value.

Forward(F)

Contains the value to forward on.

Implementations

impl<S, E, F> Outcome<S, E, F>

pub fn unwrap(self) -> S

Unwraps the Outcome, yielding the contents of a Success.

Panics

Panics if the value is not Success.

Examples

let x: Outcome<i32, &str, usize> = Success(10);
assert_eq!(x.unwrap(), 10);

pub fn expect(self, message: &str) -> S

Unwraps the Outcome, yielding the contents of a Success.

Panics

If the value is not Success, panics with the given message.

Examples

let x: Outcome<i32, &str, usize> = Success(10);
assert_eq!(x.expect("success value"), 10);

pub fn is_success(&self) -> bool

Return true if this Outcome is a Success.

Examples

let x: Outcome<i32, &str, usize> = Success(10);
assert_eq!(x.is_success(), true);

let x: Outcome<i32, &str, usize> = Error("Hi! I'm an error.");
assert_eq!(x.is_success(), false);

let x: Outcome<i32, &str, usize> = Forward(25);
assert_eq!(x.is_success(), false);

pub fn is_error(&self) -> bool

Return true if this Outcome is an Error.

Examples

let x: Outcome<i32, &str, usize> = Success(10);
assert_eq!(x.is_error(), false);

let x: Outcome<i32, &str, usize> = Error("Hi! I'm an error.");
assert_eq!(x.is_error(), true);

let x: Outcome<i32, &str, usize> = Forward(25);
assert_eq!(x.is_error(), false);

pub fn is_forward(&self) -> bool

Return true if this Outcome is a Forward.

Examples

let x: Outcome<i32, &str, usize> = Success(10);
assert_eq!(x.is_forward(), false);

let x: Outcome<i32, &str, usize> = Error("Hi! I'm an error.");
assert_eq!(x.is_forward(), false);

let x: Outcome<i32, &str, usize> = Forward(25);
assert_eq!(x.is_forward(), true);

pub fn succeeded(self) -> Option<S>

Converts from Outcome<S, E, F> to Option<S>.

Returns the Some of the Success if this is a Success, otherwise returns None. self is consumed, and all other values are discarded.

let x: Outcome<i32, &str, usize> = Success(10);
assert_eq!(x.succeeded(), Some(10));

let x: Outcome<i32, &str, usize> = Error("Hi! I'm an error.");
assert_eq!(x.succeeded(), None);

let x: Outcome<i32, &str, usize> = Forward(25);
assert_eq!(x.succeeded(), None);

pub fn failed(self) -> Option<E>

Converts from Outcome<S, E, F> to Option<E>.

Returns the Some of the Error if this is an Error, otherwise returns None. self is consumed, and all other values are discarded.

let x: Outcome<i32, &str, usize> = Success(10);
assert_eq!(x.failed(), None);

let x: Outcome<i32, &str, usize> = Error("Hi! I'm an error.");
assert_eq!(x.failed(), Some("Hi! I'm an error."));

let x: Outcome<i32, &str, usize> = Forward(25);
assert_eq!(x.failed(), None);

pub fn forwarded(self) -> Option<F>

Converts from Outcome<S, E, F> to Option<F>.

Returns the Some of the Forward if this is a Forward, otherwise returns None. self is consumed, and all other values are discarded.

let x: Outcome<i32, &str, usize> = Success(10);
assert_eq!(x.forwarded(), None);

let x: Outcome<i32, &str, usize> = Error("Hi! I'm an error.");
assert_eq!(x.forwarded(), None);

let x: Outcome<i32, &str, usize> = Forward(25);
assert_eq!(x.forwarded(), Some(25));

pub fn success_or<T>(self, value: T) -> Result<S, T>

Returns a Success value as Ok() or value in Err. Converts from Outcome<S, E, F> to Result<S, T> for a given T.

Returns Ok with the Success value if this is a Success, otherwise returns an Err with the provided value. self is consumed, and all other values are discarded.

let x: Outcome<i32, &str, usize> = Success(10);
assert_eq!(x.success_or(false), Ok(10));

let x: Outcome<i32, &str, usize> = Error("Hi! I'm an error.");
assert_eq!(x.success_or(false), Err(false));

let x: Outcome<i32, &str, usize> = Forward(25);
assert_eq!(x.success_or("whoops"), Err("whoops"));

pub fn success_or_else<T, V: FnOnce() -> T>(self, f: V) -> Result<S, T>

Returns a Success value as Ok() or f() in Err. Converts from Outcome<S, E, F> to Result<S, T> for a given T produced from a supplied function or closure.

Returns Ok with the Success value if this is a Success, otherwise returns an Err with the result of calling f. self is consumed, and all other values are discarded.

let x: Outcome<i32, &str, usize> = Success(10);
assert_eq!(x.success_or_else(|| false), Ok(10));

let x: Outcome<i32, &str, usize> = Error("Hi! I'm an error.");
assert_eq!(x.success_or_else(|| false), Err(false));

let x: Outcome<i32, &str, usize> = Forward(25);
assert_eq!(x.success_or_else(|| "whoops"), Err("whoops"));

pub fn as_ref(&self) -> Outcome<&S, &E, &F>

Converts from Outcome<S, E, F> to Outcome<&S, &E, &F>.

let x: Outcome<i32, &str, usize> = Success(10);
assert_eq!(x.as_ref(), Success(&10));

let x: Outcome<i32, &str, usize> = Error("Hi! I'm an error.");
assert_eq!(x.as_ref(), Error(&"Hi! I'm an error."));

pub fn as_mut(&mut self) -> Outcome<&mut S, &mut E, &mut F>

Converts from Outcome<S, E, F> to Outcome<&mut S, &mut E, &mut F>.

let mut x: Outcome<i32, &str, usize> = Success(10);
if let Success(val) = x.as_mut() {
    *val = 20;
}

assert_eq!(x.unwrap(), 20);

pub fn map<T, M: FnOnce(S) -> T>(self, f: M) -> Outcome<T, E, F>

Maps the Success value using f. Maps an Outcome<S, E, F> to an Outcome<T, E, F> by applying the function f to the value of type S in self if self is an Outcome::Success.

let x: Outcome<i32, &str, usize> = Success(10);

let mapped = x.map(|v| if v == 10 { "10" } else { "not 10" });
assert_eq!(mapped, Success("10"));

pub fn map_error<T, M: FnOnce(E) -> T>(self, f: M) -> Outcome<S, T, F>

Maps the Error value using f. Maps an Outcome<S, E, F> to an Outcome<S, T, F> by applying the function f to the value of type E in self if self is an Outcome::Error.

let x: Outcome<i32, &str, usize> = Error("hi");

let mapped = x.map_error(|v| if v == "hi" { 10 } else { 0 });
assert_eq!(mapped, Error(10));

pub fn map_forward<T, M: FnOnce(F) -> T>(self, f: M) -> Outcome<S, E, T>

Maps the Forward value using f. Maps an Outcome<S, E, F> to an Outcome<S, E, T> by applying the function f to the value of type F in self if self is an Outcome::Forward.

let x: Outcome<i32, &str, usize> = Forward(5);

let mapped = x.map_forward(|v| if v == 5 { "a" } else { "b" });
assert_eq!(mapped, Forward("a"));

pub fn and_then<T, M: FnOnce(S) -> Outcome<T, E, F>>( self, f: M, ) -> Outcome<T, E, F>

Converts from Outcome<S, E, F> to Outcome<T, E, F> using f to map Success(S) to Success(T).

If self is not Success, self is returned.

Examples

let x: Outcome<i32, &str, bool> = Success(10);

let mapped = x.and_then(|v| match v {
   10 => Success("10"),
   1 => Forward(false),
   _ => Error("30")
});

assert_eq!(mapped, Success("10"));

pub fn error_then<T, M: FnOnce(E) -> Outcome<S, T, F>>( self, f: M, ) -> Outcome<S, T, F>

Converts from Outcome<S, E, F> to Outcome<S, T, F> using f to map Error(E) to Error(T).

If self is not Error, self is returned.

Examples

let x: Outcome<i32, &str, bool> = Error("hi");

let mapped = x.error_then(|v| match v {
   "hi" => Error(10),
   "test" => Forward(false),
   _ => Success(10)
});

assert_eq!(mapped, Error(10));

pub fn forward_then<T, M: FnOnce(F) -> Outcome<S, E, T>>( self, f: M, ) -> Outcome<S, E, T>

Converts from Outcome<S, E, F> to Outcome<S, E, T> using f to map Forward(F) to Forward(T).

If self is not Forward, self is returned.

Examples

let x: Outcome<i32, &str, Option<bool>> = Forward(Some(false));

let mapped = x.forward_then(|v| match v {
   Some(true) => Success(10),
   Some(false) => Forward(20),
   None => Error("10")
});

assert_eq!(mapped, Forward(20));

pub fn ok_map_forward<M>(self, f: M) -> Result<S, E>

where M: FnOnce(F) -> Result<S, E>,

Converts Outcome<S, E, F> to Result<S, E> by identity mapping Success(S) and Error(E) to Result<T, E> and mapping Forward(F) to Result<T, E> using f.

let x: Outcome<i32, &str, usize> = Success(10);
assert_eq!(x.ok_map_forward(|x| Ok(x as i32 + 1)), Ok(10));

let x: Outcome<i32, &str, usize> = Error("hello");
assert_eq!(x.ok_map_forward(|x| Ok(x as i32 + 1)), Err("hello"));

let x: Outcome<i32, &str, usize> = Forward(0);
assert_eq!(x.ok_map_forward(|x| Ok(x as i32 + 1)), Ok(1));

pub fn ok_map_error<M>(self, f: M) -> Result<S, F>

where M: FnOnce(E) -> Result<S, F>,

Converts Outcome<S, E, F> to Result<S, E> by identity mapping Success(S) and Forward(F) to Result<T, F> and mapping Error(E) to Result<T, F> using f.

let x: Outcome<i32, &str, usize> = Success(10);
assert_eq!(x.ok_map_error(|s| Ok(123)), Ok(10));

let x: Outcome<i32, &str, usize> = Error("hello");
assert_eq!(x.ok_map_error(|s| Ok(123)), Ok(123));

let x: Outcome<i32, &str, usize> = Forward(0);
assert_eq!(x.ok_map_error(|s| Ok(123)), Err(0));

impl<'a, S: Send + 'a, E: Send + 'a, F: Send + 'a> Outcome<S, E, F>

pub fn pin(self) -> BoxFuture<'a, Self>

Pins a future that resolves to self, returning a BoxFuture that resolves to self.

impl<'r, 'o: 'r> Outcome<Response<'o>, Status, (Data<'o>, Status)>

pub fn from<R: Responder<'r, 'o>>( req: &'r Request<'_>, responder: R, ) -> Outcome<'r>

Return the Outcome of response to req from responder.

If the responder returns Ok, an outcome of Success is returned with the response. If the responder returns Err, an outcome of Error is returned with the status code.

Example

use rocket::{Request, Data, route};

fn str_responder<'r>(req: &'r Request, _: Data<'r>) -> route::Outcome<'r> {
    route::Outcome::from(req, "Hello, world!")
}

pub fn try_from<R, E>(req: &'r Request<'_>, result: Result<R, E>) -> Outcome<'r>

where R: Responder<'r, 'o>, E: Debug,

Return the Outcome of response to req from responder.

If the responder returns Ok, an outcome of Success is returned with the response. If the responder returns Err, an outcome of Error is returned with the status code.

Example

use rocket::{Request, Data, route};

fn str_responder<'r>(req: &'r Request, _: Data<'r>) -> route::Outcome<'r> {
    route::Outcome::from(req, "Hello, world!")
}

pub fn error(code: Status) -> Outcome<'r>

Return an Outcome of Error with the status code code. This is equivalent to Outcome::Error(code).

This method exists to be used during manual routing.

Example

use rocket::{Request, Data, route};
use rocket::http::Status;

fn bad_req_route<'r>(_: &'r Request, _: Data<'r>) -> route::Outcome<'r> {
    route::Outcome::error(Status::BadRequest)
}

pub fn forward(data: Data<'r>, status: Status) -> Outcome<'r>

Return an Outcome of Forward with the data data and status status. This is equivalent to Outcome::Forward((data, status)).

This method exists to be used during manual routing.

Example

use rocket::{Request, Data, route};
use rocket::http::Status;

fn always_forward<'r>(_: &'r Request, data: Data<'r>) -> route::Outcome<'r> {
    route::Outcome::forward(data, Status::InternalServerError)
}

Trait Implementations

impl<S: Clone, E: Clone, F: Clone> Clone for Outcome<S, E, F>

fn clone(&self) -> Outcome<S, E, F>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<S: Debug, E: Debug, F: Debug> Debug for Outcome<S, E, F>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<S: Hash, E: Hash, F: Hash> Hash for Outcome<S, E, F>

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<'r, 'o: 'r> IntoOutcome<Outcome<Response<'r>, Status, (Data<'r>, Status)>> for Result<'o>

type Error = ()

The type to use when returning an Outcome::Error.

type Forward = (Data<'r>, Status)

The type to use when returning an Outcome::Forward.

fn or_error(self, _: ()) -> Outcome<'r>

Converts self into an Outcome. If self represents a success, an Outcome::Success is returned. Otherwise, an Outcome::Error is returned with error as the inner value.

fn or_forward(self, (data, forward): (Data<'r>, Status)) -> Outcome<'r>

Converts self into an Outcome. If self represents a success, an Outcome::Success is returned. Otherwise, an Outcome::Forward is returned with forward as the inner value.

impl<S, E> IntoOutcome<Outcome<S, (Status, E), Status>> for Result<S, E>

type Error = Status

The type to use when returning an Outcome::Error.

type Forward = Status

The type to use when returning an Outcome::Forward.

fn or_error(self, error: Status) -> Outcome<S, E>

Converts self into an Outcome. If self represents a success, an Outcome::Success is returned. Otherwise, an Outcome::Error is returned with error as the inner value.

fn or_forward(self, status: Status) -> Outcome<S, E>

Converts self into an Outcome. If self represents a success, an Outcome::Success is returned. Otherwise, an Outcome::Forward is returned with forward as the inner value.

impl<S, E, F> IntoOutcome<Outcome<S, E, F>> for Option<S>

type Error = E

The type to use when returning an Outcome::Error.

type Forward = F

The type to use when returning an Outcome::Forward.

fn or_error(self, error: E) -> Outcome<S, E, F>

Converts self into an Outcome. If self represents a success, an Outcome::Success is returned. Otherwise, an Outcome::Error is returned with error as the inner value.

fn or_forward(self, forward: F) -> Outcome<S, E, F>

Converts self into an Outcome. If self represents a success, an Outcome::Success is returned. Otherwise, an Outcome::Forward is returned with forward as the inner value.

impl<'r, T: FromData<'r>> IntoOutcome<Outcome<T, (Status, <T as FromData<'r>>::Error), (Data<'r>, Status)>> for Result<T, T::Error>

type Error = Status

The type to use when returning an Outcome::Error.

type Forward = (Data<'r>, Status)

The type to use when returning an Outcome::Forward.

fn or_error(self, error: Status) -> Outcome<'r, T>

Converts self into an Outcome. If self represents a success, an Outcome::Success is returned. Otherwise, an Outcome::Error is returned with error as the inner value.

fn or_forward(self, (data, forward): (Data<'r>, Status)) -> Outcome<'r, T>

Converts self into an Outcome. If self represents a success, an Outcome::Success is returned. Otherwise, an Outcome::Forward is returned with forward as the inner value.

impl<S: Ord, E: Ord, F: Ord> Ord for Outcome<S, E, F>

fn cmp(&self, other: &Outcome<S, E, F>) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl<S: PartialEq, E: PartialEq, F: PartialEq> PartialEq for Outcome<S, E, F>

fn eq(&self, other: &Outcome<S, E, F>) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<S: PartialOrd, E: PartialOrd, F: PartialOrd> PartialOrd for Outcome<S, E, F>

fn partial_cmp(&self, other: &Outcome<S, E, F>) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl<S: Copy, E: Copy, F: Copy> Copy for Outcome<S, E, F>

impl<S: Eq, E: Eq, F: Eq> Eq for Outcome<S, E, F>

impl<S, E, F> StructuralPartialEq for Outcome<S, E, F>