Enum Outcome

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

An enum representing success (Success), failure (Failure), or forwarding (Forward).

See the top level documentation for detailed information.

Variants

Success(S)

Contains the success value.

Failure(E)

Contains the failure 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> = Failure("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_failure(&self) -> bool

Return true if this Outcome is a Failure.

Examples

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

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

let x: Outcome<i32, &str, usize> = Forward(25);
assert_eq!(x.is_failure(), 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> = Failure("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> = Failure("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 Failure if this is a Failure, 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> = Failure("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> = Failure("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>

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> = Failure("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>

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> = Failure("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> = Failure("Hi! I'm an error.");
assert_eq!(x.as_ref(), Failure(&"Hi! I'm an error."));

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

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

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

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

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>

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.

Examples

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

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

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

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

Examples

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

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

assert_eq!(mapped, Failure(10));

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

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.

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 => Failure("10")
});

assert_eq!(mapped, Forward(20));

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);

impl<'r> Outcome<Response<'r>, Status, Data>

pub fn from<T: Responder<'r>>(req: &Request<'_>, responder: T) -> 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 Failure is returned with the status code.

Example

use rocket::{Request, Data};
use rocket::handler::Outcome;

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

pub fn from_or_forward<T>( req: &Request<'_>, data: Data, responder: T, ) -> Outcome<'r>

where T: Responder<'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 Forward is returned.

Example

use rocket::{Request, Data};
use rocket::handler::Outcome;

fn str_responder(req: &Request, data: Data) -> Outcome<'static> {
    Outcome::from_or_forward(req, data, "Hello, world!")
}

pub fn failure(code: Status) -> Outcome<'static>

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

This method exists to be used during manual routing where rocket::handler::Outcome is imported instead of rocket::Outcome.

Example

use rocket::{Request, Data};
use rocket::handler::Outcome;
use rocket::http::Status;

fn bad_req_route(_: &Request, _: Data) -> Outcome<'static> {
    Outcome::failure(Status::BadRequest)
}

pub fn forward(data: Data) -> Outcome<'static>

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

This method exists to be used during manual routing where rocket::handler::Outcome is imported instead of rocket::Outcome.

Example

use rocket::{Request, Data};
use rocket::handler::Outcome;

fn always_forward(_: &Request, data: Data) -> Outcome<'static> {
    Outcome::forward(data)
}

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

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

Formats the value using the given formatter.

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

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

Formats the value using the given formatter.

impl<S, X, E: From<X>, Y, F: From<Y>> FromResidual<Outcome<!, X, Y>> for Outcome<S, E, F>

fn from_residual(r: Outcome<!, X, Y>) -> Self

🔬This is a nightly-only experimental API. (try_trait_v2)

Constructs the type from a compatible Residual type.

impl<Y, S, E: From<Y>, F> FromResidual<Result<Infallible, Y>> for Outcome<S, E, F>

fn from_residual(r: Result<Infallible, Y>) -> Self

🔬This is a nightly-only experimental API. (try_trait_v2)

Constructs the type from a compatible Residual type.

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<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<A, B, C> Try for Outcome<A, B, C>

type Output = A

🔬This is a nightly-only experimental API. (try_trait_v2)

The type of the value produced by ? when not short-circuiting.

type Residual = Outcome<!, B, C>

🔬This is a nightly-only experimental API. (try_trait_v2)

The type of the value passed to FromResidual::from_residual as part of ? when short-circuiting.

fn from_output(x: Self::Output) -> Self

🔬This is a nightly-only experimental API. (try_trait_v2)

Constructs the type from its Output type.

fn branch(self) -> ControlFlow<Self::Residual, Self::Output>

🔬This is a nightly-only experimental API. (try_trait_v2)

Used in ? to decide whether the operator should produce a value (because this returned ControlFlow::Continue) or propagate a value back to the caller (because this returned ControlFlow::Break).

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>