rocket::mtls::oid::asn1_rs::nom::lib::std::fmt

Trait Debug

1.0.0 · Source

pub trait Debug {
    // Required method
    fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>;
}

Available on crate feature mtls only.

Expand description

? formatting.

Debug should format the output in a programmer-facing, debugging context.

Generally speaking, you should just derive a Debug implementation.

When used with the alternate format specifier #?, the output is pretty-printed.

For more information on formatters, see the module-level documentation.

This trait can be used with #[derive] if all fields implement Debug. When derived for structs, it will use the name of the struct, then {, then a comma-separated list of each field’s name and Debug value, then }. For enums, it will use the name of the variant and, if applicable, (, then the Debug values of the fields, then ).

§Stability

Derived Debug formats are not stable, and so may change with future Rust versions. Additionally, Debug implementations of types provided by the standard library (std, core, alloc, etc.) are not stable, and may also change with future Rust versions.

§Examples

Deriving an implementation:

#[derive(Debug)]
struct Point {
    x: i32,
    y: i32,
}

let origin = Point { x: 0, y: 0 };

assert_eq!(
    format!("The origin is: {origin:?}"),
    "The origin is: Point { x: 0, y: 0 }",
);

Manually implementing:

use std::fmt;

struct Point {
    x: i32,
    y: i32,
}

impl fmt::Debug for Point {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_struct("Point")
         .field("x", &self.x)
         .field("y", &self.y)
         .finish()
    }
}

let origin = Point { x: 0, y: 0 };

assert_eq!(
    format!("The origin is: {origin:?}"),
    "The origin is: Point { x: 0, y: 0 }",
);

There are a number of helper methods on the Formatter struct to help you with manual implementations, such as debug_struct.

Types that do not wish to use the standard suite of debug representations provided by the Formatter trait (debug_struct, debug_tuple, debug_list, debug_set, debug_map) can do something totally custom by manually writing an arbitrary representation to the Formatter.

impl fmt::Debug for Point {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "Point [{} {}]", self.x, self.y)
    }
}

Debug implementations using either derive or the debug builder API on Formatter support pretty-printing using the alternate flag: {:#?}.

Pretty-printing with #?:

#[derive(Debug)]
struct Point {
    x: i32,
    y: i32,
}

let origin = Point { x: 0, y: 0 };

let expected = "The origin is: Point {
    x: 0,
    y: 0,
}";
assert_eq!(format!("The origin is: {origin:#?}"), expected);

Required Methods§

1.0.0 · Source

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

Formats the value using the given formatter.

§Errors

This function should return Err if, and only if, the provided Formatter returns Err. String formatting is considered an infallible operation; this function only returns a Result because writing to the underlying stream might fail and it must provide a way to propagate the fact that an error has occurred back up the stack.

§Examples

use std::fmt;

struct Position {
    longitude: f32,
    latitude: f32,
}

impl fmt::Debug for Position {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_tuple("")
         .field(&self.longitude)
         .field(&self.latitude)
         .finish()
    }
}

let position = Position { longitude: 1.987, latitude: 2.983 };
assert_eq!(format!("{position:?}"), "(1.987, 2.983)");

assert_eq!(format!("{position:#?}"), "(
    1.987,
    2.983,
)");

Trait DebugCopy item path

§Stability

§Examples

Required Methods§

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

§Errors

§Examples

Implementors§

impl Debug for CliColors

impl Debug for rocket::error::ErrorKind

impl Debug for Entity

impl Debug for rocket::http::Method

impl Debug for SameSite

impl Debug for StatusClass

impl Debug for PathError

impl Debug for rocket::http::uri::fmt::Path

impl Debug for rocket::http::uri::fmt::Query

impl Debug for rocket::listener::Endpoint

impl Debug for rocket::listener::Error

impl Debug for rocket::serde::json::Value

impl Debug for rocket::serde::msgpack::Error

impl Debug for rocket::serde::uuid::Variant

impl Debug for rocket::serde::uuid::Version

impl Debug for Allow

impl Debug for Feature

impl Debug for Sig

impl Debug for rocket::tls::CipherSuite

impl Debug for rocket::tls::Error

impl Debug for TraceFormat

impl Debug for rocket::mtls::Error

impl Debug for ASN1TimeZone

impl Debug for rocket::mtls::x509::der_parser::asn1_rs::Class

impl Debug for DerConstraint

impl Debug for rocket::mtls::x509::der_parser::asn1_rs::Error

impl Debug for Explicit

impl Debug for Implicit

impl Debug for Length

impl Debug for rocket::mtls::x509::der_parser::asn1_rs::Needed

impl Debug for OidParseError

impl Debug for Real

impl Debug for SerializeError

impl Debug for rocket::mtls::x509::der_parser::asn1_rs::nom::CompareResult

impl Debug for rocket::mtls::x509::der_parser::asn1_rs::nom::error::ErrorKind

impl Debug for VerboseErrorKind

impl Debug for rocket::mtls::x509::der_parser::asn1_rs::nom::lib::std::cmp::Ordering

impl Debug for rocket::mtls::x509::der_parser::asn1_rs::nom::lib::std::collections::TryReserveErrorKind

impl Debug for Infallible

impl Debug for rocket::mtls::x509::der_parser::asn1_rs::nom::lib::std::fmt::Alignment

impl Debug for rocket::mtls::x509::der_parser::asn1_rs::nom::lib::std::str::pattern::SearchStep

impl Debug for rocket::mtls::x509::der_parser::asn1_rs::nom::number::Endianness

impl Debug for PrettyPrinterFlag

impl Debug for Sign

impl Debug for PEMError

impl Debug for X509Error

impl Debug for AsciiChar

impl Debug for c_void

impl Debug for core::net::ip_addr::IpAddr

impl Debug for Ipv6MulticastScope

impl Debug for core::net::socket_addr::SocketAddr

impl Debug for FpCategory

impl Debug for IntErrorKind

impl Debug for core::sync::atomic::Ordering

impl Debug for BacktraceStatus

impl Debug for VarError

impl Debug for std::io::SeekFrom

impl Debug for std::io::error::ErrorKind

impl Debug for std::net::Shutdown

impl Debug for AncillaryError

impl Debug for BacktraceStyle

impl Debug for RecvTimeoutError

impl Debug for std::sync::mpsc::TryRecvError

impl Debug for _Unwind_Reason_Code

impl Debug for allocator_api2::stable::raw_vec::TryReserveErrorKind

impl Debug for TlsProtocolId

impl Debug for aws_lc_rs::cipher::AlgorithmId

impl Debug for DecryptionContext

impl Debug for EncryptionContext

impl Debug for OperatingMode

impl Debug for aws_lc_rs::kem::AlgorithmId

impl Debug for BlockCipherId

Trait Debug