Enum Error 

#[non_exhaustive]
pub enum Error {
    NotAContainer {
        found: Vec<u8>,
        expected: Vec<u8>,
    },
    Truncated {
        what: &'static str,
        needed: u64,
        available: u64,
    },
    UnsupportedFormat {
        major: u16,
        minor: u16,
        supported_major: u16,
    },
    Reserved {
        what: &'static str,
    },
    SectionOutOfBounds {
        id: u32,
        offset: u64,
        end: u64,
        file_len: u64,
    },
    DuplicateSection {
        id: u32,
    },
    MissingRecord(Tag),
    RepeatedRecord(Tag),
    UnsupportedRecord {
        tag: Tag,
        version: u16,
    },
    DigestMismatch {
        what: String,
        expected: String,
        actual: String,
    },
    Footer(Error),
    TooLarge {
        what: &'static str,
        needed: u64,
    },
    Io {
        kind: ErrorKind,
        detail: String,
    },
}

Why a container could not be read, or could not be trusted once it was read.

Every variant carries enough to put in a log line without going back to the file. An operator who gets one of these should be able to say what is wrong with the dataset without opening a hex editor, because the alternative is that they open a hex editor.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

NotAContainer

The file does not start with the container magic.

Fields

found: Vec<u8>

The first eight bytes of the file, or fewer if the file is shorter than that.

expected: Vec<u8>

What those bytes should have been.

Truncated

The file starts correctly but ends somewhere unexpected.

Fields

what: &'static str

Which part of the file ran out.

needed: u64

How many bytes that part needed.

available: u64

How many were there.

UnsupportedFormat

The container was written by a newer major version.

Fields

major: u16

The major version in the file.

minor: u16

The minor version in the file.

supported_major: u16

The major version this build understands.

Reserved

A reserved field was not zero.

Reserved fields are the only place a future version can put a change that older readers must not ignore, so an older reader has to refuse rather than carry on.

Fields

what: &'static str

Which part of the container the field is in.

SectionOutOfBounds

A section points somewhere that is not inside the payload area.

Fields

id: u32

Which section.

offset: u64

Where it claims to start.

end: u64

Where it claims to end, saturated at u64::MAX.

file_len: u64

How long the file actually is.

DuplicateSection

Two sections claim the same identifier.

Fields

id: u32

The repeated identifier.

MissingRecord(Tag)

A required footer record was missing.

RepeatedRecord(Tag)

A footer record appeared more times than it is allowed to.

UnsupportedRecord

A known footer record was written at a version this build does not read.

Fields

tag: Tag

Which record.

version: u16

The version on it.

DigestMismatch

A digest did not match the bytes it covers.

Fields

what: String

Which digest.

expected: String

What the container claims.

actual: String

What the bytes actually hash to.

Footer(Error)

The bytes inside the footer did not parse.

TooLarge

Something in the container is bigger than this build can address.

On a 64 bit host this cannot happen. It is here so that a 32 bit host gets a sentence instead of a panic.

Fields

what: &'static str

Which part of the container.

needed: u64

How many bytes it asked for.

Io

Writing a container out did not work.

Only crate::Builder::build_into produces this. Reading never touches a file: a container is parsed from bytes somebody else fetched, which is what lets the same parser run against a mapped file, a buffer and a fuzzer’s input.

The kind is kept and the error itself is not, because this enum compares by value and std::io::Error does not. The kind is the part anybody branches on anyway, and the text is there for whoever reads the message.

Fields

kind: ErrorKind

What went wrong, as the operating system classified it.

detail: String

What it said.

Trait Implementations

impl Clone for Error

fn clone(&self) -> Error

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Error

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

Formats the value using the given formatter.

impl Display for Error

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

Formats the value using the given formatter.

impl Eq for Error

impl Error for Error

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

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

Provides type-based access to context intended for error reports.

impl From<Error> for Error

fn from(source: Error) -> Self

Converts to this type from the input type.

impl PartialEq for Error

fn eq(&self, other: &Error) -> bool

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for Error