Enum AccessError

pub enum AccessError {
    IndexOutOfRange(usize),
    ValueAlreadyMutablyReferenced(usize),
    ValueStillImmutablyReferenced(usize),
    OverwriteWhileValueReferenced(usize),
    InsertAtMaxCapacityWhileAValueIsReferenced,
    RemoveWhileValueReferenced(usize),
    ValueDeleted(usize, usize),
    MaxValueForGenerationReached,
    IndexIsNotFree(usize),
    MaximumCapacityReached,
    MaximumImmutableReferencesReached(usize),
    MAJOR_MALFUNCTION(String),
}

Error type that provides helpful information about why an operation on any Prison or JailCell failed

Every error returned from functions or methods defined in this crate will be one of these variants, and all safe versions of Prison and JailCell are designed to never panic and always return errors.

Additional variants may be added in the future, therefore it is recommended you add a catch-all branch to any match statements on this enum to future-proof your code:

match acc_err {
    AccessError::IndexOutOfRange(bad_idx) => {},
    AccessError::ValueAlreadyMutablyReferenced(duplicate_idx) => {},
    // other variants
    _ => {}
}

AccessError has a custom implementation for both std::fmt::Display and std::fmt::Debug traits, with the Display version giving a short description of the problem, and the Debug version giving a more in-depth explaination of exactly why an error had to be returned

Variants

IndexOutOfRange(usize)

Indicates that an operation attempted to access an index beyond the range of the Prison, along with the offending index

ValueAlreadyMutablyReferenced(usize)

Indicates that an operation attempted to reference a value (mutably or immutably) already being mutably referenced by another operation, along with the index in question

ValueStillImmutablyReferenced(usize)

Indicates that an operation attempted to mutably reference a value already being immutably referenced by another operation, along with the index in question

OverwriteWhileValueReferenced(usize)

Indicates that an overwriteing insert would invalidate currently active references to a value

InsertAtMaxCapacityWhileAValueIsReferenced

Indicates that an insert would require re-allocation of the internal Vec, thereby invalidating any currently active references

RemoveWhileValueReferenced(usize)

Indicates that the last element in the Prison is being accessed, and remove()-ing the value from the underlying Vec would invalidate the reference

ValueDeleted(usize, usize)

Indicates that the value requested was deleted and a new value with an updated generation took its place

Contains the index and generation from the invalid CellKey, in that order

MaxValueForGenerationReached

Indicates that a very large number of removes and inserts caused the generation counter to reach its max value

IndexIsNotFree(usize)

Indicates that an attempted insert to a specific index would overwrite and invalidate a value still in use

MaximumCapacityReached

Indicates that the underlying Vec reached the maximum capacity set by Rust (isize::MAX)

MaximumImmutableReferencesReached(usize)

Indicates that you (somehow) reached the limit for reference counting immutable references

MAJOR_MALFUNCTION(String)

Indicates that the operation created an invalid and unexpected state. This may have resulted in memory leaking, mutable aliasing, undefined behavior, etc.

This error should be considered a BUG inside the library crate grit-data-prison and reported to the author of the crate

Implementations

impl AccessError

pub fn kind(&self) -> String

Returns a string that shows the AccessError variant and value, if any

Trait Implementations

impl Debug for AccessError

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

Formats the value using the given formatter.

impl Display for AccessError

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

Formats the value using the given formatter.

impl Error for AccessError

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 PartialEq for AccessError

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

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

const 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 Eq for AccessError

impl StructuralPartialEq for AccessError