stefans-utils 0.10.1

A collection of useful Rust utility functions, types, and traits.
Documentation 
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use crate::{
    comparator::Comparison, expect_comparison::ExpectedComparisonError, with_len::WithLen,
};
use core::{error::Error, fmt};

pub trait ExpectLen: WithLen + Sized {
    fn expect_len_lt(self, length: usize) -> Result<Self, ExpectedLenError>;
    fn expect_len_lte(self, length: usize) -> Result<Self, ExpectedLenError>;
    fn expect_len_eq(self, length: usize) -> Result<Self, ExpectedLenError>;
    fn expect_len_ne(self, length: usize) -> Result<Self, ExpectedLenError>;
    fn expect_len_gte(self, length: usize) -> Result<Self, ExpectedLenError>;
    fn expect_len_gt(self, length: usize) -> Result<Self, ExpectedLenError>;

    fn expect_non_empty(self) -> Result<Self, ExpectedLenError> {
        self.expect_len_gt(0)
    }
    fn expect_empty(self) -> Result<Self, ExpectedLenError> {
        self.expect_len_ne(0)
    }
    fn expect_len(self, length: usize) -> Result<Self, ExpectedLenError> {
        self.expect_len_eq(length)
    }
}

#[derive(fmt::Debug, Clone, Copy, PartialEq, Eq)]
#[cfg_attr(feature = "serde", derive(::serde::Serialize, ::serde::Deserialize))]
#[cfg_attr(feature = "schemars", derive(::schemars::JsonSchema))]
pub struct ExpectedLenError {
    pub comparison: Comparison,
    pub comparator: usize,
    pub actual: usize,
}

impl From<ExpectedComparisonError<usize>> for ExpectedLenError {
    fn from(
        ExpectedComparisonError {
            comparison,
            comparator,
            actual,
        }: ExpectedComparisonError<usize>,
    ) -> Self {
        ExpectedLenError {
            comparison,
            comparator,
            actual,
        }
    }
}

impl Error for ExpectedLenError {}

impl fmt::Display for ExpectedLenError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.write_fmt(format_args!(
            "Expected length to be {} {}, but it was {}",
            self.comparison, self.comparator, self.actual
        ))
    }
}

impl Comparison {
    pub fn expect_len_comparison<T: WithLen + Sized>(
        self,
        with_len: T,
        length_comparator: usize,
    ) -> Result<T, ExpectedLenError> {
        self.expect_comparison(with_len.len(), length_comparator)
            .map_err(ExpectedLenError::from)
            .map(|_| with_len)
    }
}

impl<T: WithLen + Sized> ExpectLen for T {
    fn expect_len_lt(self, length: usize) -> Result<Self, ExpectedLenError> {
        Comparison::Less.expect_len_comparison(self, length)
    }

    fn expect_len_lte(self, length: usize) -> Result<Self, ExpectedLenError> {
        Comparison::LessOrEqual.expect_len_comparison(self, length)
    }

    fn expect_len_eq(self, length: usize) -> Result<Self, ExpectedLenError> {
        Comparison::Equal.expect_len_comparison(self, length)
    }

    fn expect_len_ne(self, length: usize) -> Result<Self, ExpectedLenError> {
        Comparison::Unequal.expect_len_comparison(self, length)
    }

    fn expect_len_gte(self, length: usize) -> Result<Self, ExpectedLenError> {
        Comparison::GreaterOrEqual.expect_len_comparison(self, length)
    }

    fn expect_len_gt(self, length: usize) -> Result<Self, ExpectedLenError> {
        Comparison::Greater.expect_len_comparison(self, length)
    }
}