ldap-types 0.7.2

//! Types and traits related to the conversion of LDAP types to Rust types

/// represents the representation for a type that could be returned by a search
/// query, zero, one or multiple Strings and zero, one or
/// multiple binary values (`Vec<u8>`)
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct LdapAttributeResultValues {
    /// the DN of the entry we convert
    pub entry_dn: String,
    /// the name of the attribute
    pub attribute_name: String,
    /// the String result values
    pub string_values: Vec<String>,
    /// the binary result values
    pub binary_values: Vec<Vec<u8>>,
}

/// adds a method to ldap3::SearchEntry to extract the LdapResultValue
/// for a given attribute
#[cfg(feature = "ldap3")]
pub trait SearchEntryExt {
    /// extracts the results for a given attribute
    fn attribute_results(&self, attribute_name: &str) -> LdapAttributeResultValues;
}

#[cfg(feature = "ldap3")]
impl SearchEntryExt for ldap3::SearchEntry {
    fn attribute_results(&self, attribute_name: &str) -> LdapAttributeResultValues {
        let string_values = self.attrs.get(attribute_name);
        let binary_values = self.bin_attrs.get(attribute_name);
        LdapAttributeResultValues {
            entry_dn: self.dn.to_owned(),
            attribute_name: attribute_name.to_owned(),
            string_values: string_values.map_or(Vec::new(), |v| v.to_vec()),
            binary_values: binary_values.map_or(Vec::new(), |v| v.to_vec()),
        }
    }
}

/// a primitive result that can be converted from an Ldap type that is returned
/// as a String
pub trait FromStringLdapType {
    /// the type of error when the conversion fails
    type Error;

    /// parse this type from a String returned by an LDAP search
    ///
    /// # Errors
    ///
    /// fails if the type could not be parsed
    fn parse(entry_dn: &str, attribute_name: &str, value: String) -> Result<Self, Self::Error>
    where
        Self: Sized;
}

impl FromStringLdapType for String {
    type Error = std::convert::Infallible;

    fn parse(_entry_dn: &str, _attribute_name: &str, value: String) -> Result<Self, Self::Error>
    where
        Self: Sized,
    {
        Ok(value)
    }
}

/// error that occurs when a conversion encounters a value that it can not
/// convert
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct UnexpectedStringValue {
    /// source entry DN
    source_entry_dn: String,
    /// source attribute name
    source_attribute_name: String,
    /// name of the type we couldn't convert the value to
    conversion_target_name: String,
    /// value that was encountered and could not be converted
    unexpected_value: String,
}

impl std::fmt::Display for UnexpectedStringValue {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(
            f,
            "Unexpected value in conversion of {} attribute {} to {}: {}",
            self.source_entry_dn,
            self.source_attribute_name,
            self.conversion_target_name,
            self.unexpected_value,
        )
    }
}

impl std::error::Error for UnexpectedStringValue {}

impl FromStringLdapType for bool {
    type Error = UnexpectedStringValue;

    fn parse(entry_dn: &str, attribute_name: &str, value: String) -> Result<Self, Self::Error>
    where
        Self: Sized,
    {
        match std::ops::Deref::deref(&value) {
            "TRUE" => Ok(true),
            "FALSE" => Ok(false),
            v => Err(UnexpectedStringValue {
                source_entry_dn: entry_dn.to_owned(),
                source_attribute_name: attribute_name.to_owned(),
                conversion_target_name: "bool".to_string(),
                unexpected_value: v.to_owned(),
            }),
        }
    }
}

impl FromStringLdapType for u8 {
    type Error = UnexpectedStringValue;

    fn parse(entry_dn: &str, attribute_name: &str, value: String) -> Result<Self, Self::Error>
    where
        Self: Sized,
    {
        <Self as std::str::FromStr>::from_str(&value).map_err(|_err| UnexpectedStringValue {
            source_entry_dn: entry_dn.to_owned(),
            source_attribute_name: attribute_name.to_owned(),
            conversion_target_name: "u8".to_string(),
            unexpected_value: value,
        })
    }
}

impl FromStringLdapType for i8 {
    type Error = UnexpectedStringValue;

    fn parse(entry_dn: &str, attribute_name: &str, value: String) -> Result<Self, Self::Error>
    where
        Self: Sized,
    {
        <Self as std::str::FromStr>::from_str(&value).map_err(|_err| UnexpectedStringValue {
            source_entry_dn: entry_dn.to_owned(),
            source_attribute_name: attribute_name.to_owned(),
            conversion_target_name: "i8".to_string(),
            unexpected_value: value,
        })
    }
}

impl FromStringLdapType for u16 {
    type Error = UnexpectedStringValue;

    fn parse(entry_dn: &str, attribute_name: &str, value: String) -> Result<Self, Self::Error>
    where
        Self: Sized,
    {
        <Self as std::str::FromStr>::from_str(&value).map_err(|_err| UnexpectedStringValue {
            source_entry_dn: entry_dn.to_owned(),
            source_attribute_name: attribute_name.to_owned(),
            conversion_target_name: "u16".to_string(),
            unexpected_value: value,
        })
    }
}

impl FromStringLdapType for i16 {
    type Error = UnexpectedStringValue;

    fn parse(entry_dn: &str, attribute_name: &str, value: String) -> Result<Self, Self::Error>
    where
        Self: Sized,
    {
        <Self as std::str::FromStr>::from_str(&value).map_err(|_err| UnexpectedStringValue {
            source_entry_dn: entry_dn.to_owned(),
            source_attribute_name: attribute_name.to_owned(),
            conversion_target_name: "i16".to_string(),
            unexpected_value: value,
        })
    }
}

impl FromStringLdapType for u32 {
    type Error = UnexpectedStringValue;

    fn parse(entry_dn: &str, attribute_name: &str, value: String) -> Result<Self, Self::Error>
    where
        Self: Sized,
    {
        <Self as std::str::FromStr>::from_str(&value).map_err(|_err| UnexpectedStringValue {
            source_entry_dn: entry_dn.to_owned(),
            source_attribute_name: attribute_name.to_owned(),
            conversion_target_name: "u32".to_string(),
            unexpected_value: value,
        })
    }
}

impl FromStringLdapType for i32 {
    type Error = UnexpectedStringValue;

    fn parse(entry_dn: &str, attribute_name: &str, value: String) -> Result<Self, Self::Error>
    where
        Self: Sized,
    {
        <Self as std::str::FromStr>::from_str(&value).map_err(|_err| UnexpectedStringValue {
            source_entry_dn: entry_dn.to_owned(),
            source_attribute_name: attribute_name.to_owned(),
            conversion_target_name: "i32".to_string(),
            unexpected_value: value,
        })
    }
}

impl FromStringLdapType for u64 {
    type Error = UnexpectedStringValue;

    fn parse(entry_dn: &str, attribute_name: &str, value: String) -> Result<Self, Self::Error>
    where
        Self: Sized,
    {
        <Self as std::str::FromStr>::from_str(&value).map_err(|_err| UnexpectedStringValue {
            source_entry_dn: entry_dn.to_owned(),
            source_attribute_name: attribute_name.to_owned(),
            conversion_target_name: "u64".to_string(),
            unexpected_value: value,
        })
    }
}

impl FromStringLdapType for i64 {
    type Error = UnexpectedStringValue;

    fn parse(entry_dn: &str, attribute_name: &str, value: String) -> Result<Self, Self::Error>
    where
        Self: Sized,
    {
        <Self as std::str::FromStr>::from_str(&value).map_err(|_err| UnexpectedStringValue {
            source_entry_dn: entry_dn.to_owned(),
            source_attribute_name: attribute_name.to_owned(),
            conversion_target_name: "i64".to_string(),
            unexpected_value: value,
        })
    }
}

impl FromStringLdapType for u128 {
    type Error = UnexpectedStringValue;

    fn parse(entry_dn: &str, attribute_name: &str, value: String) -> Result<Self, Self::Error>
    where
        Self: Sized,
    {
        <Self as std::str::FromStr>::from_str(&value).map_err(|_err| UnexpectedStringValue {
            source_entry_dn: entry_dn.to_owned(),
            source_attribute_name: attribute_name.to_owned(),
            conversion_target_name: "u128".to_string(),
            unexpected_value: value,
        })
    }
}

impl FromStringLdapType for i128 {
    type Error = UnexpectedStringValue;

    fn parse(entry_dn: &str, attribute_name: &str, value: String) -> Result<Self, Self::Error>
    where
        Self: Sized,
    {
        <Self as std::str::FromStr>::from_str(&value).map_err(|_err| UnexpectedStringValue {
            source_entry_dn: entry_dn.to_owned(),
            source_attribute_name: attribute_name.to_owned(),
            conversion_target_name: "i128".to_string(),
            unexpected_value: value,
        })
    }
}

impl FromStringLdapType for usize {
    type Error = UnexpectedStringValue;

    fn parse(entry_dn: &str, attribute_name: &str, value: String) -> Result<Self, Self::Error>
    where
        Self: Sized,
    {
        <Self as std::str::FromStr>::from_str(&value).map_err(|_err| UnexpectedStringValue {
            source_entry_dn: entry_dn.to_owned(),
            source_attribute_name: attribute_name.to_owned(),
            conversion_target_name: "usize".to_string(),
            unexpected_value: value,
        })
    }
}

impl FromStringLdapType for isize {
    type Error = UnexpectedStringValue;

    fn parse(entry_dn: &str, attribute_name: &str, value: String) -> Result<Self, Self::Error>
    where
        Self: Sized,
    {
        <Self as std::str::FromStr>::from_str(&value).map_err(|_err| UnexpectedStringValue {
            source_entry_dn: entry_dn.to_owned(),
            source_attribute_name: attribute_name.to_owned(),
            conversion_target_name: "isize".to_string(),
            unexpected_value: value,
        })
    }
}

#[cfg(feature = "chumsky")]
impl FromStringLdapType for crate::basic::DistinguishedName {
    type Error = UnexpectedStringValue;

    fn parse(entry_dn: &str, attribute_name: &str, value: String) -> Result<Self, Self::Error>
    where
        Self: Sized,
    {
        <Self as std::str::FromStr>::from_str(&value).map_err(|_err| UnexpectedStringValue {
            source_entry_dn: entry_dn.to_owned(),
            source_attribute_name: attribute_name.to_owned(),
            conversion_target_name: "DistinguishedName".to_string(),
            unexpected_value: value,
        })
    }
}

impl FromStringLdapType for oid::ObjectIdentifier {
    type Error = UnexpectedStringValue;

    fn parse(entry_dn: &str, attribute_name: &str, value: String) -> Result<Self, Self::Error>
    where
        Self: Sized,
    {
        <Self as TryFrom<&str>>::try_from(&value).map_err(|_err| UnexpectedStringValue {
            source_entry_dn: entry_dn.to_owned(),
            source_attribute_name: attribute_name.to_owned(),
            conversion_target_name: "ObjectIdentifier".to_string(),
            unexpected_value: value,
        })
    }
}

/// a type that can be parsed from an Ldap type (on the level where
/// optional/required and single/multi-value matter as opposed to the primitives
/// above)
pub trait FromLdapType {
    /// the type of error when the conversion fails
    type Error;

    /// parse this type from the LDAP representation returned
    /// by a search query
    ///
    /// # Errors
    ///
    /// fails if the type could not be parsed or if the number or type
    /// (string/binary) does not match what is expected
    fn parse(values: LdapAttributeResultValues) -> Result<Self, Self::Error>
    where
        Self: Sized;
}

/// represents the errors that can occur when decoding a Vec of types with a
/// FromStringLdapType implementation
#[derive(Debug, Clone)]
pub enum VecOfFromStringLdapTypeError<E> {
    /// since types implementing FromStringLdapType can not handle binary values
    /// this represents the error when the input contains binary values
    LdapShouldNotReturnBinaryResult {
        /// the DN of the entry
        entry_dn: String,
        /// the attribute name
        attribute_name: String,
    },
    /// represents an error converting one of the primitive values
    PrimitiveValueConversionError(E),
}

impl<E> std::fmt::Display for VecOfFromStringLdapTypeError<E>
where
    E: std::error::Error,
{
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::LdapShouldNotReturnBinaryResult {
                entry_dn,
                attribute_name,
            } => {
                write!(f, "encountered binary values in input for {entry_dn} attribute {attribute_name} when converting a Vec of a type that only supports String inputs")
            }
            Self::PrimitiveValueConversionError(err) => {
                write!(
                    f,
                    "encountered error converting a primitive value from String: {err}",
                )
            }
        }
    }
}

impl<E> std::error::Error for VecOfFromStringLdapTypeError<E> where E: std::error::Error {}

impl<T> FromLdapType for Vec<T>
where
    T: FromStringLdapType,
{
    type Error = VecOfFromStringLdapTypeError<<T as FromStringLdapType>::Error>;

    fn parse(values: LdapAttributeResultValues) -> Result<Self, Self::Error>
    where
        Self: Sized,
    {
        if !values.binary_values.is_empty() {
            return Err(
                VecOfFromStringLdapTypeError::LdapShouldNotReturnBinaryResult {
                    entry_dn: values.entry_dn,
                    attribute_name: values.attribute_name,
                },
            );
        }
        values
            .string_values
            .into_iter()
            .map(|v| <T as FromStringLdapType>::parse(&values.entry_dn, &values.attribute_name, v))
            .collect::<Result<Self, <T as FromStringLdapType>::Error>>()
            .map_err(VecOfFromStringLdapTypeError::PrimitiveValueConversionError)
    }
}

/// represents the errors that can occur when decoding an Option of types with a
/// FromStringLdapType implementation
#[derive(Debug, Clone)]
pub enum OptionOfFromStringLdapTypeError<E> {
    /// since types implementing FromStringLdapType can not handle binary values
    /// this represents the error when the input contains binary values
    LdapShouldNotReturnBinaryResult {
        /// the DN of the entry
        entry_dn: String,
        /// the name of the attribute
        attribute_name: String,
    },
    /// since Option types can only hold 0 or 1 results there should not be more
    /// than one String input value
    LdapShouldNotReturnMultipleResults {
        /// the DN of the entry
        entry_dn: String,
        /// the name of the attribute
        attribute_name: String,
    },
    /// represents an error converting one of the primitive values
    PrimitiveValueConversionError(E),
}

impl<E> std::fmt::Display for OptionOfFromStringLdapTypeError<E>
where
    E: std::error::Error,
{
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::LdapShouldNotReturnBinaryResult {
                entry_dn,
                attribute_name,
            } => {
                write!(f, "encountered binary values in input for {entry_dn} attribute {attribute_name} when converting an Option of a type that only supports String inputs")
            }
            Self::LdapShouldNotReturnMultipleResults {
                entry_dn,
                attribute_name,
            } => {
                write!(f, "encountered multiple string values in input for {entry_dn} attribute {attribute_name} when converting an Option of a type that only supports String inputs")
            }
            Self::PrimitiveValueConversionError(err) => {
                write!(
                    f,
                    "encountered error converting a primitive value from String: {err}",
                )
            }
        }
    }
}

impl<E> std::error::Error for OptionOfFromStringLdapTypeError<E> where E: std::error::Error {}

impl<T> FromLdapType for Option<T>
where
    T: FromStringLdapType,
{
    type Error = OptionOfFromStringLdapTypeError<<T as FromStringLdapType>::Error>;

    fn parse(values: LdapAttributeResultValues) -> Result<Self, Self::Error>
    where
        Self: Sized,
    {
        if !values.binary_values.is_empty() {
            return Err(
                OptionOfFromStringLdapTypeError::LdapShouldNotReturnBinaryResult {
                    entry_dn: values.entry_dn,
                    attribute_name: values.attribute_name,
                },
            );
        }
        if values.string_values.len() > 1 {
            return Err(
                OptionOfFromStringLdapTypeError::LdapShouldNotReturnMultipleResults {
                    entry_dn: values.entry_dn,
                    attribute_name: values.attribute_name,
                },
            );
        }
        if let Some(value) = values.string_values.first() {
            Ok(Some(
                <T as FromStringLdapType>::parse(
                    &values.entry_dn,
                    &values.attribute_name,
                    value.to_owned(),
                )
                .map_err(OptionOfFromStringLdapTypeError::PrimitiveValueConversionError)?,
            ))
        } else {
            Ok(None)
        }
    }
}

/// represents the errors that can occur when decoding a required value of
/// types with a FromStringLdapType implementation
#[derive(Debug, Clone)]
pub enum RequiredFromStringLdapTypeError<E> {
    /// since types implementing FromStringLdapType can not handle binary values
    /// this represents the error when the input contains binary values
    LdapShouldNotReturnBinaryResult {
        /// the DN of the entry
        entry_dn: String,
        /// the name of the attribute
        attribute_name: String,
    },
    /// since primitive types can only hold exactly one result there should
    /// be exactly one String input value
    LdapShouldReturnExactlyOneResult {
        /// the DN of the entry
        entry_dn: String,
        /// the name of the attribute
        attribute_name: String,
        /// number of results
        count: usize,
    },
    /// represents an error converting one of the primitive values
    PrimitiveValueConversionError(E),
}

impl<E> std::fmt::Display for RequiredFromStringLdapTypeError<E>
where
    E: std::error::Error,
{
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::LdapShouldNotReturnBinaryResult {
                entry_dn,
                attribute_name,
            } => {
                write!(f, "encountered binary values in input for {entry_dn} attribute {attribute_name} when converting a required value of a type that only supports String inputs")
            }
            Self::LdapShouldReturnExactlyOneResult {
                entry_dn,
                attribute_name,
                count,
            } => {
                write!(f, "encountered {count} string values (expected exactly one) in input for {entry_dn} attribute {attribute_name} when converting a required value of a type that only supports String inputs")
            }
            Self::PrimitiveValueConversionError(err) => {
                write!(
                    f,
                    "encountered error converting a primitive value from String: {err}",
                )
            }
        }
    }
}

impl<E> std::error::Error for RequiredFromStringLdapTypeError<E> where E: std::error::Error {}

impl<T> FromLdapType for T
where
    T: FromStringLdapType,
{
    type Error = RequiredFromStringLdapTypeError<<T as FromStringLdapType>::Error>;

    fn parse(values: LdapAttributeResultValues) -> Result<Self, Self::Error>
    where
        Self: Sized,
    {
        if !values.binary_values.is_empty() {
            return Err(
                RequiredFromStringLdapTypeError::LdapShouldNotReturnBinaryResult {
                    entry_dn: values.entry_dn,
                    attribute_name: values.attribute_name,
                },
            );
        }
        if values.string_values.len() != 1 {
            return Err(
                RequiredFromStringLdapTypeError::LdapShouldReturnExactlyOneResult {
                    entry_dn: values.entry_dn,
                    attribute_name: values.attribute_name,
                    count: values.string_values.len(),
                },
            );
        }
        if let Some(value) = values.string_values.first() {
            Ok(<T as FromStringLdapType>::parse(
                &values.entry_dn,
                &values.attribute_name,
                value.to_owned(),
            )
            .map_err(RequiredFromStringLdapTypeError::PrimitiveValueConversionError)?)
        } else {
            Err(
                RequiredFromStringLdapTypeError::LdapShouldReturnExactlyOneResult {
                    entry_dn: values.entry_dn,
                    attribute_name: values.attribute_name,
                    count: values.string_values.len(),
                },
            )
        }
    }
}

/// a primitive result that can be converted from an Ldap type that is returned
/// as a `Vec<u8>`
pub trait FromBinaryLdapType {
    /// the type of error when the conversion fails
    type Error;

    /// parse this type from a `Vec<u8>` returned by an LDAP search
    ///
    /// # Errors
    ///
    /// fails if the type could not be parsed
    fn parse(entry_dn: &str, attribute_name: &str, value: Vec<u8>) -> Result<Self, Self::Error>
    where
        Self: Sized;
}

/// error that occurs when a conversion encounters a value that it can not
/// convert
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct UnexpectedBinaryValue {
    /// source entry DN
    source_entry_dn: String,
    /// source attribute name
    source_attribute_name: String,
    /// name of the type we couldn't convert the value to
    conversion_target_name: String,
    /// value that was encountered and could not be converted
    unexpected_value: Vec<u8>,
}

impl std::fmt::Display for UnexpectedBinaryValue {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(
            f,
            "Unexpected value in conversion of {} attribute {} to {}: {:?}",
            self.source_entry_dn,
            self.source_attribute_name,
            self.conversion_target_name,
            self.unexpected_value,
        )
    }
}

impl std::error::Error for UnexpectedBinaryValue {}

impl FromBinaryLdapType for Vec<u8> {
    type Error = std::convert::Infallible;

    fn parse(_entry_dn: &str, _attribute_name: &str, value: Vec<u8>) -> Result<Self, Self::Error>
    where
        Self: Sized,
    {
        Ok(value)
    }
}

/// a wrapper newtype to identify types we want to deserialize from Binary LDAP attributes
/// this avoids conflicts with e.g. `Vec<u8>` deserialized from a multi-valued number attribute
/// and `Vec<u8>` serialized from a single-valued binary attribute
#[derive(Debug, Clone)]
pub struct Binary<T>(pub T);

/// represents the errors that can occur when decoding a Vec of types with a
/// FromBinaryLdapType implementation
#[derive(Debug, Clone)]
pub enum VecOfFromBinaryLdapTypeError<E> {
    /// since types implementing FromStringLdapType can not handle String values
    /// this represents the error when the input contains String values
    LdapShouldNotReturnStringResult {
        /// the DN of the entry
        entry_dn: String,
        /// the attribute name
        attribute_name: String,
    },
    /// represents an error converting one of the primitive values
    PrimitiveValueConversionError(E),
}

impl<E> std::fmt::Display for VecOfFromBinaryLdapTypeError<E>
where
    E: std::error::Error,
{
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::LdapShouldNotReturnStringResult {
                entry_dn,
                attribute_name,
            } => {
                write!(f, "encountered String values in input for {entry_dn} attribute {attribute_name} when converting a Vec of a type that only supports binary inputs")
            }
            Self::PrimitiveValueConversionError(err) => {
                write!(
                    f,
                    "encountered error converting a primitive value from binary: {err}",
                )
            }
        }
    }
}

impl<E> std::error::Error for VecOfFromBinaryLdapTypeError<E> where E: std::error::Error {}

impl<T> FromLdapType for Binary<Vec<T>>
where
    T: FromBinaryLdapType,
{
    type Error = VecOfFromBinaryLdapTypeError<<T as FromBinaryLdapType>::Error>;

    fn parse(values: LdapAttributeResultValues) -> Result<Self, Self::Error>
    where
        Self: Sized,
    {
        if !values.string_values.is_empty() {
            return Err(
                VecOfFromBinaryLdapTypeError::LdapShouldNotReturnStringResult {
                    entry_dn: values.entry_dn,
                    attribute_name: values.attribute_name,
                },
            );
        }
        values
            .binary_values
            .into_iter()
            .map(|v| <T as FromBinaryLdapType>::parse(&values.entry_dn, &values.attribute_name, v))
            .collect::<Result<Vec<T>, <T as FromBinaryLdapType>::Error>>()
            .map(Binary)
            .map_err(VecOfFromBinaryLdapTypeError::PrimitiveValueConversionError)
    }
}

/// represents the errors that can occur when decoding an Option of types with a
/// FromBinaryLdapType implementation
#[derive(Debug, Clone)]
pub enum OptionOfFromBinaryLdapTypeError<E> {
    /// since types implementing FromBinaryLdapType can not handle String values
    /// this represents the error when the input contains String values
    LdapShouldNotReturnStringResult {
        /// the DN of the entry
        entry_dn: String,
        /// the name of the attribute
        attribute_name: String,
    },
    /// since Option types can only hold 0 or 1 results there should not be more
    /// than one String input value
    LdapShouldNotReturnMultipleResults {
        /// the DN of the entry
        entry_dn: String,
        /// the name of the attribute
        attribute_name: String,
    },
    /// represents an error converting one of the primitive values
    PrimitiveValueConversionError(E),
}

impl<E> std::fmt::Display for OptionOfFromBinaryLdapTypeError<E>
where
    E: std::error::Error,
{
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::LdapShouldNotReturnStringResult {
                entry_dn,
                attribute_name,
            } => {
                write!(f, "encountered String values in input for {entry_dn} attribute {attribute_name} when converting an Option of a type that only supports binary inputs")
            }
            Self::LdapShouldNotReturnMultipleResults {
                entry_dn,
                attribute_name,
            } => {
                write!(f, "encountered multiple binary values in input for {entry_dn} attribute {attribute_name} when converting an Option of a type that only supports binary inputs")
            }
            Self::PrimitiveValueConversionError(err) => {
                write!(
                    f,
                    "encountered error converting a primitive value from binary: {err}",
                )
            }
        }
    }
}

impl<E> std::error::Error for OptionOfFromBinaryLdapTypeError<E> where E: std::error::Error {}

impl<T> FromLdapType for Binary<Option<T>>
where
    T: FromBinaryLdapType,
{
    type Error = OptionOfFromBinaryLdapTypeError<<T as FromBinaryLdapType>::Error>;

    fn parse(values: LdapAttributeResultValues) -> Result<Self, Self::Error>
    where
        Self: Sized,
    {
        if !values.string_values.is_empty() {
            return Err(
                OptionOfFromBinaryLdapTypeError::LdapShouldNotReturnStringResult {
                    entry_dn: values.entry_dn,
                    attribute_name: values.attribute_name,
                },
            );
        }
        if values.binary_values.len() > 1 {
            return Err(
                OptionOfFromBinaryLdapTypeError::LdapShouldNotReturnMultipleResults {
                    entry_dn: values.entry_dn,
                    attribute_name: values.attribute_name,
                },
            );
        }
        if let Some(value) = values.binary_values.first() {
            Ok(Self(Some(
                <T as FromBinaryLdapType>::parse(
                    &values.entry_dn,
                    &values.attribute_name,
                    value.to_owned(),
                )
                .map_err(OptionOfFromBinaryLdapTypeError::PrimitiveValueConversionError)?,
            )))
        } else {
            Ok(Self(None))
        }
    }
}

/// represents the errors that can occur when decoding a required value of
/// types with a FromBinaryLdapType implementation
#[derive(Debug, Clone)]
pub enum RequiredFromBinaryLdapTypeError<E> {
    /// since types implementing FromBinaryLdapType can not handle String values
    /// this represents the error when the input contains String values
    LdapShouldNotReturnStringResult {
        /// the DN of the entry
        entry_dn: String,
        /// the name of the attribute
        attribute_name: String,
    },
    /// since primitive types can only hold exactly one result there should
    /// be exactly one binaryg input value
    LdapShouldReturnExactlyOneResult {
        /// the DN of the entry
        entry_dn: String,
        /// the name of the attribute
        attribute_name: String,
        /// number of results
        count: usize,
    },
    /// represents an error converting one of the primitive values
    PrimitiveValueConversionError(E),
}

impl<E> std::fmt::Display for RequiredFromBinaryLdapTypeError<E>
where
    E: std::error::Error,
{
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::LdapShouldNotReturnStringResult {
                entry_dn,
                attribute_name,
            } => {
                write!(f, "encountered String values in input for {entry_dn} attribute {attribute_name} when converting a required value of a type that only supports binary inputs")
            }
            Self::LdapShouldReturnExactlyOneResult {
                entry_dn,
                attribute_name,
                count,
            } => {
                write!(f, "encountered {count} binary values (expected exactly one) in input for {entry_dn} attribute {attribute_name} when converting a required value of a type that only supports binary inputs")
            }
            Self::PrimitiveValueConversionError(err) => {
                write!(
                    f,
                    "encountered error converting a primitive value from binary: {err}",
                )
            }
        }
    }
}

impl<E> std::error::Error for RequiredFromBinaryLdapTypeError<E> where E: std::error::Error {}

impl<T> FromLdapType for Binary<T>
where
    T: FromBinaryLdapType,
{
    type Error = RequiredFromBinaryLdapTypeError<<T as FromBinaryLdapType>::Error>;

    fn parse(values: LdapAttributeResultValues) -> Result<Self, Self::Error>
    where
        Self: Sized,
    {
        if !values.string_values.is_empty() {
            return Err(
                RequiredFromBinaryLdapTypeError::LdapShouldNotReturnStringResult {
                    entry_dn: values.entry_dn,
                    attribute_name: values.attribute_name,
                },
            );
        }
        if values.binary_values.len() != 1 {
            return Err(
                RequiredFromBinaryLdapTypeError::LdapShouldReturnExactlyOneResult {
                    entry_dn: values.entry_dn,
                    attribute_name: values.attribute_name,
                    count: values.string_values.len(),
                },
            );
        }
        if let Some(value) = values.binary_values.first() {
            Ok(<T as FromBinaryLdapType>::parse(
                &values.entry_dn,
                &values.attribute_name,
                value.to_owned(),
            )
            .map(Binary)
            .map_err(RequiredFromBinaryLdapTypeError::PrimitiveValueConversionError)?)
        } else {
            Err(
                RequiredFromBinaryLdapTypeError::LdapShouldReturnExactlyOneResult {
                    entry_dn: values.entry_dn,
                    attribute_name: values.attribute_name,
                    count: values.string_values.len(),
                },
            )
        }
    }
}