pub enum CAHash {
    Flat(NixHash),
    Nar(NixHash),
    Text([u8; 32]),
}
Expand description

A Nix CAHash describes a content-addressed hash of a path.

The way Nix prints it as a string is a bit confusing, but there’s essentially three modes, Flat, Nar and Text. Flat and Nar support all 4 algos that NixHash supports (sha1, md5, sha256, sha512), Text only supports sha256.

Variants§

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Flat(NixHash)

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Nar(NixHash)

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Text([u8; 32])

Implementations§

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impl CAHash

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pub fn hash(&self) -> Cow<'_, NixHash>

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pub fn mode(&self) -> HashMode

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pub fn from_nix_hex_str(s: &str) -> Option<Self>

Constructs a CAHash from the textual representation, which is one of the three:

  • text:sha256:$nixbase32sha256digest
  • fixed:r:$algo:$nixbase32digest
  • fixed:$algo:$nixbase32digest which is the format that’s used in the NARInfo for example.
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pub fn to_nix_nixbase32_string(&self) -> String

Formats a CAHash in the Nix default hash format, which is the format that’s used in NARInfos for example.

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pub(crate) fn from_map<'de, D>( map: &Map<String, Value> ) -> Result<Option<Self>, D::Error>
where D: Deserializer<'de>,

This takes a serde_json::Map and turns it into this structure. This is necessary to do such shenigans because we have external consumers, like the Derivation parser, who would like to know whether we have a invalid or a missing NixHashWithMode structure in another structure, e.g. Output. This means we have this combinatorial situation:

  • no hash, no hashAlgo: no CAHash so we return Ok(None).
  • present hash, missing hashAlgo: invalid, we will return missing_field
  • missing hash, present hashAlgo: same
  • present hash, present hashAlgo: either we return ourselves or a type/value validation error. This function is for internal consumption regarding those needs until we have a better solution. Now this is said, let’s explain how this works.

We want to map the serde data model into a CAHash.

The serde data model has a hash field (containing a digest in nixbase32), and a hashAlgo field, containing the stringified hash algo. In case the hash is recursive, hashAlgo also has a r: prefix.

This is to match how nix show-derivation command shows them in JSON representation.

Trait Implementations§

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impl Clone for CAHash

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fn clone(&self) -> CAHash

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl Debug for CAHash

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

Formats the value using the given formatter. Read more
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impl<'de> Deserialize<'de> for CAHash

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fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer. Read more
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impl PartialEq for CAHash

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

This method tests for self and other values to be equal, and is used by ==.
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fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl Serialize for CAHash

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fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where S: Serializer,

map a CAHash into the serde data model.

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impl Eq for CAHash

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impl StructuralPartialEq for CAHash

Auto Trait Implementations§

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> Same for T

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type Output = T

Should always be Self
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impl<T> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<T> DeserializeOwned for T
where T: for<'de> Deserialize<'de>,