lib.fetchers: functions which can be reused across fetchers

lib.fetchers.normalizeHash

Converts an attrset containing one of hash, sha256 or sha512, into one containing outputHash{,Algo} as accepted by mkDerivation.

An appropriate “fake hash” is substituted when the hash value is "", as is the convention for fetchers.

All other attributes in the set remain as-is.

Type

normalizeHash :: { hashTypes :: [String]; required :: Bool; } -> AttrSet -> AttrSet

Arguments

hashTypes : the set of attribute names accepted as hash inputs, in addition to hash

required : whether to throw if no hash was present in the input; otherwise returns the original input, unmodified

Example

normalizeHash { } { hash = ""; foo = "bar"; }
=>
{
  outputHash = lib.fakeHash;
  outputHashAlgo = null;
  foo = "bar";
}

normalizeHash { } { sha256 = lib.fakeSha256; }
=>
{
  outputHash = lib.fakeSha256;
  outputHashAlgo = "sha256";
}

normalizeHash { } { sha512 = lib.fakeSha512; }
=>
{
  outputHash = lib.fakeSha512;
  outputHashAlgo = "sha512";
}

Located at lib/fetchers.nix:112 in <nixpkgs>.

lib.fetchers.withNormalizedHash

Wraps a function which accepts outputHash{,Algo} into one which accepts hash or sha{256,512}

Example

withNormalizedHash { hashTypes = [ "sha256" "sha512" ]; } (
  { outputHash, outputHashAlgo, ... }:
  ...
)

is a function which accepts one of hash, sha256, or sha512 (or the original's outputHash and outputHashAlgo).

Its functionArgs metadata only lists hash as a parameter, optional iff. outputHash was an optional parameter of the original function. sha256, sha512, outputHash, or outputHashAlgo are not mentioned in the functionArgs metadata.

Type

withNormalizedHash :: { hashTypes :: [String]; } -> (AttrSet -> a) -> (AttrSet -> a)

Arguments

hashTypes : the set of attribute names accepted as hash inputs, in addition to hash : they must correspond to a valid value for outputHashAlgo, currently one of: md5, sha1, sha256, or sha512.

f : the function to be wrapped

Output

withNormalizedHash { inherit hashTypes; } f is functionally equivalent to

args: f (normalizeHash {
  inherit hashTypes;
  required = !(lib.functionArgs f).outputHash;
} args)

However, withNormalizedHash preserves functionArgs metadata insofar as possible, and is implemented somewhat more efficiently.

Located at lib/fetchers.nix:200 in <nixpkgs>.