core/pkgs/build-support/fetchipfs/default.nix

{ stdenv, curl }:

{ ipfs, url ? "", curlOpts ? "", outputHash ? "", outputHashAlgo ? "", md5 ? ""
, sha1 ? "", sha256 ? "", sha512 ? "", meta ? { }, port ? "8080", postFetch ? ""
, preferLocalBuild ? true }:

let

  hasHash = (outputHash != "" && outputHashAlgo != "") || md5 != "" || sha1
    != "" || sha256 != "" || sha512 != "";

in if (!hasHash) then
  throw "Specify sha for fetchipfs fixed-output derivation"
else
  stdenv.mkDerivation {
    name = ipfs;
    builder = ./builder.sh;
    nativeBuildInputs = [ curl ];

    # New-style output content requirements.
    outputHashAlgo = if outputHashAlgo != "" then
      outputHashAlgo
    else if sha512 != "" then
      "sha512"
    else if sha256 != "" then
      "sha256"
    else if sha1 != "" then
      "sha1"
    else
      "md5";
    outputHash = if outputHash != "" then
      outputHash
    else if sha512 != "" then
      sha512
    else if sha256 != "" then
      sha256
    else if sha1 != "" then
      sha1
    else
      md5;

    outputHashMode = "recursive";

    inherit curlOpts postFetch ipfs url port meta;

    # Doing the download on a remote machine just duplicates network
    # traffic, so don't do that.
    inherit preferLocalBuild;
  }