92 lines
		
	
	
		
			3.7 KiB
		
	
	
	
		
			Nix
		
	
	
	
	
	
			
		
		
	
	
			92 lines
		
	
	
		
			3.7 KiB
		
	
	
	
		
			Nix
		
	
	
	
	
	
/* Impure default args for `pkgs/top-level/default.nix`. See that file
 | 
						||
   for the meaning of each argument. */
 | 
						||
 | 
						||
with builtins;
 | 
						||
 | 
						||
let
 | 
						||
 | 
						||
  homeDir = builtins.getEnv "HOME";
 | 
						||
 | 
						||
  # Return ‘x’ if it evaluates, or ‘def’ if it throws an exception.
 | 
						||
  try = x: def: let res = tryEval x; in if res.success then res.value else def;
 | 
						||
 | 
						||
in
 | 
						||
 | 
						||
{ # We combine legacy `system` and `platform` into `localSystem`, if
 | 
						||
  # `localSystem` was not passed. Strictly speaking, this is pure desugar, but
 | 
						||
  # it is most convient to do so before the impure `localSystem.system` default,
 | 
						||
  # so we do it now.
 | 
						||
  localSystem ? builtins.intersectAttrs { system = null; platform = null; } args
 | 
						||
 | 
						||
, # These are needed only because nix's `--arg` command-line logic doesn't work
 | 
						||
  # with unnamed parameters allowed by ...
 | 
						||
  system ? localSystem.system
 | 
						||
, platform ? localSystem.platform
 | 
						||
, crossSystem ? null
 | 
						||
 | 
						||
, # Fallback: The contents of the configuration file found at $NIXPKGS_CONFIG or
 | 
						||
  # $HOME/.config/nixpkgs/config.nix.
 | 
						||
  config ? let
 | 
						||
      configFile = getEnv "NIXPKGS_CONFIG";
 | 
						||
      configFile2 = homeDir + "/.config/nixpkgs/config.nix";
 | 
						||
      configFile3 = homeDir + "/.nixpkgs/config.nix"; # obsolete
 | 
						||
    in
 | 
						||
      if configFile != "" && pathExists configFile then import configFile
 | 
						||
      else if homeDir != "" && pathExists configFile2 then import configFile2
 | 
						||
      else if homeDir != "" && pathExists configFile3 then import configFile3
 | 
						||
      else {}
 | 
						||
 | 
						||
, # Overlays are used to extend Nixpkgs collection with additional
 | 
						||
  # collections of packages.  These collection of packages are part of the
 | 
						||
  # fix-point made by Nixpkgs.
 | 
						||
  overlays ? let
 | 
						||
      isDir = path: pathExists (path + "/.");
 | 
						||
      pathOverlays = try (toString <nixpkgs-overlays>) "";
 | 
						||
      homeOverlaysFile = homeDir + "/.config/nixpkgs/overlays.nix";
 | 
						||
      homeOverlaysDir = homeDir + "/.config/nixpkgs/overlays";
 | 
						||
      overlays = path:
 | 
						||
        # check if the path is a directory or a file
 | 
						||
        if isDir path then
 | 
						||
          # it's a directory, so the set of overlays from the directory, ordered lexicographically
 | 
						||
          let content = readDir path; in
 | 
						||
          map (n: import (path + ("/" + n)))
 | 
						||
            (builtins.filter (n: builtins.match ".*\\.nix" n != null || pathExists (path + ("/" + n + "/default.nix")))
 | 
						||
              (attrNames content))
 | 
						||
        else
 | 
						||
          # it's a file, so the result is the contents of the file itself
 | 
						||
          import path;
 | 
						||
    in
 | 
						||
      if pathOverlays != "" && pathExists pathOverlays then overlays pathOverlays
 | 
						||
      else if pathExists homeOverlaysFile && pathExists homeOverlaysDir then
 | 
						||
        throw ''
 | 
						||
          Nixpkgs overlays can be specified with ${homeOverlaysFile} or ${homeOverlaysDir}, but not both.
 | 
						||
          Please remove one of them and try again.
 | 
						||
        ''
 | 
						||
      else if pathExists homeOverlaysFile then
 | 
						||
        if isDir homeOverlaysFile then
 | 
						||
          throw (homeOverlaysFile + " should be a file")
 | 
						||
        else overlays homeOverlaysFile
 | 
						||
      else if pathExists homeOverlaysDir then
 | 
						||
        if !(isDir homeOverlaysDir) then
 | 
						||
          throw (homeOverlaysDir + " should be a directory")
 | 
						||
        else overlays homeOverlaysDir
 | 
						||
      else []
 | 
						||
 | 
						||
, crossOverlays ? []
 | 
						||
 | 
						||
, ...
 | 
						||
} @ args:
 | 
						||
 | 
						||
# If `localSystem` was explicitly passed, legacy `system` and `platform` should
 | 
						||
# not be passed.
 | 
						||
assert args ? localSystem -> !(args ? system || args ? platform);
 | 
						||
 | 
						||
import ./. (builtins.removeAttrs args [ "system" "platform" ] // {
 | 
						||
  inherit config overlays crossSystem crossOverlays;
 | 
						||
  # Fallback: Assume we are building packages on the current (build, in GNU
 | 
						||
  # Autotools parlance) system.
 | 
						||
  localSystem = if builtins.isString localSystem then localSystem
 | 
						||
                else (if args ? localSystem then {}
 | 
						||
                      else { system = builtins.currentSystem; }) // localSystem;
 | 
						||
})
 |