29027fd1e1
Using pkgs.lib on the spine of module evaluation is problematic because the pkgs argument depends on the result of module evaluation. To prevent an infinite recursion, pkgs and some of the modules are evaluated twice, which is inefficient. Using ‘with lib’ prevents this problem.
43 lines
733 B
Nix
43 lines
733 B
Nix
{ config, lib, pkgs, ... }:
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with lib;
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let
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pkg = if config.hardware.sane.snapshot then pkgs.saneBackendsGit else pkgs.saneBackends;
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in
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{
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###### interface
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options = {
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hardware.sane.enable = mkOption {
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type = types.bool;
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default = false;
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description = "Enable support for SANE scanners.";
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};
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hardware.sane.snapshot = mkOption {
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type = types.bool;
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default = false;
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description = "Use a development snapshot of SANE scanner drivers.";
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};
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};
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###### implementation
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config = mkIf config.hardware.sane.enable {
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environment.systemPackages = [ pkg ];
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services.udev.packages = [ pkg ];
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users.extraGroups."scanner".gid = config.ids.gids.scanner;
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};
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}
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