Re: [PATCH] profiles: Add 'hicolor' and 'HighContrast' icon theme hooks.

[宋文武 <iyzsong@gmail.com>]

This is WIP.
> * guix/profiles.scm (gtk-icon-theme-hook): New function.
>   (%default-profile-hooks): Add `(gtk-icon-theme-hook "hicolor")' and
>   `(gtk-icon-theme-hook "HighContrast")'.
> ---
>  guix/profiles.scm | 36 +++++++++++++++++++++++++++++++++++-
>  1 file changed, 35 insertions(+), 1 deletion(-)
>
> diff --git a/guix/profiles.scm b/guix/profiles.scm
> index 11d9bf0..9756685 100644
> --- a/guix/profiles.scm
> +++ b/guix/profiles.scm
> @@ -573,12 +573,46 @@ MANIFEST.  Single-file bundles are required by programs such as Git and Lynx."
>                      #:modules '((guix build utils))
>                      #:local-build? #t))
>  
> +(define (gtk-icon-theme-hook name)
> +  "Return a profile hook that unions all NAME icons from manifest entries and
> +rebuilds the 'icon-theme.cache' file for the NAME icon theme."
> +  (define gtk+
> +    (module-ref (resolve-interface '(gnu packages gtk)) 'gtk+))
> +
> +  (lambda (manifest)
> +    (define build
> +      #~(begin
> +          (use-modules (guix build utils)
> +                       (guix build union))
> +          (let* ((icon-dir (lambda (base)
> +                             (string-append base "/share/icons/" #$name)))
> +                 (destdir  (icon-dir #$output))
> +                 (icons    (filter
> +                            file-exists?
> +                            (map icon-dir '#$(manifest-inputs manifest))))
> +                 (update-icon-cache (string-append
> +                                     #+gtk+ "/bin/gtk-update-icon-cache")))
> +            ;; mkdir -p $out/share/icons
> +            (mkdir-p destdir)
> +            (rmdir destdir)
> +            ;; Unions all the icons and update the 'icon-theme.cache'.
> +            (union-build destdir icons)
> +            (system* update-icon-cache "-t" destdir))))
> +
> +    (gexp->derivation (string-append (string-downcase name) "-icon-theme")
> +                      build
> +                      #:modules '((guix build utils)
> +                                  (guix build union))
> +                      #:local-build? #t)))
When to exclude this derivation?

1. the best would be whether icon dir exists or not
   but is this posibble to implement? and how?

2. whether we have a gtk+ package in profile

And any better way?
> +
>  (define %default-profile-hooks
>    ;; This is the list of derivation-returning procedures that are called by
>    ;; default when making a non-empty profile.
>    (list info-dir-file
>          ghc-package-cache-file
> -        ca-certificate-bundle))
> +        ca-certificate-bundle
> +        (gtk-icon-theme-hook "hicolor")
> +        (gtk-icon-theme-hook "HighContrast")))
Does these 2 enough?  I think in practical, it does.
Or (better) as Federico Beffa said in:

  http://lists.gnu.org/archive/html/guix-devel/2015-01/msg00108.html

We should rebuilds all the icon themes?
If so, I think the code will be more complex...
>  
>  (define* (profile-derivation manifest
>                               #:key
> -- 
> 2.2.1