lib.meta: introduce `availableOn`

1 files changed, 12 insertions, 0 deletions

diff --git a/lib/meta.nix b/lib/meta.nix
index 2e83c4247ddfb..bc04394dcf0b5 100644
--- a/lib/meta.nix
+++ b/lib/meta.nix
@@ -87,4 +87,16 @@ rec {
         then { system = elem; }
         else { parsed = elem; };
     in lib.matchAttrs pattern platform;
+
+  /* Check if a package is available on a given platform.
+
+     A package is available on a platform if both
+
+       1. One of `meta.platforms` pattern matches the given platform.
+
+       2. None of `meta.badPlatforms` pattern matches the given platform.
+  */
+  availableOn = platform: pkg:
+    lib.any (platformMatch platform) pkg.meta.platforms &&
+    lib.all (elem: !platformMatch platform elem) (pkg.meta.badPlatforms or []);
 }