signing-party: use a requirement for gpg

Signed-off-by: Jack Nagel <jacknagel@gmail.com>

1 files changed, 23 insertions, 1 deletions

diff --git a/Library/Formula/signing-party.rb b/Library/Formula/signing-party.rb
index 53ae23f52..eccb85799 100644
--- a/Library/Formula/signing-party.rb
+++ b/Library/Formula/signing-party.rb
@@ -1,11 +1,33 @@
 require 'formula'
 
+class GnupgInstalled < Requirement
+  def message; <<-EOS.undent
+    Gnupg is required to use these tools.
+
+    You can install Gnupg or Gnupg2 with Homebrew:
+      brew install gnupg
+      brew install gnupg2
+
+    Or you can use one of several different
+    prepackaged installers that are available.
+    EOS
+  end
+
+  def satisified?
+    which 'gpg' or which 'gpg2'
+  end
+
+  def fatal?
+    false
+  end
+end
+
 class SigningParty < Formula
   homepage 'http://pgp-tools.alioth.debian.org/'
   url 'http://ftp.debian.org/debian/pool/main/s/signing-party/signing-party_1.1.4.orig.tar.gz'
   md5 '675f8f1edd01baa8b58a743927d13750'
 
-  depends_on 'gnupg' unless which 'gpg'
+  depends_on GnupgInstalled.new
   depends_on 'dialog'
   depends_on 'qprint'
   depends_on 'MIME::Tools' => :perl