fetch: use new checksum verification

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

Library/Homebrew/cmd/fetch.rb

@@ -36,14 +36,10 @@ module Homebrew extend self
       puts "SHA1: #{the_tarball.sha1}"
       puts "SHA256: #{the_tarball.sha2}"
 
-      unless previous_md5.nil? or previous_md5.empty? or the_tarball.md5 == previous_md5
-        opoo "Formula reports different MD5: #{previous_md5}"
-      end
-      unless previous_sha1.nil? or previous_sha1.empty? or the_tarball.sha1 == previous_sha1
-        opoo "Formula reports different SHA1: #{previous_sha1}"
-      end
-      unless previous_sha2.nil? or previous_sha2.empty? or the_tarball.sha2 == previous_sha2
-        opoo "Formula reports different SHA256: #{previous_sha2}"
+      begin
+        f.verify_download_integrity the_tarball
+      rescue ChecksumMismatchError => e
+        opoo "Formula reports different #{e.hash_type}: #{e.expected}"
       end
     end
   end

Library/Homebrew/exceptions.rb

@@ -158,15 +158,17 @@ class ChecksumMismatchError < RuntimeError
   attr :advice, true
   attr :expected
   attr :actual
+  attr :hash_type
 
   def initialize expected, actual
     @expected = expected
     @actual = actual
+    @hash_type = expected.hash_type.to_s.upcase
 
     super <<-EOS.undent
-      #{expected.hash_type.to_s.upcase} mismatch
-      Expected: #{expected}
-      Actual: #{actual}
+      #{@hash_type} mismatch
+      Expected: #{@expected}
+      Actual: #{@actual}
       EOS
   end