More hashing refactoring to work with byte chunks

Signed-off-by: Adam Vandenberg <flangy@gmail.com>

Library/Homebrew/extend/pathname.rb

@@ -155,15 +155,29 @@ class Pathname
     nil
   end
   
-  def md5
+  def incremental_hash(hasher)
-    require 'digest'
+    incr_hash = hasher.new
-    incr_md5 = Digest::MD5.new
     self.open('r') do |f|
-      f.each_line do |line|
+      while(buf = f.read(1024))
-        incr_md5 << line
+        incr_hash << buf
       end
     end
-    incr_md5.hexdigest
+    incr_hash.hexdigest
+  end
+
+  def md5
+    require 'digest/md5'
+    incremental_hash(Digest::MD5)
+  end
+  
+  def sha1
+    require 'digest/sha1'
+    incremental_hash(Digest::SHA1)
+  end
+  
+  def sha2
+    require 'digest/sha2'
+    incremental_hash(Digest::SHA2)
   end
 
   if '1.9' <= RUBY_VERSION

Library/Homebrew/formula.rb

@@ -326,13 +326,7 @@ private
     supplied=instance_variable_get("@#{type}")
     type=type.to_s.upcase
     hasher = Digest.const_get(type)
-
+    hash = fn.incremental_hash(hasher)
-    # Most are MD5 and it should be efficient.
-    if hasher == Digest::MD5
-      hash = fn.md5
-    else
-      hash = hasher.hexdigest(fn.read)
-    end
 
     if supplied and not supplied.empty?
       raise "#{type} mismatch\nExpected: #{hash}\nArchive: #{fn}" unless supplied.upcase == hash.upcase