[libgxps] regtest: Read test results in chunks to get the md5 digest

[Carlos Garcia Campos <carlosgc src gnome org>]

commit 151e161f6823069f1efc027e2acf69d0062d2ece
Author: Carlos Garcia Campos <carlosgc gnome org>
Date:   Tue Jun 23 18:28:32 2015 +0200

    regtest: Read test results in chunks to get the md5 digest
    
    Instead of creating the md5 object with the entire file, we feed it with
    chunks of data using the update method. This improves a lot the memory
    consumption and performance as well.

 regtest/Test.py |   18 +++++++++++-------
 1 files changed, 11 insertions(+), 7 deletions(-)
---
diff --git a/regtest/Test.py b/regtest/Test.py
index 3e22e74..6f5374e 100644
--- a/regtest/Test.py
+++ b/regtest/Test.py
@@ -16,7 +16,7 @@
 # along with this program; if not, write to the Free Software
 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 
-from hashlib import md5
+import hashlib
 import os
 import subprocess
 import shutil
@@ -30,6 +30,14 @@ class Test:
         self._xpstopng = os.path.join(Config().tools_dir, 'xpstopng')
         self.printer = get_printer()
 
+    def __md5sum(self, ref_path):
+        md5 = hashlib.md5()
+        with open(ref_path,'rb') as f:
+            for chunk in iter(lambda: f.read(128 * md5.block_size), b''):
+                md5.update(chunk)
+
+        return md5.hexdigest()
+
     def __should_have_checksum(self, entry):
         return entry not in ('md5', 'crashed', 'failed', 'stderr');
 
@@ -42,9 +50,7 @@ class Test:
                 continue
 
             ref_path = os.path.join(refs_path, entry)
-            f = open(ref_path, 'rb')
-            md5_file.write("%s %s\n" % (md5(f.read()).hexdigest(), ref_path))
-            f.close()
+            md5_file.write("%s %s\n" % (self.__md5sum(ref_path), ref_path))
             if delete_refs:
                 os.remove(ref_path)
 
@@ -70,10 +76,8 @@ class Test:
                 continue
 
             result_path = os.path.join(out_path, basename)
-            f = open(result_path, 'rb')
-            result_md5sum = md5(f.read()).hexdigest()
+            result_md5sum = self.__md5sum(result_path);
             matched = md5sum == result_md5sum
-            f.close()
 
             if update_refs:
                 result_md5.append("%s %s\n" % (result_md5sum, ref_path))