[pitivi/ges] utils/misc: Add utility to compute the hash of a file

[Jean-FranÃois Fortin Tam <jfft src gnome org>]

commit e0a98dedb0e3c2cd34353c7fa0030dc1d223fe3d
Author: Daniel Thul <daniel thul googlemail com>
Date:   Mon Apr 23 19:17:36 2012 +0200

    utils/misc: Add utility to compute the hash of a file

 pitivi/utils/misc.py |   13 +++++++++++++
 1 files changed, 13 insertions(+), 0 deletions(-)
---
diff --git a/pitivi/utils/misc.py b/pitivi/utils/misc.py
index 45e2e4b..0103a51 100644
--- a/pitivi/utils/misc.py
+++ b/pitivi/utils/misc.py
@@ -26,6 +26,7 @@ import sys
 import gobject
 import gst
 import gtk
+import hashlib
 import bisect
 import os
 import struct
@@ -204,6 +205,18 @@ class PathWalker(Thread):
         self.stopme.set()
 
 
+def hash_file(uri):
+    """Hashes the first 256KB of the specified file"""
+    sha256 = hashlib.sha256()
+    with open(uri, "rb") as file:
+        for _ in range(1024):
+            chunk = file.read(256)
+            if not chunk:
+                break
+            sha256.update(chunk)
+    return sha256.hexdigest()
+
+
 #------------------------------ Gst helpers   --------------------------------#
 def get_controllable_properties(element):
     """