src: consolidate compute_md5 functions

Add compute_md5 function in src/utils/fs.py

Remove identical md5 functions from src/live/ogOperations.py and
src/utils/tiptorrent.py

Move error checks from ogOperations.py into compute_md5 function in
src/utils/fs.py

1 files changed, 17 insertions, 0 deletions

diff --git a/src/utils/fs.py b/src/utils/fs.py
index d6cf36a..8446f08 100644
--- a/src/utils/fs.py
+++ b/src/utils/fs.py
@@ -8,6 +8,7 @@
 
 import logging
 import os
+import hashlib
 import subprocess
 import shlex
 from src.log import OgError
@@ -340,3 +341,19 @@ def _extend_ntfsresize(partdev):
     proc = subprocess.run(cmd, input=b'y')
     if proc.returncode != 0:
         raise OgError(f'Error growing ntfs filesystem at {partdev}')
+
+def compute_md5(path, bs=2**20):
+    if not os.path.exists(path):
+        raise OgError(f"Failed to calculate checksum, image file {path} does not exist")
+
+    m = hashlib.md5()
+    try:
+        with open(path, 'rb') as f:
+            while True:
+                buf = f.read(bs)
+                if not buf:
+                    break
+                m.update(buf)
+    except Exception as e:
+        raise OgError(f'Failed to calculate checksum for {path}: {e}') from e
+    return m.hexdigest()