PASS1-56: Use XFP in backups filename and don't save `backup_num` (#32)

ports/stm32/boards/Passport/modules/export.py

@@ -484,8 +484,9 @@ async def write_complete_backup(words, auto_backup=False, is_first_backup=False)
 
     body = render_backup_contents().encode()
 
-    backup_num = settings.get('backup_num', 1)
-    # print('backup_num={}'.format(backup_num))
+    backup_num = 1
+    xfp = xfp2str(settings.get('xfp')).lower()
+    # print('XFP: {}'.format(xfp))
 
     gc.collect()
 
@@ -520,7 +521,7 @@ async def write_complete_backup(words, auto_backup=False, is_first_backup=False)
 
                 # Make a unique filename
                 while True:
-                    base_filename = 'passport-backup-{}.7z'.format(backup_num)
+                    base_filename = '{}-backup-{}.7z'.format(xfp, backup_num)
                     fname = '{}/{}'.format(backups_path, base_filename)
 
                     # Ensure filename doesn't already exist
@@ -529,7 +530,6 @@ async def write_complete_backup(words, auto_backup=False, is_first_backup=False)
 
                     # Ooops...that exists, so increment and try again
                     backup_num += 1
-                    # print('backup_num={}'.format(backup_num))
 
                 # print('Saving to fname={}'.format(fname))
 
@@ -558,10 +558,6 @@ async def write_complete_backup(words, auto_backup=False, is_first_backup=False)
             else:
                 return
 
-        # Update backup counter
-        backup_num += 1
-        settings.set('backup_num', backup_num)
-
         if not auto_backup:
             await ux_show_story('Saved backup to\n\n{}\n\nin /backups folder.'.format(base_filename),
                 title='Success', left_btn='NEXT', center=True, center_vertically=True)

ports/stm32/boards/Passport/modules/schema_evolution.py

@@ -29,6 +29,14 @@ async def handle_schema_evolutions(update_from_to):
             from_version = to_version
             continue
 
+        elif from_version == '1.0.6' and to_version == '1.0.7':
+            # Handle evolutions
+
+            # This no longer used, so clean it out
+            settings.remove('backup_num')
+            from_version = to_version
+            continue
+
         # We only reach here if no more evolutions are possible.
         # Remove the update indicator from the settings.
         # NOTE: There is a race condition here, but these evolutions should be extremely fast, and ideally

ports/stm32/boards/Passport/modules/utils.py

@@ -491,10 +491,14 @@ def ensure_folder_exists(path):
         return
 
 def file_exists(path):
+    import os
+    from stat import S_ISREG
+
     try:
-        with open(fname, 'wb') as fd:
-            return True
-    except:
+        s = os.stat(path)
+        mode = s[0]
+        return S_ISREG(mode)
+    except OSError as e:
         return False
 
 def folder_exists(path):