implement text.shorten_path/filename methods

gallery_dl/text.py

@@ -8,7 +8,9 @@
 
 """Collection of functions that work in strings/text"""
 
+import sys
 import re
+import os.path
 import html.parser
 import urllib.parse
 import platform
@@ -40,6 +42,17 @@ def clean_path_posix(path):
     except AttributeError:
         return path
 
+def shorten_path(path, limit=255, encoding=sys.getfilesystemencoding()):
+    """Shorten a path segment to at most 'limit' bytes"""
+    return (path.encode(encoding)[:limit]).decode(encoding, "ignore")
+
+def shorten_filename(filename, limit=255, encoding=sys.getfilesystemencoding()):
+    """Shorten a filename to at most 'limit' bytes while preserving extension"""
+    name, extension = os.path.splitext(filename)
+    bext = extension.encode(encoding)
+    bname = name.encode(encoding)[:limit-len(bext)]
+    return bname.decode(encoding, "ignore") + extension
+
 def extract(txt, begin, end, pos=0):
     try:
         first = txt.index(begin, pos) + len(begin)