Refactor, make default notrim

yt_dlp/YoutubeDL.py

@@ -70,7 +70,6 @@ from .update import (
 )
 from .utils import (
     DEFAULT_OUTTMPL,
-    DEFAULT_MAX_FILE_NAME,
     IDENTITY,
     LINK_TEMPLATES,
     MEDIA_EXTENSIONS,
@@ -267,6 +266,7 @@ class YoutubeDL:
     outtmpl_na_placeholder: Placeholder for unavailable meta fields.
     restrictfilenames: Do not allow "&" and spaces in file names
     trim_file_name:    Limit length of filename (extension excluded)
+    trim_file_name_mode: Mode of filename trimming ('c' for characters or 'b' for bytes)
     filesystem_encoding: Encoding to use when calculating filename length in bytes
     windowsfilenames:  True: Force filenames to be Windows compatible
                        False: Sanitize filenames only minimally
@@ -1438,31 +1438,8 @@ class YoutubeDL:
         outtmpl = self.escape_outtmpl(outtmpl)
         filename = outtmpl % info_dict
 
-        def parse_max_file_name(max_file_name: str):
-            # old --trim-filenames format
-            try:
-                return 'c', int(max_file_name)
-            except ValueError:
-                pass
-
-            try:
-                max_length = int(max_file_name[:-1])
-            except ValueError:
-                raise ValueError('Invalid --trim-filenames specified')
-
-            if max_file_name[-1].lower() == 'c':
-                return 'c', max_length
-            elif max_file_name[-1].lower() == 'b':
-                return 'b', max_length
-            else:
-                raise ValueError("--trim-filenames must end with 'b' or 'c'")
-
         max_file_name = self.params.get('trim_file_name')
-        if max_file_name is None:
-            max_file_name = DEFAULT_MAX_FILE_NAME
-        mode, max_file_name = parse_max_file_name(max_file_name)
-        if max_file_name < 0:
-            raise ValueError('Invalid --trim-filenames specified')
+        mode = self.params.get('trim_file_name_mode')
         if max_file_name == 0:
             # no maximum
             return filename + suffix

yt_dlp/__init__.py

@@ -1,3 +1,4 @@
+import codecs
 import sys
 
 if sys.version_info < (3, 9):
@@ -429,6 +430,21 @@ def validate_options(opts):
     }
 
     # Other options
+    opts.trim_file_name_mode = 'c'
+    if opts.trim_file_name is not None:
+        mobj = re.match(r'(?:(?P<length>\d+)(?P<mode>b|c)?|notrim)', opts.trim_file_name)
+        validate(mobj, 'trim filenames', opts.trim_file_name)
+        if opts.trim_file_name == 'notrim':
+            opts.trim_file_name = 0
+        else:
+            opts.trim_file_name = int(mobj.group('length'))
+            opts.trim_file_name_mode = mobj.group('mode') or 'c'
+    if opts.filesystem_encoding is not None:
+        try:
+            codecs.lookup(opts.filesystem_encoding)
+        except LookupError:
+            raise ValueError(f'Invalid filesystem encoding: {opts.filesystem_encoding}')
+
     if opts.playlist_items is not None:
         try:
             tuple(PlaylistEntries.parse_playlist_items(opts.playlist_items))
@@ -886,6 +902,7 @@ def parse_options(argv=None):
         'max_downloads': opts.max_downloads,
         'prefer_free_formats': opts.prefer_free_formats,
         'trim_file_name': opts.trim_file_name,
+        'trim_file_name_mode': opts.trim_file_name_mode,
         'filesystem_encoding': opts.filesystem_encoding,
         'verbose': opts.verbose,
         'dump_intermediate_pages': opts.dump_intermediate_pages,

yt_dlp/options.py

@@ -1378,7 +1378,7 @@ def create_parser():
         help='Sanitize filenames only minimally')
     filesystem.add_option(
         '--trim-filenames', '--trim-file-names', metavar='LENGTH',
-        dest='trim_file_name',
+        dest='trim_file_name', default='notrim',
         help='Limit the filename length (excluding extension) to the specified number of characters or bytes')
     filesystem.add_option(
         '--filesystem-encoding', metavar='ENCODING',

yt_dlp/utils/_utils.py

@@ -2852,12 +2852,6 @@ OUTTMPL_TYPES = {
     'pl_infojson': 'info.json',
 }
 
-# https://en.m.wikipedia.org/wiki/Comparison_of_file_systems#Limits
-if platform.system() in ('Darwin', 'Windows'):
-    DEFAULT_MAX_FILE_NAME = f'{255 - len(".annotations.xml")}c'
-else:
-    DEFAULT_MAX_FILE_NAME = f'{255 - len(".annotations.xml".encode(sys.getfilesystemencoding()))}b'
-
 # As of [1] format syntax is:
 #  %[mapping_key][conversion_flags][minimum_width][.precision][length_modifier]type
 # 1. https://docs.python.org/2/library/stdtypes.html#string-formatting