CBR Input: Fix comics with extremely long filenames not working on Windows. Fixes #2031047 [Private bug](https://bugs.launchpad.net/calibre/+bug/2031047)

src/calibre/ebooks/comic/input.py

@@ -115,7 +115,8 @@ class PageProcessor(list):  # {{{
         from qt.core import QImage
 
         from calibre.utils.img import crop_image, image_from_data, scale_image
-        with open(self.path_to_page, 'rb') as f:
+        from calibre.utils.filenames import make_long_path_useable
+        with open(make_long_path_useable(self.path_to_page), 'rb') as f:
             img = image_from_data(f.read())
         width, height = img.width(), img.height()
         if self.num == 0:  # First image so create a thumbnail from it

src/calibre/utils/filenames.py

@@ -601,8 +601,8 @@ rmtree = shutil.rmtree
 if iswindows:
     long_path_prefix = '\\\\?\\'
 
-    def make_long_path_useable(path):
-        if len(path) > 200 and os.path.isabs(path) and not path.startswith(long_path_prefix):
+    def make_long_path_useable(path, threshold=200):
+        if len(path) > threshold and os.path.isabs(path) and not path.startswith(long_path_prefix):
             path = long_path_prefix + os.path.normpath(path)
         return path
 
@@ -636,7 +636,7 @@ if iswindows:
             raise
 
 else:
-    def make_long_path_useable(path):
+    def make_long_path_useable(path, threshold=200):
         return path
 
     def get_long_path_name(path):

src/calibre/utils/unrar.py

@@ -12,6 +12,7 @@ from io import BytesIO
 
 from calibre.constants import filesystem_encoding, iswindows
 from calibre.ptempfile import PersistentTemporaryFile, TemporaryDirectory
+from calibre.utils.filenames import make_long_path_useable
 from polyglot.builtins import string_or_bytes
 
 
@@ -52,19 +53,19 @@ class StreamAsPath:
 def extract(path_or_stream, location):
     from unrardll import extract
     with StreamAsPath(path_or_stream) as path:
-        return extract(path, location)
+        return extract(make_long_path_useable(path), make_long_path_useable(location, threshold=0))
 
 
 def names(path_or_stream):
     from unrardll import names
     with StreamAsPath(path_or_stream) as path:
-        yield from names(path, only_useful=True)
+        yield from names(make_long_path_useable(path), only_useful=True)
 
 
 def headers(path_or_stream):
     from unrardll import headers, is_useful
     with StreamAsPath(path_or_stream) as path:
-        for h in headers(path):
+        for h in headers(make_long_path_useable(path)):
             if is_useful(h):
                 yield h
 
@@ -72,7 +73,7 @@ def headers(path_or_stream):
 def comment(path_or_stream):
     from unrardll import comment
     with StreamAsPath(path_or_stream) as path:
-        return comment(path)
+        return comment(make_long_path_useable(path))
 
 
 def extract_member(
@@ -89,7 +90,7 @@ def extract_member(
                (match is not None and match.search(fname) is not None)
 
     with StreamAsPath(path_or_stream) as path:
-        name, data = extract_member(path, is_match)
+        name, data = extract_member(make_long_path_useable(path), is_match)
         if name is not None:
             return name, data
 
@@ -97,7 +98,7 @@ def extract_member(
 def extract_members(path_or_stream, callback):
     from unrardll import extract_members
     with StreamAsPath(path_or_stream) as path:
-        extract_members(path, callback)
+        extract_members(make_long_path_useable(path), callback)
 
 
 def extract_first_alphabetically(stream):