From 46b9a7a325d863179ff154cc34a67caf34c78b08 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Wed, 10 Apr 2019 15:05:46 +0530
Subject: [PATCH] py3: Fix various call sites of ascii_filename() that assume
 the result is a bytestring

---
 src/calibre/db/backend.py               | 13 ++++++-------
 src/calibre/ebooks/mobi/writer2/main.py |  5 ++++-
 src/calibre/ebooks/mobi/writer8/mobi.py |  6 ++++--
 src/calibre/library/database2.py        | 11 +++++------
 4 files changed, 19 insertions(+), 16 deletions(-)

diff --git a/src/calibre/db/backend.py b/src/calibre/db/backend.py
index 8800b47885..f51fb88e90 100644
--- a/src/calibre/db/backend.py
+++ b/src/calibre/db/backend.py
@@ -1179,8 +1179,8 @@ class DB(object):
         '''
         book_id = ' (%d)' % book_id
         l = self.PATH_LIMIT - (len(book_id) // 2) - 2
-        author = ascii_filename(author)[:l].decode('ascii', 'replace')
-        title  = ascii_filename(title.lstrip())[:l].decode('ascii', 'replace').rstrip()
+        author = ascii_filename(author)[:l]
+        title  = ascii_filename(title.lstrip())[:l].rstrip()
         if not title:
             title = 'Unknown'[:l]
         try:
@@ -1189,8 +1189,7 @@ class DB(object):
         except IndexError:
             author = ''
         if not author:
-            author = ascii_filename(_('Unknown')).decode(
-                    'ascii', 'replace')
+            author = ascii_filename(_('Unknown'))
         if author.upper() in WINDOWS_RESERVED_NAMES:
             author += 'w'
         return '%s/%s%s' % (author, title, book_id)
@@ -1207,15 +1206,15 @@ class DB(object):
         l = (self.PATH_LIMIT - (extlen // 2) - 2) if iswindows else ((self.PATH_LIMIT - extlen - 2) // 2)
         if l < 5:
             raise ValueError('Extension length too long: %d' % extlen)
-        author = ascii_filename(author)[:l].decode('ascii', 'replace')
-        title  = ascii_filename(title.lstrip())[:l].decode('ascii', 'replace').rstrip()
+        author = ascii_filename(author)[:l]
+        title  = ascii_filename(title.lstrip())[:l].rstrip()
         if not title:
             title = 'Unknown'[:l]
         name   = title + ' - ' + author
         while name.endswith('.'):
             name = name[:-1]
         if not name:
-            name = ascii_filename(_('Unknown')).decode('ascii', 'replace')
+            name = ascii_filename(_('Unknown'))
         return name
 
     # Database layer API {{{
diff --git a/src/calibre/ebooks/mobi/writer2/main.py b/src/calibre/ebooks/mobi/writer2/main.py
index 5edd7eebfe..74f1cf79f0 100644
--- a/src/calibre/ebooks/mobi/writer2/main.py
+++ b/src/calibre/ebooks/mobi/writer2/main.py
@@ -460,7 +460,10 @@ class MobiWriter(object):
         Write the PalmDB header
         '''
         title = ascii_filename(unicode_type(self.oeb.metadata.title[0])).replace(
-                ' ', '_')[:31]
+                ' ', '_')
+        if not isinstance(title, bytes):
+            title = title.encode('ascii')
+        title = title[:31]
         title = title + (b'\0' * (32 - len(title)))
         now = int(time.time())
         nrecords = len(self.records)
diff --git a/src/calibre/ebooks/mobi/writer8/mobi.py b/src/calibre/ebooks/mobi/writer8/mobi.py
index c88523b5fc..cf92006a41 100644
--- a/src/calibre/ebooks/mobi/writer8/mobi.py
+++ b/src/calibre/ebooks/mobi/writer8/mobi.py
@@ -332,8 +332,10 @@ class KF8Book(object):
 
             # Write PalmDB Header
 
-            title = ascii_filename(self.full_title.decode('utf-8')).replace(
-                    ' ', '_')[:31]
+            title = ascii_filename(self.full_title.decode('utf-8')).replace(' ', '_')
+            if not isinstance(title, bytes):
+                title = title.encode('ascii')
+            title = title[:31]
             title += (b'\0' * (32 - len(title)))
             now = int(time.time())
             nrecords = len(records)
diff --git a/src/calibre/library/database2.py b/src/calibre/library/database2.py
index 35cc22f8e6..e73f76bf5b 100644
--- a/src/calibre/library/database2.py
+++ b/src/calibre/library/database2.py
@@ -611,14 +611,13 @@ class LibraryDatabase2(LibraryDatabase, SchemaUpgrade, CustomColumns):
         if not authors:
             authors = _('Unknown')
         author = ascii_filename(authors.split(',')[0].replace('|', ',')
-                    )[:self.PATH_LIMIT].decode('ascii', 'replace')
+                    )[:self.PATH_LIMIT]
         title  = ascii_filename(self.title(id, index_is_id=True)
-                    )[:self.PATH_LIMIT].decode('ascii', 'replace')
+                    )[:self.PATH_LIMIT]
         while author[-1] in (' ', '.'):
             author = author[:-1]
         if not author:
-            author = ascii_filename(_('Unknown')).decode(
-                    'ascii', 'replace')
+            author = ascii_filename(_('Unknown'))
         path = author + '/' + title + ' (%d)'%id
         return path
 
@@ -630,9 +629,9 @@ class LibraryDatabase2(LibraryDatabase, SchemaUpgrade, CustomColumns):
         if not authors:
             authors = _('Unknown')
         author = ascii_filename(authors.split(',')[0].replace('|', ',')
-                    )[:self.PATH_LIMIT].decode('ascii', 'replace')
+                    )[:self.PATH_LIMIT]
         title  = ascii_filename(self.title(id, index_is_id=True)
-                    )[:self.PATH_LIMIT].decode('ascii', 'replace')
+                    )[:self.PATH_LIMIT]
         name   = title + ' - ' + author
         while name.endswith('.'):
             name = name[:-1]