When creating ZIP/EPUB files encode all file names in UTF-8 and set the UTF-8 bit marker. When extracting from a ZIP/EPUB file, if the UTF-8 bit marker is not set, still assume that the file name is encoded in UTF-8. If UTF-8 decoding fails try to detect character encoding using chardet. This is because most ZIP/EPUB files calibre comes across seem to be utf-8 encoded.

src/calibre/utils/zipfile.py

@@ -138,12 +138,16 @@ class LargeZipFile(Exception):
 
 def decode_arcname(name):
     if not isinstance(name, unicode):
-        encoding = detect(name)['encoding']
         try:
-            name = name.decode(encoding)
+            name = name.decode('utf-8')
         except:
-            name = name.decode('utf-8', 'replace')
-    return name.encode(filesystem_encoding, 'replace')
+            res = detect(name)
+            encoding = res['encoding']
+            try:
+                name = name.decode(encoding)
+            except:
+                name = name.decode('utf-8', 'replace')
+    return name
 
 
 def is_zipfile(filename):
@@ -352,10 +356,7 @@ def FileHeader(self):
 
     def _encodeFilenameFlags(self):
         if isinstance(self.filename, unicode):
-            try:
-                return self.filename.encode('ascii'), self.flag_bits
-            except:
-                return self.filename.encode('utf-8'), self.flag_bits | 0x800
+            return self.filename.encode('utf-8'), self.flag_bits | 0x800
         else:
             return self.filename, self.flag_bits
 
@@ -363,7 +364,7 @@ def _decodeFilename(self):
         if self.flag_bits & 0x800:
             return self.filename.decode('utf-8')
         else:
-            return self.filename
+            return decode_arcname(self.filename)
 
     def _decodeExtra(self):
         # Try to decode the extra field.
@@ -1059,7 +1060,9 @@ def _extract_member(self, member, targetpath, pwd):
             targetpath = targetpath[:-1]
 
         # don't include leading "/" from file name if present
-        fname = decode_arcname(member.filename)
+        fname = member.filename
+        if isinstance(fname, unicode):
+            fname = fname.encode(filesystem_encoding, 'replace')
         if fname.startswith('/'):
             fname = fname[1:]
         targetpath = os.path.join(targetpath, fname)
@@ -1111,8 +1114,6 @@ def _writecheck(self, zinfo):
     def write(self, filename, arcname=None, compress_type=None):
         """Put the bytes from filename into the archive under the name
         arcname."""
-        if isinstance(filename, unicode):
-            filename = filename.encode('utf-8')
         if not self.fp:
             raise RuntimeError(
                   "Attempt to write to ZIP archive that was already closed")
@@ -1126,6 +1127,8 @@ def write(self, filename, arcname=None, compress_type=None):
         arcname = os.path.normpath(os.path.splitdrive(arcname)[1])
         while arcname[0] in (os.sep, os.altsep):
             arcname = arcname[1:]
+        if not isinstance(arcname, unicode):
+            arcname = arcname.decode(filesystem_encoding)
         zinfo = ZipInfo(arcname, date_time)
         zinfo.external_attr = (st[0] & 0xFFFF) << 16L      # Unix attributes
         if compress_type is None:
@@ -1187,8 +1190,8 @@ def writestr(self, zinfo_or_arcname, bytes, permissions=0600,
         assert not raw_bytes or (raw_bytes and
                 isinstance(zinfo_or_arcname, ZipInfo))
         if not isinstance(zinfo_or_arcname, ZipInfo):
-            if isinstance(zinfo_or_arcname, unicode):
-                zinfo_or_arcname = zinfo_or_arcname.encode('utf-8')
+            if not isinstance(zinfo_or_arcname, unicode):
+                zinfo_or_arcname = zinfo_or_arcname.decode(filesystem_encoding)
             zinfo = ZipInfo(filename=zinfo_or_arcname,
                             date_time=time.localtime(time.time())[:6])
             zinfo.compress_type = compression