Issue #19623: Fixed writing to unseekable files in the aifc module.
diff --git a/Lib/aifc.py b/Lib/aifc.py
index 86a5edc..db0924a 100644
--- a/Lib/aifc.py
+++ b/Lib/aifc.py
@@ -771,7 +771,10 @@
self._datalength = (self._datalength + 3) // 4
if self._datalength & 1:
self._datalength = self._datalength + 1
- self._form_length_pos = self._file.tell()
+ try:
+ self._form_length_pos = self._file.tell()
+ except (AttributeError, OSError):
+ self._form_length_pos = None
commlength = self._write_form_length(self._datalength)
if self._aifc:
self._file.write(b'AIFC')
@@ -783,7 +786,8 @@
self._file.write(b'COMM')
_write_ulong(self._file, commlength)
_write_short(self._file, self._nchannels)
- self._nframes_pos = self._file.tell()
+ if self._form_length_pos is not None:
+ self._nframes_pos = self._file.tell()
_write_ulong(self._file, self._nframes)
if self._comptype in (b'ULAW', b'ulaw', b'ALAW', b'alaw', b'G722'):
_write_short(self._file, 8)
@@ -794,7 +798,8 @@
self._file.write(self._comptype)
_write_string(self._file, self._compname)
self._file.write(b'SSND')
- self._ssnd_length_pos = self._file.tell()
+ if self._form_length_pos is not None:
+ self._ssnd_length_pos = self._file.tell()
_write_ulong(self._file, self._datalength + 8)
_write_ulong(self._file, 0)
_write_ulong(self._file, 0)