Smarter handling of TemporaryDirectory disk space

[glennmatthews]

When converting disks between formats, COT may need to use one or more temporary directories to store files. COT uses the tempfile module for this purpose. which by default creates temporary directories in, by preference:

1. The directory named by the TMPDIR environment variable.
2. The directory named by the TEMP environment variable.
3. The directory named by the TMP environment variable.
4. A platform-specific location:
   • On RiscOS, the directory named by the Wimp$ScrapDir environment variable.
   • On Windows, the directories C:\TEMP, C:\TMP, \TEMP, and \TMP, in that order.
   • On all other platforms, the directories /tmp, /var/tmp, and /usr/tmp, in that order.
     5. As a last resort, the current working directory.

When working with large files (such as RAW disk images), /tmp is often not large enough to contain these files, and COT fails ungracefully in this case.

COT should check the available disk space in the created temporary directory against the expected size of any file(s) it will store there and warn the user.

If an out of space error occurs, COT should recognize this and advise the user how to set their environment variables to select a different location.

[glennmatthews]

Fixed in 2.0.0