Submitted by: Basil A. Sidorov (basid)

Votes: 1

Add ability automatic (de)compressor filter for backup (gbak) and dump (nbackup) on engine level via firebird.conf settings.
Motivation - universal (de)compression for services "by suffix".

New directives in firebird.conf:
FilterCompressor: type - string, value - suffix and compressor command line (.zst,"zstd -1q" and so on). Multiple directives allowed. Default value - None (no filter).
FilterDecompressor: type - sting, value - suffix and decompressor command line (.zst,"zstd -qd" and soon). Mulitple directives allowed. Default value - None (no filter).

Compressor filters not used for special name stdout and apply only for file with "known" suffix.
If input stream (from stdin or from file) not accepted "by suffix" (filter command return non-zero error code) and not accepted "without filter", engine may try all known decompressors (in some order).
If filter applied, engine must add message about filter into log.