1 files changed, 52 insertions, 0 deletions
diff --git a/lib/PublicInbox/MboxReader.pm b/lib/PublicInbox/MboxReader.pm
index 6302d1fa..9291f00b 100644
--- a/lib/PublicInbox/MboxReader.pm
+++ b/lib/PublicInbox/MboxReader.pm
@@ -138,4 +138,56 @@ sub reads {
          $ifmt =~ /\Ambox(?:rd|cl|cl2|o)\z/ ? __PACKAGE__->can($ifmt) : undef
  }
  
+# all of these support -c for stdout and -d for decompression,
+# mutt is commonly distributed with hooks for gz, bz2 and xz, at least
+# { foo => '' } means "--foo" is passed to the command-line,
+# otherwise { foo => '--bar' } passes "--bar"
+my %zsfx2cmd = (
+        gz => [ qw(GZIP pigz gzip), { rsyncable => '' } ],
+        bz2 => [ 'bzip2', {} ],
+        xz => [ 'xz', {} ],
+        # don't add new entries here unless MUA support is widely available
+);
+
+sub zsfx ($) {
+        my ($pathname) = @_;
+        my $allow = join('|', keys %zsfx2cmd);
+        $pathname =~ /\.($allow)\z/ ? $1 : undef;
+}
+
+sub zsfx2cmd ($$$) {
+        my ($zsfx, $decompress, $lei) = @_;
+        my $x = $zsfx2cmd{$zsfx} // die "BUG: no support for suffix=.$zsfx";
+        my @info = @$x;
+        my $cmd_opt = pop @info;
+        my @cmd = (undef, $decompress ? qw(-dc) : qw(-c));
+        require PublicInbox::Spawn;
+        for my $exe (@info) {
+                # I think respecting client's ENV{GZIP} is OK, not sure
+                # about ENV overrides for other, less-common compressors
+                if ($exe eq uc($exe)) {
+                        $exe = $lei->{env}->{$exe} or next;
+                }
+                $cmd[0] = PublicInbox::Spawn::which($exe) and last;
+        }
+        $cmd[0] // die join(' or ', @info)." missing for .$zsfx";
+        # push @cmd, @{$cmd_opt->{-default}} if $cmd_opt->{-default};
+        for my $bool (qw(rsyncable)) {
+                my $switch = $cmd_opt->{rsyncable} // next;
+                push @cmd, '--'.($switch || $bool);
+        }
+        for my $key (qw(rsyncable)) { # support compression level?
+                my $switch = $cmd_opt->{$key} // next;
+                my $val = $lei->{opt}->{$key} // next;
+                push @cmd, $switch, $val;
+        }
+        \@cmd;
+}
+
+sub zsfxcat ($$$) {
+        my ($in, $zsfx, $lei) = @_;
+        my $cmd = zsfx2cmd($zsfx, 1, $lei);
+        PublicInbox::Spawn::popen_rd($cmd, undef, { 0 => $in, 2 => $lei->{2} });
+}
+
  1;