lei_input: support compressed mboxes

Since "lei q" and "lei convert" already support writing these
compressed inboxes, it makes sense that all mbox readers support
them, as well.

Using compression is one reliable way to know an mboxrd or mboxo
hasn't been unexpectedly truncated.

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;