add open_compressed_file routine to Debbugs::Common

diff --git a/Debbugs/Common.pm b/Debbugs/Common.pm
index 276cbd0fdfc46217a262055f363db6d4d1af6c5c..e892d701d411164e742ec47d0dd9242e445e0ce0 100644 (file)
--- a/Debbugs/Common.pm
+++ b/Debbugs/Common.pm
@@ -45,6 +45,7 @@ BEGIN{
                                qw(getpseudodesc),
                                qw(package_maintainer),
                                qw(sort_versions),
+                               qw(open_compressed_file),
                               ],
                     misc   => [qw(make_list globify_scalar english_join checkpid),
                                qw(cleanup_eval_fail),
@@ -239,7 +240,40 @@ sub overwritefile {
            die "Unable to rename ${file}.new to $file: $!";
 }
 
+=head2 open_compressed_file
 
+     my $fh = open_compressed_file('foo.gz') or
+          die "Unable to open compressed file: $!";
+
+
+Opens a file; if the file ends in .gz, .xz, or .bz2, the appropriate
+decompression program is forked and output from it is read.
+
+This routine by default opens the file with UTF-8 encoding; if you want some
+other encoding, specify it with the second option.
+
+=cut
+sub open_compressed_file {
+    my ($file,$encoding) = @_;
+    $encoding //= ':encoding(UTF-8)';
+    my $fh;
+    my $mode = "<$encoding";
+    my @opts;
+    if ($file =~ /\.gz$/) {
+       $mode = "-|$encoding";
+       push @opts,'gzip','-dc';
+    }
+    if ($file =~ /\.xz$/) {
+       $mode = "-|$encoding";
+       push @opts,'xz','-dc';
+    }
+    if ($file =~ /\.bz2$/) {
+       $mode = "-|$encoding";
+       push @opts,'bzip2','-dc';
+    }
+    open($fh,$mode,@opts,$file);
+    return $fh;
+}