+sub fast_file_copy (@) { #{{{
+ my $srcfile=shift;
+ my $destfile=shift;
+ my $srcfd=shift;
+ my $destfd=shift;
+ my $cleanup=shift;
+
+ my $blksize = 16384;
+ my ($len, $buf, $written);
+ while ($len = sysread $srcfd, $buf, $blksize) {
+ if (! defined $len) {
+ next if $! =~ /^Interrupted/;
+ error("failed to read $srcfile: $!", $cleanup);
+ }
+ my $offset = 0;
+ while ($len) {
+ defined($written = syswrite $destfd, $buf, $len, $offset)
+ or error("failed to write $destfile: $!", $cleanup);
+ $len -= $written;
+ $offset += $written;
+ }
+ }
+}
+