1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
|
# Wait till both the local clock and the timestamps of files are newer than
# those of the given files. If no files are given, wait till the next second.
sub wait_timestamp(@) {
my $ts = 0;
my $tmp;
# Pick out the newest file.
for( @_ ) {
$tmp = (stat)[9];
$ts = $tmp if $tmp && $tmp > $ts;
}
# If none was given, default to now.
$ts ||= time;
my $hires = eval { require Time::HiRes };
# Wait until the next second starts, if we can.
if( $hires ) {
$tmp = Time::HiRes::time();
Time::HiRes::sleep( int( $tmp + 1 ) - $tmp );
# Just in case something got rounded down, go forward in tiny steps:
Time::HiRes::sleep( .01 ) while $ts >= time;
} else {
# More expensive than sleep, but we waste little real time.
select undef, undef, undef, .1 while $ts >= time;
}
# If this is a remote file system, timestamps may not yet have changed.
# So recheck in .1 second steps.
while() {
open my $fh, ">wait_timestamp.$$";
# NOTE: Overwriting an existing empty file may not update its mod time,
# so we also have to write to it.
print $fh "x";
last if (stat $fh)[9] > $ts;
if( $hires ) {
Time::HiRes::sleep( .1 );
} else {
select undef, undef, undef, .1;
}
}
unlink "wait_timestamp.$$";
}
# If called as a standalone program or pseudo-standalone from run(), call the
# function.
wait_timestamp( @ARGV ) if !caller or caller eq 'Mpp::Subs';
1;
|
