rewrite Linux nodatacow use in pure Perl w/o system

[public-inbox.git] / lib / PublicInbox / SharedKV.pm

diff --git a/lib/PublicInbox/SharedKV.pm b/lib/PublicInbox/SharedKV.pm
index b0588060435aae9525c6480b029d12f49b059988..95a3cb147d2973fa3c91e84593936c487d9723c6 100644 (file)
--- a/lib/PublicInbox/SharedKV.pm
+++ b/lib/PublicInbox/SharedKV.pm
@@ -1,4 +1,4 @@
-# Copyright (C) 2020-2021 all contributors <meta@public-inbox.org>
+# Copyright (C) all contributors <meta@public-inbox.org>
 # License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
 
 # fork()-friendly key-value store.  Will be used for making
@@ -11,11 +11,11 @@ use parent qw(PublicInbox::Lock);
 use File::Temp qw(tempdir);
 use DBI ();
 use PublicInbox::Spawn;
-use File::Path qw(rmtree);
+use File::Path qw(rmtree make_path);
 
 sub dbh {
        my ($self, $lock) = @_;
-       $self->{dbh} //= do {
+       $self->{dbh} // do {
                my $f = $self->{filename};
                $lock //= $self->lock_for_scope_fast;
                my $dbh = DBI->connect("dbi:SQLite:dbname=$f", '', '', {
@@ -27,7 +27,6 @@ sub dbh {
                });
                my $opt = $self->{opt} // {};
                $dbh->do('PRAGMA synchronous = OFF') if !$opt->{fsync};
-               $dbh->do('PRAGMA cache_size = '.($opt->{cache_size} || 80000));
                $dbh->do('PRAGMA journal_mode = '.
                                ($opt->{journal_mode} // 'WAL'));
                $dbh->do(<<'');
@@ -37,21 +36,22 @@ CREATE TABLE IF NOT EXISTS kv (
        UNIQUE (k)
 )
 
-               $dbh;
+               $self->{dbh} = $dbh;
        }
 }
 
 sub new {
        my ($cls, $dir, $base, $opt) = @_;
        my $self = bless { opt => $opt }, $cls;
+       make_path($dir) if defined($dir) && !-d $dir;
        $dir //= $self->{"tmp$$.$self"} = tempdir("skv.$$-XXXX", TMPDIR => 1);
-       -d $dir or mkdir($dir) or die "mkdir($dir): $!";
        $base //= '';
        my $f = $self->{filename} = "$dir/$base.sqlite3";
        $self->{lock_path} = $opt->{lock_path} // "$dir/$base.flock";
-       unless (-f $f) {
+       unless (-s $f) {
+               require PublicInbox::Syscall;
+               PublicInbox::Syscall::nodatacow_dir($dir); # for journal/shm/wal
                open my $fh, '+>>', $f or die "failed to open $f: $!";
-               PublicInbox::Spawn::nodatacow_fd(fileno($fh));
        }
        $self;
 }
@@ -81,6 +81,22 @@ SELECT k,v FROM kv
        $sth
 }
 
+sub keys {
+       my ($self, @pfx) = @_;
+       my $sql = 'SELECT k FROM kv';
+       if (defined $pfx[0]) {
+               $sql .= ' WHERE k LIKE ? ESCAPE ?';
+               my $anywhere = !!$pfx[1];
+               $pfx[1] = '\\';
+               $pfx[0] =~ s/([%_\\])/\\$1/g; # glob chars
+               $pfx[0] .= '%';
+               substr($pfx[0], 0, 0, '%') if $anywhere;
+       } else {
+               @pfx = (); # [0] may've been undef
+       }
+       map { $_->[0] } @{$self->dbh->selectall_arrayref($sql, undef, @pfx)};
+}
+
 sub delete_by_val {
        my ($self, $val, $lock) = @_;
        $lock //= $self->lock_for_scope_fast;
@@ -143,6 +159,13 @@ SELECT COUNT(k) FROM kv
        $sth->fetchrow_array;
 }
 
+# faster than ->count due to how SQLite works
+sub has_entries {
+       my ($self) = @_;
+       my @n = $self->{dbh}->selectrow_array('SELECT k FROM kv LIMIT 1');
+       scalar(@n) ? 1 : undef;
+}
+
 sub dbh_release {
        my ($self, $lock) = @_;
        my $dbh = delete $self->{dbh} or return;