[PATCH 26/57] ds: favor `delete' over assigning fields to `undef'

[Eric Wong <e@80x24.org>]

This is cleaner in most cases and may allow Perl to reuse memory
from unused fields.

We can do this now that we no longer support Perl 5.8; since
Danga::Socket was written with struct-like pseudo-hash support
in mind, and Perl 5.9+ dropped support for pseudo-hashes over
a decade ago.
---
 lib/PublicInbox/DS.pm          |  1 +
 lib/PublicInbox/HTTP.pm        | 21 +++++++++------------
 lib/PublicInbox/HTTPD/Async.pm |  9 +++++----
 lib/PublicInbox/NNTP.pm        |  4 ++--
 4 files changed, 17 insertions(+), 18 deletions(-)

diff --git a/lib/PublicInbox/DS.pm b/lib/PublicInbox/DS.pm
index f5986e55..482710f7 100644
--- a/lib/PublicInbox/DS.pm
+++ b/lib/PublicInbox/DS.pm
@@ -23,6 +23,7 @@ use Time::HiRes qw(clock_gettime CLOCK_MONOTONIC);
 use parent qw(Exporter);
 our @EXPORT_OK = qw(now msg_more write_in_full);
 use warnings;
+use 5.010_001;
 
 use PublicInbox::Syscall qw(:epoll);
 
diff --git a/lib/PublicInbox/HTTP.pm b/lib/PublicInbox/HTTP.pm
index 4738e156..94972054 100644
--- a/lib/PublicInbox/HTTP.pm
+++ b/lib/PublicInbox/HTTP.pm
@@ -118,8 +118,7 @@ sub read_input ($) {
 
 	# env->{CONTENT_LENGTH} (identity)
 	my $sock = $self->{sock};
-	my $len = $self->{input_left};
-	$self->{input_left} = undef;
+	my $len = delete $self->{input_left};
 	my $rbuf = \($self->{rbuf});
 	my $input = $env->{'psgi.input'};
 
@@ -246,8 +245,7 @@ sub next_request ($) {
 sub response_done_cb ($$) {
 	my ($self, $alive) = @_;
 	sub {
-		my $env = $self->{env};
-		$self->{env} = undef;
+		my $env = delete $self->{env};
 		$self->write(\"0\r\n\r\n") if $alive == 2;
 		$self->write(sub{$alive ? next_request($self) : $self->close});
 	}
@@ -279,7 +277,7 @@ sub getline_cb ($$$) {
 		}
 	}
 
-	$self->{forward} = $self->{pull} = undef;
+	delete @$self{qw(forward pull)};
 	# avoid recursion
 	if ($forward) {
 		eval { $forward->close };
@@ -370,8 +368,7 @@ sub read_input_chunked { # unlikely...
 	my ($self) = @_;
 	my $input = $self->{env}->{'psgi.input'};
 	my $sock = $self->{sock};
-	my $len = $self->{input_left};
-	$self->{input_left} = undef;
+	my $len = delete $self->{input_left};
 	my $rbuf = \($self->{rbuf});
 
 	while (1) { # chunk start
@@ -442,11 +439,11 @@ sub quit {
 
 sub close {
 	my $self = shift;
-	my $forward = $self->{forward};
-	my $env = $self->{env};
-	delete $env->{'psgix.io'} if $env; # prevent circular references
-	$self->{pull} = $self->{forward} = $self->{env} = undef;
-	if ($forward) {
+	if (my $env = delete $self->{env}) {
+		delete $env->{'psgix.io'}; # prevent circular references
+	}
+	delete $self->{pull};
+	if (my $forward = delete $self->{forward}) {
 		eval { $forward->close };
 		err($self, "forward ->close error: $@") if $@;
 	}
diff --git a/lib/PublicInbox/HTTPD/Async.pm b/lib/PublicInbox/HTTPD/Async.pm
index 9cc41f17..bec49337 100644
--- a/lib/PublicInbox/HTTPD/Async.pm
+++ b/lib/PublicInbox/HTTPD/Async.pm
@@ -63,7 +63,7 @@ sub main_cb ($$$) {
 
 		# Done! Error handling will happen in $fh->close
 		# called by the {cleanup} handler
-		$http->{forward} = undef;
+		delete $http->{forward};
 		$self->close;
 	}
 }
@@ -81,12 +81,13 @@ sub event_step { $_[0]->{cb}->(@_) }
 
 sub close {
 	my $self = shift;
-	my $cleanup = $self->{cleanup};
-	$self->{cleanup} = $self->{cb} = undef;
+	delete $self->{cb};
 	$self->SUPER::close(@_);
 
 	# we defer this to the next timer loop since close is deferred
-	PublicInbox::EvCleanup::next_tick($cleanup) if $cleanup;
+	if (my $cleanup = delete $self->{cleanup}) {
+		PublicInbox::EvCleanup::next_tick($cleanup);
+	}
 }
 
 1;
diff --git a/lib/PublicInbox/NNTP.pm b/lib/PublicInbox/NNTP.pm
index fbdf1364..6a582ea4 100644
--- a/lib/PublicInbox/NNTP.pm
+++ b/lib/PublicInbox/NNTP.pm
@@ -624,7 +624,7 @@ sub long_response ($$) {
 	$self->{long_res} = sub {
 		my $more = eval { $cb->() };
 		if ($@ || !$self->{sock}) { # something bad happened...
-			$self->{long_res} = undef;
+			delete $self->{long_res};
 
 			if ($@) {
 				err($self,
@@ -646,7 +646,7 @@ sub long_response ($$) {
 			push @$nextq, $self;
 			$nextt ||= PublicInbox::EvCleanup::asap(*next_tick);
 		} else { # all done!
-			$self->{long_res} = undef;
+			delete $self->{long_res};
 			check_read($self);
 			res($self, '.');
 			out($self, " deferred[$fd] done - %0.6f", now() - $t0);
-- 
EW