user/dev discussion of public-inbox itself
 help / color / Atom feed
From: Eric Wong <e@80x24.org>
To: meta@public-inbox.org
Subject: [PATCH 1/9] ds: simplify write buffer accounting
Date: Mon, 10 Jun 2019 05:18:38 +0000
Message-ID: <20190610051846.26757-2-e@80x24.org> (raw)
In-Reply-To: <20190610051846.26757-1-e@80x24.org>

Keeping track of write_buf_size was redundant and pointless when
we can simply check the number of elements in the buffer array.
Multiple sources of truth leads to confusion; confusion leads to
bugs.

Finally, rename the prefixes to 'wbuf' to ensure we loudly
(instead of silently) break any external dependencies being
ported over from Danga::Socket, as further changes are pending.
---
 lib/PublicInbox/DS.pm          | 41 ++++++++++++++--------------------
 lib/PublicInbox/HTTP.pm        |  6 ++---
 lib/PublicInbox/HTTPD/Async.pm |  2 +-
 lib/PublicInbox/NNTP.pm        |  8 +++----
 4 files changed, 25 insertions(+), 32 deletions(-)

diff --git a/lib/PublicInbox/DS.pm b/lib/PublicInbox/DS.pm
index 03612ce8..172a9f52 100644
--- a/lib/PublicInbox/DS.pm
+++ b/lib/PublicInbox/DS.pm
@@ -27,9 +27,8 @@ use PublicInbox::Syscall qw(:epoll);
 
 use fields ('sock',              # underlying socket
             'fd',                # numeric file descriptor
-            'write_buf',         # arrayref of scalars, scalarrefs, or coderefs to write
-            'write_buf_offset',  # offset into first array of write_buf to start writing at
-            'write_buf_size',    # total length of data in all write_buf items
+            'wbuf',              # arrayref of scalars, scalarrefs, or coderefs to write
+            'wbuf_off',  # offset into first element of wbuf to start writing at
             'closed',            # bool: socket is closed
             'event_watch',       # bitmask of events the client is interested in (POLLIN,OUT,etc.)
             );
@@ -449,9 +448,8 @@ sub new {
         unless $sock && $fd;
 
     $self->{fd}          = $fd;
-    $self->{write_buf}      = [];
-    $self->{write_buf_offset} = 0;
-    $self->{write_buf_size} = 0;
+    $self->{wbuf} = [];
+    $self->{wbuf_off} = 0;
     $self->{closed} = 0;
 
     my $ev = $self->{event_watch} = POLLERR|POLLHUP|POLLNVAL;
@@ -552,7 +550,7 @@ sub _cleanup {
     # we need to flush our write buffer, as there may
     # be self-referential closures (sub { $client->close })
     # preventing the object from being destroyed
-    $self->{write_buf} = [];
+    @{$self->{wbuf}} = ();
 
     # if we're using epoll, we have to remove this from our epoll fd so we stop getting
     # notifications about it
@@ -612,12 +610,12 @@ sub write {
 
     # just queue data if there's already a wait
     my $need_queue;
+    my $wbuf = $self->{wbuf};
 
     if (defined $data) {
         $bref = ref $data ? $data : \$data;
-        if ($self->{write_buf_size}) {
-            push @{$self->{write_buf}}, $bref;
-            $self->{write_buf_size} += ref $bref eq "SCALAR" ? length($$bref) : 1;
+        if (scalar @$wbuf) {
+            push @$wbuf, $bref;
             return 0;
         }
 
@@ -629,7 +627,7 @@ sub write {
 
   WRITE:
     while (1) {
-        return 1 unless $bref ||= $self->{write_buf}[0];
+        return 1 unless $bref ||= $wbuf->[0];
 
         my $len;
         eval {
@@ -638,8 +636,7 @@ sub write {
         if ($@) {
             if (UNIVERSAL::isa($bref, "CODE")) {
                 unless ($need_queue) {
-                    $self->{write_buf_size}--; # code refs are worth 1
-                    shift @{$self->{write_buf}};
+                    shift @$wbuf;
                 }
                 $bref->();
 
@@ -654,9 +651,9 @@ sub write {
             die "Write error: $@ <$bref>";
         }
 
-        my $to_write = $len - $self->{write_buf_offset};
+        my $to_write = $len - $self->{wbuf_off};
         my $written = syswrite($self->{sock}, $$bref, $to_write,
-                               $self->{write_buf_offset});
+                               $self->{wbuf_off});
 
         if (! defined $written) {
             if ($! == EPIPE) {
@@ -665,8 +662,7 @@ sub write {
                 # since connection has stuff to write, it should now be
                 # interested in pending writes:
                 if ($need_queue) {
-                    push @{$self->{write_buf}}, $bref;
-                    $self->{write_buf_size} += $len;
+                    push @$wbuf, $bref;
                 }
                 $self->watch_write(1);
                 return 0;
@@ -681,19 +677,17 @@ sub write {
             DebugLevel >= 2 && $self->debugmsg("Wrote PARTIAL %d bytes to %d",
                                                $written, $self->{fd});
             if ($need_queue) {
-                push @{$self->{write_buf}}, $bref;
-                $self->{write_buf_size} += $len;
+                push @$wbuf, $bref;
             }
             # since connection has stuff to write, it should now be
             # interested in pending writes:
-            $self->{write_buf_offset} += $written;
-            $self->{write_buf_size} -= $written;
+            $self->{wbuf_off} += $written;
             $self->on_incomplete_write;
             return 0;
         } elsif ($written == $to_write) {
             DebugLevel >= 2 && $self->debugmsg("Wrote ALL %d bytes to %d (nq=%d)",
                                                $written, $self->{fd}, $need_queue);
-            $self->{write_buf_offset} = 0;
+            $self->{wbuf_off} = 0;
             $self->watch_write(0);
 
             # this was our only write, so we can return immediately
@@ -702,8 +696,7 @@ sub write {
             # can't be anything else to write.
             return 1 if $need_queue;
 
-            $self->{write_buf_size} -= $written;
-            shift @{$self->{write_buf}};
+            shift @$wbuf;
             undef $bref;
             next WRITE;
         }
diff --git a/lib/PublicInbox/HTTP.pm b/lib/PublicInbox/HTTP.pm
index 977614b4..fd103251 100644
--- a/lib/PublicInbox/HTTP.pm
+++ b/lib/PublicInbox/HTTP.pm
@@ -260,7 +260,7 @@ sub getline_cb ($$$) {
 			$write->($buf); # may close in PublicInbox::DS::write
 			unless ($self->{closed}) {
 				my $next = $self->{pull};
-				if ($self->{write_buf_size}) {
+				if (scalar @{$self->{wbuf}}) {
 					$self->write($next);
 				} else {
 					PublicInbox::EvCleanup::asap($next);
@@ -315,7 +315,7 @@ use constant MSG_MORE => ($^O eq 'linux') ? 0x8000 : 0;
 sub more ($$) {
 	my $self = $_[0];
 	return if $self->{closed};
-	if (MSG_MORE && !$self->{write_buf_size}) {
+	if (MSG_MORE && !scalar(@{$self->{wbuf}})) {
 		my $n = send($self->{sock}, $_[1], MSG_MORE);
 		if (defined $n) {
 			my $nlen = length($_[1]) - $n;
@@ -487,7 +487,7 @@ sub close {
 # for graceful shutdown in PublicInbox::Daemon:
 sub busy () {
 	my ($self) = @_;
-	($self->{rbuf} ne '' || $self->{env} || $self->{write_buf_size});
+	($self->{rbuf} ne '' || $self->{env} || scalar(@{$self->{wbuf}}));
 }
 
 1;
diff --git a/lib/PublicInbox/HTTPD/Async.pm b/lib/PublicInbox/HTTPD/Async.pm
index dbe8a84a..60701085 100644
--- a/lib/PublicInbox/HTTPD/Async.pm
+++ b/lib/PublicInbox/HTTPD/Async.pm
@@ -46,7 +46,7 @@ sub main_cb ($$$) {
 		if ($r) {
 			$fh->write($$bref);
 			unless ($http->{closed}) { # PublicInbox::DS sets this
-				if ($http->{write_buf_size}) {
+				if (scalar @{$http->{wbuf}}) {
 					$self->watch_read(0);
 					$http->write(restart_read_cb($self));
 				}
diff --git a/lib/PublicInbox/NNTP.pm b/lib/PublicInbox/NNTP.pm
index be80560f..b62c2187 100644
--- a/lib/PublicInbox/NNTP.pm
+++ b/lib/PublicInbox/NNTP.pm
@@ -619,7 +619,7 @@ sub long_response ($$) {
 				update_idle_time($self);
 				check_read($self);
 			}
-		} elsif ($more) { # $self->{write_buf_size}:
+		} elsif ($more) { # scalar @{$self->{wbuf}}:
 			# no recursion, schedule another call ASAP
 			# but only after all pending writes are done
 			update_idle_time($self);
@@ -925,7 +925,7 @@ use constant MSG_MORE => ($^O eq 'linux') ? 0x8000 : 0;
 
 sub do_more ($$) {
 	my ($self, $data) = @_;
-	if (MSG_MORE && !$self->{write_buf_size}) {
+	if (MSG_MORE && !scalar(@{$self->{wbuf}})) {
 		my $n = send($self->{sock}, $data, MSG_MORE);
 		if (defined $n) {
 			my $dlen = length($data);
@@ -1004,8 +1004,8 @@ sub not_idle_long ($$) {
 # for graceful shutdown in PublicInbox::Daemon:
 sub busy {
 	my ($self, $now) = @_;
-	($self->{rbuf} ne '' || $self->{long_res} || $self->{write_buf_size} ||
-	 not_idle_long($self, $now));
+	($self->{rbuf} ne '' || $self->{long_res} ||
+		scalar(@{$self->{wbuf}}) || not_idle_long($self, $now));
 }
 
 1;
-- 
EW


  reply index

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-10  5:18 [PATCH 0/9] ds: Diet Socket Eric Wong
2019-06-10  5:18 ` Eric Wong [this message]
2019-06-10  5:18 ` [PATCH 2/9] ds: cleanup Errno imports and favor constant comparisons Eric Wong
2019-06-10  5:18 ` [PATCH 3/9] ds: reduce Errno imports and drop ->close reason Eric Wong
2019-06-10  5:18 ` [PATCH 4/9] ds: remove {fd} field Eric Wong
2019-06-10  5:18 ` [PATCH 5/9] ds: remove steal_socket method Eric Wong
2019-06-10  5:18 ` [PATCH 6/9] nntp: use sysread to append to existing buffer Eric Wong
2019-06-10  5:18 ` [PATCH 7/9] ds: remove read method, here, too Eric Wong
2019-06-10  5:18 ` [PATCH 8/9] ds: do not distinguish between POLLHUP and POLLERR Eric Wong
2019-06-10  5:18 ` [PATCH 9/9] ds: stop caring about event flags set by epoll/poll/kqueue Eric Wong

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

  List information: http://public-inbox.org/README

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190610051846.26757-2-e@80x24.org \
    --to=e@80x24.org \
    --cc=meta@public-inbox.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

user/dev discussion of public-inbox itself

Archives are clonable:
	git clone --mirror http://public-inbox.org/meta
	git clone --mirror http://czquwvybam4bgbro.onion/meta
	git clone --mirror http://hjrcffqmbrq6wope.onion/meta
	git clone --mirror http://ou63pmih66umazou.onion/meta

Example config snippet for mirrors

Newsgroups are available over NNTP:
	nntp://news.public-inbox.org/inbox.comp.mail.public-inbox.meta
	nntp://ou63pmih66umazou.onion/inbox.comp.mail.public-inbox.meta
	nntp://czquwvybam4bgbro.onion/inbox.comp.mail.public-inbox.meta
	nntp://hjrcffqmbrq6wope.onion/inbox.comp.mail.public-inbox.meta
	nntp://news.gmane.io/gmane.mail.public-inbox.general

 note: .onion URLs require Tor: https://www.torproject.org/

AGPL code for this site: git clone https://public-inbox.org/public-inbox.git