[PATCH] www: rework async_* to use method table

[PATCH] www: rework async_* to use method table

[Eric Wong]

Although the ->async_next method does not take $self as
a receiver, but rather a PublicInbox::HTTP object, we may
still retrieve it to be called with the HTTP object via
UNIVERSAL->can.
---
 lib/PublicInbox/GzipFilter.pm    | 16 +++++++---------
 lib/PublicInbox/Mbox.pm          |  6 +++---
 lib/PublicInbox/MboxGz.pm        |  5 +++--
 lib/PublicInbox/WwwAtomStream.pm |  4 ++--
 lib/PublicInbox/WwwAttach.pm     |  4 +---
 lib/PublicInbox/WwwStream.pm     |  4 ++--
 6 files changed, 18 insertions(+), 21 deletions(-)

diff --git a/lib/PublicInbox/GzipFilter.pm b/lib/PublicInbox/GzipFilter.pm
index f1354d2b7..20030433f 100644
--- a/lib/PublicInbox/GzipFilter.pm
+++ b/lib/PublicInbox/GzipFilter.pm
@@ -7,8 +7,8 @@
 #
 # In newer versions, public-inbox-httpd supports a backpressure-aware
 # pull/push model which also accounts for slow git blob storage.
-# {async_next} callbacks only run when the DS {wbuf} is drained
-# {async_eml} callbacks only run when a blob arrives from git.
+# async_next callbacks only run when the DS {wbuf} is drained
+# async_eml callbacks only run when a blob arrives from git.
 #
 # We continue to support getline+close for generic PSGI servers.
 package PublicInbox::GzipFilter;
@@ -46,18 +46,16 @@ sub gz_or_noop {
 sub gzf_maybe ($$) { bless { gz => gz_or_noop(@_) }, __PACKAGE__ }
 
 sub psgi_response {
-	my ($self, $code, $res_hdr, $next_cb, $eml_cb) = @_;
+	my ($self, $code, $res_hdr) = @_;
 	my $env = $self->{env};
 	$self->{gz} //= gz_or_noop($res_hdr, $env);
 	if ($env->{'pi-httpd.async'}) {
-		$self->{async_next} = $next_cb;
-		$self->{async_eml} = $eml_cb;
 		my $http = $env->{'psgix.io'}; # PublicInbox::HTTP
 		$http->{forward} = $self;
 		sub {
 			my ($wcb) = @_; # -httpd provided write callback
 			$self->{http_out} = $wcb->([$code, $res_hdr]);
-			$next_cb->($http); # start stepping
+			$self->can('async_next')->($http); # start stepping
 		};
 	} else { # generic PSGI code path
 		[ $code, $res_hdr, $self ];
@@ -172,12 +170,12 @@ sub async_blob_cb { # git->cat_async callback
 		# it's possible to have TOCTOU if an admin runs
 		# public-inbox-(edit|purge), just move onto the next message
 		warn "E: $smsg->{blob} missing in $self->{-inbox}->{inboxdir}\n";
-		return $http->next_step($self->{async_next});
+		return $http->next_step($self->can('async_next'));
 	}
 	$smsg->{blob} eq $oid or bail($self, "BUG: $smsg->{blob} != $oid");
-	eval { $self->{async_eml}->($self, PublicInbox::Eml->new($bref)) };
+	eval { $self->async_eml(PublicInbox::Eml->new($bref)) };
 	bail($self, "E: async_eml: $@") if $@;
-	$http->next_step($self->{async_next});
+	$http->next_step($self->can('async_next'));
 }
 
 sub smsg_blob {
diff --git a/lib/PublicInbox/Mbox.pm b/lib/PublicInbox/Mbox.pm
index 115321c61..fc83a893c 100644
--- a/lib/PublicInbox/Mbox.pm
+++ b/lib/PublicInbox/Mbox.pm
@@ -29,7 +29,7 @@ sub getline {
 	}
 }
 
-# called by PublicInbox::DS::write
+# called by PublicInbox::DS::write after http->next_step
 sub async_next {
 	my ($http) = @_; # PublicInbox::HTTP
 	my $ctx = $http->{forward} or return; # client aborted
@@ -40,7 +40,7 @@ sub async_next {
 	warn "E: $@" if $@;
 }
 
-sub async_eml { # ->{async_eml} for async_blob_cb
+sub async_eml { # for async_blob_cb
 	my ($ctx, $eml) = @_;
 	my $smsg = delete $ctx->{smsg};
 	# next message
@@ -87,7 +87,7 @@ sub emit_raw {
 	my $smsg = $ctx->{smsg} = $over->next_by_mid(@$mip) or return;
 	my $res_hdr = res_hdr($ctx, $smsg->{subject});
 	bless $ctx, __PACKAGE__;
-	$ctx->psgi_response(200, $res_hdr, \&async_next, \&async_eml);
+	$ctx->psgi_response(200, $res_hdr);
 }
 
 sub msg_hdr ($$;$) {
diff --git a/lib/PublicInbox/MboxGz.pm b/lib/PublicInbox/MboxGz.pm
index 967af9c68..913be6e42 100644
--- a/lib/PublicInbox/MboxGz.pm
+++ b/lib/PublicInbox/MboxGz.pm
@@ -29,8 +29,7 @@ sub mbox_gz {
 	bless $self, __PACKAGE__;
 	my $res_hdr = [ 'Content-Type' => 'application/gzip',
 		'Content-Disposition' => "inline; filename=$fn.mbox.gz" ];
-	$self->psgi_response(200, $res_hdr, \&async_next,
-				\&PublicInbox::Mbox::async_eml);
+	$self->psgi_response(200, $res_hdr);
 }
 
 # called by Plack::Util::foreach or similar (generic PSGI)
@@ -47,4 +46,6 @@ sub getline {
 	$self->zflush;
 }
 
+no warnings 'once';
+*async_eml = \&PublicInbox::Mbox::async_eml;
 1;
diff --git a/lib/PublicInbox/WwwAtomStream.pm b/lib/PublicInbox/WwwAtomStream.pm
index 2f9b953b2..1ed806fd4 100644
--- a/lib/PublicInbox/WwwAtomStream.pm
+++ b/lib/PublicInbox/WwwAtomStream.pm
@@ -35,7 +35,7 @@ sub async_next ($) {
 	warn "E: $@" if $@;
 }
 
-sub async_eml { # ->{async_eml} for async_blob_cb
+sub async_eml { # for async_blob_cb
 	my ($ctx, $eml) = @_;
 	my $smsg = delete $ctx->{smsg};
 	$ctx->{http_out}->write($ctx->translate(feed_entry($ctx, $smsg, $eml)))
@@ -45,7 +45,7 @@ sub response {
 	my ($class, $ctx, $code, $cb) = @_;
 	my $res_hdr = [ 'Content-Type' => 'application/atom+xml' ];
 	$class->new($ctx, $cb);
-	$ctx->psgi_response($code, $res_hdr, \&async_next, \&async_eml);
+	$ctx->psgi_response($code, $res_hdr);
 }
 
 # called once for each message by PSGI server
diff --git a/lib/PublicInbox/WwwAttach.pm b/lib/PublicInbox/WwwAttach.pm
index 20417295e..0b2cda900 100644
--- a/lib/PublicInbox/WwwAttach.pm
+++ b/lib/PublicInbox/WwwAttach.pm
@@ -35,7 +35,7 @@ sub get_attach_i { # ->each_part callback
 	$res->[2]->[0] = $part;
 }
 
-sub async_eml { # ->{async_eml} for async_blob_cb
+sub async_eml { # for async_blob_cb
 	my ($ctx, $eml) = @_;
 	eval { $eml->each_part(\&get_attach_i, $ctx, 1) };
 	if ($@) {
@@ -55,8 +55,6 @@ sub async_next {
 sub scan_attach ($) { # public-inbox-httpd only
 	my ($ctx) = @_;
 	$ctx->{env}->{'psgix.io'}->{forward} = $ctx;
-	$ctx->{async_eml} = \&async_eml;
-	$ctx->{async_next} = \&async_next;
 	$ctx->smsg_blob($ctx->{smsg});
 }
 
diff --git a/lib/PublicInbox/WwwStream.pm b/lib/PublicInbox/WwwStream.pm
index 23b03f0e8..d79770ed1 100644
--- a/lib/PublicInbox/WwwStream.pm
+++ b/lib/PublicInbox/WwwStream.pm
@@ -28,7 +28,7 @@ sub init {
 	bless $ctx, __PACKAGE__;
 }
 
-sub async_eml { # ->{async_eml} for async_blob_cb
+sub async_eml { # for async_blob_cb
 	my ($ctx, $eml) = @_;
 	$ctx->{http_out}->write($ctx->translate($ctx->{cb}->($ctx, $eml)));
 }
@@ -198,7 +198,7 @@ sub aresponse {
 	my ($ctx, $code, $cb) = @_;
 	my $res_hdr = [ 'Content-Type' => 'text/html; charset=UTF-8' ];
 	init($ctx, $cb);
-	$ctx->psgi_response($code, $res_hdr, \&async_next, \&async_eml);
+	$ctx->psgi_response($code, $res_hdr);
 }
 
 1;