[PATCH] view: support SHA-1 of Message-IDs for message links

[PATCH] view: support SHA-1 of Message-IDs for message links

[Eric Wong]

Some Message-IDs are crazy long, so support SHA-1s for them
instead.  This allows shorter URLs to be generated and are
less likely

However, we'll still favor short Message-IDs whenever possible.
---
 lib/PublicInbox/Hval.pm | 22 +++++++++++++++-------
 lib/PublicInbox/WWW.pm  | 16 +++++++++++-----
 2 files changed, 26 insertions(+), 12 deletions(-)

diff --git a/lib/PublicInbox/Hval.pm b/lib/PublicInbox/Hval.pm
index a93e8c2..9be163a 100644
--- a/lib/PublicInbox/Hval.pm
+++ b/lib/PublicInbox/Hval.pm
@@ -5,28 +5,36 @@
 package PublicInbox::Hval;
 use strict;
 use warnings;
-use fields qw(raw);
+use fields qw(raw href);
 use Encode qw(find_encoding);
 use URI::Escape qw(uri_escape_utf8);
 
 my $enc_ascii = find_encoding('us-ascii');
 
 sub new {
-	my ($class, $raw) = @_;
+	my ($class, $raw, $href) = @_;
 	my $self = fields::new($class);
 
 	# we never care about leading/trailing whitespace
 	$raw =~ s/\A\s*//;
 	$raw =~ s/\s*\z//;
 	$self->{raw} = $raw;
+	$self->{href} = defined $href ? $href : $raw;
 	$self;
 }
 
 sub new_msgid {
-	my ($class, $raw) = @_;
-	$raw =~ s/\A<//;
-	$raw =~ s/>\z//;
-	$class->new($raw);
+	my ($class, $msgid) = @_;
+	$msgid =~ s/\A\s*<?//;
+	$msgid =~ s/>?\s*\z//;
+
+	if (length($msgid) <= 40) {
+		$class->new($msgid);
+	} else {
+		require Digest::SHA;
+		my $hex = Digest::SHA::sha1_hex($msgid);
+		$class->new($msgid, $hex);
+	}
 }
 
 sub new_oneline {
@@ -52,7 +60,7 @@ sub ascii_html {
 }
 
 sub as_html { ascii_html($_[0]->{raw}) }
-sub as_href { ascii_html(uri_escape_utf8($_[0]->{raw})) }
+sub as_href { ascii_html(uri_escape_utf8($_[0]->{href})) }
 
 sub raw {
 	if (defined $_[1]) {
diff --git a/lib/PublicInbox/WWW.pm b/lib/PublicInbox/WWW.pm
index f67e72c..1814286 100644
--- a/lib/PublicInbox/WWW.pm
+++ b/lib/PublicInbox/WWW.pm
@@ -130,13 +130,19 @@ sub get_index {
 # just returns a string ref for the blob in the current ctx
 sub mid2blob {
 	my ($ctx) = @_;
-	require Digest::SHA;
-	my $hex = Digest::SHA::sha1_hex($ctx->{mid});
-	$hex =~ /\A([a-f0-9]{2})([a-f0-9]{38})\z/i or
-			die "BUG: not a SHA-1 hex: $hex";
+	my $hex = $ctx->{mid};
+	my ($x2, $x38) = ($hex =~ /\A([a-f0-9]{2})([a-f0-9]{38})\z/);
+
+	unless (defined $x38) {
+		# compatibility with old links
+		require Digest::SHA;
+		$hex = Digest::SHA::sha1_hex($hex);
+		($x2, $x38) = ($hex =~ /\A([a-f0-9]{2})([a-f0-9]{38})\z/);
+		defined $x38 or die "BUG: not a SHA-1 hex: $hex";
+	}
 
 	my @cmd = ('git', "--git-dir=$ctx->{git_dir}",
-			qw(cat-file blob), "HEAD:$1/$2");
+			qw(cat-file blob), "HEAD:$x2/$x38");
 	my $cmd = join(' ', @cmd);
 	my $pid = open my $fh, '-|';
 	defined $pid or die "fork failed: $!\n";
-- 
EW