From 3abe3ae530ca922a77888c86261ba7b1dfcfce27 Mon Sep 17 00:00:00 2001
From: Tom Molesworth <tom@deriv.com>
Date: Thu, 4 Jul 2024 11:11:41 +0800
Subject: [PATCH] Support for `list_count` storage method

---
 lib/Myriad/Role/Storage.pm                  | 17 +++++++++++++++++
 lib/Myriad/Storage/Implementation/Memory.pm |  4 ++++
 lib/Myriad/Storage/Implementation/Redis.pm  |  4 ++++
 3 files changed, 25 insertions(+)

diff --git a/lib/Myriad/Role/Storage.pm b/lib/Myriad/Role/Storage.pm
index 751c83ee..1daa2856 100644
--- a/lib/Myriad/Role/Storage.pm
+++ b/lib/Myriad/Role/Storage.pm
@@ -351,6 +351,7 @@ our @READ_METHODS = qw(
     hash_exists
     hash_count
     hash_as_list
+    list_count
     list_range
     orderedset_member_count
     orderedset_members
@@ -483,6 +484,22 @@ suitable for assigning to a hash.
 
 method hash_as_list;
 
+=head2 list_count
+
+Takes the following parameters:
+
+=over 4
+
+=item * key
+
+=back
+
+Returns a L<Future> which will resolve to the integer count of values currently in the list.
+
+=cut
+
+method list_count;
+
 =head2 list_range
 
 Takes the following parameters:
diff --git a/lib/Myriad/Storage/Implementation/Memory.pm b/lib/Myriad/Storage/Implementation/Memory.pm
index a199a508..a726a6d8 100644
--- a/lib/Myriad/Storage/Implementation/Memory.pm
+++ b/lib/Myriad/Storage/Implementation/Memory.pm
@@ -413,6 +413,10 @@ async method hash_as_list : Defer ($k) {
     return $data{$k}->%*;
 }
 
+async method list_count : Defer ($k) {
+    return 0 + $data{$k}->@*;
+}
+
 async method list_range : Defer ($k, $start = 0, $end = -1) {
     my $len = 0 + $data{$k}->@*
         or return [ ];
diff --git a/lib/Myriad/Storage/Implementation/Redis.pm b/lib/Myriad/Storage/Implementation/Redis.pm
index c9d8e29e..bb57e4d1 100644
--- a/lib/Myriad/Storage/Implementation/Redis.pm
+++ b/lib/Myriad/Storage/Implementation/Redis.pm
@@ -215,6 +215,10 @@ async method watch_keyspace ($keyspace) {
     });
 }
 
+async method list_count ($k) {
+    await $redis->llen($self->apply_prefix($k));
+}
+
 async method list_range ($k, $start = 0, $end = -1) {
     await $redis->lrange($self->apply_prefix($k), $start, $end);
 }