From a5362f2af0241ab0776e0952a500f14a27762415 Mon Sep 17 00:00:00 2001
From: Joe Bryan <joemfb@gmail.com>
Date: Wed, 14 Dec 2022 01:48:20 -0500
Subject: [PATCH] vere: ports u3_disk_read_list()

---
 pkg/urbit/include/vere/vere.h |  5 ++++
 pkg/urbit/vere/disk.c         | 46 +++++++++++++++++++++++++++++++++++
 2 files changed, 51 insertions(+)

diff --git a/pkg/urbit/include/vere/vere.h b/pkg/urbit/include/vere/vere.h
index 4b5682f243..ed718fd796 100644
--- a/pkg/urbit/include/vere/vere.h
+++ b/pkg/urbit/include/vere/vere.h
@@ -1015,6 +1015,11 @@
         void
         u3_disk_plan(u3_disk* log_u, u3_fact* tac_u);
 
+      /* u3_disk_read_list(): synchronously read a cons list of events.
+      */
+        u3_weak
+        u3_disk_read_list(u3_disk* log_u, c3_d eve_d, c3_d len_d, c3_l* mug_l);
+
       /* u3_disk_walk_init(): init iterator.
       */
         u3_disk_walk*
diff --git a/pkg/urbit/vere/disk.c b/pkg/urbit/vere/disk.c
index 66a8df398e..61fe9f754a 100644
--- a/pkg/urbit/vere/disk.c
+++ b/pkg/urbit/vere/disk.c
@@ -500,6 +500,52 @@ u3_disk_read(u3_disk* log_u, c3_d eve_d, c3_d len_d)
   uv_timer_start(&red_u->tim_u, _disk_read_start_cb, 0, 0);
 }
 
+struct _cd_list {
+  u3_disk* log_u;
+  u3_noun    eve;
+  c3_l     mug_l;
+};
+
+/* _disk_read_list_cb(): lmdb read callback, invoked for each event in order
+*/
+static c3_o
+_disk_read_list_cb(void* ptr_v, c3_d eve_d, size_t val_i, void* val_p)
+{
+  struct _cd_list* ven_u = ptr_v;
+  u3_disk* log_u = ven_u->log_u;
+
+  {
+    u3_noun job;
+    c3_l  mug_l;
+
+    if ( c3n == u3_disk_sift(log_u, val_i, (c3_y*)val_p, &mug_l, &job) ) {
+      return c3n;
+    }
+
+    ven_u->mug_l = mug_l;
+    ven_u->eve   = u3nc(job, ven_u->eve);
+  }
+
+  return c3y;
+}
+
+/* u3_disk_read_list(): synchronously read a cons list of events.
+*/
+u3_weak
+u3_disk_read_list(u3_disk* log_u, c3_d eve_d, c3_d len_d, c3_l* mug_l)
+{
+  struct _cd_list ven_u = { log_u, u3_nul, 0 };
+
+  if ( c3n == u3_lmdb_read(log_u->mdb_u, &ven_u,
+                           eve_d, len_d, _disk_read_list_cb) )
+  {
+    return u3_none;
+  }
+
+  *mug_l = ven_u.mug_l;
+  return u3kb_flop(ven_u.eve);
+}
+
 /* u3_disk_walk_init(): init iterator.
 */
 u3_disk_walk*