From ef576d966adf187ec84c4f9f3fe8c39645330c8a Mon Sep 17 00:00:00 2001
From: Marko Lindqvist <cazfi74@gmail.com>
Date: Thu, 6 Jan 2022 19:04:17 +0200
Subject: [PATCH 42/42] Cache ruleset modpacks just once

See osdn #43569

Signed-off-by: Marko Lindqvist <cazfi74@gmail.com>
---
 common/modpack.c  | 10 ++++++
 common/modpack.h  |  3 ++
 server/gamehand.c | 77 ++++++++++++++++++++++++++++++-----------------
 3 files changed, 63 insertions(+), 27 deletions(-)

diff --git a/common/modpack.c b/common/modpack.c
index 480f0bc539..96730b4eb3 100644
--- a/common/modpack.c
+++ b/common/modpack.c
@@ -195,3 +195,13 @@ const char *modpack_file_from_ruleset_cache(const char *name)
 
   return NULL;
 }
+
+/************************************************************************//**
+  Call callback for each item in the ruleset cache.
+****************************************************************************/
+void modpack_ruleset_cache_iterate(mrc_cb cb, void *data)
+{
+  modpack_cache_iterate(modpack_rulesets, item) {
+    cb(item->modpack_name, item->filename, data);
+  } modpack_cache_iterate_end;
+}
diff --git a/common/modpack.h b/common/modpack.h
index 06da618a24..366b4eb930 100644
--- a/common/modpack.h
+++ b/common/modpack.h
@@ -36,6 +36,9 @@ bool modpack_check_capabilities(struct section_file *file, const char *us_capstr
 const char *modpack_serv_file(struct section_file *sf);
 const char *modpack_rulesetdir(struct section_file *sf);
 
+typedef void (*mrc_cb)(const char*, const char *, void *data);
+void modpack_ruleset_cache_iterate(mrc_cb cb, void *data);
+
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */
diff --git a/server/gamehand.c b/server/gamehand.c
index 5e53a63866..550ee24222 100644
--- a/server/gamehand.c
+++ b/server/gamehand.c
@@ -1080,6 +1080,34 @@ const char *new_challenge_filename(struct connection *pc)
   return get_challenge_filename(pc);
 }
 
+struct mrc_data {
+  int count;
+  struct packet_ruleset_choices *packet;
+};
+
+/************************************************************************//**
+  Callback called from modpack ruleset cache iteration.
+****************************************************************************/
+static void ruleset_cache_cb(const char *mp_name, const char *filename,
+                             void *data_in)
+{
+  struct mrc_data *data = (struct mrc_data *)data_in;
+  const int maxlen = sizeof(data->packet->rulesets[data->count]);
+
+  if (data->count >= MAX_NUM_RULESETS) {
+    log_verbose("Can't send more than %d ruleset names to client, "
+                "skipping some", MAX_NUM_RULESETS);
+    return;
+  }
+
+  if (fc_strlcpy(data->packet->rulesets[data->count], mp_name, maxlen) < maxlen) {
+    data->count++;
+  } else {
+    log_verbose("Modpack name '%s' too long to send to client, skipped",
+                mp_name);
+  }
+}
+
 /************************************************************************//**
   Call this on a connection with HACK access to send it a set of ruleset
   choices.  Probably this should be called immediately when granting
@@ -1087,43 +1115,38 @@ const char *new_challenge_filename(struct connection *pc)
 ****************************************************************************/
 static void send_ruleset_choices(struct connection *pc)
 {
-  struct fileinfo_list *ruleset_choices;
   struct packet_ruleset_choices packet;
-  size_t i = 0;
+  static bool rulesets_cached = FALSE;
+  struct mrc_data data;
 
-  ruleset_choices = get_modpacks_list();
+  if (!rulesets_cached) {
+    struct fileinfo_list *ruleset_choices;
 
-  fileinfo_list_iterate(ruleset_choices, pfile) {
-    const int maxlen = sizeof(packet.rulesets[i]);
-    struct section_file *sf;
+    ruleset_choices = get_modpacks_list();
 
-    if (i >= MAX_NUM_RULESETS) {
-      log_verbose("Can't send more than %d ruleset names to client, "
-                  "skipping some", MAX_NUM_RULESETS);
-      break;
-    }
-
-    sf = secfile_load(pfile->fullname, FALSE);
+    fileinfo_list_iterate(ruleset_choices, pfile) {
+      struct section_file *sf;
 
-    if (sf != NULL) {
-      const char *name = modpack_cache_ruleset(sf);
+      sf = secfile_load(pfile->fullname, FALSE);
 
-      if (name != NULL) {
-        if (fc_strlcpy(packet.rulesets[i], name, maxlen) < maxlen) {
-          i++;
-        } else {
-          log_verbose("Modpack name '%s' too long to send to client, skipped", name);
-        }
+      if (sf != NULL) {
+        modpack_cache_ruleset(sf);
+        secfile_destroy(sf);
       }
+    } fileinfo_list_iterate_end;
 
-      secfile_destroy(sf);
-    }
-  } fileinfo_list_iterate_end;
-  packet.ruleset_count = i;
+    fileinfo_list_destroy(ruleset_choices);
 
-  send_packet_ruleset_choices(pc, &packet);
+    rulesets_cached = TRUE;
+  }
 
-  fileinfo_list_destroy(ruleset_choices);
+  data.count = 0;
+  data.packet = &packet;
+  modpack_ruleset_cache_iterate(ruleset_cache_cb, &data);
+
+  packet.ruleset_count = data.count;
+
+  send_packet_ruleset_choices(pc, &packet);
 }
 
 /************************************************************************//**
-- 
2.34.1