From 64846381f41e1779f93e6d7e79dc4946430f5f9e Mon Sep 17 00:00:00 2001
From: p2r3 <p2r3@p2r3.com>
Date: Tue, 2 Sep 2025 00:29:21 +0300
Subject: [PATCH] add option to sync block changes on an interval

---
 include/globals.h | 11 ++++++++---
 src/procedures.c  | 13 ++++++++++++-
 src/serialize.c   |  6 ++++++
 3 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/include/globals.h b/include/globals.h
index 2a2392f..1ae63bf 100644
--- a/include/globals.h
+++ b/include/globals.h
@@ -49,10 +49,15 @@
   #define SYNC_WORLD_TO_DISK
 #endif
 // The minimum interval (in microseconds) at which certain data is written
-// to disk/flash. Bounded on the low end by TIME_BETWEEN_TICKS. Currently
-// only applies to player data. Block changes are written as soon as they
-// are made, but in much smaller portions.
+// to disk/flash. Bounded on the low end by TIME_BETWEEN_TICKS. By default,
+// applies only to player data. Block changes are written as soon as they
+// are made, but in much smaller portions. Set DISK_SYNC_BLOCKS_ON_INTERVAL
+// to make this apply to block changes as well.
 #define DISK_SYNC_INTERVAL 15000000
+// Whether to sync block changes to disk on an interval, instead of syncing
+// on each change. On systems with fast random disk access, this shouldn't
+// be necessary.
+// #define DISK_SYNC_BLOCKS_ON_INTERVAL
 // Time in microseconds to spend waiting for data transmission before
 // timing out. Default is 15s, which leaves 5s to prevent starving other
 // clients from Keep Alive packets.
diff --git a/src/procedures.c b/src/procedures.c
index f0bbe08..c07e16e 100644
--- a/src/procedures.c
+++ b/src/procedures.c
@@ -412,7 +412,9 @@ uint8_t makeBlockChange (short x, uint8_t y, short z, uint8_t block) {
       #endif
       if (is_base_block) block_changes[i].block = 0xFF;
       else block_changes[i].block = block;
+      #ifndef DISK_SYNC_BLOCKS_ON_INTERVAL
       writeBlockChangesToDisk(i, i);
+      #endif
       return 0;
     }
   }
@@ -450,7 +452,9 @@ uint8_t makeBlockChange (short x, uint8_t y, short z, uint8_t block) {
         block_changes_count = i + 1;
       }
       // Write changes to disk (if applicable)
+      #ifndef DISK_SYNC_BLOCKS_ON_INTERVAL
       writeBlockChangesToDisk(last_real_entry + 1, last_real_entry + 15);
+      #endif
       return 0;
     }
     // If we're here, no changes were made
@@ -471,7 +475,9 @@ uint8_t makeBlockChange (short x, uint8_t y, short z, uint8_t block) {
   block_changes[first_gap].z = z;
   block_changes[first_gap].block = block;
   // Write change to disk (if applicable)
+  #ifndef DISK_SYNC_BLOCKS_ON_INTERVAL
   writeBlockChangesToDisk(first_gap, first_gap);
+  #endif
   // Extend future search range if we've appended to the end
   if (first_gap == block_changes_count) {
     block_changes_count ++;
@@ -1441,8 +1447,11 @@ void handleServerTick (int64_t time_since_last_tick) {
     sc_setHealth(player->client_fd, player->health, player->hunger, player->saturation);
   }
 
-  // Write player data to file (if applicable)
+  // Write data to file (if applicable)
   writePlayerDataToDisk();
+  #ifdef DISK_SYNC_BLOCKS_ON_INTERVAL
+  writeBlockChangesToDisk(0, block_changes_count);
+  #endif
 
   /**
    * If the RNG seed ever hits 0, it'll never generate anything
@@ -1618,7 +1627,9 @@ void broadcastChestUpdate (int origin_fd, uint8_t *storage_ptr, uint16_t item, u
     sc_setContainerSlot(player_data[i].client_fd, 2, slot, count, item);
   }
 
+  #ifndef DISK_SYNC_BLOCKS_ON_INTERVAL
   writeChestChangesToDisk(storage_ptr, slot);
+  #endif
 
 }
 #endif
diff --git a/src/serialize.c b/src/serialize.c
index 422fb0c..5ba2cf2 100644
--- a/src/serialize.c
+++ b/src/serialize.c
@@ -115,6 +115,12 @@ int initSerializer () {
 // Writes a range of block change entries to disk
 void writeBlockChangesToDisk (int from, int to) {
 
+  #ifdef DISK_SYNC_BLOCKS_ON_INTERVAL
+    // Skip this write if enough time hasn't passed since the last one
+    if (get_program_time() - last_disk_sync_time < DISK_SYNC_INTERVAL) return;
+    last_disk_sync_time = get_program_time();
+  #endif
+
   // Try to open the file in rw (without overwriting)
   FILE *file = fopen(FILE_PATH, "r+b");
   if (!file) {