From 1ca22508fcbff9771bd618712a121851a61ba85f Mon Sep 17 00:00:00 2001
From: Kay0u <pierre@kayou.io>
Date: Wed, 2 Sep 2020 12:57:16 +0200
Subject: [PATCH] Reload the conf only if files has been modified

---
 config.lua | 56 +++++++++++++++++++++++++++++++++++++++---------------
 1 file changed, 41 insertions(+), 15 deletions(-)

diff --git a/config.lua b/config.lua
index 90141f8..dfceedb 100644
--- a/config.lua
+++ b/config.lua
@@ -6,15 +6,41 @@
 
 module('config', package.seeall)
 
+local config_attributes = nil
+local config_persistent_attributes = nil
+
+local conf = {}
+
+function compare_attributes(file_attributes1, file_attributes2)
+    if file_attributes1 == nil and file_attributes2 == nil then
+        return true
+    elseif file_attributes1 == nil and file_attributes2 ~= nil or file_attributes1 ~= nil and file_attributes2 == nil then
+        return false
+    end
+    return file_attributes1["modification"] == file_attributes2["modification"] and file_attributes1["size"] == file_attributes2["size"]
+end
+
 function get_config()
 
-    -- Load the configuration file
-    local conf_file = assert(io.open(conf_path, "r"), "Configuration file is missing")
-    local conf = json.decode(conf_file:read("*all"))
-    if conf_file ~= nil then
-        conf_file:close()
+    -- Get config files attributes (timestamp modification and size)
+    local new_config_attributes = lfs.attributes(conf_path, {"modification", "size"})
+    local new_config_persistent_attributes = lfs.attributes(conf_path..".persistent", {"modification", "size"})
+
+    if compare_attributes(new_config_attributes, config_attributes) and compare_attributes(new_config_persistent_attributes, config_persistent_attributes) then
+        return conf
+    -- If the file is being written, its size may be 0 and reloading fails, return the last valid config
+    elseif new_config_attributes == nil or new_config_attributes["size"] == 0 then
+        return conf
     end
 
+    -- If the timestamp of the modification or the size is different, reload the configuration.
+    config_attributes = new_config_attributes
+    config_persistent_attributes = new_config_persistent_attributes
+    
+    local conf_file = assert(io.open(conf_path, "r"), "Configuration file is missing")
+    conf = json.decode(conf_file:read("*all"))
+    conf_file:close()
+
     -- Load additional rules from the `.persistent` configuration file.
     -- The `.persistent` file contains rules that will overwrite previous rules.
     -- It typically enables you to set custom rules.
@@ -24,19 +50,19 @@ function get_config()
         persistent_conf_file:close()
         for k, v in pairs(perm_conf) do
 
-           -- If the configuration key already exists and is a table, merge it
-           if conf[k] and type(v) == "table" then
-               for subk, subv in pairs(v) do
-                   if type(subk) == "number" then
-                       table.insert(conf[k], subv)
-                   else
-                       conf[k][subk] = subv
-                   end
-               end
+            -- If the configuration key already exists and is a table, merge it
+            if conf[k] and type(v) == "table" then
+                for subk, subv in pairs(v) do
+                    if type(subk) == "number" then
+                        table.insert(conf[k], subv)
+                    else
+                        conf[k][subk] = subv
+                    end
+                end
 
             -- Else just take the persistent rule's value
             else
-               conf[k] = v
+                conf[k] = v
             end
         end
     end