From 63762921e2890e5260d5d2c954a32e769f6889eb Mon Sep 17 00:00:00 2001
From: Michael Tremer <michael.tremer@ipfire.org>
Date: Wed, 22 May 2024 15:35:28 +0000
Subject: [PATCH] lua: Implement setting a log callback function

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
---
 src/lua/location.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++
 tests/lua/main.lua | 22 ++++++++++++++++++
 2 files changed, 78 insertions(+)

diff --git a/src/lua/location.c b/src/lua/location.c
index b7d2c0e..1c94889 100644
--- a/src/lua/location.c
+++ b/src/lua/location.c
@@ -15,6 +15,7 @@
 */
 
 #include <errno.h>
+#include <stdlib.h>
 #include <string.h>
 
 #include <lua.h>
@@ -33,12 +34,67 @@
 
 struct loc_ctx* ctx = NULL;
 
+static int log_callback_ref = 0;
+
+static void log_callback(struct loc_ctx* _ctx, void* data, int priority, const char* file,
+		int line, const char* fn, const char* format, va_list args) {
+	char* message = NULL;
+	int r;
+
+	lua_State* L = data;
+
+	// Format the log message
+	r = vasprintf(&message, format, args);
+	if (r < 0)
+		return;
+
+	// Fetch the Lua callback function
+	lua_rawgeti(L, LUA_REGISTRYINDEX, log_callback_ref);
+
+	// Pass the priority as first argument
+	lua_pushnumber(L, priority);
+
+	// Pass the message as second argument
+	lua_pushstring(L, message);
+
+	// Call the function
+	lua_call(L, 2, 0);
+
+	free(message);
+}
+
+static int set_log_callback(lua_State* L) {
+	// Check if we have received a function
+	luaL_checktype(L, 1, LUA_TFUNCTION);
+
+	// Store a reference to the callback function
+	log_callback_ref = luaL_ref(L, LUA_REGISTRYINDEX);
+
+	// Register our callback helper
+	if (ctx)
+		loc_set_log_callback(ctx, log_callback, L);
+
+	return 0;
+}
+
+static int set_log_level(lua_State* L) {
+	const int level = luaL_checknumber(L, 1);
+
+	// Store the new log level
+	if (ctx)
+		loc_set_log_priority(ctx, level);
+
+	return 0;
+}
+
 static int version(lua_State* L) {
 	lua_pushstring(L, PACKAGE_VERSION);
 	return 1;
 }
 
 static const struct luaL_Reg location_functions[] = {
+	{ "set_log_callback", set_log_callback },
+	{ "set_log_level", set_log_level },
 	{ "version", version },
 	{ NULL, NULL },
 };
diff --git a/tests/lua/main.lua b/tests/lua/main.lua
index e139b2d..0133dc5 100755
--- a/tests/lua/main.lua
+++ b/tests/lua/main.lua
@@ -30,6 +30,28 @@ function test_load()
 	print(location.version())
 end
 
+log_callback_called = 0
+
+function log_callback(level, message)
+	log_callback_called = 1
+	print("LOG " .. message)
+end
+
+function test_log_callback()
+	location = require("location")
+
+	-- Set the callback
+	location.set_log_callback(log_callback)
+
+	-- Enable debugging
+	location.set_log_level(7)
+
+	-- Perform some random operation
+	local db = location.Database.open(ENV_TEST_DATABASE)
+
+	luaunit.assertIsTrue(log_callback_called)
+end
+
 function test_open_database()
 	location = require("location")
 
-- 
2.39.5