From a97300a77b2c10fbd8eedc07e658f67f7a3ec7a5 Mon Sep 17 00:00:00 2001
From: Sandy Carter <bwrsandman@gmail.com>
Date: Wed, 3 Jan 2024 00:13:15 -0500
Subject: [PATCH] logging: Add handler pointer for logging

Default to old stderr logging method.
Add function pointer and userdata pointer as static globals.
---
 lib/libunshield.h |  2 ++
 lib/log.c         | 25 +++++++++++++++++++++----
 2 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/lib/libunshield.h b/lib/libunshield.h
index d7e2dda..18eb2bb 100644
--- a/lib/libunshield.h
+++ b/lib/libunshield.h
@@ -32,7 +32,9 @@ typedef struct _Unshield Unshield;
 
 #define UNSHIELD_LOG_LEVEL_HIGHEST   4
 
+typedef void (UnshieldLogCallback)(void* userdata, int level, const char* file, int line, const char* format, va_list ap);
 void unshield_set_log_level(int level);
+void unshield_set_log_handler(UnshieldLogCallback* handler, void* userdata);
 
 /*
    Open/close functions
diff --git a/lib/log.c b/lib/log.c
index 42673b8..f573641 100644
--- a/lib/log.c
+++ b/lib/log.c
@@ -4,25 +4,42 @@
 
 /* evil static data */
 static int current_log_level = UNSHIELD_LOG_LEVEL_HIGHEST;
+static UnshieldLogCallback* current_log_handler = NULL;
+static void* current_log_handler_userdata = NULL;
 
 void unshield_set_log_level(int level)
 {
 	current_log_level = level;
 }
 
-void _unshield_log(int level, const char* file, int line, const char* format, ...)
+void unshield_set_log_handler(UnshieldLogCallback* handler, void* userdata)
 {
-	va_list ap;
+	current_log_handler = handler;
+	current_log_handler_userdata = userdata;
+}
+
+void unshield_default_log_handler(void* userdata, int level, const char* file, int line, const char* format, va_list ap)
+{
+	(void)userdata;
 
 	if (level > current_log_level)
 		return;
 
 	fprintf(stderr, "[%s:%i] ", file, line);
 	
-	va_start(ap, format);
 	vfprintf(stderr, format, ap);
-	va_end(ap);
 	
 	fprintf(stderr, "\n");
 }
 
+void _unshield_log(int level, const char* file, int line, const char* format, ...)
+{
+	va_list ap;
+
+	if (current_log_handler == NULL)
+		unshield_set_log_handler(unshield_default_log_handler, NULL);
+
+	va_start(ap, format);
+	current_log_handler(current_log_handler_userdata, level, file, line, format, ap);
+	va_end(ap);
+}