Overrides default Lua print with tracing alternative

src/engine/arcan_general.h

@@ -170,6 +170,11 @@ extern bool arcan_trace_enabled;
  */
 void arcan_trace_setbuffer(uint8_t* buf, size_t buf_sz, bool* finish_flag);
 
+/*
+ * appends a plain log message to the trace buffer
+ */
+void arcan_trace_log(const char* message, size_t len);
+
 /* add a trace entry-point (though call through the TRACE_MARK macros),
  * sys returns to the main system group (graphics, video, 3d, ...) and
  * subsys for a group specific subsystem (where useful distinctions exist).

src/engine/arcan_lua.c

@@ -802,6 +802,40 @@ static bool validblendmode(int m)
 		m == BLEND_PREMUL;
 }
 
+#ifndef MIN
+#define MIN(x,y) (((x)<(y))?(x):(y))
+#endif
+#define CUSTOM_PRINT_BUFFER_LEN 4096
+static char custom_print_buffer[CUSTOM_PRINT_BUFFER_LEN] = "LUA_PRINT: ";
+static int custom_print(lua_State* ctx)
+{
+	int n = lua_gettop(ctx);
+	int total_len = 11;
+
+	for (int i = 1; i <= n; i++) {
+		size_t str_len = 0;
+		const char* str = lua_tolstring(ctx, i, &str_len);
+		size_t write_len = MIN(str_len, CUSTOM_PRINT_BUFFER_LEN - 2 - total_len);
+		memcpy(&custom_print_buffer[total_len], str, write_len);
+		total_len += write_len + 1;
+
+		if (total_len == CUSTOM_PRINT_BUFFER_LEN - 1) {
+			break;
+		} else {
+			custom_print_buffer[total_len - 1] = '\t';
+		}
+	}
+
+	if (n > 0)
+		custom_print_buffer[total_len - 1] = '\n';
+	custom_print_buffer[total_len] = '\0';
+
+	fprintf(stdout, "%s", custom_print_buffer);
+	arcan_trace_log(custom_print_buffer, total_len);
+
+	return 0;
+}
+
 static int zapresource(lua_State* ctx)
 {
 	LUA_TRACE("zap_resource");
@@ -12173,6 +12207,10 @@ static const luaL_Reg netfuns[] = {
 #undef EXT_MAPTBL_NETWORK
 	register_tbl(ctx, netfuns);
 
+/* Define a custom print function for integration with tracer */
+	lua_pushcfunction(ctx, custom_print);
+	lua_setglobal(ctx, "print");
+
 /*
  * METATABLE definitions
  *  [calcImage] => used for calctargets

src/engine/arcan_trace.c

@@ -56,6 +56,22 @@ static bool append_string(const char* str)
 	return true;
 }
 
+void arcan_trace_log(const char* message, size_t len)
+{
+	if (!arcan_trace_enabled)
+		return;
+
+#ifdef WITH_TRACY
+	TracyCMessage(message, len);
+#else
+	for (int i=0; i < len; i++) {
+		if (buffer_pos == buffer_sz)
+			return;
+		buffer[buffer_pos + i] = message[i];
+	}
+#endif
+}
+
 #ifdef WITH_TRACY
 const uint32_t color_lut[] = {
 	0x000000, // DEFAULT