From 61e015ce4f2aa02973012ae0eef3bc53a5c59102 Mon Sep 17 00:00:00 2001
From: Gergely Nagy <algernon@madhouse-project.org>
Date: Mon, 26 Dec 2016 07:41:48 +0100
Subject: [PATCH] Do not crash if there are no LED effects

When trying to update the LEDs, do not unconditionally call `modes[mode]->init`
and `modes[mode]->update`: we may have no effects installed. This change stops
the firmware from crashing with an NPE if no LED effects are enabled.

Also sets mode and previousMode to zero in the constructor, so we start with a
deterministic state.

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
---
 src/LEDControl.cpp | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/src/LEDControl.cpp b/src/LEDControl.cpp
index ba7e06b9..22ee98bf 100644
--- a/src/LEDControl.cpp
+++ b/src/LEDControl.cpp
@@ -6,6 +6,7 @@ LEDMode::activate (void) {
 }
 
 LEDControl_::LEDControl_(void) {
+  mode = previousMode = 0;
   memset (modes, 0, LED_MAX_MODES * sizeof (modes[0]));
 }
 
@@ -38,10 +39,12 @@ void
 LEDControl_::update (void) {
   if (previousMode != mode) {
     set_all_leds_to ({0, 0, 0});
-    (modes[mode]->init) ();
+    if (modes[mode])
+      (modes[mode]->init) ();
   }
 
-  (modes[mode]->update) ();
+  if (modes[mode])
+    (modes[mode]->update) ();
 
   led_sync ();
 
@@ -49,9 +52,9 @@ LEDControl_::update (void) {
 }
 
 void
-LEDControl_::set_mode (uint8_t mode) {
-  if (mode < LED_MAX_MODES)
-    this->mode = mode;
+LEDControl_::set_mode (uint8_t mode_) {
+  if (mode_ < LED_MAX_MODES)
+    mode = mode;
 }
 
 uint8_t