fix(battery): Make it possible to disable polling

README.md

@@ -205,7 +205,8 @@ the resulting output might not be award-winning.
   ;battery = BAT0
   ;adapter = ADP1
 
-  ; Seconds between reading battery capacity
+  ; Seconds between reading battery capacity.
+  ; If set to 0, polling will be disabled.
   ;poll_interval = 3
   ~~~
 

src/modules/battery.cpp

@@ -78,7 +78,7 @@ void BatteryModule::subthread_runner()
 
     // TODO(jaagr): Keep track of when the values were last read to determine
     // if we need to trigger the event manually or not.
-    if ((++i % poll_seconds) == 0) {
+    if (poll_seconds > 0 && (++i % poll_seconds) == 0) {
       // Trigger an inotify event in case the underlying filesystem doesn't
       log_debug("Poll battery capacity");
       io::file::get_contents("/sys/class/power_supply/BAT0/capacity");