lib/Ticker: add bool active() (esp8266#2722)

* lib/Ticker: add bool active()

Makes it easier to self detach, and check if a timer is still operating.

Signed-off-by: Karl Palsson <karlp@tweak.net.au>

* Code cleanup Ticker.cpp

Author: karlp

libraries/Ticker/Ticker.cpp

@@ -22,20 +22,18 @@
 #include <stddef.h>
 #include <stdint.h>
 
-extern "C" {
 #include "c_types.h"
 #include "eagle_soc.h"
 #include "ets_sys.h"
 #include "osapi.h"
-}
 
-const int ONCE   = 0;
-const int REPEAT = 1;
+static const int ONCE   = 0;
+static const int REPEAT = 1;
 
 #include "Ticker.h"
 
 Ticker::Ticker()
-: _timer(0)
+: _timer(nullptr)
 {
 }
 
@@ -66,5 +64,10 @@ void Ticker::detach()
 
 	os_timer_disarm(_timer);
 	delete _timer;
-	_timer = 0;
+	_timer = nullptr;
+}
+
+bool Ticker::active()
+{
+	return (bool)_timer;
 }

libraries/Ticker/Ticker.h

@@ -23,6 +23,7 @@
 #define TICKER_H
 
 #include <stdint.h>
+#include <stdbool.h>
 #include <stddef.h>
 
 extern "C" {
@@ -93,6 +94,7 @@ class Ticker
 	}
 
 	void detach();
+	bool active();
 
 protected:	
 	void _attach_ms(uint32_t milliseconds, bool repeat, callback_with_arg_t callback, uint32_t arg);

libraries/Ticker/keywords.txt

@@ -15,6 +15,7 @@ attach_ms	KEYWORD2
 once	KEYWORD2
 once_ms	KEYWORD2
 detach	KEYWORD2
+active  KEYWORD2
 
 #######################################
 # Instances (KEYWORD2)