Add Schedule.(h|cpp) from ESP8266 to run off loopTask.

Author: dok-net

CMakeLists.txt

@@ -28,6 +28,7 @@ set(CORE_SRCS
   cores/esp32/MD5Builder.cpp
   cores/esp32/Print.cpp
   cores/esp32/stdlib_noniso.c
+  cores/esp32/Schedule.cpp
   cores/esp32/Stream.cpp
   cores/esp32/StreamString.cpp
   cores/esp32/wiring_pulse.c

cores/esp32/Arduino.h

@@ -159,6 +159,7 @@ void shiftOut(uint8_t dataPin, uint8_t clockPin, uint8_t bitOrder, uint8_t val);
 #include "Udp.h"
 #include "HardwareSerial.h"
 #include "Esp.h"
+#include "Schedule.h"
 
 using std::isinf;
 using std::isnan;

cores/esp32/Schedule.cpp

@@ -0,0 +1,78 @@
+#include "Schedule.h"
+
+struct scheduled_fn_t
+{
+    scheduled_fn_t* mNext;
+    std::function<void(void)> mFunc;
+};
+
+static scheduled_fn_t* sFirst = 0;
+static scheduled_fn_t* sLast = 0;
+
+static scheduled_fn_t* sFirstUnused = 0;
+static scheduled_fn_t* sLastUnused = 0;
+
+static int sCount = 0;
+
+static scheduled_fn_t* get_fn() {
+    scheduled_fn_t* result = NULL;
+    // try to get an item from unused items list
+    if (sFirstUnused) {
+        result = sFirstUnused;
+        sFirstUnused = result->mNext;
+        if (sFirstUnused == NULL) {
+            sLastUnused = NULL;
+        }
+    }
+    // if no unused items, and count not too high, allocate a new one
+    else if (sCount != SCHEDULED_FN_MAX_COUNT) {
+        result = new scheduled_fn_t;
+        result->mNext = NULL;
+        ++sCount;
+    }
+    return result;
+}
+
+static void recycle_fn(scheduled_fn_t* fn)
+{
+    if (!sLastUnused) {
+        sFirstUnused = fn;
+    }
+    else {
+        sLastUnused->mNext = fn;
+    }
+    fn->mNext = NULL;
+    sLastUnused = fn;
+}
+
+bool schedule_function(std::function<void(void)> fn)
+{
+    scheduled_fn_t* item = get_fn();
+    if (!item) {
+        return false;
+    }
+    item->mFunc = fn;
+    item->mNext = NULL;
+    if (!sFirst) {
+        sFirst = item;
+    }
+    else {
+        sLast->mNext = item;
+    }
+    sLast = item;
+    return true;
+}
+
+void run_scheduled_functions()
+{
+	scheduled_fn_t* rFirst = sFirst;
+	sFirst = NULL;
+	sLast  = NULL;
+    while (rFirst) {
+        scheduled_fn_t* item = rFirst;
+        rFirst = item->mNext;
+        item->mFunc();
+        item->mFunc = std::function<void(void)>();
+        recycle_fn(item);
+    }
+}

cores/esp32/Schedule.h

@@ -0,0 +1,27 @@
+#ifndef ESP_SCHEDULE_H
+#define ESP_SCHEDULE_H
+
+#include <functional>
+
+#define SCHEDULED_FN_MAX_COUNT 32
+#define SCHEDULED_FN_INITIAL_COUNT 4
+
+// Warning 
+// This API is not considered stable. 
+// Function signatures will change.
+// You have been warned.
+
+// Run given function next time `loop` function returns, 
+// or `run_scheduled_functions` is called.
+// Use std::bind to pass arguments to a function, or call a class member function.
+// Note: there is no mechanism for cancelling scheduled functions.
+// Keep that in mind when binding functions to objects which may have short lifetime.
+// Returns false if the number of scheduled functions exceeds SCHEDULED_FN_MAX_COUNT.
+bool schedule_function(std::function<void(void)> fn);
+
+// Run all scheduled functions. 
+// Use this function if your are not using `loop`, or `loop` does not return
+// on a regular basis.
+void run_scheduled_functions();
+
+#endif //ESP_SCHEDULE_H

cores/esp32/main.cpp

@@ -17,6 +17,7 @@ void loopTask(void *pvParameters)
             esp_task_wdt_reset();
         }
         loop();
+        run_scheduled_functions();
     }
 }