Update code for require("timer").add({type:"EXEC",fn:...}) to look up the function that is being called. It's much safer than storing the reference directly as defrags could have moved the function

Author: gfwilliams

src/jsdevices.h

@@ -87,7 +87,7 @@ typedef enum {
 #ifdef BLUETOOTH
   EV_BLUETOOTH_PENDING,      // Tasks that came from the Bluetooth Stack in an IRQ
 #endif
-  EV_RUN_INTERRUPT_JS,   ///< Run some JavaScript code. See EXEC_RUN_INTERRUPT_JS. data is JsVarRef of code to run
+  EV_RUN_INTERRUPT_JS,   ///< Run some JavaScript code. See EXEC_RUN_INTERRUPT_JS. JS function to run is in hiddenRoot.TMFN[data]
   EV_CUSTOM, ///< Custom event (First byte is IOCustomEventFlags to determine the event type)
 #ifdef BANGLEJS
   EV_BANGLEJS,               // sent whenever Bangle.js-specific data needs to be queued

src/jsinteractive.c

@@ -2207,13 +2207,14 @@ void jsiHandleIOEventForConsole(uint8_t *eventData, int eventLen) {
 /** This is called if a EV_RUN_INTERRUPT_JS is received, or when a EXEC_RUN_INTERRUPT_JS is set.
 It executes JavaScript code that was pushed to the queue by a require("timer").add({type:"EXEC", fn:myFunction... */
 static void jsiOnRunInterruptJSEvent(const uint8_t *eventData, unsigned int eventLen) {
-  for (unsigned int i=0;i<eventLen-1;i+=2) {
-    JsVarRef codeRef = *(JsVarRef *)&eventData[i];
-    if (codeRef) {
-      JsVar *code = jsvLock(codeRef);
-      if (!jsvIsFunction(code)) return; // invalid code - maybe things got moved?
-      jsvUnLock(jspExecuteFunction(code, execInfo.root, 0, NULL));
-      jsvUnLock(code);
+  for (unsigned int i=0;i<eventLen;i++) {
+    uint8_t timerIdx = eventData[i];
+    JsVar *timerFns = jsvObjectGetChildIfExists(execInfo.hiddenRoot, JSI_TIMER_RUN_JS_NAME);
+    if (timerFns) {
+      JsVar *fn = jsvGetArrayItem(timerFns, timerIdx);
+      if (jsvIsFunction(fn))
+        jsvUnLock(jspExecuteFunction(fn, execInfo.root, 0, NULL));
+      jsvUnLock2(timerFns, fn);
     }
   }
 }

src/jsinteractive.h

@@ -21,6 +21,7 @@
 #define JSI_TIMERS_NAME "timers"
 #define JSI_DEBUG_HISTORY_NAME "dbghist"
 #define JSI_HISTORY_NAME "history"
+#define JSI_TIMER_RUN_JS_NAME "TMFN"
 #define JSI_INIT_CODE_NAME "init" ///< used to temporarily store initialisation JS code for state in save()
 #define JSI_LOAD_CODE_NAME "load" ///< used to temporarily store the name of a file to load from Storage when load(xyz) is used
 #define JSI_JSFLAGS_NAME "flags"

src/jstimer.c

@@ -366,7 +366,6 @@ bool utilTimerRemoveTask(int id) {
         }
         // move 'end' pointer back
         utilTimerTasksTail = (utilTimerTasksTail+1) & (UTILTIMERTASK_TASKS-1);
-        utilTimerTaskInfo[id].type = UET_NONE;
         jshInterruptOn();
         return true;
       }
@@ -703,6 +702,13 @@ void jstOnCustomEvent(IOEventFlags eventFlags, uint8_t *data, int dataLen) {
   if ((customFlags&EVC_TYPE_MASK)==EVC_TIMER_FINISHED) {
     int id = customFlags >> EVC_DATA_SHIFT;
     if (utilTimerTaskInfo[id].type & UET_FINISHED) {
+      if (utilTimerTaskInfo[id].type == (UET_FINISHED|UET_EXECUTE)) { // if EXEC with a JS function, free the function
+        JsVar *timerFns = jsvObjectGetChildIfExists(execInfo.hiddenRoot, JSI_TIMER_RUN_JS_NAME);
+        if (timerFns) {
+          jsvRemoveArrayItem(timerFns, id);
+          jsvUnLock(timerFns);
+        }
+      }
       utilTimerTaskInfo[id].type = UET_NONE;
     }
   }

src/jswrap_timer.c

@@ -34,8 +34,8 @@ This replaces `E.dumpTimers()` and `Pin.writeAtTime`
 */
 
 static void jswrap_timer_queue_interrupt_js(JsSysTime time, void* userdata) {
-  JsVarRef code = (JsVarRef)(size_t)userdata;
-  jshPushIOCharEvents(EV_RUN_INTERRUPT_JS, (char*)&code, sizeof(code));
+  uint8_t timerIdx = (uint8_t)(size_t)userdata;
+  jshPushIOCharEvents(EV_RUN_INTERRUPT_JS, (char*)&timerIdx, 1);
   execInfo.execute |= EXEC_RUN_INTERRUPT_JS;
   jshHadEvent();
 }
@@ -131,20 +131,25 @@ JsVar *jswrap_timer_get(int id) {
     typeStr="EXEC";
 #ifndef SAVE_ON_FLASH
     if (task.data.execute.fn == jswrap_timer_queue_interrupt_js) {
-      JsVar *fn = jsvLock((JsVarRef)(size_t)task.data.execute.userdata);
-      jsvObjectSetChildAndUnLock(obj, "fn", fn);
+      int timerIdx = (int)(size_t)task.data.execute.userdata;
+      JsVar *timerFns = jsvObjectGetChildIfExists(execInfo.hiddenRoot, JSI_TIMER_RUN_JS_NAME);
+      if (timerFns) {
+        jsvObjectSetChildAndUnLock(obj, "fn", jsvGetArrayItem(timerFns, timerIdx));
+        jsvUnLock(timerFns);
+      }
     } else {
       jsvObjectSetChildAndUnLock(obj, "ptr", jsvNewFromInteger((size_t)task.data.execute.fn));
       jsvObjectSetChildAndUnLock(obj, "userdata", jsvNewFromInteger((size_t)task.data.execute.userdata));
     }
 #endif
     break;
+  default: break; // could be other things if ORDed with UET_FINISHED - ignore them (fixed warning)
   }
 #ifndef SAVE_ON_FLASH
   if (UET_EVENT_HAS_PINS(task.type)) {
     JsVar *pinsArr = jsvNewEmptyArray();
     int pinCount = UET_PIN_COUNT(task.type);
-    for (int i=0;i<UTILTIMERTASK_PIN_COUNT;i++)
+    for (int i=0;i<pinCount;i++)
       if (task.data.set.pins[i] != PIN_UNDEFINED)
         jsvArrayPushAndUnLock(pinsArr, jsvNewFromPin(task.data.set.pins[i]));
     jsvObjectSetChildAndUnLock(obj, "pins", pinsArr);
@@ -213,11 +218,17 @@ require("timer").add({
 })
 // eg. execute myFunction in 100ms, then 200ms thereafter
 require("timer").add({
-  type:"EXEC", fn:myFunction,
+  type:"EXEC", fn: () => LED.toggle(),
   time:100,
   interval:200,
 });
 ```
+
+**Note:** `require("timer").add({type:"EXEC",fn:...})` differs from `setInterval`/`setTimeout` in that
+it is scheduled using a hardware timer. When the timer fires, JavaScript that's executing will be
+paused at the next statement and the JS will be executed right away. This can be great for things
+like scanning out screens where you don't want your execution to be paused even if you're executing
+JavaScript code.
 */
 int jswrap_timer_add(JsVar *timer) {
   JsVarFloat time=0, interval=0;
@@ -265,13 +276,11 @@ int jswrap_timer_add(JsVar *timer) {
     task->data.set.value = value;
   } else if (evtType == UET_EXECUTE) {
     if (jsvIsFunction(fn)) { // if a function is passed we use EXEC_RUN_INTERRUPT_JS
-      if (jsvGetRefs(fn) == 0) {
-        jsExceptionHere(JSET_ERROR, "Function passed to timer must be referenced elsewhere");
-        jsvUnLock(fn);
-        return -1;
-      }
+      JsVar *timerFns = jsvObjectGetChild(execInfo.hiddenRoot, JSI_TIMER_RUN_JS_NAME, JSV_ARRAY); // set the timer function in the hidden scope so we can look it up later
+      if (timerFns) jsvSetArrayItem(timerFns, idx, fn);
+      jsvUnLock(timerFns);
       ptr = (size_t)jswrap_timer_queue_interrupt_js;
-      userdata = jsvGetRef(fn);
+      userdata = idx;
     }
     task->data.execute.fn = (UtilTimerTaskExecFn)(size_t)ptr;
     task->data.execute.userdata = (void*)(size_t)userdata;