From 2ba2b90b06b21ed0dbcf0fa29278104b7efc9d3c Mon Sep 17 00:00:00 2001
From: Michael Davidsaver <mdavidsaver@bnl.gov>
Date: Mon, 5 Jan 2015 16:26:47 -0500
Subject: [PATCH] dbScan: add scanOnce3() w/ completion callback

---
 src/ioc/db/dbScan.c | 55 ++++++++++++++++++++++++++++++++-------------
 src/ioc/db/dbScan.h |  8 ++++---
 2 files changed, 44 insertions(+), 19 deletions(-)

diff --git a/src/ioc/db/dbScan.c b/src/ioc/db/dbScan.c
index 272b185b0..3cd93da1a 100644
--- a/src/ioc/db/dbScan.c
+++ b/src/ioc/db/dbScan.c
@@ -26,10 +26,9 @@
 #include "ellLib.h"
 #include "epicsEvent.h"
 #include "epicsExit.h"
-#include "epicsInterrupt.h"
 #include "epicsMutex.h"
 #include "epicsPrint.h"
-#include "epicsRingPointer.h"
+#include "epicsRingBytes.h"
 #include "epicsStdio.h"
 #include "epicsStdlib.h"
 #include "epicsString.h"
@@ -64,7 +63,7 @@ static volatile enum ctl scanCtl;
 
 static int onceQueueSize = 1000;
 static epicsEventId onceSem;
-static epicsRingPointerId onceQ;
+static epicsRingBytesId onceQ;
 static epicsThreadId onceTaskId;
 static void *exitOnce;
 
@@ -172,7 +171,7 @@ void scanShutdown(void)
     deletePeriodic();
     ioscanDestroy();
 
-    epicsRingPointerDelete(onceQ);
+    epicsRingBytesDelete(onceQ);
 
     epicsEventDestroy(startStopEvent);
     epicsEventDestroy(onceSem);
@@ -609,15 +608,27 @@ void scanIoSetComplete(IOSCANPVT piosh, io_scan_complete cb, void *arg)
     piosh->arg = arg;
 }
 
-void scanOnce(struct dbCommon *precord)
+int scanOnce(struct dbCommon *precord) {
+    return scanOnce3(precord, NULL, NULL);
+}
+
+typedef struct {
+    struct dbCommon *prec;
+    once_complete cb;
+    void *usr;
+} onceEntry;
+
+int scanOnce3(struct dbCommon *precord, once_complete cb, void *usr)
 {
     static int newOverflow = TRUE;
-    int lockKey;
+    onceEntry ent;
     int pushOK;
 
-    lockKey = epicsInterruptLock();
-    pushOK = epicsRingPointerPush(onceQ, precord);
-    epicsInterruptUnlock(lockKey);
+    ent.prec = precord;
+    ent.cb = cb;
+    ent.usr = usr;
+
+    pushOK = epicsRingBytesPut(onceQ, (void*)&ent, sizeof(ent));
 
     if (!pushOK) {
         if (newOverflow) errlogPrintf("scanOnce: Ring buffer overflow\n");
@@ -626,6 +637,8 @@ void scanOnce(struct dbCommon *precord)
         newOverflow = TRUE;
     }
     epicsEventSignal(onceSem);
+
+    return !pushOK;
 }
 
 static void onceTask(void *arg)
@@ -634,14 +647,24 @@ static void onceTask(void *arg)
     epicsEventSignal(startStopEvent);
 
     while (TRUE) {
-        void *precord;
 
         epicsEventMustWait(onceSem);
-        while ((precord = epicsRingPointerPop(onceQ))) {
-            if (precord == &exitOnce) goto shutdown;
-            dbScanLock(precord);
-            dbProcess(precord);
-            dbScanUnlock(precord);
+        while(1) {
+            onceEntry ent;
+            int bytes = epicsRingBytesGet(onceQ, (void*)&ent, sizeof(ent));
+            if(bytes==0)
+                break;
+            if(bytes!=sizeof(ent)) {
+                errlogPrintf("onceTask: received incomplete %d of %u\n",
+                             bytes, (unsigned)sizeof(ent));
+                continue; /* what to do? */
+            } else if (ent.prec == (void*)&exitOnce) goto shutdown;
+
+            dbScanLock(ent.prec);
+            dbProcess(ent.prec);
+            dbScanUnlock(ent.prec);
+            if(ent.cb)
+                ent.cb(ent.usr, ent.prec);
         }
     }
 
@@ -658,7 +681,7 @@ int scanOnceSetQueueSize(int size)
 
 static void initOnce(void)
 {
-    if ((onceQ = epicsRingPointerCreate(onceQueueSize)) == NULL) {
+    if ((onceQ = epicsRingBytesLockedCreate(sizeof(onceEntry)*onceQueueSize)) == NULL) {
         cantProceed("initOnce: Ring buffer create failed\n");
     }
     onceSem = epicsEventMustCreate(epicsEventEmpty);
diff --git a/src/ioc/db/dbScan.h b/src/ioc/db/dbScan.h
index 8bd2bba22..fffae23d1 100644
--- a/src/ioc/db/dbScan.h
+++ b/src/ioc/db/dbScan.h
@@ -39,10 +39,11 @@ struct ioscan_head;
 typedef struct ioscan_head *IOSCANPVT;
 typedef struct event_list *EVENTPVT;
 
-typedef void (*io_scan_complete)(void *usr, IOSCANPVT, int prio);
-
 struct dbCommon;
 
+typedef void (*io_scan_complete)(void *usr, IOSCANPVT, int prio);
+typedef void (*once_complete)(void *usr, struct dbCommon*);
+
 epicsShareFunc long scanInit(void);
 epicsShareFunc void scanRun(void);
 epicsShareFunc void scanPause(void);
@@ -54,7 +55,8 @@ epicsShareFunc void post_event(int event) EPICS_DEPRECATED;
 epicsShareFunc void scanAdd(struct dbCommon *);
 epicsShareFunc void scanDelete(struct dbCommon *);
 epicsShareFunc double scanPeriod(int scan);
-epicsShareFunc void scanOnce(struct dbCommon *);
+epicsShareFunc int scanOnce(struct dbCommon *);
+epicsShareFunc int scanOnce3(struct dbCommon *, once_complete cb, void *usr);
 epicsShareFunc int scanOnceSetQueueSize(int size);
 
 /*print periodic lists*/