From 3341d9a2baf63c96e997cd61d1f7c59c17bf8194 Mon Sep 17 00:00:00 2001
From: Michael Davidsaver <mdavidsaver@gmail.com>
Date: Wed, 23 May 2018 13:57:43 -0700
Subject: [PATCH] spamme example use MonitorFIFO

---
 examples/spamme.cpp | 155 +++++++++-----------------------------------
 1 file changed, 29 insertions(+), 126 deletions(-)

diff --git a/examples/spamme.cpp b/examples/spamme.cpp
index d66942b..3977715 100644
--- a/examples/spamme.cpp
+++ b/examples/spamme.cpp
@@ -32,6 +32,8 @@ typedef epicsGuard<epicsMutex> Guard;
 
 epicsEvent done;
 
+bool debug;
+
 #ifdef USE_SIGNAL
 void alldone(int num)
 {
@@ -48,145 +50,39 @@ pvd::Structure::const_shared_pointer spamtype(pvd::getFieldCreate()->createField
 struct SpamProvider;
 struct SpamChannel;
 
-struct SpamMonitor : public pva::Monitor,
-                     public std::tr1::enable_shared_from_this<SpamMonitor>
+struct SpamSource : public pva::MonitorFIFO::Source
 {
-    const std::tr1::shared_ptr<SpamChannel> channel;
-    const requester_type::weak_pointer requester;
-    pvd::int32 maxQueue;
-    bool pipeline;
-    // Has the client seen poll()==NULL
-    bool clientEmpty;
     epicsMutex mutex;
 
-    bool running;
-    epicsUInt32 remoteQueue;
-    std::deque<epics::pvData::MonitorElementPtr> filled, empty;
-    pvd::PVStructure::shared_pointer value;
     epicsUInt32 counter;
 
-    SpamMonitor(const std::tr1::shared_ptr<SpamChannel>& chan,
-                const pva::MonitorRequester::shared_pointer &requester,
-                const pvd::PVStructure::shared_pointer &pvRequest)
-        :channel(chan)
-        ,requester(requester)
-        ,maxQueue(0)
-        ,pipeline(false)
-        ,clientEmpty(true)
-        ,running(false)
-        ,remoteQueue(0)
-        ,counter(0)
+    const pvd::PVStructurePtr cur;
+    const pvd::PVIntPtr val;
+    pvd::BitSet changed;
+
+    SpamSource()
+        :counter(0)
+        ,cur(pvd::getPVDataCreate()->createPVStructure(spamtype))
+        ,val(cur->getSubFieldT<pvd::PVInt>("value"))
     {
-        pvd::PVScalar::shared_pointer fld;
-
-        fld = pvRequest->getSubField<pvd::PVScalar>("record._options.queueSize");
-        if(fld)
-            maxQueue = fld->getAs<pvd::int32>();
-        if(maxQueue<3)
-            maxQueue = 3;
-
-        fld = pvRequest->getSubField<pvd::PVScalar>("record._options.pipeline");
-        if(fld)
-            pipeline = fld->getAs<pvd::boolean>();
-
-        pvd::PVDataCreatePtr create(pvd::getPVDataCreate());
-        value = create->createPVStructure(spamtype);
-        for(pvd::int32 i=0; i<maxQueue; i++)
-        {
-            pvd::MonitorElementPtr elem(new pvd::MonitorElement(create->createPVStructure(spamtype)));
-            empty.push_back(elem);
-        }
+        changed.set(val->getFieldOffset()); // our value always changes
     }
-    virtual ~SpamMonitor() {}
-
-    virtual void destroy() OVERRIDE FINAL {(void)stop();}
-
-    virtual pvd::Status start() OVERRIDE FINAL
-    {
-        {
-            Guard G(mutex);
-            running = true;
-            clientEmpty = true;
-        }
-        pushall();
-        return pvd::Status::Ok;
-    }
-    virtual pvd::Status stop() OVERRIDE FINAL
-    {
-        {
-            Guard G(mutex);
-            running = false;
-        }
-        return pvd::Status::Ok;
-    }
-    virtual pva::MonitorElementPtr poll() OVERRIDE FINAL
+    virtual ~SpamSource() {}
+    virtual void freeHighMark(pva::MonitorFIFO *mon, size_t numEmpty) OVERRIDE FINAL
     {
         Guard G(mutex);
-        pva::MonitorElementPtr ret;
-        if(!filled.empty()) {
-            ret = filled.front();
-            filled.pop_front();
-        }
-        clientEmpty = !ret;
-        return ret;
-    }
-    virtual void release(const pva::MonitorElementPtr& elem) OVERRIDE FINAL
-    {
-        if(elem->pvStructurePtr->getField().get()!=spamtype.get())
-            return;
+        for(;numEmpty; numEmpty--)
         {
-            Guard G(mutex);
-            empty.push_back(elem);
-        }
-        pushall();
-    }
-
-    virtual void reportRemoteQueueStatus(pvd::int32 freeElements) OVERRIDE FINAL
-    {
-        {
-            Guard G(mutex);
-            remoteQueue += freeElements;
-        }
-        pushall();
-    }
-
-    void pushall()
-    {
-        bool signal;
-        {
-            Guard G(mutex);
-
-            signal = clientEmpty && filled.empty();
-
-            while(!empty.empty() && (!pipeline || remoteQueue>0)) {
-                pva::MonitorElementPtr elem(empty.front());
-
-                pvd::PVIntPtr fld(value->getSubFieldT<pvd::PVInt>("value"));
-                fld->put(counter++);
-
-                elem->pvStructurePtr->copyUnchecked(*value);
-                elem->changedBitSet->clear();
-                elem->changedBitSet->set(0);
-                elem->overrunBitSet->clear();
-
-                filled.push_back(elem);
-                empty.pop_front();
-                remoteQueue--;
+            val->put(counter);
+            if(!mon->tryPost(*cur, changed) && numEmpty!=1) {
+                std::cerr<<"spam tryPost() inconsistent "<<numEmpty<<"\n";
+                return;
             }
-
-            signal &= !filled.empty();
-            if(signal)
-                clientEmpty = false;
-        }
-        if(signal) {
-            requester_type::shared_pointer req(requester.lock());
-            if(req)
-                req->monitorEvent(shared_from_this());
+            counter++;
         }
     }
 };
 
-
 struct SpamChannel : public pva::Channel,
         public std::tr1::enable_shared_from_this<SpamChannel>
 {
@@ -226,8 +122,11 @@ struct SpamChannel : public pva::Channel,
     virtual pva::Monitor::shared_pointer createMonitor(const pva::MonitorRequester::shared_pointer &requester,
                                                        const pvd::PVStructure::shared_pointer &pvRequest) OVERRIDE FINAL
     {
-        std::tr1::shared_ptr<SpamMonitor> ret(new SpamMonitor(shared_from_this(), requester, pvRequest));
-        requester->monitorConnect(pvd::Status::Ok, ret, spamtype);
+        std::tr1::shared_ptr<SpamSource> us(new SpamSource);
+        std::tr1::shared_ptr<pva::MonitorFIFO> ret(new pva::MonitorFIFO(requester, pvRequest, us));
+        // ret holds strong ref. to us
+        ret->open(spamtype);
+        ret->notify();
         return ret;
     }
 };
@@ -277,6 +176,10 @@ struct SpamProvider : public pva::ChannelProvider,
 
 int main(int argc, char *argv[]) {
     try {
+        for(int i=1; i<argc; i++) {
+            if(strcmp("-d", argv[i])==0)
+                debug = true;
+        }
         std::tr1::shared_ptr<SpamProvider> provider(new SpamProvider("spam"));
         pva::ServerContext::shared_pointer server(pva::ServerContext::create(pva::ServerContext::Config()
                                                                              .provider(provider)