caProvider: Convert caChannelList into a tsDLList

This should provide a significant performance boost when creating
many thousands of CA channels. The only time it is necessary to
traverse the list is in the CAChannelProvider's destructor; when
individual channels are added or destroyed they can insert or
remove themselves from the list without having to do a search.

src/ca/caChannel.cpp

@@ -132,7 +132,7 @@ void CAChannel::activate(short priority)
         channelCreated = true;
         CAChannelProviderPtr provider(channelProvider.lock());
         if (provider)
-            provider->addChannel(shared_from_this());
+            provider->addChannel(*this);
         EXCEPTION_GUARD(req->channelCreated(Status::Ok, shared_from_this()));
     }
     else {
@@ -167,10 +167,14 @@ void CAChannel::disconnectChannel()
     /* Clear CA Channel */
     Attach to(ca_context);
     int result = ca_clear_channel(channelID);
-    if (result == ECA_NORMAL) return;
-    string mess("CAChannel::disconnectChannel() ");
-    mess += ca_message(result);
-    cerr << mess << endl;
+    if (result != ECA_NORMAL) {
+        string mess("CAChannel::disconnectChannel() ");
+        mess += ca_message(result);
+        cerr << mess << endl;
+    }
+    CAChannelProviderPtr provider(channelProvider.lock());
+    if (provider)
+        provider->delChannel(*this);
 }
 
 chid CAChannel::getChannelID()

src/ca/caChannel.h

@@ -18,6 +18,7 @@
 #include <epicsMutex.h>
 #include <epicsEvent.h>
 #include <cadef.h>
+#include <tsDLList.h>
 
 #include <pv/pvAccess.h>
 
@@ -66,6 +67,7 @@ private:
 
 class CAChannel :
     public Channel,
+    public tsDLNode<CAChannel>,
     public NotifierClient,
     public std::tr1::enable_shared_from_this<CAChannel>
 {

src/ca/caProvider.cpp

@@ -31,22 +31,9 @@ CAChannelProvider::CAChannelProvider(const std::tr1::shared_ptr<Configuration> &
 
 CAChannelProvider::~CAChannelProvider()
 {
-    std::queue<CAChannelPtr> channelQ;
-    {
-        std::vector<CAChannelWPtr>::iterator it;
-        epicsGuard<epicsMutex> G(channelListMutex);
-        for (it = caChannelList.begin(); it != caChannelList.end(); ++it)
-        {
-            CAChannelPtr caChannel(it->lock());
-            if (caChannel)
-                channelQ.push(caChannel);
-        }
-        caChannelList.clear();
-    }
-    while (!channelQ.empty())
-    {
-        channelQ.front()->disconnectChannel();
-        channelQ.pop();
+    epicsGuard<epicsMutex> G(channelListMutex);
+    while (CAChannel *ch = caChannelList.first()) {
+        ch->disconnectChannel();    // Removes itself from the list
     }
 }
 
@@ -106,18 +93,16 @@ Channel::shared_pointer CAChannelProvider::createChannel(
     return CAChannel::create(shared_from_this(), channelName, priority, channelRequester);
 }
 
-void CAChannelProvider::addChannel(const CAChannelPtr &channel)
+void CAChannelProvider::addChannel(CAChannel &channel)
 {
-    std::vector<CAChannelWPtr>::iterator it;
     epicsGuard<epicsMutex> G(channelListMutex);
-    for (it = caChannelList.begin(); it != caChannelList.end(); ++it)
-    {
-        if (it->expired()) {
-            *it = channel;
-            return;
-        }
-    }
-    caChannelList.push_back(channel);
+    caChannelList.add(channel);
+}
+
+void CAChannelProvider::delChannel(CAChannel &channel)
+{
+    epicsGuard<epicsMutex> G(channelListMutex);
+    caChannelList.remove(channel);
 }
 
 void CAChannelProvider::configure(epics::pvData::PVStructure::shared_pointer /*configuration*/)

src/ca/caProviderPvt.h

@@ -14,6 +14,7 @@
 
 #include <cadef.h>
 #include <epicsMutex.h>
+#include <tsDLList.h>
 
 #include <pv/logger.h>
 #include <pv/pvAccess.h>
@@ -80,7 +81,8 @@ public:
     virtual void flush();
     virtual void poll();
 
-    void addChannel(const CAChannelPtr & channel);
+    void addChannel(CAChannel &channel);
+    void delChannel(CAChannel &channel);
 
     CAContextPtr caContext() {
         return ca_context;
@@ -94,7 +96,7 @@ public:
 private:
     CAContextPtr ca_context;
     epicsMutex channelListMutex;
-    std::vector<CAChannelWPtr> caChannelList;
+    tsDLList<CAChannel> caChannelList;
 
     NotifierConveyor connectNotifier;
     NotifierConveyor resultNotifier;