io: provide kSTLp text write action

In original code direct class streamer is called, 
which is impossible to handle with TBufferJSON.
Keep binary code as well in the action to have possibility
use same code-base for binary use-case

io/io/src/TStreamerInfoActions.cxx

@@ -243,6 +243,70 @@ namespace TStreamerInfoActions
       return 0;
    }
 
+   /** Direct copy of code from TStreamerInfo::WriteBufferAux,
+    * potentially can be used later for non-text streaming */
+   template<bool isText>
+   INLINE_TEMPLATE_ARGS Int_t WriteSTLp(TBuffer &buf, void *addr, const TConfiguration *config)
+   {
+      TClass *cl                 = config->fCompInfo->fClass;
+      TMemberStreamer *pstreamer = config->fCompInfo->fStreamer;
+      TVirtualCollectionProxy *proxy = cl->GetCollectionProxy();
+      TClass* vClass = proxy ? proxy->GetValueClass() : 0;
+      UInt_t eoffset = 0; // extra parameter of TStreamerInfo::WriteBufferAux, 0 for all kind of objects writing
+      UInt_t ioffset = eoffset + config->fOffset;
+
+      if (!buf.TestBit(TBuffer::kCannotHandleMemberWiseStreaming)
+          && proxy && vClass
+          && config->fInfo->GetStreamMemberWise()
+          && cl->CanSplit()
+          && !(strspn(config->fCompInfo->fElem->GetTitle(),"||") == 2)
+          && !(vClass->TestBit(TClass::kHasCustomStreamerMember)) ) {
+         // Let's save the collection member-wise.
+
+         UInt_t pos = buf.WriteVersionMemberWise(config->fInfo->IsA(),kTRUE);
+         buf.WriteVersion( vClass, kFALSE );
+
+         // TODO: subinfo used for WriteBufferSTL call, which is private for the moment
+         //TStreamerInfo *subinfo = (TStreamerInfo*)vClass->GetStreamerInfo();
+
+         //for (int k = 0; k < narr; ++k) {
+            char **contp = (char **)((char *)addr + ioffset);
+            for(int j=0;j<config->fCompInfo->fLength;++j) {
+               char *cont = contp[j];
+               TVirtualCollectionProxy::TPushPop helper( proxy, cont );
+               Int_t nobjects = cont ? proxy->Size() : 0;
+               buf << nobjects;
+
+               // TODO: method is private, should be made accesible from here
+               // subinfo->WriteBufferSTL(buf,proxy,nobjects);
+            }
+         //}
+         buf.SetByteCount(pos,kTRUE);
+         return 0;
+      }
+      UInt_t pos = buf.WriteVersion(config->fInfo->IsA(),kTRUE);
+      if (isText) {
+         // use same method which is used in kSTL
+         buf.WriteFastArray((void **)((char *) addr + ioffset), cl, config->fCompInfo->fLength, kFALSE, 0);
+      } else
+      if (pstreamer == 0) {
+         //for (int k = 0; k < narr; ++k) {
+            char **contp = (char**)((char *) addr + ioffset);
+            for(int j=0; j<config->fCompInfo->fLength; ++j) {
+               char *cont = contp[j];
+               cl->Streamer( cont, buf );
+            }
+         // }
+      } else {
+         //for (int k = 0; k < narr; ++k) {
+            (*pstreamer)(buf,(char *) addr + ioffset, config->fCompInfo->fLength);
+         //}
+      }
+      buf.SetByteCount(pos,kTRUE);
+      return 0;
+   }
+
+
    /** Direct copy of code from TStreamerInfo::WriteBufferAux,
     * potentially can be used later for non-text streaming */
    template<bool isText>
@@ -3061,6 +3125,11 @@ void TStreamerInfo::AddWriteTextAction(TStreamerInfoActions::TActionSequence *wr
             writeSequence->AddAction( WriteTextTNamed, new TConfiguration(this,i,compinfo,compinfo->fOffset) );
          break;
 
+      case TStreamerInfo::kSTLp:                // Pointer to container with no virtual table (stl) and no comment
+      case TStreamerInfo::kSTLp + TStreamerInfo::kOffsetL:     // array of pointers to container with no virtual table (stl) and no comment
+         writeSequence->AddAction( WriteSTLp<true>, new TConfiguration(this,i,compinfo,compinfo->fOffset) );
+         break;
+
       case TStreamerInfo::kStreamLoop:
       case TStreamerInfo::kOffsetL + TStreamerInfo::kStreamLoop:
           writeSequence->AddAction( WriteStreamerLoop<true>, new TConfiguration(this,i,compinfo,compinfo->fOffset) );