Partial fix for ICE-3393:

 - strealined StreamTraits.h
 - added ability to define custom dictionaries in C++ (with cpp:type:...)
 - added tests for custom dictionaries in test/Ice/custom

Fixed ICE-4867:
 - clear parameter before unmarshaling into dictionary/map in C++
 - added test

3 files changed, 79 insertions, 20 deletions

diff --git a/cpp/src/Ice/StreamI.cpp b/cpp/src/Ice/StreamI.cpp
index 431926d64b0..e533b77ceda 100644
--- a/cpp/src/Ice/StreamI.cpp
+++ b/cpp/src/Ice/StreamI.cpp
@@ -702,6 +702,13 @@ void
 ObjectReader::__read(BasicStream* is)
 {
     InputStreamI* stream = reinterpret_cast<InputStreamI*>(is->closure());
+ 
+    if(stream == 0)
+    {
+        Ice::ObjectNotExistException ex(__FILE__, __LINE__);
+        cerr << ex.ice_stackTrace() << endl;
+    }
+    
     assert(stream);
     read(stream);
 }
diff --git a/cpp/src/Slice/CPlusPlusUtil.cpp b/cpp/src/Slice/CPlusPlusUtil.cpp
index 9eaed2ebcc5..992ba303cda 100644
--- a/cpp/src/Slice/CPlusPlusUtil.cpp
+++ b/cpp/src/Slice/CPlusPlusUtil.cpp
@@ -116,6 +116,21 @@ sequenceTypeToString(const SequencePtr& seq, const StringList& metaData, int typ
     }
 }
 
+string
+dictionaryTypeToString(const DictionaryPtr& dict, const StringList& metaData, int typeCtx)
+{
+    string dictType = findMetaData(metaData, typeCtx);
+    if(!dictType.empty())
+    {
+        return dictType;
+    }
+    else
+    {
+        return fixKwd(dict->scoped());
+    }
+}
+
+
 void
 writeParamAllocateCode(Output& out, const TypePtr& type, bool optional, const string& fixedName,
                        const StringList& metaData, int typeCtx)
@@ -472,7 +487,13 @@ Slice::typeToString(const TypePtr& type, const StringList& metaData, int typeCtx
     {
         return sequenceTypeToString(seq, metaData, typeCtx);
     }
-            
+   
+    DictionaryPtr dict = DictionaryPtr::dynamicCast(type);
+    if(dict)
+    {
+        return dictionaryTypeToString(dict, metaData, typeCtx);
+    }
+
     ContainedPtr contained = ContainedPtr::dynamicCast(type);
     if(contained)
     {
@@ -596,6 +617,12 @@ Slice::inputTypeToString(const TypePtr& type, bool optional, const StringList& m
     {
         return "const " + sequenceTypeToString(seq, metaData, typeCtx) + "&";
     }
+
+    DictionaryPtr dict = DictionaryPtr::dynamicCast(type);
+    if(dict)
+    {
+        return "const " + dictionaryTypeToString(dict, metaData, typeCtx) + "&";
+    }
             
     ContainedPtr contained = ContainedPtr::dynamicCast(type);
     if(contained)
@@ -678,6 +705,12 @@ Slice::outputTypeToString(const TypePtr& type, bool optional, const StringList&
         return sequenceTypeToString(seq, metaData, typeCtx) + "&";
     }
 
+    DictionaryPtr dict = DictionaryPtr::dynamicCast(type);
+    if(dict)
+    {
+        return dictionaryTypeToString(dict, metaData, typeCtx) + "&";
+    }
+
     ContainedPtr contained = ContainedPtr::dynamicCast(type);
     if(contained)
     {
diff --git a/cpp/src/slice2cpp/Gen.cpp b/cpp/src/slice2cpp/Gen.cpp
index b0c4f5666db..e7477b1bd95 100644
--- a/cpp/src/slice2cpp/Gen.cpp
+++ b/cpp/src/slice2cpp/Gen.cpp
@@ -1384,31 +1384,48 @@ void
 Slice::Gen::TypesVisitor::visitDictionary(const DictionaryPtr& p)
 {
     string name = fixKwd(p->name());
-    TypePtr keyType = p->keyType();
-    if(SequencePtr::dynamicCast(keyType))
+    string dictType = findMetaData(p->getMetaData());
+
+    if(dictType.empty())
     {
-        SequencePtr s = SequencePtr::dynamicCast(keyType);
-        BuiltinPtr builtin = BuiltinPtr::dynamicCast(s->type());
-        if(builtin && builtin->kind() == Builtin::KindByte)
+        //
+        // A default std::map dictionary
+        //
+
+        TypePtr keyType = p->keyType();
+        if(SequencePtr::dynamicCast(keyType))
         {
-            StringList metaData = s->getMetaData();
-            bool protobuf;
-            findMetaData(s, metaData, protobuf);
-            if(protobuf)
+            SequencePtr s = SequencePtr::dynamicCast(keyType);
+            BuiltinPtr builtin = BuiltinPtr::dynamicCast(s->type());
+            if(builtin && builtin->kind() == Builtin::KindByte)
             {
-                emitWarning(p->file(), p->line(), "protobuf cannot be used as a dictionary key in C++");
+                StringList metaData = s->getMetaData();
+                bool protobuf;
+                findMetaData(s, metaData, protobuf);
+                if(protobuf)
+                {
+                    emitWarning(p->file(), p->line(), "protobuf cannot be used as a dictionary key in C++");
+                }
             }
         }
+        
+        TypePtr valueType = p->valueType();
+        string ks = typeToString(keyType, p->keyMetaData(), _useWstring);
+        if(ks[0] == ':')
+        {
+            ks.insert(0, " ");
+        }
+        string vs = typeToString(valueType, p->valueMetaData(), _useWstring);
+        
+        H << sp << nl << "typedef ::std::map<" << ks << ", " << vs << "> " << name << ';';
     }
-
-    TypePtr valueType = p->valueType();
-    string ks = typeToString(keyType, p->keyMetaData(), _useWstring);
-    if(ks[0] == ':')
+    else
     {
-        ks.insert(0, " ");
+        //
+        // A custom dictionary
+        //
+        H << sp << nl << "typedef " << dictType << ' ' << name << ';';
     }
-    string vs = typeToString(valueType, p->valueMetaData(), _useWstring);
-    H << sp << nl << "typedef ::std::map<" << ks << ", " << vs << "> " << name << ';';
 }
 
 void
@@ -6143,7 +6160,6 @@ Slice::Gen::StreamVisitor::visitStructStart(const StructPtr& p)
             H << nl << "static const ::Ice::StreamTraitType type = ::Ice::StreamTraitTypeStruct;";
         }
         H << nl << "static const int minWireSize = " << p->minWireSize() << ";";
-        H << nl << "static const bool isVariableLength = " << p->isVariableLength() << ";";
         if(p->isVariableLength())
         {
             H << nl << "static const ::Ice::OptionalType optionalType = ::Ice::OptionalTypeFSize;";
@@ -6167,7 +6183,6 @@ Slice::Gen::StreamVisitor::visitEnum(const EnumPtr& p)
     H << nl << "static const ::Ice::StreamTraitType type = ::Ice::StreamTraitTypeEnum;";
     H << nl << "static const int enumLimit = " << p->getEnumerators().size() << ";";
     H << nl << "static const int minWireSize = " << p->minWireSize() << ";";
-    H << nl << "static const bool isVariableLength = true;";
     H << nl << "static const ::Ice::OptionalType optionalType = ::Ice::OptionalTypeSize;";
     H << eb << ";" << nl;
 }
@@ -6431,6 +6446,10 @@ Slice::Gen::MetaDataVisitor::validate(const SyntaxTreeBasePtr& cont, const Strin
                         continue;
                     }
                 }
+                if(DictionaryPtr::dynamicCast(cont) && ss.find("type:") == 0) 
+                {
+                    continue;
+                }
                 if(StructPtr::dynamicCast(cont) && ss.find("class") == 0)
                 {
                     continue;