--- a/Core/DicomFormat/DicomMap.h	Wed Mar 11 16:57:01 2015 +0100
+++ b/Core/DicomFormat/DicomMap.h	Thu Mar 12 10:47:32 2015 +0100
@@ -77,6 +77,11 @@
     {
       Clear();
     }
+
+    size_t GetSize() const
+    {
+      return map_.size();
+    }
     
     DicomMap* Clone() const;
 

--- a/NEWS	Wed Mar 11 16:57:01 2015 +0100
+++ b/NEWS	Thu Mar 12 10:47:32 2015 +0100
@@ -1,6 +1,8 @@
 Pending changes in the mainline
 ===============================
 
+* Prevent freeze on C-FIND if no DICOM tag is to be returned
+
 
 Version 0.8.6 (2015/02/12)
 ==========================

--- a/OrthancServer/OrthancFindRequestHandler.cpp	Wed Mar 11 16:57:01 2015 +0100
+++ b/OrthancServer/OrthancFindRequestHandler.cpp	Thu Mar 12 10:47:32 2015 +0100
@@ -197,7 +197,8 @@
 
   static void AddAnswer(DicomFindAnswers& answers,
                         const Json::Value& resource,
-                        const DicomArray& query)
+                        const DicomArray& query,
+                        bool isFirst)
   {
     DicomMap result;
 
@@ -220,7 +221,17 @@
       }
     }
 
-    answers.Add(result);
+    if (result.GetSize() == 0)
+    {
+      if (isFirst)
+      {
+        LOG(WARNING) << "The C-FIND request does not return any DICOM tag";
+      }
+    }
+    else
+    {
+      answers.Add(result);
+    }
   }
 
 
@@ -563,7 +574,6 @@
     std::list<std::string>  resources;
     candidates.Flatten(resources);
 
-    LOG(INFO) << "Number of candidate resources after exact filtering: " << resources.size();
 
     /**
      * Apply filtering on modalities for studies, if asked (this is an
@@ -581,11 +591,14 @@
       }
     }
 
-
     /**
      * Loop over all the resources for this query level.
      **/
 
+    LOG(INFO) << "Number of candidate resources after exact filtering on the identifiers only: " << resources.size();
+
+    bool isFirst = true;
+    
     for (std::list<std::string>::const_iterator 
            resource = resources.begin(); resource != resources.end(); ++resource)
     {
@@ -596,7 +609,7 @@
         {
           Json::Value info;
           context_.ReadJson(info, instance);
-        
+
           if (Matches(info, query))
           {
             if (HasReachedLimit(answers, level))
@@ -605,7 +618,8 @@
               return false;
             }
 
-            AddAnswer(answers, info, query);
+            AddAnswer(answers, info, query, isFirst);
+            isFirst = false;
           }
         }
       }
@@ -615,6 +629,8 @@
       }
     }
 
+    LOG(INFO) << "Number of candidate resources after filtering on all tags: " << answers.GetSize();
+
     return true;  // All the matching resources have been returned
   }
 }

--- a/OrthancServer/ServerIndex.cpp	Wed Mar 11 16:57:01 2015 +0100
+++ b/OrthancServer/ServerIndex.cpp	Thu Mar 12 10:47:32 2015 +0100
@@ -148,7 +148,7 @@
       virtual void SignalRemainingAncestor(ResourceType parentType,
                                            const std::string& publicId)
       {
-        LOG(INFO) << "Remaining ancestor \"" << publicId << "\" (" << parentType << ")";
+        VLOG(1) << "Remaining ancestor \"" << publicId << "\" (" << parentType << ")";
 
         if (hasRemainingLevel_)
         {
@@ -175,9 +175,9 @@
 
       virtual void SignalChange(const ServerIndexChange& change)
       {
-        LOG(INFO) << "Change related to resource " << change.GetPublicId() << " of type " 
-                  << EnumerationToString(change.GetResourceType()) << ": " 
-                  << EnumerationToString(change.GetChangeType());
+        VLOG(1) << "Change related to resource " << change.GetPublicId() << " of type " 
+                << EnumerationToString(change.GetResourceType()) << ": " 
+                << EnumerationToString(change.GetChangeType());
 
         if (insideTransaction_)
         {
@@ -1316,7 +1316,7 @@
         throw OrthancException(ErrorCode_FullStorage);
       }
       
-      LOG(INFO) << "Recycling one patient";
+      VLOG(1) << "Recycling one patient";
       db_.DeleteResource(patientToRecycle);
 
       if (!IsRecyclingNeeded(instanceSize))