fixed race condition in MNS and added info output when clients are still...

fixed race condition in MNS and added info output when clients are still waiting for servers (with Fabian R.)

source/RobotAPI/libraries/armem/mns/MemoryNameSystem.cpp

 #include "MemoryNameSystem.h"
 
-
 namespace armarx::armem::mns
 {
 
     // dto::WaitForServerResult MemoryNameSystem::waitForServer(const dto::WaitForServerInput& input)
-    void MemoryNameSystem::waitForServer_async(
+    void
+    MemoryNameSystem::waitForServer_async(
         const AMD_MemoryNameSystemInterface_waitForServerPtr& future,
         const dto::WaitForServerInput& input)
     {
-        waitForServerFutures[input.name].push_back(future);
+        ARMARX_INFO << "Waiting for server `" << input.name << "`.";
+
+        {
+            std::lock_guard g{futuresMtx};
+            waitForServerFutures[input.name].push_back(future);
+        }
+
         waitForServer_processOnce();
     }
 
-
-    void MemoryNameSystem::waitForServer_processOnce()
+    void
+    MemoryNameSystem::waitForServer_processOnce()
     {
+        std::lock_guard g{futuresMtx};
+
         for (auto it = waitForServerFutures.begin(); it != waitForServerFutures.end();)
         {
             auto& [name, futures] = *it;
@@ -32,16 +40,20 @@ namespace armarx::armem::mns
                 {
                     future->ice_response(result);
                 }
+
+                // it: iterator following the last removed element (https://en.cppreference.com/w/cpp/container/map/erase)
                 it = waitForServerFutures.erase(it);
             }
             else
             {
-                ++it;  // Skip.
+                ++it; // Skip.
+                ARMARX_INFO << "Server `" << name << "` not available yet.";
             }
         }
     }
-    
-    dto::RegisterServerResult MemoryNameSystem::registerServer(const dto::RegisterServerInput& input) 
+
+    dto::RegisterServerResult
+    MemoryNameSystem::registerServer(const dto::RegisterServerInput& input)
     {
         const auto result = Registry::registerServer(input);
         waitForServer_processOnce();
@@ -49,8 +61,8 @@ namespace armarx::armem::mns
         return result;
     }
 
-
-    armarx::RemoteGui::Client::GridLayout MemoryNameSystem::RemoteGui_buildInfoGrid()
+    armarx::RemoteGui::Client::GridLayout
+    MemoryNameSystem::RemoteGui_buildInfoGrid()
     {
         using namespace armarx::RemoteGui::Client;
 
@@ -58,10 +70,9 @@ namespace armarx::armem::mns
 
         int row = 0;
         grid.add(Label("Memory Name"), {row, 0})
-        .add(Label("Component Name"), {row, 1})
-        .add(Label("R/W/P/A"), {row, 2})
-        .add(Label("Registration Time"), {row, 3})
-        ;
+            .add(Label("Component Name"), {row, 1})
+            .add(Label("R/W/P/A"), {row, 2})
+            .add(Label("Registration Time"), {row, 3});
         row++;
 
         for (const auto& [name, info] : servers)
@@ -109,4 +120,4 @@ namespace armarx::armem::mns
         return grid;
     }
 
-}
+} // namespace armarx::armem::mns

source/RobotAPI/libraries/armem/mns/MemoryNameSystem.h

 #pragma once
 
-#include "Registry.h"
-
-#include <RobotAPI/interface/armem/mns/MemoryNameSystemInterface.h>
+#include <map>
+#include <mutex>
+#include <string>
 
 #include <ArmarXGui/libraries/ArmarXGuiComponentPlugins/LightweightRemoteGuiComponentPlugin.h>
 
-#include <map>
-#include <string>
+#include <RobotAPI/interface/armem/mns/MemoryNameSystemInterface.h>
 
+#include "Registry.h"
 
 namespace armarx::armem::mns
 {
@@ -16,18 +16,15 @@ namespace armarx::armem::mns
     class MemoryNameSystem : public Registry
     {
     public:
-
         using WaitForServerFuturePtr = AMD_MemoryNameSystemInterface_waitForServerPtr;
 
 
     public:
-
         /**
          * @brief Store the call in a container for later response.
          */
-        void waitForServer_async(
-            const AMD_MemoryNameSystemInterface_waitForServerPtr& future,
-            const dto::WaitForServerInput& input);
+        void waitForServer_async(const AMD_MemoryNameSystemInterface_waitForServerPtr& future,
+                                 const dto::WaitForServerInput& input);
 
         void waitForServer_processOnce();
 
@@ -38,11 +35,11 @@ namespace armarx::armem::mns
         armarx::RemoteGui::Client::GridLayout RemoteGui_buildInfoGrid();
 
 
-    public:
-
+    private:
         /// Queued calls to `waitForServer`.
         std::map<std::string, std::vector<WaitForServerFuturePtr>> waitForServerFutures;
 
+        std::mutex futuresMtx;
     };
 
-}
+} // namespace armarx::armem::mns