Merge branch 'IDCClassTraits' into 'master'

IDC: Class trait tweak

See merge request atlas/athena!35673

Event/EventContainers/EventContainers/I_InternalIDC.h

@@ -8,7 +8,6 @@
 #include "Identifier/IdentifierHash.h"
 #include "GaudiKernel/StatusCode.h"
 #include <vector>
-#include <utility>
 
 namespace EventContainers{
 class IDC_WriteHandleBase;
@@ -22,9 +21,19 @@ virtualised.
 
 A standard iterator is provided for fast iteration in a sequential order.
 */
+template<typename T>
+struct hashPair{
+   IdentifierHash::value_type first;
+   const T*                second;
+   constexpr hashPair(IdentifierHash::value_type f, const T* s) : first(f), second(s) {  }
+   bool operator <(const hashPair &b) const noexcept{
+      return first < b.first;
+   }
+};
+
 class I_InternalIDC{
 public:
-    typedef std::pair < IdentifierHash::value_type, const void* > hashPair;
+    typedef EventContainers::hashPair<void> hashPair;
     typedef std::vector < hashPair >::const_iterator InternalConstItr;
     #include "EventContainers/deleter.h"
     virtual InternalConstItr cbegin() const=0;

Event/EventContainers/EventContainers/IdentifiableContainerMT.h

@@ -215,9 +215,10 @@ public:
         return IdentifiableContainerBase::numberOfCollections();
     }
 
-    const std::vector < std::pair<IdentifierHash::value_type, const T*> >& GetAllHashPtrPair() const{
+    const std::vector < EventContainers::hashPair<T> >& GetAllHashPtrPair() const{
         static_assert(sizeof(const T*) == sizeof(const void*) && std::is_pointer<const T*>::value);
-        return reinterpret_cast<const std::vector < std::pair<IdentifierHash::value_type, const T*> >&>
+        static_assert(sizeof(EventContainers::hashPair<T>) == sizeof(EventContainers::hashPair<void>));
+        return reinterpret_cast<const std::vector < EventContainers::hashPair<T> >&>
                 (m_link->getAllHashPtrPair());
     }
     

Event/EventContainers/EventContainers/InternalOffline.h

@@ -38,7 +38,7 @@ public:
     virtual void* removeCollection( IdentifierHash hashId ) override;
     virtual void destructor(deleter_f*) noexcept override;
 private:
-    std::vector<std::pair<IdentifierHash::value_type, const void*>> m_map;
+    std::vector<I_InternalIDC::hashPair> m_map;
     size_t m_maximumSize;
 };
 

Event/EventContainers/EventContainers/InternalOfflineFast.h

@@ -39,7 +39,7 @@ public:
     virtual void* removeCollection( IdentifierHash hashId ) override;
     virtual void destructor(deleter_f*) noexcept override;
 private:
-    mutable std::vector<std::pair<IdentifierHash::value_type, const void*>> m_map;
+    mutable std::vector<I_InternalIDC::hashPair> m_map;
     std::vector<const void*> m_fullMap;
     mutable std::mutex m_waitMutex ATLAS_THREAD_SAFE;
     mutable std::atomic<bool> m_needsupdate ATLAS_THREAD_SAFE; //These mutables are carefully thought out, do not change

Event/EventContainers/EventContainers/InternalOfflineMap.h

@@ -40,7 +40,7 @@ public:
     virtual void* removeCollection( IdentifierHash hashId ) override;
     virtual void destructor(deleter_f*) noexcept override;
 private:
-    mutable std::vector<std::pair<IdentifierHash::value_type, const void*>> m_map;
+    mutable std::vector<I_InternalIDC::hashPair> m_map;
     std::unordered_map<IdentifierHash::value_type, const void*> m_fullMap;
     mutable std::mutex m_waitMutex ATLAS_THREAD_SAFE;
     mutable std::atomic<bool> m_needsupdate ATLAS_THREAD_SAFE; //These mutables are carefully thought out, do not change

Event/EventContainers/EventContainers/InternalOnline.h

@@ -49,7 +49,7 @@ public:
 private:
     EventContainers::IdentifiableCacheBase *m_cacheLink;
     mutable std::vector< IdentifierHash > m_waitlist ATLAS_THREAD_SAFE;
-    mutable std::vector<std::pair<IdentifierHash::value_type, const void*>> m_map ATLAS_THREAD_SAFE;
+    mutable std::vector<I_InternalIDC::hashPair> m_map ATLAS_THREAD_SAFE;
     mutable std::mutex m_waitMutex ATLAS_THREAD_SAFE;
     mutable std::vector<bool> m_mask ATLAS_THREAD_SAFE;
     mutable std::atomic<bool> m_waitNeeded ATLAS_THREAD_SAFE; //These mutables are carefully thought out, do not change

Event/EventContainers/src/InternalOffline.cxx

@@ -9,7 +9,13 @@
 
 using namespace EventContainers;
 typedef I_InternalIDC::InternalConstItr InternalConstItr;
-InternalOffline::InternalOffline(size_t max) : m_maximumSize(max) {}
+InternalOffline::InternalOffline(size_t max) : m_maximumSize(max) {
+  //Check optimization assumptions
+  static_assert(std::is_trivially_copyable<hashPair>::value);
+  static_assert(std::is_trivially_destructible<hashPair>::value);
+  static_assert(std::is_trivially_copyable<IdentifierHash>::value);
+  static_assert(std::is_trivially_destructible<IdentifierHash>::value);
+}
 
 
 bool InternalOffline::tryAddFromCache(IdentifierHash hash, EventContainers::IDC_WriteHandleBase&) {