From b84b672185520e52a25d63b4487f285a068abc34 Mon Sep 17 00:00:00 2001
From: mpv <mpv@opencascade.com>
Date: Mon, 16 Nov 2020 16:49:23 +0300
Subject: [PATCH] 0031921: Application Framework - reading OCAF data from
 several threads is not possible

Make myLastFoundChild field of TDF_LabelNode that can be changed during accessing to different sub-labels in different threads as atomic (only for newer versions of compilers which support this "atomic").

Added definition of Standard_ATOMIC macro to the Standard_Macro.hxx
---
 src/Standard/Standard_Macro.hxx | 15 +++++++++++++++
 src/TDF/TDF_LabelNode.hxx       | 20 ++++++++++++--------
 2 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/src/Standard/Standard_Macro.hxx b/src/Standard/Standard_Macro.hxx
index 63303b2de1..430c03bd82 100644
--- a/src/Standard/Standard_Macro.hxx
+++ b/src/Standard/Standard_Macro.hxx
@@ -281,4 +281,19 @@
  #endif
 #endif
 
+//! @def Standard_ATOMIC
+//! Definition of Standard_ATOMIC for C++11 or visual studio that supports it.
+//! Before usage there must be "atomic" included in the following way:
+//! #ifdef Standard_HASATOMIC
+//!   #include <atomic>
+//! #endif
+#if (defined(__cplusplus) && __cplusplus >= 201100L) || (defined(_MSC_VER) && _MSC_VER >= 1800) || \
+    (defined(__GNUC__) && ((__GNUC__ > 4) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 7)))
+  #define Standard_HASATOMIC
+  #define Standard_ATOMIC(theType) std::atomic<theType> 
+#else
+  #define Standard_ATOMIC(theType) theType
+#endif
+
+
 #endif
diff --git a/src/TDF/TDF_LabelNode.hxx b/src/TDF/TDF_LabelNode.hxx
index 4be1660e60..244ff7b937 100644
--- a/src/TDF/TDF_LabelNode.hxx
+++ b/src/TDF/TDF_LabelNode.hxx
@@ -22,6 +22,10 @@
 #include <TDF_HAllocator.hxx>
 #include <NCollection_DefineAlloc.hxx>
 
+#ifdef Standard_HASATOMIC
+  #include <atomic>
+#endif
+
 class TDF_Attribute;
 class TDF_AttributeIterator;
 class TDF_ChildIterator;
@@ -160,15 +164,15 @@ class TDF_LabelNode {
   // Private Fields
   // --------------------------------------------------------------------------
 
-  TDF_LabelNodePtr       myFather; 
-  TDF_LabelNodePtr       myBrother; 
-  TDF_LabelNodePtr       myFirstChild;
-  TDF_LabelNodePtr       myLastFoundChild; //jfa 10.01.2003
-  Standard_Integer       myTag;
-  Standard_Integer       myFlags; // Flags & Depth
-  Handle(TDF_Attribute)  myFirstAttribute;
+  TDF_LabelNodePtr      myFather; 
+  TDF_LabelNodePtr      myBrother; 
+  TDF_LabelNodePtr      myFirstChild;
+  Standard_ATOMIC(TDF_LabelNodePtr) myLastFoundChild; //jfa 10.01.2003
+  Standard_Integer      myTag;
+  Standard_Integer      myFlags; // Flags & Depth
+  Handle(TDF_Attribute) myFirstAttribute;
 #ifdef KEEP_LOCAL_ROOT
-  TDF_Data *             myData;
+  TDF_Data *            myData;
 #endif
 #ifdef OCCT_DEBUG
   TCollection_AsciiString myDebugEntry;