Fixed EsentCursor and EsentModel resources disposal

Author: daniilch

Xbim.IO.Esent/Esent/EsentCursor.cs

@@ -53,19 +53,36 @@ public abstract class EsentCursor : IDisposable
 
         protected EsentCursor(EsentModel model, string database,  OpenDatabaseGrbit mode)
         {
-            LockObject = new Object();
-            Model = model;
-            Instance = model.Cache.JetInstance;
-            Sesid = new Session(Instance);
-            Api.JetOpenDatabase(Sesid, database, String.Empty, out DbId, mode);
-            Api.JetOpenTable(Sesid, DbId, GlobalsTableName, null, 0,  mode == OpenDatabaseGrbit.ReadOnly ? OpenTableGrbit.ReadOnly : 
-                                                                                mode == OpenDatabaseGrbit.Exclusive ? OpenTableGrbit.DenyWrite : OpenTableGrbit.None, 
-                                                                                out GlobalsTable);
-            EntityCountColumn = Api.GetTableColumnid(Sesid, GlobalsTable, EntityCountColumnName);
-            GeometryCountColumn = Api.GetTableColumnid(Sesid, GlobalsTable, GeometryCountColumnName);
-            FlushColumn = Api.GetTableColumnid(Sesid, GlobalsTable, FlushColumnName);
-            IfcHeaderColumn = Api.GetTableColumnid(Sesid, GlobalsTable, ifcHeaderColumnName);
-            ReadOnly = (mode == OpenDatabaseGrbit.ReadOnly);
+            try
+            {
+                LockObject = new Object();
+                Model = model;
+                Instance = model.Cache.JetInstance;
+                Sesid = new Session(Instance);
+                Api.JetOpenDatabase(Sesid, database, String.Empty, out DbId, mode);
+                Api.JetOpenTable(Sesid, DbId, GlobalsTableName, null, 0, mode == OpenDatabaseGrbit.ReadOnly ? OpenTableGrbit.ReadOnly :
+                                                                                    mode == OpenDatabaseGrbit.Exclusive ? OpenTableGrbit.DenyWrite : OpenTableGrbit.None,
+                                                                                    out GlobalsTable);
+                EntityCountColumn = Api.GetTableColumnid(Sesid, GlobalsTable, EntityCountColumnName);
+                GeometryCountColumn = Api.GetTableColumnid(Sesid, GlobalsTable, GeometryCountColumnName);
+                FlushColumn = Api.GetTableColumnid(Sesid, GlobalsTable, FlushColumnName);
+                IfcHeaderColumn = Api.GetTableColumnid(Sesid, GlobalsTable, ifcHeaderColumnName);
+                ReadOnly = (mode == OpenDatabaseGrbit.ReadOnly);
+            }
+            catch
+            {
+                if (Sesid != null)
+                {
+                    if (Table != JET_TABLEID.Nil && !Table.IsInvalid)
+                        Api.JetCloseTable(Sesid, Table);
+                    if (GlobalsTable != JET_TABLEID.Nil && !GlobalsTable.IsInvalid)
+                        Api.JetCloseTable(Sesid, GlobalsTable);
+                    if (DbId != JET_DBID.Nil && DbId != default(JET_DBID))
+                        Api.JetCloseDatabase(Sesid, DbId, CloseDatabaseGrbit.None);
+                    Api.JetEndSession(Sesid, EndSessionGrbit.None);
+                }
+                throw;
+            }
         }
 
         internal abstract int RetrieveCount();

Xbim.IO.Esent/Esent/EsentModel.cs

@@ -1138,18 +1138,21 @@ public IGeometryStore GeometryStore
 
         public static IStepFileHeader GetStepFileHeader(string fileName)
         {
-            //create a temporary model
-            var esentModel = new EsentModel();
-            esentModel.InstanceCache = new PersistedEntityInstanceCache(esentModel, null);
+            EsentModel esentModel = null;
+            EsentEntityCursor entTable = null;
 
-            esentModel.InstanceCache.DatabaseName = fileName;
-            IStepFileHeader header;
-            var entTable = esentModel.InstanceCache.GetEntityTable();
             try
             {
+                //create a temporary model
+                esentModel = new EsentModel();
+                esentModel.InstanceCache = new PersistedEntityInstanceCache(esentModel, null);
+                esentModel.InstanceCache.DatabaseName = fileName;
+
+                entTable = esentModel.InstanceCache.GetEntityTable();
                 using (entTable.BeginReadOnlyTransaction())
                 {
-                    header = entTable.ReadHeader();
+                    var header = entTable.ReadHeader();
+                    return header;
                 }
             }
             catch (Exception e)
@@ -1158,10 +1161,14 @@ public static IStepFileHeader GetStepFileHeader(string fileName)
             }
             finally
             {
-                esentModel.InstanceCache.FreeTable(entTable);
-                esentModel.Dispose();
+                if (esentModel != null)
+                {
+                    if (entTable != null)
+                        esentModel.InstanceCache.FreeTable(entTable);
+
+                    esentModel.Dispose();
+                }
             }
-            return header;
         }
 
         public void CreateFrom(IModel model, string fileName, ReportProgressDelegate progDelegate = null)