Use SP.ParentPart instead of ParentID in places where it's more efficient (saving extra null checks, etc.)

However, it looks like we should retain SP.ParentID since it's much easier to use that in places where another thread could change ParentPart to null.
Otherwise one has to clumsily put ParentPart in a reference, etc. to avoid a race.

4 files changed, 32 insertions, 68 deletions

diff --git a/OpenSim/Region/Framework/Scenes/SceneGraph.cs b/OpenSim/Region/Framework/Scenes/SceneGraph.cs
index 66fb493..dd0ca43 100644
--- a/OpenSim/Region/Framework/Scenes/SceneGraph.cs
+++ b/OpenSim/Region/Framework/Scenes/SceneGraph.cs
@@ -215,27 +215,13 @@ namespace OpenSim.Region.Framework.Scenes
                 if (sp.IsChildAgent)
                     continue;
 
-                if (sp.ParentID != 0)
-                {
-                    // sitting avatar
-                    SceneObjectPart sop = m_parentScene.GetSceneObjectPart(sp.ParentID);
-                    if (sop != null)
-                    {
-                        coarseLocations.Add(sop.AbsolutePosition + sp.OffsetPosition);
-                        avatarUUIDs.Add(sp.UUID);
-                    }
-                    else
-                    {
-                        // we can't find the parent..  ! arg!
-                        coarseLocations.Add(sp.AbsolutePosition);
-                        avatarUUIDs.Add(sp.UUID);
-                    }
-                }
+                SceneObjectPart sitPart = sp.ParentPart;
+                if (sitPart != null)
+                    coarseLocations.Add(sitPart.AbsolutePosition + sp.OffsetPosition);
                 else
-                {
                     coarseLocations.Add(sp.AbsolutePosition);
-                    avatarUUIDs.Add(sp.UUID);
-                }
+
+                avatarUUIDs.Add(sp.UUID);
             }
         }
 
diff --git a/OpenSim/Region/Framework/Scenes/ScenePresence.cs b/OpenSim/Region/Framework/Scenes/ScenePresence.cs
index c9dc7fd..aab0bf0 100644
--- a/OpenSim/Region/Framework/Scenes/ScenePresence.cs
+++ b/OpenSim/Region/Framework/Scenes/ScenePresence.cs
@@ -432,7 +432,7 @@ namespace OpenSim.Region.Framework.Scenes
         {
             get
             {
-                if (PhysicsActor != null && m_parentID == 0)
+                if (PhysicsActor != null && ParentID == 0)
                 {
                     m_pos = PhysicsActor.Position;
 
@@ -504,6 +504,7 @@ namespace OpenSim.Region.Framework.Scenes
                 // There is no offset position when not seated
                 if (ParentID == 0)
                     return;
+
                 m_pos = value;
             }
         }
@@ -562,19 +563,18 @@ namespace OpenSim.Region.Framework.Scenes
 
         public bool IsChildAgent { get; set; }
 
-        public uint ParentID
-        {
-            get { return m_parentID; }
-            set { m_parentID = value; }
-        }
-        private uint m_parentID;
+        /// <summary>
+        /// If the avatar is sitting, the local ID of the prim that it's sitting on.  If not sitting then zero.
+        /// </summary>
+        public uint ParentID { get; set; }
 
-        public SceneObjectPart ParentPart
-        {
-            get { return m_parentPart; }
-            set { m_parentPart = value; }
-        }
-        private SceneObjectPart m_parentPart = null;
+        /// <summary>
+        /// If the avatar is sitting, the prim that it's sitting on.  If not sitting then null.
+        /// </summary>
+        /// <remarks>
+        /// If you use this property then you must take a reference since another thread could set it to null.
+        /// </remarks>
+        public SceneObjectPart ParentPart { get; set; }
 
         public float Health
         {
diff --git a/OpenSim/Region/RegionCombinerModule/RegionCombinerModule.cs b/OpenSim/Region/RegionCombinerModule/RegionCombinerModule.cs
index 09da97a..a2e3ac2 100644
--- a/OpenSim/Region/RegionCombinerModule/RegionCombinerModule.cs
+++ b/OpenSim/Region/RegionCombinerModule/RegionCombinerModule.cs
@@ -716,29 +716,17 @@ namespace OpenSim.Region.RegionCombinerModule
             {
                 if (sp.UUID != presence.UUID)
                 {
-                    if (sp.ParentID != 0)
-                    {
-                        // sitting avatar
-                        SceneObjectPart sop = connectiondata.RegionScene.GetSceneObjectPart(sp.ParentID);
-                        if (sop != null)
-                        {
-                            CoarseLocations.Add(sop.AbsolutePosition + sp.AbsolutePosition);
-                            AvatarUUIDs.Add(sp.UUID);
-                        }
-                        else
-                        {
-                            // we can't find the parent..  ! arg!
-                            CoarseLocations.Add(sp.AbsolutePosition);
-                            AvatarUUIDs.Add(sp.UUID);
-                        }
-                    }
+                    SceneObjectPart sitPart = sp.ParentPart;
+
+                    if (sitPart != null)
+                        CoarseLocations.Add(sitPart.AbsolutePosition + sp.AbsolutePosition);
                     else
-                    {
                         CoarseLocations.Add(sp.AbsolutePosition);
-                        AvatarUUIDs.Add(sp.UUID);
-                    }
+
+                    AvatarUUIDs.Add(sp.UUID);
                 }
             });
+
             DistributeCourseLocationUpdates(CoarseLocations, AvatarUUIDs, connectiondata, presence);
         }
 
diff --git a/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/LSL_Api.cs b/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/LSL_Api.cs
index 786ae6e..bb374ed 100644
--- a/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/LSL_Api.cs
+++ b/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/LSL_Api.cs
@@ -3825,7 +3825,8 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
             List<String> nametable = new List<String>();
             World.ForEachRootScenePresence(delegate(ScenePresence presence)
             {
-                if (presence.ParentID != 0 && m_host.ParentGroup.HasChildPrim(presence.ParentID))
+                SceneObjectPart sitPart = presence.ParentPart;
+                if (sitPart != null && m_host.ParentGroup.HasChildPrim(sitPart.LocalId))
                     nametable.Add(presence.ControllingClient.Name);
             });
 
@@ -4393,22 +4394,11 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
 
                 // Find pushee position
                 // Pushee Linked?
-                if (pusheeav.ParentID != 0)
-                {
-                    SceneObjectPart parentobj = World.GetSceneObjectPart(pusheeav.ParentID);
-                    if (parentobj != null)
-                    {
-                        PusheePos = parentobj.AbsolutePosition;
-                    }
-                    else
-                    {
-                        PusheePos = pusheeav.AbsolutePosition;
-                    }
-                }
+                SceneObjectPart sitPart = pusheeav.ParentPart;
+                if (sitPart != null)
+                    PusheePos = sitPart.AbsolutePosition;
                 else
-                {
                     PusheePos = pusheeav.AbsolutePosition;
-                }
             }
 
             if (!pusheeIsAvatar)
@@ -5603,7 +5593,7 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
                     flags |= ScriptBaseClass.AGENT_IN_AIR;
             }
 
-             if (agent.ParentID != 0)
+             if (agent.ParentPart != null)
              {
                  flags |= ScriptBaseClass.AGENT_ON_OBJECT;
                  flags |= ScriptBaseClass.AGENT_SITTING;
@@ -7692,7 +7682,7 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
             World.ForEachRootScenePresence(delegate(ScenePresence presence)
             {
                 if (presence.ParentID != 0 && m_host.ParentGroup.HasChildPrim(presence.ParentID))
-                        avatarCount++;
+                    avatarCount++;
             });
 
             return m_host.ParentGroup.PrimCount + avatarCount;