Prevent adding a land object if it overlaps any existing objects that have not had their bitmaps adjusted.

This is to prevent an immediate problem in http://opensimulator.org/mantis/view.php?id=7035 where a development code bug occasionally overlays all the existing parcels with a blank parcel owned by the estate manager and to gather more data.
My guess is that this parcel is being created by the new code in LandManagementModule.GetLandObject(), probably some race between threads since this only happens occasionally.
Adds regression tests for this case and for parcel subdivide.

2 files changed, 190 insertions, 19 deletions

diff --git a/OpenSim/Region/CoreModules/World/Land/LandManagementModule.cs b/OpenSim/Region/CoreModules/World/Land/LandManagementModule.cs
index 99db7ff..5c20899 100644
--- a/OpenSim/Region/CoreModules/World/Land/LandManagementModule.cs
+++ b/OpenSim/Region/CoreModules/World/Land/LandManagementModule.cs
@@ -66,6 +66,11 @@ namespace OpenSim.Region.CoreModules.World.Land
         private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
         private static readonly string LogHeader = "[LAND MANAGEMENT MODULE]";
 
+        /// <summary>
+        /// Minimum land unit size in region co-ordinates.
+        /// </summary>
+        public const int LandUnit = 4;
+
         private static readonly string remoteParcelRequestPath = "0009/";
 
         private LandChannel landChannel;
@@ -79,7 +84,6 @@ namespace OpenSim.Region.CoreModules.World.Land
         /// Local land ids at specified region co-ordinates (region size / 4)
         /// </value>
         private int[,] m_landIDList;
-        private const int landUnit = 4;
 
         /// <value>
         /// Land objects keyed by local id
@@ -112,7 +116,7 @@ namespace OpenSim.Region.CoreModules.World.Land
         public void AddRegion(Scene scene)
         {
             m_scene = scene;
-            m_landIDList = new int[m_scene.RegionInfo.RegionSizeX / landUnit, m_scene.RegionInfo.RegionSizeY / landUnit];
+            m_landIDList = new int[m_scene.RegionInfo.RegionSizeX / LandUnit, m_scene.RegionInfo.RegionSizeY / LandUnit];
 
             m_landIDList.Initialize();
             landChannel = new LandChannel(scene, this);
@@ -296,7 +300,7 @@ namespace OpenSim.Region.CoreModules.World.Land
             {
                 m_landList.Clear();
                 m_lastLandLocalID = LandChannel.START_LAND_LOCAL_ID - 1;
-                m_landIDList = new int[m_scene.RegionInfo.RegionSizeX / landUnit, m_scene.RegionInfo.RegionSizeY / landUnit];
+                m_landIDList = new int[m_scene.RegionInfo.RegionSizeX / LandUnit, m_scene.RegionInfo.RegionSizeY / LandUnit];
                 m_landIDList.Initialize();
             }
         }
@@ -590,7 +594,10 @@ namespace OpenSim.Region.CoreModules.World.Land
         /// <summary>
         /// Adds a land object to the stored list and adds them to the landIDList to what they own
         /// </summary>
-        /// <param name="new_land">The land object being added</param>
+        /// <param name="new_land">
+        /// The land object being added.  
+        /// Will return null if this overlaps with an existing parcel that has not had its bitmap adjusted.
+        /// </param>
         public ILandObject AddLandObject(ILandObject land)
         {
             ILandObject new_land = land.Copy();
@@ -602,7 +609,7 @@ namespace OpenSim.Region.CoreModules.World.Land
 
             lock (m_landList)
             {
-                int newLandLocalID = ++m_lastLandLocalID;
+                int newLandLocalID = m_lastLandLocalID + 1;
                 new_land.LandData.LocalID = newLandLocalID;
 
                 bool[,] landBitmap = new_land.GetLandBitmap();
@@ -617,6 +624,33 @@ namespace OpenSim.Region.CoreModules.World.Land
                 }
                 else
                 {
+                    // If other land objects still believe that they occupy any parts of the same space, 
+                    // then do not allow the add to proceed.
+                    for (int x = 0; x < landBitmap.GetLength(0); x++)
+                    {
+                        for (int y = 0; y < landBitmap.GetLength(1); y++)
+                        {
+                            if (landBitmap[x, y])
+                            {
+                                int lastRecordedLandId = m_landIDList[x, y];
+
+                                if (lastRecordedLandId > 0)
+                                {
+                                    ILandObject lastRecordedLo = m_landList[lastRecordedLandId];
+
+                                    if (lastRecordedLo.LandBitmap[x, y])
+                                    {
+                                        m_log.ErrorFormat(
+                                            "{0}: Cannot add parcel \"{1}\", local ID {2} at tile {3},{4} because this is still occupied by parcel \"{5}\", local ID {6}.",
+                                            LogHeader, new_land.LandData.Name, new_land.LandData.LocalID, x, y, lastRecordedLo.LandData.Name, lastRecordedLo.LandData.LocalID);
+
+                                        return null;
+                                    }
+                                }
+                            }
+                        }
+                    }
+
                     for (int x = 0; x < landBitmap.GetLength(0); x++)
                     {
                         for (int y = 0; y < landBitmap.GetLength(1); y++)
@@ -626,7 +660,7 @@ namespace OpenSim.Region.CoreModules.World.Land
                                 // m_log.DebugFormat(
                                 //     "[LAND MANAGEMENT MODULE]: Registering parcel {0} for land co-ord ({1}, {2}) on {3}", 
                                 //     new_land.LandData.Name, x, y, m_scene.RegionInfo.RegionName);
-
+                                    
                                 m_landIDList[x, y] = newLandLocalID;
                             }
                         }
@@ -634,10 +668,12 @@ namespace OpenSim.Region.CoreModules.World.Land
                 }
 
                 m_landList.Add(newLandLocalID, new_land);
+                m_lastLandLocalID++;
             }
 
             new_land.ForceUpdateLandInfo();
             m_scene.EventManager.TriggerLandObjectAdded(new_land);
+
             return new_land;
         }
 
@@ -801,8 +837,18 @@ namespace OpenSim.Region.CoreModules.World.Land
             return GetLandObject(x, y, false /* returnNullIfLandObjectNotFound */);
         }
 
-        // Given a region position, return the parcel land object for that location
-        private ILandObject GetLandObject(int x, int y, bool returnNullIfLandObjectNotFound)
+        /// <summary>
+        /// Given a region position, return the parcel land object for that location
+        /// </summary>
+        /// <returns>
+        /// The land object.
+        /// </returns>
+        /// <param name='x'></param>
+        /// <param name='y'></param>
+        /// <param name='returnNullIfLandObjectNotFound'>
+        /// Return null if the land object requested is not within the region's bounds.
+        /// </param>
+        private ILandObject GetLandObject(int x, int y, bool returnNullIfLandObjectOutsideBounds)
         {
             ILandObject ret = null;
 
@@ -810,7 +856,7 @@ namespace OpenSim.Region.CoreModules.World.Land
             {
                 // These exceptions here will cause a lot of complaints from the users specifically because
                 // they happen every time at border crossings
-                if (returnNullIfLandObjectNotFound)
+                if (returnNullIfLandObjectOutsideBounds)
                     return null;
                 else
                     throw new Exception(
@@ -823,7 +869,7 @@ namespace OpenSim.Region.CoreModules.World.Land
             {
                 try
                 {
-                    int landID = m_landIDList[x / landUnit, y / landUnit];
+                    int landID = m_landIDList[x / LandUnit, y / LandUnit];
                     if (landID == 0)
                     {
                         // Zero is the uninitialized value saying there is no parcel for this location.
@@ -856,7 +902,11 @@ namespace OpenSim.Region.CoreModules.World.Land
                             newLand.SetLandBitmap(CreateBitmapForID(0));
                             newLand.LandData.OwnerID = m_scene.RegionInfo.EstateSettings.EstateOwner;
                             newLand.LandData.ClaimDate = Util.UnixTimeSinceEpoch();
-                            AddLandObject(newLand);
+                            newLand = AddLandObject(newLand);
+
+                            if (newLand == null)
+                                return null;
+
                             landID = m_lastLandLocalID;
                         }
                     }
@@ -868,16 +918,19 @@ namespace OpenSim.Region.CoreModules.World.Land
                     m_log.ErrorFormat(
                         "{0} GetLandObject: Tried to retrieve land object from out of bounds co-ordinate ({1},{2}) in {3}. landListSize=({4},{5})",
                         LogHeader, x, y, m_scene.RegionInfo.RegionName, m_landIDList.GetLength(0), m_landIDList.GetLength(1));
+
                     return null;
                 }
                 catch
                 {
                     m_log.ErrorFormat(
                         "{0} GetLandObject: LandID not in landlist. XY=<{1},{2}> in {3}. landID[x,y]={4}",
-                        LogHeader, x, y, m_scene.RegionInfo.RegionName, m_landIDList[x/landUnit, y/landUnit]);
+                        LogHeader, x, y, m_scene.RegionInfo.RegionName, m_landIDList[x/LandUnit, y/LandUnit]);
+
                     return null;
                 }
             }
+
             return ret;
         }
 
@@ -1062,8 +1115,12 @@ namespace OpenSim.Region.CoreModules.World.Land
 
             //Now add the new land object
             ILandObject result = AddLandObject(newLand);
-            UpdateLandObject(startLandObject.LandData.LocalID, startLandObject.LandData);
-            result.SendLandUpdateToAvatarsOverMe();
+
+            if (result != null)
+            {
+                UpdateLandObject(startLandObject.LandData.LocalID, startLandObject.LandData);
+                result.SendLandUpdateToAvatarsOverMe();
+            }
         }
 
         /// <summary>
@@ -1157,11 +1214,11 @@ namespace OpenSim.Region.CoreModules.World.Land
             int sequenceID = 0;
 
             // Layer data is in landUnit (4m) chunks
-            for (int y = 0; y < m_scene.RegionInfo.RegionSizeY / Constants.TerrainPatchSize * (Constants.TerrainPatchSize / landUnit); y++)
+            for (int y = 0; y < m_scene.RegionInfo.RegionSizeY / Constants.TerrainPatchSize * (Constants.TerrainPatchSize / LandUnit); y++)
             {
-                for (int x = 0; x < m_scene.RegionInfo.RegionSizeX / Constants.TerrainPatchSize * (Constants.TerrainPatchSize / landUnit); x++)
+                for (int x = 0; x < m_scene.RegionInfo.RegionSizeX / Constants.TerrainPatchSize * (Constants.TerrainPatchSize / LandUnit); x++)
                 {
-                    byteArray[byteArrayCount] = BuildLayerByte(GetLandObject(x * landUnit, y * landUnit), x, y, remote_client);
+                    byteArray[byteArrayCount] = BuildLayerByte(GetLandObject(x * LandUnit, y * LandUnit), x, y, remote_client);
                     byteArrayCount++;
                     if (byteArrayCount >= LAND_BLOCKS_PER_PACKET)
                     {
@@ -1214,11 +1271,11 @@ namespace OpenSim.Region.CoreModules.World.Land
                 ILandObject southParcel = null;
                 if (x > 0)
                 {
-                    westParcel = GetLandObject((x - 1) * landUnit, y * landUnit);
+                    westParcel = GetLandObject((x - 1) * LandUnit, y * LandUnit);
                 }
                 if (y > 0)
                 {
-                    southParcel = GetLandObject(x * landUnit, (y - 1) * landUnit);
+                    southParcel = GetLandObject(x * LandUnit, (y - 1) * LandUnit);
                 }
 
                 if (x == 0)
diff --git a/OpenSim/Region/CoreModules/World/Land/Tests/LandManagementModuleTests.cs b/OpenSim/Region/CoreModules/World/Land/Tests/LandManagementModuleTests.cs
new file mode 100644
index 0000000..a886e33
--- /dev/null
+++ b/OpenSim/Region/CoreModules/World/Land/Tests/LandManagementModuleTests.cs
@@ -0,0 +1,114 @@
+/*
+ * Copyright (c) Contributors, http://opensimulator.org/
+ * See CONTRIBUTORS.TXT for a full list of copyright holders.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the OpenSimulator Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+using System;
+using NUnit.Framework;
+using OpenMetaverse;
+using OpenSim.Framework;
+using OpenSim.Region.Framework.Scenes;
+using OpenSim.Tests.Common;
+using OpenSim.Tests.Common.Mock;
+
+namespace OpenSim.Region.CoreModules.World.Land.Tests
+{
+    public class LandManagementModuleTests
+    {
+        [Test]
+        public void TestAddLandObject()
+        {
+            TestHelpers.InMethod();
+//            TestHelpers.EnableLogging();
+
+            UUID userId = TestHelpers.ParseTail(0x1);
+
+            LandManagementModule lmm = new LandManagementModule();
+            Scene scene = new SceneHelpers().SetupScene();            
+            SceneHelpers.SetupSceneModules(scene, lmm);             
+            
+            ILandObject lo = new LandObject(userId, false, scene);
+            lo.LandData.Name = "lo1";
+            lo.SetLandBitmap(
+                lo.GetSquareLandBitmap(0, 0, (int)Constants.RegionSize, (int)Constants.RegionSize));
+            lo = lmm.AddLandObject(lo);          
+
+            // TODO: Should add asserts to check that land object was added properly.
+
+            // At the moment, this test just makes sure that we can't add a land object that overlaps the areas that
+            // the first still holds.
+            ILandObject lo2 = new LandObject(userId, false, scene);
+            lo2.SetLandBitmap(
+                lo2.GetSquareLandBitmap(0, 0, (int)Constants.RegionSize, (int)Constants.RegionSize));
+            lo2.LandData.Name = "lo2";
+            lo2 = lmm.AddLandObject(lo2);
+
+            {
+                ILandObject loAtCoord = lmm.GetLandObject(0, 0);
+                Assert.That(loAtCoord.LandData.LocalID, Is.EqualTo(lo.LandData.LocalID));
+                Assert.That(loAtCoord.LandData.GlobalID, Is.EqualTo(lo.LandData.GlobalID));                          
+            }
+
+            {
+                ILandObject loAtCoord = lmm.GetLandObject((int)Constants.RegionSize - 1, ((int)Constants.RegionSize - 1));
+                Assert.That(loAtCoord.LandData.LocalID, Is.EqualTo(lo.LandData.LocalID));
+                Assert.That(loAtCoord.LandData.GlobalID, Is.EqualTo(lo.LandData.GlobalID));
+            }
+        }
+
+        [Test]
+        public void TestSubdivide()
+        {
+            TestHelpers.InMethod();
+//            TestHelpers.EnableLogging();
+
+            UUID userId = TestHelpers.ParseTail(0x1);
+
+            LandManagementModule lmm = new LandManagementModule();
+            Scene scene = new SceneHelpers().SetupScene();            
+            SceneHelpers.SetupSceneModules(scene, lmm);             
+            
+            ILandObject lo = new LandObject(userId, false, scene);
+            lo.LandData.Name = "lo1";
+            lo.SetLandBitmap(
+                lo.GetSquareLandBitmap(0, 0, (int)Constants.RegionSize, (int)Constants.RegionSize));
+            lo = lmm.AddLandObject(lo);          
+
+            lmm.Subdivide(0, 0, LandManagementModule.LandUnit, LandManagementModule.LandUnit, userId);
+
+            {
+                ILandObject loAtCoord = lmm.GetLandObject(0, 0);
+                Assert.That(loAtCoord.LandData.LocalID, Is.Not.EqualTo(lo.LandData.LocalID));
+                Assert.That(loAtCoord.LandData.GlobalID, Is.Not.EqualTo(lo.LandData.GlobalID));                          
+            }
+
+            {
+                ILandObject loAtCoord = lmm.GetLandObject(LandManagementModule.LandUnit, LandManagementModule.LandUnit);
+                Assert.That(loAtCoord.LandData.LocalID, Is.EqualTo(lo.LandData.LocalID));
+                Assert.That(loAtCoord.LandData.GlobalID, Is.EqualTo(lo.LandData.GlobalID));
+            }
+        }
+    }
+}
\ No newline at end of file