Add new hook `preDataChanged`

2 files changed, 16 insertions, 2 deletions

diff --git a/src/main/java/gregtech/api/metatileentity/CoverableTileEntity.java b/src/main/java/gregtech/api/metatileentity/CoverableTileEntity.java
index 5958b515be..e26d12f311 100644
--- a/src/main/java/gregtech/api/metatileentity/CoverableTileEntity.java
+++ b/src/main/java/gregtech/api/metatileentity/CoverableTileEntity.java
@@ -422,10 +422,13 @@ public abstract class CoverableTileEntity extends BaseTileEntity implements ICov
     public void receiveCoverData(
             byte aCoverSide, int aCoverID, ISerializableObject aCoverData, EntityPlayerMP aPlayer) {
         if ((aCoverSide >= 0 && aCoverSide < 6)) {
+            GT_CoverBehaviorBase<?> behaviorBase = getCoverBehaviorAtSideNew(aCoverSide);
+            behaviorBase.preDataChanged(aCoverSide, getCoverIDAtSide(aCoverSide), aCoverID, getComplexCoverDataAtSide(aCoverSide), aCoverData, this);
+            
             setCoverIDAtSideNoUpdate(aCoverSide, aCoverID);
             setCoverDataAtSide(aCoverSide, aCoverData);
-            if (isClientSide()) {
-                getCoverBehaviorAtSideNew(aCoverSide).onDataChanged(aCoverSide, aCoverID, aCoverData, this);
+            if (!isClientSide()) {
+                behaviorBase.onDataChanged(aCoverSide, aCoverID, aCoverData, this);
             }
         }
     }
diff --git a/src/main/java/gregtech/api/util/GT_CoverBehaviorBase.java b/src/main/java/gregtech/api/util/GT_CoverBehaviorBase.java
index e0879cda86..47cb866653 100644
--- a/src/main/java/gregtech/api/util/GT_CoverBehaviorBase.java
+++ b/src/main/java/gregtech/api/util/GT_CoverBehaviorBase.java
@@ -131,6 +131,14 @@ public abstract class GT_CoverBehaviorBase<T extends ISerializableObject> {
     }
 
     /**
+     * Called before receiving data from network. Use {@link ICoverable#isClientSide()} to determine the side.
+     */
+    public final void preDataChanged(
+            byte aSide, int aCoverID, int aNewCoverId, ISerializableObject aCoverVariable, ISerializableObject aNewCoverVariable, ICoverable aTileEntity) {
+        preDataChangedImpl(aSide, aCoverID, aNewCoverId, forceCast(aCoverVariable), forceCast(aNewCoverVariable), aTileEntity);
+    }
+
+    /**
      * Called upon cover being removed. Called on both server and client.
      */
     public final void onDropped(byte aSide, int aCoverID, ISerializableObject aCoverVariable, ICoverable aTileEntity) {
@@ -417,6 +425,9 @@ public abstract class GT_CoverBehaviorBase<T extends ISerializableObject> {
     }
 
     protected void onDataChangedImpl(byte aSide, int aCoverID, T aCoverVariable, ICoverable aTileEntity) {}
+    
+    protected void preDataChangedImpl(
+            byte aSide, int aCoverID, int aNewCoverId, T aCoverVariable, T aNewCoverVariable, ICoverable aTileEntity) {}
 
     protected void onDroppedImpl(byte aSide, int aCoverID, T aCoverVariable, ICoverable aTileEntity) {}