From 39d604ae6ccdb8b1fed477216643ff96615a39bb Mon Sep 17 00:00:00 2001
From: peace-maker <peace-maker@wcfan.de>
Date: Wed, 20 Apr 2022 15:32:37 +0200
Subject: [PATCH] DHooks: Allow setting CBaseEntity* param to NULL #1751
 (#1754)

* DHooks: Allow setting CBaseEntity* param to NULL #1751

The param had to be a valid entity and wasn't allowed to be set to NULL. Behave similar to SetReturn which maps INVALID_ENT_REFERENCE (or -1) to NULL.

* Update include documentation
---
 extensions/dhooks/natives.cpp | 17 ++++++++++++-----
 plugins/include/dhooks.inc    | 12 ++++++++++--
 2 files changed, 22 insertions(+), 7 deletions(-)

diff --git a/extensions/dhooks/natives.cpp b/extensions/dhooks/natives.cpp
index 72abe9e7..db1384f8 100644
--- a/extensions/dhooks/natives.cpp
+++ b/extensions/dhooks/natives.cpp
@@ -700,14 +700,21 @@ cell_t Native_SetParam(IPluginContext *pContext, const cell_t *params)
 			break;
 		case HookParamType_CBaseEntity:
 		{
-			CBaseEntity *pEnt = gamehelpers->ReferenceToEntity(params[2]);
-
-			if(!pEnt)
+			if(params[2] == -1)
 			{
-				return pContext->ThrowNativeError("Invalid entity index passed for param value");
+				*(CBaseEntity **)addr = nullptr;
 			}
+			else
+			{
+				CBaseEntity *pEnt = gamehelpers->ReferenceToEntity(params[2]);
 
-			*(CBaseEntity **)addr = pEnt;
+				if(!pEnt)
+				{
+					return pContext->ThrowNativeError("Invalid entity index passed for param value");
+				}
+
+				*(CBaseEntity **)addr = pEnt;
+			}
 			break;
 		}
 		case HookParamType_Edict:
diff --git a/plugins/include/dhooks.inc b/plugins/include/dhooks.inc
index a2611dc4..76ff8c4d 100644
--- a/plugins/include/dhooks.inc
+++ b/plugins/include/dhooks.inc
@@ -273,6 +273,8 @@ methodmap DHookParam < Handle
 	// Set the value of a parameter.
 	// Use only for: int, entity, edict, bool or float parameter types.
 	//
+	// An entity parameter type can be set to NULL using INVALID_ENT_REFERENCE (-1).
+	//
 	// The changes are only applied when MRES_ChangedHandled or MRES_ChangedOverride
 	// is returned in the callback.
 	//
@@ -390,6 +392,8 @@ methodmap DHookReturn < Handle
  	// Retrieves or sets the return value.
  	// Use only for: int, entity, edict, bool or float return types.
  	//
+ 	// An entity return type can be set to NULL using INVALID_ENT_REFERENCE (-1).
+ 	//
  	// The return value is only readable in a post hook.
  	// The value is only applied when MRES_Override or MRES_Supercede is returned
  	// in the callback.
@@ -781,7 +785,7 @@ native int DHookRaw(Handle setup, bool post, Address addr, DHookRemovalCB remova
 native bool DHookRemoveHookID(int hookid);
 
 /**
- * Get param value (Use only for: int, entity, bool or float param types)
+ * Get param value (Use only for: int, entity, edict, bool or float param types)
  *
  * @param hParams           Handle to params structure
  * @param num               Param number to get. (Example if the function has 2 params and you need the value of the first
@@ -818,7 +822,9 @@ native void DHookGetParamVector(Handle hParams, int num, float vec[3]);
 native void DHookGetParamString(Handle hParams, int num, char[] buffer, int size);
 
 /**
- * Set param value (Use only for: int, entity, bool or float param types)
+ * Set param value (Use only for: int, entity, edict, bool or float param types)
+ *
+ * An entity param type can be set to NULL using INVALID_ENT_REFERENCE (-1).
  *
  * @param hParams           Handle to params structure
  * @param num               Param number to set (Example if the function has 2 params and you need to set the value of the
@@ -887,6 +893,8 @@ native void DHookGetReturnString(Handle hReturn, char[] buffer, int size);
 /**
  * Set return value (Use only for: int, entity, bool or float return types)
  *
+ * An entity return type can be set to NULL using INVALID_ENT_REFERENCE (-1).
+ *
  * @param hReturn           Handle to return structure
  * @param value             Value to set return as
  *