Implement svc_exec support in the engine and HLTV (#737)

* Added `svc_exec` to the list of svc commands in engine
* Added `svc_exec` support to HLTV code
* Made the engine code forward-compatible with future svc_* additions
* Added reserved svc_* slots in the enumerations

rehlds/HLTV/Core/src/Server.cpp

@@ -89,6 +89,7 @@ Server::svc_func_s Server::m_ClientFuncs[]
 	{ svc_resourcelocation,    "svc_resourcelocation",    &Server::ParseResourceLocation },
 	{ svc_sendcvarvalue,       "svc_sendcvarvalue",       &Server::ParseSendCvarValue },
 	{ svc_sendcvarvalue2,      "svc_sendcvarvalue2",      &Server::ParseSendCvarValue2 },
+	{ svc_exec,                "svc_exec",                &Server::ParseExec },
 	{ svc_endoflist,           "End of List",             nullptr }
 };
 
@@ -377,7 +378,12 @@ void Server::ProcessMessage(unsigned int seqNr)
 			break;
 		}
 
+// With `HLTV_FIXES` enabled meaning of `svc_startofusermessages` changed a bit: now it is an id of the first user message
+#ifdef HLTV_FIXES
+		if (cmd >= svc_startofusermessages)
+#else // HLTV_FIXES
 		if (cmd > svc_startofusermessages)
+#endif // HLTV_FIXES
 		{
 			if (!ParseUserMessage(cmd)) {
 				break;
@@ -2291,7 +2297,12 @@ void Server::Reset()
 char *Server::GetCmdName(int cmd)
 {
 	static char description[64];
+// With `HLTV_FIXES` enabled meaning of `svc_startofusermessages` changed a bit: now it is an id of the first user message
+#ifdef HLTV_FIXES
+	if (cmd >= svc_startofusermessages && m_World)
+#else // HLTV_FIXES
 	if (cmd > svc_startofusermessages && m_World)
+#endif // HLTV_FIXES
 	{
 		UserMsg *usermsg = m_World->GetUserMsg(cmd);
 		if (usermsg)
@@ -2345,6 +2356,15 @@ void Server::ParseSendCvarValue2()
 	char *name = m_Instream->ReadString();
 }
 
+void Server::ParseExec()
+{
+	bool execClassScript = m_Instream->ReadByte() != 0;
+	if (execClassScript)
+	{
+		int scriptId = m_Instream->ReadByte();
+	}
+}
+
 void Server::ReceiveSignal(ISystemModule *module, unsigned int signal, void *data)
 {
 	BaseSystemModule::ReceiveSignal(module, signal, data);

rehlds/HLTV/Core/src/Server.h

@@ -216,6 +216,7 @@ public:
 	void ParseResourceLocation();
 	void ParseSendCvarValue();
 	void ParseSendCvarValue2();
+	void ParseExec();
 
 protected:
 	struct svc_func_s {

rehlds/HLTV/common/net_internal.h

@@ -159,10 +159,25 @@ enum svc_commands_e
 	svc_resourcelocation,
 	svc_sendcvarvalue,
 	svc_sendcvarvalue2,
-	svc_startofusermessages = svc_sendcvarvalue2,
+	svc_exec,
+	svc_reserve60,
+	svc_reserve61,
+	svc_reserve62,
+	svc_reserve63,
+// Let's just use an id of the first user message instead of the last svc_*
+// This change doesn't make the parsing code forward-compatible with future svc_* additions, but error-reporting should be better
+#ifdef HLTV_FIXES
+	svc_startofusermessages = svc_reserve63 + 1,
+#else // HLTV_FIXES
+	svc_startofusermessages = svc_exec,
+#endif // HLTV_FIXES
 	svc_endoflist = 255,
 };
 
+#ifdef HLTV_FIXES
+static_assert(svc_startofusermessages == 64, "svc_startofusermessages should be equal to 64 for backward and forward compatibility");
+#endif // HLTV_FIXES
+
 enum clc_commands : byte
 {
 	clc_bad,

rehlds/engine/net.h

@@ -208,10 +208,25 @@ typedef enum svc_commands_e
 	svc_resourcelocation,
 	svc_sendcvarvalue,
 	svc_sendcvarvalue2,
-	svc_startofusermessages = svc_sendcvarvalue2,
+	svc_exec,
+	svc_reserve60,
+	svc_reserve61,
+	svc_reserve62,
+	svc_reserve63,
+// Let's just use an id of the first user message instead of the last svc_*
+// This change makes code in `PF_MessageEnd_I` forward-compatible with future svc_* additions
+#ifdef REHLDS_FIXES
+	svc_startofusermessages = svc_reserve63 + 1,
+#else // REHLDS_FIXES
+	svc_startofusermessages = svc_exec,
+#endif // REHLDS_FIXES
 	svc_endoflist = 255,
 } svc_commands_t;
 
+#ifdef REHLDS_FIXES
+static_assert(svc_startofusermessages == 64, "svc_startofusermessages should be equal to 64 for backward and forward compatibility");
+#endif // REHLDS_FIXES
+
 typedef enum clc_commands_e
 {
 	clc_bad,

rehlds/engine/pr_cmds.cpp

@@ -2122,8 +2122,12 @@ void EXT_FUNC PF_MessageEnd_I(void)
 	if (gMsgBuffer.flags & SIZEBUF_OVERFLOWED)
 		Sys_Error("%s: called, but message buffer from .dll had overflowed\n", __func__);
 
-
+// With `REHLDS_FIXES` enabled meaning of `svc_startofusermessages` changed a bit: now it is an id of the first user message
+#ifdef REHLDS_FIXES
+	if (gMsgType >= svc_startofusermessages)
+#else // REHLDS_FIXES
 	if (gMsgType > svc_startofusermessages)
+#endif // REHLDS_FIXES
 	{
 		UserMsg* pUserMsg = sv_gpUserMsgs;
 		while (pUserMsg && pUserMsg->iMsg != gMsgType)
@@ -2164,7 +2168,12 @@ void EXT_FUNC PF_MessageEnd_I(void)
 		if ((gMsgDest == MSG_BROADCAST && gMsgBuffer.cursize + pBuffer->cursize > pBuffer->maxsize) || !pBuffer->data)
 			return;
 
+// With `REHLDS_FIXES` enabled meaning of `svc_startofusermessages` changed a bit: now it is an id of the first user message
+#ifdef REHLDS_FIXES
+		if (gMsgType >= svc_startofusermessages && (gMsgDest == MSG_ONE || gMsgDest == MSG_ONE_UNRELIABLE))
+#else // REHLDS_FIXES
 		if (gMsgType > svc_startofusermessages && (gMsgDest == MSG_ONE || gMsgDest == MSG_ONE_UNRELIABLE))
+#endif // REHLDS_FIXES
 		{
 			int entnum = NUM_FOR_EDICT((const edict_t *)gMsgEntity);
 			if (entnum < 1 || entnum > g_psvs.maxclients)

rehlds/engine/sv_main.cpp

@@ -105,7 +105,12 @@ qboolean allow_cheats;
 char *gNullString = "";
 int SV_UPDATE_BACKUP = SINGLEPLAYER_BACKUP;
 int SV_UPDATE_MASK = (SINGLEPLAYER_BACKUP - 1);
+// With `REHLDS_FIXES` enabled we can simply use `svc_startofusermessages` instead of the hard-coded constant
+#ifdef REHLDS_FIXES
+int giNextUserMsg = svc_startofusermessages;
+#else // REHLDS_FIXES
 int giNextUserMsg = 64;
+#endif // REHLDS_FIXES
 
 cvar_t sv_lan = { "sv_lan", "0", 0, 0.0f, NULL };
 cvar_t sv_lan_rate = { "sv_lan_rate", "20000.0", 0, 0.0f, NULL };