From 5ea2e295c131c3bbb7f12514efff0bd72146b581 Mon Sep 17 00:00:00 2001
From: Alibek Omarov <a1ba.omarov@gmail.com>
Date: Tue, 30 Jul 2024 15:22:32 +0300
Subject: [PATCH] engine: prevent rescanning filesystem when new player
 connects or on late precache

By reusing a padding hole in resource_t structure, we put a bit indicating that this archive
was already mounted by filesystem and skip it.

Because we associate this with resource, theoretical use of late precache with archives
will rescan filesystem and allow using newly downloaded assets.
---
 engine/client/cl_main.c | 17 ++++++++++++-----
 engine/custom.h         |  5 +++++
 2 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/engine/client/cl_main.c b/engine/client/cl_main.c
index 9a0f92dc..95e320e0 100644
--- a/engine/client/cl_main.c
+++ b/engine/client/cl_main.c
@@ -2830,19 +2830,26 @@ static void CL_Physinfo_f( void )
 static qboolean CL_ShouldRescanFilesystem( void )
 {
 	resource_t *res;
+	qboolean retval = false;
 
 	for( res = cl.resourcesonhand.pNext; res && res != &cl.resourcesonhand; res = res->pNext )
 	{
 		if( res->type == t_generic )
 		{
 			const char *ext = COM_FileExtension( res->szFileName );
-			// TODO: query supported archives format from fs_stdio
-			// TODO: query if was already opened
-			if( !Q_stricmp( ext, "wad" ) || !Q_stricmp( ext, "pk3" ) || !Q_stricmp( ext, "pak" ))
-				return true;
+
+			if( !g_fsapi.IsArchiveExtensionSupported( ext, IAES_ONLY_REAL_ARCHIVES ))
+				continue;
+
+			if( FBitSet( res->ucExtraFlags, RES_EXTRA_ARCHIVE_CHECKED ))
+				continue;
+
+			SetBits( res->ucExtraFlags, RES_EXTRA_ARCHIVE_CHECKED );
+			retval = true;
 		}
 	}
-	return false;
+
+	return retval;
 }
 
 qboolean CL_PrecacheResources( void )
diff --git a/engine/custom.h b/engine/custom.h
index 04d84894..3c8a0818 100644
--- a/engine/custom.h
+++ b/engine/custom.h
@@ -53,6 +53,10 @@ typedef struct resourceinfo_s
 #define RES_ALWAYS		(1<<5)	// Download always even if available on client
 #define RES_CHECKFILE	(1<<7)	// Check file on client
 
+// this archive was already mounted after rescan
+// only makes sense for archives and on client
+#define RES_EXTRA_ARCHIVE_CHECKED BIT( 0 )
+
 typedef struct resource_s
 {
 	char			szFileName[64];	// File name to download/precache.
@@ -67,6 +71,7 @@ typedef struct resource_s
 						// if it's a custom resource.
 
 	unsigned char		rguc_reserved[32];	// For future expansion
+	unsigned short		ucExtraFlags; // fwgs extension, doesn't change the size of struct because of compiler padding
 	struct resource_s		*pNext;		// Next in chain.
 	struct resource_s		*pPrev;
 } resource_t;