From acbadb9fbad343cca189b550e198f77ec7da0dc7 Mon Sep 17 00:00:00 2001
From: Whindmar Saksit <whindsaks@proton.me>
Date: Sat, 8 Mar 2025 13:34:23 +0100
Subject: [PATCH] [USER32] PrivateExtractIcons must return 0 for empty files
 (#7767)

This bug breaks the documented S_FALSE return value for SHDefExtractIconW when the icon is not found.
---
 win32ss/user/user32/misc/exticon.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/win32ss/user/user32/misc/exticon.c b/win32ss/user/user32/misc/exticon.c
index fec6103b2bb..04d129ea0b0 100644
--- a/win32ss/user/user32/misc/exticon.c
+++ b/win32ss/user/user32/misc/exticon.c
@@ -347,6 +347,14 @@ static UINT ICO_ExtractIconExW(
 	hFile = CreateFileW(szExePath, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, 0, 0);
 	if (hFile == INVALID_HANDLE_VALUE) return ret;
 	fsizel = GetFileSize(hFile,&fsizeh);
+#ifdef __REACTOS__
+    if (!(fsizel | fsizeh))
+    {
+        /* Cannot map empty file */
+        CloseHandle(hFile);
+        return 0; /* No icons */
+    }
+#endif
 
 	/* Map the file */
 	fmapping = CreateFileMappingW(hFile, NULL, PAGE_READONLY | SEC_COMMIT, 0, 0, NULL);