Fix issue #3000: Shell extension performance issue

Author: sdottaka

DownloadDeps.cmd

@@ -11,7 +11,7 @@ if not %ERRORLEVEL% == 0 (
 set downloadsdir=%~dp0\build\WinMergeDownloadDeps
 set urls_destdirs=^
 https://github.com/WinMerge/winmerge/releases/download/winmerge_manual_another_build_tools_v2/winmerge_manual_another_build_tools_v2.zip!Docs\Manual\Tools ^
-https://github.com/WinMerge/winmerge/releases/download/ShellExtension-1.18.7.0/ShellExtension-1.18.7.0.zip!Build ^
+https://github.com/WinMerge/winmerge/releases/download/ShellExtension-1.18.8.0/ShellExtension-1.18.8.0.zip!Build ^
 https://github.com/WinMerge/winmerge/releases/download/Merge7z2501.0/Merge7z2501.0-x86.zip!Build\x86\Release ^
 https://github.com/WinMerge/winmerge/releases/download/Merge7z2501.0/Merge7z2501.0-x64.zip!Build\X64\Release ^
 https://github.com/WinMerge/winmerge/releases/download/Merge7z2501.0/Merge7z2501.0-ARM.zip!Build\ARM64\Release ^

ShellExtension/ShellExtension/ShellExtension.rc

@@ -53,8 +53,8 @@ END
 //
 
 VS_VERSION_INFO VERSIONINFO
- FILEVERSION 1,18,7,0
- PRODUCTVERSION 1,18,7,0
+ FILEVERSION 1,18,8,0
+ PRODUCTVERSION 1,18,8,0
  FILEFLAGSMASK 0x3fL
 #ifdef _DEBUG
  FILEFLAGS 0x1L
@@ -71,12 +71,12 @@ BEGIN
         BEGIN
             VALUE "CompanyName", "https://winmerge.org"
             VALUE "FileDescription", "WinMerge Shell Integration library"
-            VALUE "FileVersion", "1.18.7.0"
+            VALUE "FileVersion", "1.18.8.0"
             VALUE "InternalName", "ShellExtension"
-            VALUE "LegalCopyright", "Copyright 2003-2023"
+            VALUE "LegalCopyright", "Copyright 2003-2025"
             VALUE "OriginalFilename", "ShellExtension.DLL"
             VALUE "ProductName", "WinMerge Shell Integration library"
-            VALUE "ProductVersion", "1.18.7.0"
+            VALUE "ProductVersion", "1.18.8.0"
         END
     END
     BLOCK "VarFileInfo"

ShellExtension/ShellExtension/WinMergeShell.cpp

@@ -43,6 +43,7 @@
 #include "../Common/WinMergeContextMenu.h"
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <algorithm>
 
 OBJECT_ENTRY_AUTO(CLSID_WinMergeShell, CWinMergeShell)
 
@@ -182,8 +183,11 @@ HRESULT CWinMergeShell::Initialize(LPCITEMIDLIST pidlFolder,
 
 		hr = S_OK;
 
+		/// Max. filecount to select
+		constexpr unsigned MaxFileCount = 3u;
+
 		// Get all file names.
-		for (UINT x = 0 ; x < uNumFilesDropped; x++)
+		for (UINT x = 0 ; x < (std::min)(MaxFileCount + 1, uNumFilesDropped); x++)
 		{
 			// Get the number of bytes required by the file's full pathname
 			UINT wPathnameSize = DragQueryFile(hDropInfo, x, NULL, 0);

ShellExtension/WinMergeContextMenu/WinMergeContextMenu.rc

@@ -45,8 +45,8 @@ END
 //
 
 VS_VERSION_INFO VERSIONINFO
- FILEVERSION 1,0,6,0
- PRODUCTVERSION 1,0,6,0
+ FILEVERSION 1,0,7,0
+ PRODUCTVERSION 1,0,7,0
  FILEFLAGSMASK 0x3fL
 #ifdef _DEBUG
  FILEFLAGS 0x1L
@@ -63,12 +63,12 @@ BEGIN
         BEGIN
             VALUE "CompanyName", "https://winmerge.org"
             VALUE "FileDescription", "WinMerge Shell Integration library"
-            VALUE "FileVersion", "1.0.6.0"
+            VALUE "FileVersion", "1.0.7.0"
             VALUE "InternalName", "WinMergeContextMenu"
-            VALUE "LegalCopyright", "Copyright 2021-2023"
+            VALUE "LegalCopyright", "Copyright 2021-2025"
             VALUE "OriginalFilename", "WinMergeContextMenu.dll"
             VALUE "ProductName", "WinMerge Shell Integration library"
-            VALUE "ProductVersion", "1.0.6.0"
+            VALUE "ProductVersion", "1.0.7.0"
         END
     END
     BLOCK "VarFileInfo"

ShellExtension/WinMergeContextMenu/dllmain.cpp

@@ -12,6 +12,7 @@
 #include <vector>
 #include <sstream>
 #include <memory>
+#include <algorithm>
 #include <Shlwapi.h>
 #include <ExDisp.h>
 #include <ShlObj.h>
@@ -164,8 +165,10 @@ class WinMergeExplorerCommandBase : public RuntimeClass<RuntimeClassFlags<WinRtC
         }
         else
         {
+            /// Max. filecount to select
+            constexpr DWORD MaxFileCount = 3u;
             selection->GetCount(&dwNumItems);
-            for (DWORD i = 0; i < dwNumItems; ++i)
+            for (DWORD i = 0; i < (std::min)(MaxFileCount + 1, dwNumItems); ++i)
             {
                 ComPtr<IShellItem> psi;
                 wil::unique_cotaskmem_string pszFilePath;