From 6fe69b538c7e4e32c2b05ca6cce7bdc05137c672 Mon Sep 17 00:00:00 2001
From: cjee21 <77721854+cjee21@users.noreply.github.com>
Date: Sat, 4 Jan 2025 19:03:15 +0800
Subject: [PATCH] ShellExt: Add shortcut (*.lnk) handling

---
 Source/WindowsShellExtension/dllmain.cpp | 72 +++++++++++++++++++++++-
 Source/WindowsShellExtension/pch.h       |  2 +
 2 files changed, 72 insertions(+), 2 deletions(-)

diff --git a/Source/WindowsShellExtension/dllmain.cpp b/Source/WindowsShellExtension/dllmain.cpp
index 11688be9a..bcad537ae 100644
--- a/Source/WindowsShellExtension/dllmain.cpp
+++ b/Source/WindowsShellExtension/dllmain.cpp
@@ -297,6 +297,58 @@ namespace {
         };
         return std::any_of(supported_extensions.begin(), supported_extensions.end(), [extension](const std::string& extension_iter) {return (extension_iter.compare(extension) == 0); });
     }
+
+    // ResolveIt - Uses the Shell's IShellLink and IPersistFile interfaces 
+    //             to retrieve the path and description from an existing shortcut.
+    // Adapted from: https://learn.microsoft.com/en-us/windows/win32/shell/links#resolving-a-shortcut
+    //
+    // Returns the result of calling the member functions of the interfaces. 
+    //
+    // Parameters:
+    // hwnd         - A handle to the parent window. The Shell uses this window to 
+    //                display a dialog box if it needs to prompt the user for more 
+    //                information while resolving the link.
+    // lpszLinkFile - Address of a buffer that contains the path of the link,
+    //                including the file name.
+    // lpszPath     - Address of a buffer that receives the path of the link
+    //                target, including the file name.
+    HRESULT ResolveIt(_In_opt_ HWND hwnd, _In_ LPCWSTR lpszLinkFile, _Out_ LPWSTR lpszPath, _In_ int iPathBufferSize) {
+        HRESULT hres;
+        IShellLink* psl = nullptr;
+        WCHAR szGotPath[MAX_PATH];
+        WIN32_FIND_DATA wfd{};
+
+        *lpszPath = 0; // Assume failure 
+
+        // Get a pointer to the IShellLink interface. It is assumed that CoInitialize
+        // has already been called. 
+        hres = CoCreateInstance(CLSID_ShellLink, NULL, CLSCTX_INPROC_SERVER, IID_IShellLink, reinterpret_cast<LPVOID*>(&psl));
+        if (SUCCEEDED(hres)) {
+            IPersistFile* ppf = nullptr;
+            // Get a pointer to the IPersistFile interface. 
+            hres = psl->QueryInterface(IID_IPersistFile, reinterpret_cast<void**>(&ppf));
+            if (SUCCEEDED(hres)) {
+                // Load the shortcut. 
+                hres = ppf->Load(lpszLinkFile, STGM_READ);
+                if (SUCCEEDED(hres)) {
+                    // Resolve the link. 
+                    hres = psl->Resolve(hwnd, 0);
+                    if (SUCCEEDED(hres)) {
+                        // Get the path to the link target. 
+                        hres = psl->GetPath(szGotPath, MAX_PATH, reinterpret_cast<WIN32_FIND_DATA*>(&wfd), SLGP_SHORTPATH);
+                        if (SUCCEEDED(hres)) {
+                            hres = StringCbCopy(lpszPath, iPathBufferSize, szGotPath);
+                        }
+                    }
+                }
+                // Release the pointer to the IPersistFile interface. 
+                ppf->Release();
+            }
+            // Release the pointer to the IShellLink interface. 
+            psl->Release();
+        }
+        return hres;
+    }
 }
 
 struct ExplorerCommandHandler : public winrt::implements<ExplorerCommandHandler, IExplorerCommand> {
@@ -352,7 +404,16 @@ struct ExplorerCommandHandler : public winrt::implements<ExplorerCommandHandler,
                             wil::unique_cotaskmem_string path;
                             if (SUCCEEDED(item->GetDisplayName(SIGDN_FILESYSPATH, &path))) {
                                 std::filesystem::path filepath = path.get();
-                                is_supported_extension = IsSupportedFileExtension(filepath.extension().string());
+                                // resolve shortcuts
+                                if (filepath.extension().string().compare(".lnk") == 0) {
+                                    WCHAR target_path[MAX_PATH];
+                                    if (SUCCEEDED(ResolveIt(nullptr, filepath.wstring().c_str(), target_path, sizeof(target_path))))
+                                        filepath = target_path;
+                                }
+                                if (std::filesystem::is_directory(filepath))
+                                    is_folder = true;
+                                else
+                                    is_supported_extension = IsSupportedFileExtension(filepath.extension().string());
                             }
                         }
                     }
@@ -435,8 +496,15 @@ struct ExplorerCommandHandler : public winrt::implements<ExplorerCommandHandler,
                 wil::unique_cotaskmem_string path;
                 result = item->GetDisplayName(SIGDN_FILESYSPATH, &path);
                 if (SUCCEEDED(result)) {
+                    std::filesystem::path filepath = path.get();
+                    // Resolve shortcuts
+                    if (filepath.extension().string().compare(".lnk") == 0) {
+                        WCHAR target_path[MAX_PATH];
+                        if (SUCCEEDED(ResolveIt(nullptr, filepath.wstring().c_str(), target_path, sizeof(target_path))))
+                            filepath = target_path;
+                    }
                     // Append the item path to the existing command, adding quotes and escapes as needed
-                    command = wil::str_printf<std::wstring>(LR"-(%s %s)-", command.c_str(), QuoteForCommandLineArg(path.get()).c_str());
+                    command = wil::str_printf<std::wstring>(LR"-(%s %s)-", command.c_str(), QuoteForCommandLineArg(filepath.wstring()).c_str());
                 }
             }
         }
diff --git a/Source/WindowsShellExtension/pch.h b/Source/WindowsShellExtension/pch.h
index 17677c3d0..634b3cc89 100644
--- a/Source/WindowsShellExtension/pch.h
+++ b/Source/WindowsShellExtension/pch.h
@@ -13,6 +13,8 @@
 #include <filesystem>
 #include <string>
 
+#include <strsafe.h>
+
 #include <shlobj_core.h>
 #include <shlwapi.h>
 #pragma comment(lib, "shlwapi.lib")