ShellExtension/WinMergeContextMenu/dllmain.cpp

   1 // SPDX-License-Identifier: MIT
   2 // Based on code from https://github.com/microsoft/AppModelSamples/tree/master/Samples/SparsePackages
   3 // dllmain.cpp : Defines the entry point for the DLL application.
   4 #include "pch.h"
   5 #include <wrl/module.h>
   6 #include <wrl/implements.h>
   7 #include <wrl/client.h>
   8 #include <shobjidl_core.h>
   9 #include <wil/resource.h>
  10 #include <wil/win32_helpers.h>
  11 #include <string>
  12 #include <vector>
  13 #include <sstream>
  14 #include <memory>
  15 #include <Shlwapi.h>
  16 #include <ExDisp.h>
  17 #include <ShlObj.h>
  18 #include "../Common/WinMergeContextMenu.h"
  19 #include "resource.h"
  20
  21 #pragma comment(lib, "shlwapi.lib")
  22
  23 using namespace Microsoft::WRL;
  24
  25 BOOL APIENTRY DllMain( HMODULE hModule,
  26                        DWORD  ul_reason_for_call,
  27                        LPVOID lpReserved
  28                      )
  29 {
  30     switch (ul_reason_for_call)
  31     {
  32     case DLL_PROCESS_ATTACH:
  33     case DLL_THREAD_ATTACH:
  34     case DLL_THREAD_DETACH:
  35     case DLL_PROCESS_DETACH:
  36         break;
  37     }
  38     return TRUE;
  39 }
  40
  41 class WinMergeExplorerCommandBase : public RuntimeClass<RuntimeClassFlags<ClassicCom>, IExplorerCommand>
  42 {
  43 public:
  44     WinMergeExplorerCommandBase(WinMergeContextMenu* pContextMenu) : m_pContextMenu(pContextMenu) {}
  45     virtual const wchar_t* Title() = 0;
  46     virtual const EXPCMDFLAGS Flags() { return ECF_DEFAULT; }
  47     virtual const EXPCMDSTATE State(_In_opt_ IShellItemArray* selection) { return ECS_ENABLED; }
  48     virtual const int IconId(_In_opt_ IShellItemArray* selection) { return 0; }
  49     virtual const int Verb() { return 0; }
  50
  51     // IExplorerCommand
  52     IFACEMETHODIMP GetTitle(_In_opt_ IShellItemArray* items, _Outptr_result_nullonfailure_ PWSTR* name)
  53     {
  54         *name = nullptr;
  55         auto title = wil::make_cotaskmem_string_nothrow(Title());
  56         RETURN_IF_NULL_ALLOC(title);
  57         *name = title.release();
  58         return S_OK;
  59     }
  60     IFACEMETHODIMP GetIcon(_In_opt_ IShellItemArray* items, _Outptr_result_nullonfailure_ PWSTR* icon)
  61     {
  62         const int id = IconId(items);
  63         if (id == 0)
  64         {
  65             *icon = nullptr;
  66             return E_NOTIMPL;
  67         }
  68         auto modulefilename = wil::GetModuleFileNameW(wil::GetModuleInstanceHandle());
  69         std::wstring path = modulefilename.get() + std::wstring(L",-") + std::to_wstring(id);
  70         SHStrDupW(path.c_str(), icon);
  71         return S_OK;
  72     }
  73     IFACEMETHODIMP GetToolTip(_In_opt_ IShellItemArray*, _Outptr_result_nullonfailure_ PWSTR* infoTip)
  74     {
  75         *infoTip = nullptr;
  76         return E_NOTIMPL;
  77     }
  78     IFACEMETHODIMP GetCanonicalName(_Out_ GUID* guidCommandName)
  79     {
  80         *guidCommandName = GUID_NULL;
  81         return S_OK;
  82     }
  83     IFACEMETHODIMP GetState(_In_opt_ IShellItemArray* selection, _In_ BOOL okToBeSlow, _Out_ EXPCMDSTATE* cmdState)
  84     {
  85         *cmdState = State(selection);
  86         return S_OK;
  87     }
  88     IFACEMETHODIMP Invoke(_In_opt_ IShellItemArray* selection, _In_opt_ IBindCtx*) noexcept try
  89     {
  90         m_pContextMenu->InvokeCommand(Verb());
  91         return S_OK;
  92     }
  93     CATCH_RETURN();
  94
  95     IFACEMETHODIMP GetFlags(_Out_ EXPCMDFLAGS* flags)
  96     {
  97         *flags = Flags();
  98         return S_OK;
  99     }
 100     IFACEMETHODIMP EnumSubCommands(_COM_Outptr_ IEnumExplorerCommand** enumCommands)
 101     {
 102         *enumCommands = nullptr;
 103         return E_NOTIMPL;
 104     }
 105
 106 protected:
 107
 108     // code from https://github.com/microsoft/terminal/blob/main/src/cascadia/ShellExtension/OpenTerminalHere.cpp
 109     std::wstring _GetPathFromExplorer() const
 110     {
 111         std::wstring path;
 112         HRESULT hr = NOERROR;
 113
 114         auto hwnd = ::GetForegroundWindow();
 115         if (hwnd == nullptr)
 116         {
 117             return path;
 118         }
 119
 120         TCHAR szName[MAX_PATH] = { 0 };
 121         ::GetClassName(hwnd, szName, MAX_PATH);
 122         if (0 == StrCmp(szName, L"WorkerW") ||
 123             0 == StrCmp(szName, L"Progman"))
 124         {
 125             //special folder: desktop
 126             hr = ::SHGetFolderPath(NULL, CSIDL_DESKTOP, NULL, SHGFP_TYPE_CURRENT, szName);
 127             if (FAILED(hr))
 128             {
 129                 return path;
 130             }
 131
 132             path = szName;
 133             return path;
 134         }
 135
 136         if (0 != StrCmp(szName, L"CabinetWClass"))
 137         {
 138             return path;
 139         }
 140
 141         ComPtr<IShellWindows> shell;
 142         hr = CoCreateInstance(CLSID_ShellWindows, nullptr, CLSCTX_ALL, IID_IShellWindows, &shell);
 143         if (FAILED(hr) || shell == nullptr)
 144         {
 145             return path;
 146         }
 147
 148         ComPtr<IDispatch> disp;
 149         wil::unique_variant variant;
 150         variant.vt = VT_I4;
 151
 152         ComPtr<IWebBrowserApp> browser;
 153         // look for correct explorer window
 154         for (variant.intVal = 0;
 155             shell->Item(variant, &disp) == S_OK;
 156             variant.intVal++)
 157         {
 158             ComPtr<IWebBrowserApp> tmp;
 159             if (FAILED(disp->QueryInterface<IWebBrowserApp>(&tmp)))
 160             {
 161                 disp = nullptr; // get rid of DEBUG non-nullptr warning
 162                 continue;
 163             }
 164
 165             HWND tmpHWND = NULL;
 166             hr = tmp->get_HWND(reinterpret_cast<SHANDLE_PTR*>(&tmpHWND));
 167             if (hwnd == tmpHWND)
 168             {
 169                 browser = tmp;
 170                 disp = nullptr; // get rid of DEBUG non-nullptr warning
 171                 break; //found
 172             }
 173
 174             disp = nullptr; // get rid of DEBUG non-nullptr warning
 175         }
 176
 177         if (browser != nullptr)
 178         {
 179             wil::unique_bstr url;
 180             hr = browser->get_LocationURL(&url);
 181             if (FAILED(hr))
 182             {
 183                 return path;
 184             }
 185
 186             std::wstring sUrl(url.get(), SysStringLen(url.get()));
 187             DWORD size = MAX_PATH;
 188             hr = ::PathCreateFromUrl(sUrl.c_str(), szName, &size, NULL);
 189             if (SUCCEEDED(hr))
 190             {
 191                 path = szName;
 192             }
 193         }
 194
 195         return path;
 196     }
 197
 198     std::vector<std::wstring> GetPaths(_In_opt_ IShellItemArray* selection)
 199     {
 200         std::vector<std::wstring> paths;
 201         DWORD dwNumItems = 0;
 202         if (!selection)
 203         {
 204             std::wstring path = _GetPathFromExplorer();
 205             if (!path.empty())
 206                 paths.push_back(path);
 207         }
 208         else
 209         {
 210             selection->GetCount(&dwNumItems);
 211             for (DWORD i = 0; i < dwNumItems; ++i)
 212             {
 213                 ComPtr<IShellItem> psi;
 214                 wil::unique_cotaskmem_string pszFilePath;
 215                 if (SUCCEEDED(selection->GetItemAt(i, &psi)) &&
 216                     SUCCEEDED(psi->GetDisplayName(SIGDN_FILESYSPATH, &pszFilePath)))
 217                 {
 218                     paths.push_back(pszFilePath.get());
 219                 }
 220             }
 221         }
 222         return paths;
 223     }
 224     WinMergeContextMenu* m_pContextMenu;
 225 };
 226
 227 class SubExplorerCommandHandler final : public WinMergeExplorerCommandBase
 228 {
 229 public:
 230     SubExplorerCommandHandler(WinMergeContextMenu *pContextMenu, const MenuItem& menuItem)
 231         : WinMergeExplorerCommandBase(pContextMenu)
 232         , m_menuItem(menuItem)
 233     {
 234     }
 235     const wchar_t* Title() override
 236     {
 237         return m_menuItem.text.c_str();
 238     }
 239     const int IconId(_In_opt_ IShellItemArray* selection) override
 240     {
 241         return m_menuItem.icon;
 242     }
 243     const int Verb() override
 244     {
 245         return m_menuItem.verb;
 246     }
 247     const EXPCMDSTATE State(_In_opt_ IShellItemArray* selection) override
 248     {
 249         return m_menuItem.enabled ? ECS_ENABLED : ECS_DISABLED;
 250     }
 251 private:
 252     MenuItem m_menuItem;
 253 };
 254
 255 class EnumCommands : public RuntimeClass<RuntimeClassFlags<ClassicCom>, IEnumExplorerCommand>
 256 {
 257 public:
 258     explicit EnumCommands(WinMergeContextMenu* pContextMenu)
 259     {
 260         for (auto& menuItem : pContextMenu->GetMenuItemList())
 261             m_commands.push_back(Make<SubExplorerCommandHandler>(pContextMenu, menuItem));
 262         m_current = m_commands.cbegin();
 263     }
 264
 265     // IEnumExplorerCommand
 266     IFACEMETHODIMP Next(ULONG celt, __out_ecount_part(celt, *pceltFetched) IExplorerCommand** apUICommand, __out_opt ULONG* pceltFetched)
 267     {
 268         ULONG fetched{ 0 };
 269         wil::assign_to_opt_param(pceltFetched, 0ul);
 270
 271         for (ULONG i = 0; (i < celt) && (m_current != m_commands.cend()); i++)
 272         {
 273             m_current->CopyTo(&apUICommand[0]);
 274             m_current++;
 275             fetched++;
 276         }
 277
 278         wil::assign_to_opt_param(pceltFetched, fetched);
 279         return (fetched == celt) ? S_OK : S_FALSE;
 280     }
 281
 282     IFACEMETHODIMP Skip(ULONG /*celt*/) { return E_NOTIMPL; }
 283     IFACEMETHODIMP Reset()
 284     {
 285         m_current = m_commands.cbegin();
 286         return S_OK;
 287     }
 288     IFACEMETHODIMP Clone(__deref_out IEnumExplorerCommand** ppenum) { *ppenum = nullptr; return E_NOTIMPL; }
 289
 290 private:
 291     std::vector<ComPtr<IExplorerCommand>> m_commands;
 292     std::vector<ComPtr<IExplorerCommand>>::const_iterator m_current;
 293 };
 294
 295 class __declspec(uuid("90340779-F37E-468E-9728-A2593498ED32")) WinMergeFileDirExplorerCommandHandler : public WinMergeExplorerCommandBase
 296 {
 297 public:
 298     WinMergeFileDirExplorerCommandHandler()
 299         : m_contextMenu(wil::GetModuleInstanceHandle())
 300         , WinMergeExplorerCommandBase(&m_contextMenu)
 301     {
 302     }
 303     const wchar_t* Title() override { return L"&WinMerge"; }
 304     const int IconId(_In_opt_ IShellItemArray* selection) override
 305     {
 306         auto paths = GetPaths(selection);
 307         if (paths.size() > 0 && PathIsDirectory(paths[0].c_str()))
 308             return IDI_WINMERGEDIR;
 309         return IDI_WINMERGE;
 310     }
 311     const int Verb() override { return WinMergeContextMenu::CMD_COMPARE; }
 312     const EXPCMDFLAGS Flags() override
 313     {
 314         // Due to stability issues, the advanced menu is currently disabled.
 315         return ECF_DEFAULT;
 316         /*
 317         if ((m_contextMenu.GetContextMenuEnabled() & (WinMergeContextMenu::EXT_ENABLED | WinMergeContextMenu::EXT_ADVANCED)) == (WinMergeContextMenu::EXT_ENABLED | WinMergeContextMenu::EXT_ADVANCED))
 318             return ECF_HASSUBCOMMANDS;
 319         else
 320             return ECF_DEFAULT;
 321          */
 322     }
 323     const EXPCMDSTATE State(_In_opt_ IShellItemArray* selection) override
 324     {
 325         auto paths = GetPaths(selection);
 326         if (paths.size() > 3)
 327             return ECS_DISABLED;
 328         m_contextMenu.UpdateMenuState(paths);
 329         if (m_contextMenu.GetMenuState() == WinMergeContextMenu::MENU_HIDDEN)
 330         {
 331             return ECS_HIDDEN;
 332         }
 333         return ECS_ENABLED;
 334     }
 335     IFACEMETHODIMP EnumSubCommands(_COM_Outptr_ IEnumExplorerCommand** enumCommands)
 336     {
 337         *enumCommands = nullptr;
 338         auto e = Make<EnumCommands>(&m_contextMenu);
 339         return e->QueryInterface(IID_PPV_ARGS(enumCommands));
 340     }
 341 private:
 342     WinMergeContextMenu m_contextMenu;
 343 };
 344
 345 CoCreatableClass(WinMergeFileDirExplorerCommandHandler)
 346
 347 CoCreatableClassWrlCreatorMapInclude(WinMergeFileDirExplorerCommandHandler)
 348
 349
 350 STDAPI DllGetActivationFactory(_In_ HSTRING activatableClassId, _COM_Outptr_ IActivationFactory** factory)
 351 {
 352     return Module<ModuleType::InProc>::GetModule().GetActivationFactory(activatableClassId, factory);
 353 }
 354
 355 STDAPI DllCanUnloadNow()
 356 {
 357     return Module<InProc>::GetModule().GetObjectCount() == 0 ? S_OK : S_FALSE;
 358 }
 359
 360 STDAPI DllGetClassObject(_In_ REFCLSID rclsid, _In_ REFIID riid, _COM_Outptr_ void** instance)
 361 {
 362     return Module<InProc>::GetModule().GetClassObject(rclsid, riid, instance);
 363 }