Separate pruning of elevated/unelevated session buffers (#19546)

Previously, launching an unelevated session after an elevated one would
delete the latter's persisted buffers, and vice versa of course. Also,
elevated buffers didn't have an ACL forbidding access to unelevated
users. That's also fixed now.

Closes #19526

## Validation Steps Performed
* Unelevated/elevated WT doesn't erase each other's buffers ✅
* Old buffers named `buffer_` are renamed to `elevated_` if needed ✅

Author: lhecker

.github/actions/spelling/expect/expect.txt

@@ -1139,6 +1139,7 @@ NOYIELD
 NOZORDER
 NPFS
 nrcs
+NRNW
 NSTATUS
 ntapi
 ntdef

src/buffer/out/textBuffer.cpp

@@ -2628,11 +2628,8 @@ void TextBuffer::_AppendRTFText(std::string& contentBuilder, const std::wstring_
     }
 }
 
-void TextBuffer::SerializeToPath(const wchar_t* destination) const
+void TextBuffer::SerializeTo(HANDLE handle) const
 {
-    const wil::unique_handle file{ CreateFileW(destination, GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_DELETE, nullptr, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, nullptr) };
-    THROW_LAST_ERROR_IF(!file);
-
     static constexpr size_t writeThreshold = 32 * 1024;
     std::wstring buffer;
     buffer.reserve(writeThreshold + writeThreshold / 2);
@@ -2661,7 +2658,7 @@ void TextBuffer::SerializeToPath(const wchar_t* destination) const
         {
             const auto fileSize = gsl::narrow<DWORD>(buffer.size() * sizeof(wchar_t));
             DWORD bytesWritten = 0;
-            THROW_IF_WIN32_BOOL_FALSE(WriteFile(file.get(), buffer.data(), fileSize, &bytesWritten, nullptr));
+            THROW_IF_WIN32_BOOL_FALSE(WriteFile(handle, buffer.data(), fileSize, &bytesWritten, nullptr));
             THROW_WIN32_IF_MSG(ERROR_WRITE_FAULT, bytesWritten != fileSize, "failed to write");
             buffer.clear();
         }

src/buffer/out/textBuffer.hpp

@@ -288,7 +288,7 @@ class TextBuffer final
                        const bool isIntenseBold,
                        std::function<std::tuple<COLORREF, COLORREF, COLORREF>(const TextAttribute&)> GetAttributeColors) const noexcept;
 
-    void SerializeToPath(const wchar_t* destination) const;
+    void SerializeTo(HANDLE handle) const;
 
     struct PositionInformation
     {

src/cascadia/TerminalApp/IPaneContent.idl

@@ -8,8 +8,7 @@ namespace TerminalApp
         None,
         Content,
         MovePane,
-        PersistLayout,
-        PersistAll
+        Persist,
     };
 
     runtimeclass BellEventArgs

src/cascadia/TerminalApp/TerminalPage.cpp

@@ -2218,7 +2218,7 @@ namespace winrt::TerminalApp::implementation
         }
     }
 
-    void TerminalPage::PersistState(bool serializeBuffer)
+    void TerminalPage::PersistState()
     {
         // This method may be called for a window even if it hasn't had a tab yet or lost all of them.
         // We shouldn't persist such windows.
@@ -2233,7 +2233,7 @@ namespace winrt::TerminalApp::implementation
         for (auto tab : _tabs)
         {
             auto t = winrt::get_self<implementation::Tab>(tab);
-            auto tabActions = t->BuildStartupActions(serializeBuffer ? BuildStartupKind::PersistAll : BuildStartupKind::PersistLayout);
+            auto tabActions = t->BuildStartupActions(BuildStartupKind::Persist);
             actions.insert(actions.end(), std::make_move_iterator(tabActions.begin()), std::make_move_iterator(tabActions.end()));
         }
 
@@ -2319,6 +2319,29 @@ namespace winrt::TerminalApp::implementation
         CloseWindowRequested.raise(*this, nullptr);
     }
 
+    std::vector<IPaneContent> TerminalPage::Panes() const
+    {
+        std::vector<IPaneContent> panes;
+
+        for (const auto tab : _tabs)
+        {
+            const auto impl = _GetTabImpl(tab);
+            if (!impl)
+            {
+                continue;
+            }
+
+            impl->GetRootPane()->WalkTree([&](auto&& pane) {
+                if (auto content = pane->GetContent())
+                {
+                    panes.push_back(std::move(content));
+                }
+            });
+        }
+
+        return panes;
+    }
+
     // Method Description:
     // - Move the viewport of the terminal of the currently focused tab up or
     //      down a number of lines.
@@ -3527,9 +3550,12 @@ namespace winrt::TerminalApp::implementation
 
         if (hasSessionId)
         {
+            using namespace std::string_view_literals;
+
             const auto settingsDir = CascadiaSettings::SettingsDirectory();
-            const auto idStr = Utils::GuidToPlainString(sessionId);
-            const auto path = fmt::format(FMT_COMPILE(L"{}\\buffer_{}.txt"), settingsDir, idStr);
+            const auto admin = IsRunningElevated();
+            const auto filenamePrefix = admin ? L"elevated_"sv : L"buffer_"sv;
+            const auto path = fmt::format(FMT_COMPILE(L"{}\\{}{}.txt"), settingsDir, filenamePrefix, sessionId);
             control.RestoreFromPath(path);
         }
 

src/cascadia/TerminalApp/TerminalPage.h

@@ -122,7 +122,8 @@ namespace winrt::TerminalApp::implementation
 
         safe_void_coroutine RequestQuit();
         safe_void_coroutine CloseWindow();
-        void PersistState(bool serializeBuffer);
+        void PersistState();
+        std::vector<IPaneContent> Panes() const;
 
         void ToggleFocusMode();
         void ToggleFullscreen();

src/cascadia/TerminalApp/TerminalPaneContent.cpp

@@ -140,22 +140,16 @@ namespace winrt::TerminalApp::implementation
             // "attach existing" rather than a "create"
             args.ContentId(_control.ContentId());
             break;
-        case BuildStartupKind::PersistAll:
+        case BuildStartupKind::Persist:
         {
             const auto connection = _control.Connection();
             const auto id = connection ? connection.SessionId() : winrt::guid{};
-
             if (id != winrt::guid{})
             {
-                const auto settingsDir = CascadiaSettings::SettingsDirectory();
-                const auto idStr = ::Microsoft::Console::Utils::GuidToPlainString(id);
-                const auto path = fmt::format(FMT_COMPILE(L"{}\\buffer_{}.txt"), settingsDir, idStr);
-                _control.PersistToPath(path);
                 args.SessionId(id);
             }
             break;
         }
-        case BuildStartupKind::PersistLayout:
         default:
             break;
         }

src/cascadia/TerminalApp/TerminalWindow.cpp

@@ -253,11 +253,11 @@ namespace winrt::TerminalApp::implementation
         AppLogic::Current()->NotifyRootInitialized();
     }
 
-    void TerminalWindow::PersistState(bool serializeBuffer)
+    void TerminalWindow::PersistState()
     {
         if (_root)
         {
-            _root->PersistState(serializeBuffer);
+            _root->PersistState();
         }
     }
 
@@ -830,6 +830,11 @@ namespace winrt::TerminalApp::implementation
         return _root.as<winrt::Windows::UI::Xaml::Controls::Control>();
     }
 
+    winrt::Windows::Foundation::Collections::IVector<IPaneContent> TerminalWindow::Panes() const
+    {
+        return winrt::single_threaded_vector(_root->Panes());
+    }
+
     // Method Description:
     // - Gets the title of the currently focused terminal control. If there
     //   isn't a control selected for any reason, returns "Terminal"

src/cascadia/TerminalApp/TerminalWindow.h

@@ -71,7 +71,7 @@ namespace winrt::TerminalApp::implementation
 
         void Create();
 
-        void PersistState(bool serializeBuffer);
+        void PersistState();
 
         void UpdateSettings(winrt::TerminalApp::SettingsLoadEventArgs args);
 
@@ -111,6 +111,7 @@ namespace winrt::TerminalApp::implementation
         float CalcSnappedDimension(const bool widthOrHeight, const float dimension) const;
 
         Windows::UI::Xaml::UIElement GetRoot() noexcept;
+        winrt::Windows::Foundation::Collections::IVector<IPaneContent> Panes() const;
 
         hstring Title();
         void TitlebarClicked();

src/cascadia/TerminalApp/TerminalWindow.idl

@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT license.
 
+import "IPaneContent.idl";
 import "TerminalPage.idl";
 import "ShortcutActionDispatch.idl";
 
@@ -59,9 +60,10 @@ namespace TerminalApp
         Boolean ShouldImmediatelyHandoffToElevated();
         void HandoffToElevated();
 
-        void PersistState(Boolean serializeBuffer);
+        void PersistState();
 
         Windows.UI.Xaml.UIElement GetRoot();
+        IVector<IPaneContent> Panes { get; };
 
         String Title { get; };
         Boolean FocusMode { get; };