Download updates automatically, ask to install from a modeless dialog

src/engine/UpdateInstallDialog.cpp

 #include <sstream>
 #include <string>
 #include <Windows.h>
 
 #include "../shared/Dictionary.h"
 #include "../shared/Utils.h"
 #include "UpdateInstallDialog.h"
 
 namespace
 {
   LRESULT CALLBACK ProcessWindowMessage(HWND window, UINT message,
                                         WPARAM wParam, LPARAM lParam)
   {
     switch (message)
     {
     case WM_CLOSE:
-      PostQuitMessage(0);
+      PostQuitMessage(1);
       return 0;
     case WM_COMMAND:
       switch (LOWORD(wParam))
       {
       case IDYES:
-        PostQuitMessage(1);
+        PostQuitMessage(0);
         return 0;
       case IDNO:
-        PostQuitMessage(0);
+        PostQuitMessage(1);
         return 0;
       }
       break;
     }
     return DefWindowProc(window, message, wParam, lParam);
   }
+
+  HWND CreateDialogWindow()
+  {
+    const std::wstring windowClassName = L"ABP_UPDATE_INSTALL_DIALOG";
+    WNDCLASSEXW windowClass = {};
+    windowClass.cbSize = sizeof(windowClass);
+    windowClass.lpfnWndProc = ProcessWindowMessage;
+    windowClass.hbrBackground = reinterpret_cast<HBRUSH>(COLOR_MENU + 1);
+    windowClass.lpszClassName = windowClassName.c_str();
+    RegisterClassEx(&windowClass);
+
+    Dictionary* dictionary = Dictionary::GetInstance();
+    std::wstring title =
+      dictionary->Lookup("updater", "install-question-title");
+
+    return CreateWindowExW(WS_EX_TOOLWINDOW | WS_EX_TOPMOST,
+                           windowClassName.c_str(), title.c_str(), WS_SYSMENU,
+                           0, 0, 0, 0, 0, 0, 0, 0);
+  }
+
+  int GetAverageCharacterWidth(HDC deviceContext)
+  {
+    std::wstring alphabet;
+    for (wchar_t letter = L'A'; letter != 'Z'; letter++)
+      alphabet += letter;
+    RECT alphabetRect = {};
+    DrawTextW(deviceContext, alphabet.c_str(), -1, &alphabetRect,
+              DT_CALCRECT | DT_NOPREFIX);
+    return alphabetRect.right / alphabet.length();
+  }
+
+  HWND CreateText(HWND parent)
+  {
+    Dictionary* dictionary = Dictionary::GetInstance();
+    std::wstring text = dictionary->Lookup("updater", "install-question-text");
+
+    HDC deviceContext = GetDC(parent);
+    const int characterWidth = GetAverageCharacterWidth(deviceContext);
+    const int lineLength = 40;
+    const int textWidth = lineLength * characterWidth;
+
+    RECT textRect = {};
+    textRect.right = textWidth;
+    DrawTextW(deviceContext, text.c_str(), -1, &textRect,
+              DT_CALCRECT | DT_NOPREFIX | DT_WORDBREAK);
+    const int textHeight = textRect.bottom;
+
+    return CreateWindowW(L"STATIC", text.c_str(),
+                         WS_CHILD | WS_VISIBLE| SS_LEFT, 0, 0,
+                         textWidth, textHeight, parent, 0, 0, 0);
+  }
+
+  HWND CreateButtons(HWND parent)
+  {
+    const std::wstring panelClassName = L"ABP_PANEL";
+    WNDCLASSW panelClass = {};
+    panelClass.lpfnWndProc =
+      reinterpret_cast<WNDPROC>(GetWindowLongPtr(parent, GWLP_WNDPROC));
+    panelClass.lpszClassName = panelClassName.c_str();
+    RegisterClass(&panelClass);
+
+    Dictionary* dictionary = Dictionary::GetInstance();
+    const std::wstring yesLabel = dictionary->Lookup("general", "button-yes");
+    const std::wstring noLabel = dictionary->Lookup("general", "button-no");
+
+    HDC deviceContext = GetDC(parent);
+    RECT yesButtonRect = {};
+    DrawTextW(deviceContext, yesLabel.c_str(), -1, &yesButtonRect,
+              DT_CALCRECT | DT_NOPREFIX);
+    RECT noButtonRect = {};
+    DrawTextW(deviceContext, noLabel.c_str(), -1, &noButtonRect,
+              DT_CALCRECT | DT_NOPREFIX);
+
+    const int minButtonWidth = 120;
+    const int minButtonHeight = 30;
+    const int buttonPadding = 5;
+    int yesButtonWidth = yesButtonRect.right + buttonPadding * 2;
+    yesButtonWidth = max(yesButtonWidth, minButtonWidth);
+    int noButtonWidth =  noButtonRect.right + buttonPadding * 2;
+    noButtonWidth = max(noButtonWidth, minButtonWidth);
+    int buttonHeight = max(yesButtonRect.bottom, noButtonRect.bottom)
+      + buttonPadding * 2;
+    buttonHeight = max(buttonHeight, minButtonHeight);
+
+    const int gap = 10;
+    const int panelWidth = yesButtonWidth + gap + noButtonWidth;
+    const int panelHeight = buttonHeight;
+
+    const DWORD flags = WS_CHILD | WS_VISIBLE;
+    HWND buttons = CreateWindowW(panelClassName.c_str(), 0, flags, 0, 0,
+                                 panelWidth, panelHeight, parent, 0, 0, 0);
+    CreateWindowW(L"BUTTON", yesLabel.c_str(), flags,
+                  0, 0, yesButtonWidth, buttonHeight,
+                  buttons, reinterpret_cast<HMENU>(IDYES), 0, 0);
+    CreateWindowW(L"BUTTON", noLabel.c_str(), flags,
+                  yesButtonWidth + gap, 0, noButtonWidth, buttonHeight,
+                  buttons, reinterpret_cast<HMENU>(IDNO), 0, 0);
+    return buttons;
+  }
+
+  void UpdateSizes(HWND window, const HWND text, const HWND buttons)
+  {
+    RECT textRect;
+    GetWindowRect(text, &textRect);
+
+    RECT buttonsRect;
+    GetWindowRect(buttons, &buttonsRect);
+
+    const int padding = 10;
+    const int margin = 10;
+    const int gap = 10;
+    const int contentWidth = max(textRect.right, buttonsRect.right);
+    const int contentHeight = textRect.bottom + buttonsRect.bottom + margin;
+    const int windowWidth = contentWidth + padding * 2;
+    const int windowHeight = contentHeight + padding * 2;
+
+    RECT workArea;
+    SystemParametersInfo(SPI_GETWORKAREA, 0, &workArea, 0);
+    const int windowX = workArea.right - windowWidth - margin;
+    const int windowY = workArea.bottom - windowHeight - margin;
+    SetWindowPos(window, 0, windowX, windowY, windowWidth, windowHeight, 0);
+
+    const int textX = padding;
+    const int textY = padding;
+    SetWindowPos(text, 0, padding, padding, 0, 0, SWP_NOSIZE);
+
+    const int buttonsX = windowWidth - buttonsRect.right - padding;
+    const int buttonsY = windowHeight - buttonsRect.bottom - padding;
+    SetWindowPos(buttons, 0, buttonsX, buttonsY, 0, 0, SWP_NOSIZE);
+  }
 }
 
 UpdateInstallDialog::UpdateInstallDialog()
 {
-  const std::wstring windowClassName = L"UPDATE_INSTALL_DIALOG";
-  WNDCLASSEX windowClass = {};

[Wladimir Palant, 2013/08/01 09:58:24]

We should use WNDCLASSEXW explicitly.

-  windowClass.cbSize = sizeof(WNDCLASSEX);

[Wladimir Palant, 2013/08/01 09:58:24]

sizeof(windowClass) to avoid repeating the type name?

[Felix Dahlke, 2013/08/02 10:48:01]

Done.

-  windowClass.lpfnWndProc = ProcessWindowMessage;
-  windowClass.hbrBackground = reinterpret_cast<HBRUSH>(COLOR_MENU + 1);
-  windowClass.lpszClassName = windowClassName.c_str();

[Oleksandr, 2013/08/01 07:05:12]

Maybe use hIcon here with ABP logo? A default window icon popping up out of the
blue isn't exactly a good user experience, I think.

-  if (!RegisterClassEx(&windowClass))
-  {
-    std::stringstream stream;
-    stream << "Failed to register window class "
-           << ToUtf8String(windowClassName) << ": " << GetLastError();
-    throw std::runtime_error(stream.str());
-  }
-
-  Dictionary* dictionary = Dictionary::GetInstance();
-  std::wstring title = dictionary->Lookup("updater", "install-question-title");

[Oleksandr, 2013/07/31 22:16:59]

This is fine only for when download is ready. How about also having an
overridden constructor that would be something like:
UpdateInstallDialog::UpdateInstallDialog(std::wstring title, std::wstring
message)? 

[Felix Dahlke, 2013/08/01 07:21:17]

Like I said earlier, I think it's better to focus on what we want to do for now,
not on what we could do. We can always change this later.

-
-  RECT workArea;
-  SystemParametersInfo(SPI_GETWORKAREA, 0, &workArea, 0);
-
-  const int width = 300;
-  const int height = 150;

[Wladimir Palant, 2013/08/01 09:58:24]

Where do these numbers come from? What will happen on high-DPI screens or with
lengthy translations? I suggest you measure the text size to determine window
size.

[Felix Dahlke, 2013/08/02 10:48:01]

Done.

-  const int margin = 10;
-
-  window = CreateWindowExW(WS_EX_TOOLWINDOW | WS_EX_TOPMOST,
-                           windowClassName.c_str(), title.c_str(), WS_SYSMENU,
-                           workArea.right - width - margin,
-                           workArea.bottom - height - margin,
-                           width, height, 0, 0, 0, 0);

[Oleksandr, 2013/08/01 07:05:12]

Should we do something like:

SetForegroundWindow(window);

It will flash the window in the taskbar, if the user is working in another
window. So that the user will notice it.

-  CreateText();
-  CreateButtons();

[Oleksandr, 2013/07/31 22:16:59]

No CreateButtons() in the overridden constructor I suggest. Or maybe something
like CreateOKButton().

[Felix Dahlke, 2013/08/01 07:21:17]

As I said above, let's make this more generic when we need that.

+  window = CreateDialogWindow();
+  HWND text = CreateText(window);
+  HWND buttons = CreateButtons(window);
+  UpdateSizes(window, text, buttons);
 }
 
 UpdateInstallDialog::~UpdateInstallDialog()
 {
   DestroyWindow(window);
 }
 
 bool UpdateInstallDialog::Show()
 {
   ShowWindow(window, SW_SHOW);
   MSG message;
   while(GetMessage(&message, 0, 0, 0) > 0)
   {
     TranslateMessage(&message);
     DispatchMessage(&message);
   }
   ShowWindow(window, SW_HIDE);
-  return message.wParam;

[Wladimir Palant, 2013/08/01 09:58:24]

Doesn't this cause a warning? I would rather cast to bool explicitly here.

[Felix Dahlke, 2013/08/02 10:48:01]

Done. Opted for message.wParam == 0 in case of yes. This is logically an exit
code, so 0 makes more sense for the positive outcome.

+  return message.wParam == 0;
 }
-
-void UpdateInstallDialog::CreateText()
-{
-  Dictionary* dictionary = Dictionary::GetInstance();
-  std::wstring text = dictionary->Lookup("updater", "install-question-text");
-
-  RECT clientRect;
-  GetClientRect(window, &clientRect);
-
-  const int margin = 10;
-  const int width = clientRect.right - margin * 2;
-  const int height = 60;
-
-  CreateWindowW(L"STATIC", text.c_str(), WS_CHILD | WS_VISIBLE| SS_LEFT,
-                margin, margin, width, height, window, 0, 0, 0);
-}
-
-void UpdateInstallDialog::CreateButtons()
-{
-  Dictionary* dictionary = Dictionary::GetInstance();
-  const std::wstring yesLabel = dictionary->Lookup("general", "button-yes");
-  const std::wstring noLabel = dictionary->Lookup("general", "button-no");
-
-  const DWORD buttonFlags = WS_CHILD | WS_VISIBLE;
-
-  RECT clientRect;
-  GetClientRect(window, &clientRect);
-
-  const int buttonWidth = 100;
-  const int buttonHeight = 30;

[Felix Dahlke, 2013/08/02 10:48:01]

Done.

-  const int margin = 10;
-  const int combinedWidth = buttonWidth * 2 + margin;
-  const int yesButtonX = clientRect.right - combinedWidth - margin;
-  const int noButtonX = yesButtonX + buttonWidth + margin;
-  const int buttonY = clientRect.bottom - buttonHeight - margin;
-
-  CreateWindowW(L"BUTTON", yesLabel.c_str(), buttonFlags,
-                yesButtonX, buttonY, buttonWidth, buttonHeight,
-                window, reinterpret_cast<HMENU>(IDYES), 0, 0);
-  CreateWindowW(L"BUTTON", noLabel.c_str(), buttonFlags,
-                noButtonX, buttonY, buttonWidth, buttonHeight,
-                window, reinterpret_cast<HMENU>(IDNO), 0, 0);
-}