feat(qt): Port win_taskbar_progress to Qt6

[kwsantiago]

Replace QtWinExtras (removed in Qt6) with native Windows ITaskbarList3 COM API, making the Windows taskbar progress feature compatible with both Qt5 and Qt6.

Closes #191

Changes

• Replace QtWinExtras with direct ITaskbarList3 COM interface
• Create new WinTaskbarProgress class using Windows COM API
• Use consistent Q_OS_WIN macro for Windows platform detection
• Update CMakeLists.txt to link ole32 instead of Qt WinExtras

Implementation

The new WinTaskbarProgress class uses Windows ITaskbarList3 directly, maintaining full feature parity with the Qt5 implementation while working with both Qt5 and Qt6.

[luke-jr]

I think this would be easier to review if the Qt6 depends changes were split to a separate PR, and the fixups squashed.

[kwsantiago]

I've split this PR as requested:

• Qt6 depends changes moved to build: Upgrade depends to Qt6 #231
• This PR now contains only the squashed taskbar port commit
• Once PR build: Upgrade depends to Qt6 #231 merges, this PR will automatically show only 1 commit

[luke-jr]

My thought was more of having this PR just port win_taskbar_progress to native Windows, and have the Qt6 PR independently change depends builds, neither depending on each other.

[kwsantiago]

Gotcha @luke-jr I've updated both PRs to reflect.

[luke-jr]

Not sure if windowHandle() can return null, but it should only ever return itself anyway, so might as well just pass this?

[bigshiny90]

Testing this a little today but ran into some unexpected difficulties.

1. built as is, the progress bar never shows/initiates for me. I ended up moving the m_taskbar_progress->setWindow out of the constructor (line 235) back down closer to its original position inside of setNumBlocks. Something like:
   Line 1270

#ifdef BITCOIN_QT_WIN_TASKBAR
           if (!m_taskbar_progress->window()) {
               m_taskbar_progress->setWindow(this);
           }
           m_taskbar_progress->setValue(qRound(nVerificationProgress * 100.0));
           m_taskbar_progress->setVisible(true);
#endif

This fixed the issue but with a caveat (see #2)

2. with it now working, the progress bar will still take 1 to 3 minutes to actually show up. (variable)

Not sure what the issue is - I'm wondering if having setWindow in the constructor is problematic (windowhandle still null?)

[bigshiny90]

Since this PR replaces Qt5 WinExtras, do you want to remove the old dependencies?

• CMakeLists.txt, line 242 - remove list(APPEND qt_components WinExtras)
• depends/packages/qt.mk - has references to qtwinextras

[kwsantiago]

@bigshiny90 should be resolved in 972972c

[bigshiny90]

@bigshiny90 should be resolved in [972972c]

Running the new code. New Taskbar progress is now loading. But, i'm still having the issue where the actual taskbar progress takes over a minute (1.5 minutes in my last test) before it switches from normal taskbar style to actually showing progress.

Screenshots showing INITIAL STATE / POST 1.5 minutes:

Running normal QtWinExtras taskbar progress will show progress indicator immediately.

[kwsantiago]

@bigshiny90 thank you for testing, I pushed up some fixes in eee7c82, let me know if that helped.

[bigshiny90]

@bigshiny90 thank you for testing, I pushed up some fixes in [eee7c82]

So i don't think these changes are addressing the real issue. i did some quick research and came up with the idea that it is missing the proper QT NativeEventFilter. Made some changes and tested and everything now works correctly - instant taskbar progress. (Note - not sure it matters - but i'm building using the windows msvc method and QT5. Not sure if the same issue exists with QT6).

(I hope you don't mind me hacking away at this!)

My guess:

Windows needs us to wait for a TaskbarButtonCreated message before calling ITaskbarList3 methods. Looks like Qt5 WinExtras handled this behind the scenes (from somequick research), but since we're going native we need to do it ourselves.

The fix?

I followed the same pattern already used in winshutdownmonitor.cpp - hook into Qt's native event filter and wait for that message.

Here are the changes that worked for me, all pretty boilerplate stuff:

---

wintaskbarprogress.h

#include <QAbstractNativeEventFilter>
#include <QObject>

#include <windows.h>

// ...

class WinTaskbarProgress : public QObject, public QAbstractNativeEventFilter
{
    Q_OBJECT

public:
    // ... existing methods ...

    /** Implements QAbstractNativeEventFilter interface for processing Windows messages */
    bool nativeEventFilter(const QByteArray &eventType, void *pMessage, long *pnResult) override;

private:
    // ... existing members ...
    UINT m_taskbar_button_created_msg = 0;
    bool m_taskbar_ready = false;
};

---

wintaskbarprogress.cpp

Constructor - register the message:

WinTaskbarProgress::WinTaskbarProgress(QObject *parent)
    : QObject(parent)
{
    m_taskbar_button_created_msg = RegisterWindowMessage(L"TaskbarButtonCreated");
}

Add native event filter:

bool WinTaskbarProgress::nativeEventFilter(const QByteArray &eventType, void *pMessage, long *pnResult)
{
    Q_UNUSED(eventType);
    Q_UNUSED(pnResult);

    MSG *msg = static_cast<MSG *>(pMessage);

    if (msg->message == m_taskbar_button_created_msg && m_window) {
        // Taskbar button is now ready - safe to initialize ITaskbarList3
        m_taskbar_ready = true;
        initTaskbarButton();
        updateProgress();
    }

    return false; // Allow normal processing
}

Update initTaskbarButton() guard:

void WinTaskbarProgress::initTaskbarButton()
{
    if (m_taskbar_button || !m_window || !m_taskbar_ready) {
        return;
    }
    // ... rest unchanged ...
}

---

bitcoingui.cpp

Constructor - install filter:

#ifdef BITCOIN_QT_WIN_TASKBAR
    m_taskbar_progress = new WinTaskbarProgress(this);
    QApplication::instance()->installNativeEventFilter(m_taskbar_progress);
#endif

Destructor - remove filter:

#ifdef BITCOIN_QT_WIN_TASKBAR
    QApplication::instance()->removeNativeEventFilter(m_taskbar_progress);
#endif

---

Tested and confirmed working - progress shows up immediately now

[kwsantiago]

@bigshiny90 thank you, that's helpful. Reflected in 23b4023

[bigshiny90]

Working great. Everything has been addressed as far as what i can see.

I will run it through the day during IBD just to confirm end-to-end that everything works. I will let you know if any surprises...

[bigshiny90]

Tested and working. Ran thru a full IBD to watch progress bar and visibility.

Big ACK from me as this is necessary for moving forward with QT6