winrt: Fix crash when camera unloaded while searching focus.

Return early from focus related methods when async operation reports
that it is write protected.

Change-Id: I41bf9121e7ae431e5158b5e4c43cde582c30dfd7
Task-Id: QTBUG-49347
Reviewed-by: Peng Wu <peng.wu@intopalo.com>
Reviewed-by: Andrew Knight <andrew.knight@intopalo.com>

2 files changed, 14 insertions, 8 deletions

diff --git a/src/plugins/winrt/qwinrtcameracontrol.cpp b/src/plugins/winrt/qwinrtcameracontrol.cpp
index 7a926ad60..0c9d0e5cb 100644
--- a/src/plugins/winrt/qwinrtcameracontrol.cpp
+++ b/src/plugins/winrt/qwinrtcameracontrol.cpp
@@ -1154,8 +1154,11 @@ bool QWinRTCameraControl::focus()
         return false;
     ComPtr<IAsyncAction> op;
     HRESULT hr = d->focusControl->FocusAsync(&op);
-    if (HRESULT_CODE(hr) == ERROR_OPERATION_IN_PROGRESS)
-        return true;
+    const long errorCode = HRESULT_CODE(hr);
+    if (errorCode == ERROR_OPERATION_IN_PROGRESS
+        || errorCode == ERROR_WRITE_PROTECT) {
+        return false;
+    }
     Q_ASSERT_SUCCEEDED(hr);
     hr = QWinRTFunctions::await(op, QWinRTFunctions::ProcessThreadEvents);
     Q_ASSERT_SUCCEEDED(hr);
@@ -1184,6 +1187,8 @@ bool QWinRTCameraControl::lockFocus()
     Q_ASSERT_SUCCEEDED(hr);
     ComPtr<IAsyncAction> op;
     hr = focusControl2->LockAsync(&op);
+    if (HRESULT_CODE(hr) == ERROR_WRITE_PROTECT)
+        return false;
     Q_ASSERT_SUCCEEDED(hr);
     return QWinRTFunctions::await(op) == S_OK;
 }
@@ -1198,6 +1203,8 @@ bool QWinRTCameraControl::unlockFocus()
     Q_ASSERT_SUCCEEDED(hr);
     ComPtr<IAsyncAction> op;
     hr = focusControl2->UnlockAsync(&op);
+    if (HRESULT_CODE(hr) == ERROR_WRITE_PROTECT)
+        return false;
     Q_ASSERT_SUCCEEDED(hr);
     return QWinRTFunctions::await(op) == S_OK;
 }
diff --git a/src/plugins/winrt/qwinrtcameralockscontrol.cpp b/src/plugins/winrt/qwinrtcameralockscontrol.cpp
index e429c5ff1..11e576be0 100644
--- a/src/plugins/winrt/qwinrtcameralockscontrol.cpp
+++ b/src/plugins/winrt/qwinrtcameralockscontrol.cpp
@@ -104,10 +104,10 @@ void QWinRTCameraLocksControl::searchAndLockFocus()
     } else {
         m_focusLockStatus = QCamera::Searching;
         emit lockStatusChanged(QCamera::LockFocus, m_focusLockStatus, QCamera::LockAcquired);
-        cameraControl->focus();
-        cameraControl->lockFocus();
-        m_focusLockStatus = QCamera::Locked;
-        emit lockStatusChanged(QCamera::LockFocus, m_focusLockStatus, QCamera::LockAcquired);
+        if (cameraControl->focus()) {
+            m_focusLockStatus = cameraControl->lockFocus() ? QCamera::Locked : QCamera::Unlocked;
+            emit lockStatusChanged(QCamera::LockFocus, m_focusLockStatus, QCamera::LockAcquired);
+        }
     }
 }
 
@@ -117,8 +117,7 @@ void QWinRTCameraLocksControl::unlockFocus()
         return;
     QWinRTCameraControl *cameraControl = qobject_cast<QWinRTCameraControl *>(parent());
     Q_ASSERT(cameraControl);
-    cameraControl->unlockFocus();
-    m_focusLockStatus = QCamera::Unlocked;
+    m_focusLockStatus = cameraControl->unlockFocus() ? QCamera::Unlocked : QCamera::Locked;
     emit lockStatusChanged(QCamera::LockFocus, m_focusLockStatus, QCamera::UserRequest);
 }