Windows: acquire identifiers using the SetupDiGetDeviceInstanceId function

This decision uses one identification string of the device instead of the
list of hardware identifiers. See more detail in MSDN:

* http://msdn.microsoft.com/en-us/library/windows/hardware/ff551106%28v=vs.85%29.aspx
* http://msdn.microsoft.com/en-us/library/windows/hardware/ff541327%28v=vs.85%29.aspx

The device instance ID unambiguously identifies the device in system and
contains necessary values of identifiers, that allows to resolve some
issues:

* we can abandon a patch: https://codereview.qt-project.org/#change,61633
and Task-number: QTBUG-32684 automatically will be resolved
* we can apply a patch: https://codereview.qt-project.org/#change,61752
because instance ID also contains the serial number info

Checked on Windows 7 and 8 with USB PL2303 converter, USB Modem ZTE MF180,
USB Android Modems, USB Motorola CDC ACM device.

Change-Id: If3b67b5b34d65de060a0e7682ba426cd94a01fa7
Reviewed-by: Laszlo Papp <lpapp@kde.org>
Reviewed-by: Sergey Belyashov <Sergey.Belyashov@gmail.com>

1 files changed, 18 insertions, 1 deletions

diff --git a/src/serialport/qserialportinfo_win.cpp b/src/serialport/qserialportinfo_win.cpp
index b1ab76b..45236a0 100644
--- a/src/serialport/qserialportinfo_win.cpp
+++ b/src/serialport/qserialportinfo_win.cpp
@@ -114,6 +114,23 @@ static QVariant deviceRegistryProperty(HDEVINFO deviceInfoSet,
     return QVariant();
 }
 
+static QString deviceInstanceIdentifier(HDEVINFO deviceInfoSet,
+                                        PSP_DEVINFO_DATA deviceInfoData)
+{
+    DWORD requiredSize = 0;
+    if (::SetupDiGetDeviceInstanceId(deviceInfoSet, deviceInfoData, NULL, 0, &requiredSize))
+        return QString();
+
+    QByteArray data(requiredSize * sizeof(wchar_t), 0);
+    if (!::SetupDiGetDeviceInstanceId(deviceInfoSet, deviceInfoData,
+                                      reinterpret_cast<wchar_t *>(data.data()), data.size(), NULL)) {
+        // TODO: error handling with GetLastError
+        return QString();
+    }
+
+    return QString::fromWCharArray(reinterpret_cast<const wchar_t *>(data.constData()));
+}
+
 static QString devicePortName(HDEVINFO deviceInfoSet, PSP_DEVINFO_DATA deviceInfoData)
 {
     static const wchar_t portKeyName[] = L"PortName";
@@ -177,7 +194,7 @@ QList<QSerialPortInfo> QSerialPortInfo::availablePorts()
             serialPortInfo.d_ptr->manufacturer =
                     deviceRegistryProperty(deviceInfoSet, &deviceInfoData, SPDRP_MFG).toString();
 
-            s = deviceRegistryProperty(deviceInfoSet, &deviceInfoData, SPDRP_HARDWAREID).toStringList().first().toUpper();
+            s = deviceInstanceIdentifier(deviceInfoSet, &deviceInfoData).toUpper();
 
             int index = s.indexOf(usbVendorIdentifierPrefix);
             if (index != -1) {