Add accessor methods for checking the availability of the PID/VID

As mentioned in the previous change, this is necessary for those end users who
would like to explicitly know if the device on the serial port has a valid
vendor or/and product identifier.

This is now providing a nice and convenient API for having a dedicated boolean
method for making this query possible. It is a lot more readable and convenient
to use than other alternatives including the extended scope for the integer
query method and so forth. It is more explicit and clear about the intention
that one checks if the device has a valid identifier. It would be more vague
with error codes and so forth. One somewhat reasonable alternative could be
this, albeit this is also more inconvenient:

    a) bool vendorIdentifier(quint16 &vendorIdentifier) const;
    b) bool productIdentifier(quint16 &vendorIdentifier) const;

    ... as this would require an additional variable from the user, and this
    could not be used with ternary operators so easily, et cetera.

There are even worse ideas like how the exceptional conversion happens in
QString and so forth, but that also requires an explicit variable or zero if one
is sure the conversion should succeed. One can pass zero in there, but that is
still inconvenient and more than passing nothing, and zero can become unclear
what it supposed to present half or one year later.

The change has been tested on Linux with Qt4 and Qt5, and cenumerator works as
expected. The documentation has been added accodingly.

Task-number: QTPLAYGROUND-21
Change-Id: I905708ce0e67307bf89d69e645462486ad869b0c
Reviewed-by: Sergey Belyashov <Sergey.Belyashov@gmail.com>
Reviewed-by: Denis Shienkov <denis.shienkov@gmail.com>

9 files changed, 55 insertions, 19 deletions

diff --git a/examples/cenumerator/main.cpp b/examples/cenumerator/main.cpp
index 3ae7d65..f55b92d 100644
--- a/examples/cenumerator/main.cpp
+++ b/examples/cenumerator/main.cpp
@@ -59,8 +59,8 @@ int main(int argc, char *argv[])
             << QObject::tr("Location: ") << serialPortInfo.systemLocation() << endl
             << QObject::tr("Description: ") << serialPortInfo.description() << endl
             << QObject::tr("Manufacturer: ") << serialPortInfo.manufacturer() << endl
-            << QObject::tr("Vendor Identifier: ") << QByteArray::number(serialPortInfo.vendorIdentifier(), 16) << endl
-            << QObject::tr("Product Identifier: ") << QByteArray::number(serialPortInfo.productIdentifier(), 16) << endl
+            << QObject::tr("Vendor Identifier: ") << (serialPortInfo.hasVendorIdentifier() ? QByteArray::number(serialPortInfo.vendorIdentifier(), 16) : QByteArray()) << endl
+            << QObject::tr("Product Identifier: ") << (serialPortInfo.hasProductIdentifier() ? QByteArray::number(serialPortInfo.productIdentifier(), 16) : QByteArray()) << endl
             << QObject::tr("Busy: ") << (serialPortInfo.isBusy() ? QObject::tr("Yes") : QObject::tr("No")) << endl;
     }
 
diff --git a/examples/enumerator/main.cpp b/examples/enumerator/main.cpp
index a95ee76..9e34d38 100644
--- a/examples/enumerator/main.cpp
+++ b/examples/enumerator/main.cpp
@@ -61,8 +61,8 @@ int main(int argc, char *argv[])
                     + QObject::tr("Location: ") + info.systemLocation() + "\n"
                     + QObject::tr("Description: ") + info.description() + "\n"
                     + QObject::tr("Manufacturer: ") + info.manufacturer() + "\n"
-                    + QObject::tr("Vendor Identifier: ") + QString::number(info.vendorIdentifier(), 16) + "\n"
-                    + QObject::tr("Product Identifier: ") + QString::number(info.productIdentifier(), 16) + "\n"
+                    + QObject::tr("Vendor Identifier: ") + (info.hasVendorIdentifier() ? QString::number(info.vendorIdentifier(), 16) : QString()) + "\n"
+                    + QObject::tr("Product Identifier: ") + (info.hasProductIdentifier() ?QString::number(info.productIdentifier(), 16) : QString()) + "\n"
                     + QObject::tr("Busy: ") + (info.isBusy() ? QObject::tr("Yes") : QObject::tr("No")) + "\n";
 
         QLabel *label = new QLabel(s);
diff --git a/examples/terminal/settingsdialog.cpp b/examples/terminal/settingsdialog.cpp
index 4533da9..65f6b87 100644
--- a/examples/terminal/settingsdialog.cpp
+++ b/examples/terminal/settingsdialog.cpp
@@ -157,8 +157,8 @@ void SettingsDialog::fillPortsInfo()
              << info.description()
              << info.manufacturer()
              << info.systemLocation()
-             << QString::number(info.vendorIdentifier(), 16)
-             << QString::number(info.productIdentifier(), 16);
+             << (info.vendorIdentifier() ? QString::number(info.vendorIdentifier(), 16) : QString())
+             << (info.productIdentifier() ? QString::number(info.productIdentifier(), 16) : QString());
 
         ui->serialPortInfoListBox->addItem(list.first(), list);
     }
diff --git a/src/serialport/qserialportinfo.cpp b/src/serialport/qserialportinfo.cpp
index e16e13e..b78c9eb 100644
--- a/src/serialport/qserialportinfo.cpp
+++ b/src/serialport/qserialportinfo.cpp
@@ -204,6 +204,26 @@ quint16 QSerialPortInfo::productIdentifier() const
 }
 
 /*!
+    Returns true if there is a valid 16-bit vendor number present; otherwise
+    returns false.
+*/
+bool QSerialPortInfo::hasVendorIdentifier() const
+{
+    Q_D(const QSerialPortInfo);
+    return !d ? false : d->hasVendorIdentifier;
+}
+
+/*!
+    Returns true if there is a valid 16-bit product number present; otherwise
+    returns false.
+*/
+bool QSerialPortInfo::hasProductIdentifier() const
+{
+    Q_D(const QSerialPortInfo);
+    return !d ? false : d->hasProductIdentifier;
+}
+
+/*!
     \fn bool QSerialPortInfo::isNull() const
 
     Returns whether this QSerialPortInfo object holds a
diff --git a/src/serialport/qserialportinfo.h b/src/serialport/qserialportinfo.h
index 19fd5b7..900b91b 100644
--- a/src/serialport/qserialportinfo.h
+++ b/src/serialport/qserialportinfo.h
@@ -71,9 +71,13 @@ public:
     QString systemLocation() const;
     QString description() const;
     QString manufacturer() const;
+
     quint16 vendorIdentifier() const;
     quint16 productIdentifier() const;
 
+    bool hasVendorIdentifier() const;
+    bool hasProductIdentifier() const;
+
     bool isNull() const;
     bool isBusy() const;
     bool isValid() const;
diff --git a/src/serialport/qserialportinfo_mac.cpp b/src/serialport/qserialportinfo_mac.cpp
index 59cfad9..44f26b5 100644
--- a/src/serialport/qserialportinfo_mac.cpp
+++ b/src/serialport/qserialportinfo_mac.cpp
@@ -235,20 +235,18 @@ QList<QSerialPortInfo> QSerialPortInfo::availablePorts()
             quint16 value = 0;
 
             if (vendorIdentifier) {
-                if (::CFNumberGetValue(CFNumberRef(vendorIdentifier),
-                                       kCFNumberIntType,
-                                       &value)) {
+                serialPortInfo.d_ptr->hasVendorIdentifier = ::CFNumberGetValue(CFNumberRef(vendorIdentifier), kCFNumberIntType, &value);
+                if (serialPortInfo.d_ptr->hasVendorIdentifier)
                     serialPortInfo.d_ptr->vendorIdentifier = value;
-                }
+
                 ::CFRelease(vendorIdentifier);
             }
 
             if (productIdentifier) {
-                if (::CFNumberGetValue(CFNumberRef(productIdentifier),
-                                       kCFNumberIntType,
-                                       &value)) {
+                serialPortInfo.d_ptr->hasProductIdentifier = ::CFNumberGetValue(CFNumberRef(productIdentifier), kCFNumberIntType, &value);
+                if (serialPortInfo.d_ptr->hasProductIdentifier)
                     serialPortInfo.d_ptr->productIdentifier = value;
-                }
+
                 ::CFRelease(productIdentifier);
             }
 
diff --git a/src/serialport/qserialportinfo_p.h b/src/serialport/qserialportinfo_p.h
index ee7b884..1f12e69 100644
--- a/src/serialport/qserialportinfo_p.h
+++ b/src/serialport/qserialportinfo_p.h
@@ -51,15 +51,25 @@ QT_BEGIN_NAMESPACE
 class QSerialPortInfoPrivate
 {
 public:
-    QSerialPortInfoPrivate() : vendorIdentifier(0), productIdentifier(0) {}
+    QSerialPortInfoPrivate()
+        : vendorIdentifier(0)
+        , productIdentifier(0)
+        , hasVendorIdentifier(false)
+        , hasProductIdentifier(false)
+    {}
+
     ~QSerialPortInfoPrivate() {}
 
     QString portName;
     QString device;
     QString description;
     QString manufacturer;
+
     quint16 vendorIdentifier;
     quint16 productIdentifier;
+
+    bool    hasVendorIdentifier;
+    bool    hasProductIdentifier;
 };
 
 class QSerialPortInfoPrivateDeleter
diff --git a/src/serialport/qserialportinfo_unix.cpp b/src/serialport/qserialportinfo_unix.cpp
index bfdc3d0..ee76fc6 100644
--- a/src/serialport/qserialportinfo_unix.cpp
+++ b/src/serialport/qserialportinfo_unix.cpp
@@ -147,10 +147,12 @@ QList<QSerialPortInfo> QSerialPortInfo::availablePorts()
                                                                                    "ID_VENDOR"))).replace('_', ' ');
 
                             serialPortInfo.d_ptr->vendorIdentifier =
-                                    QString::fromLatin1(::udev_device_get_property_value(dev, "ID_VENDOR_ID")).toInt(0, 16);
+                                    QString::fromLatin1(::udev_device_get_property_value(dev,
+                                                "ID_VENDOR_ID")).toInt(&serialPortInfo.d_ptr->hasVendorIdentifier, 16);
 
                             serialPortInfo.d_ptr->productIdentifier =
-                                    QString::fromLatin1(::udev_device_get_property_value(dev, "ID_MODEL_ID")).toInt(0, 16);
+                                    QString::fromLatin1(::udev_device_get_property_value(dev,
+                                                "ID_MODEL_ID")).toInt(&serialPortInfo.d_ptr->hasProductIdentifier, 16);
 
                         } else if (subsys == QLatin1String("pnp")) { // PNP bus type
                             // Append this device.
diff --git a/src/serialport/qserialportinfo_win.cpp b/src/serialport/qserialportinfo_win.cpp
index 0a6618e..7ca1f5e 100644
--- a/src/serialport/qserialportinfo_win.cpp
+++ b/src/serialport/qserialportinfo_win.cpp
@@ -178,11 +178,13 @@ QList<QSerialPortInfo> QSerialPortInfo::availablePorts()
 
             int index = s.indexOf(vendorIdentifierPrefix);
             if (index != -1)
-                serialPortInfo.d_ptr->vendorIdentifier = s.mid(index + vendorIdentifierPrefix.size(), vendorIdentifierSize).toInt(0, 16);
+                serialPortInfo.d_ptr->vendorIdentifier = s.mid(index + vendorIdentifierPrefix.size(), vendorIdentifierSize)
+                                                            .toInt(&serialPortInfo.d_ptr->hasVendorIdentifier, 16);
 
             index = s.indexOf(productIdentifierPrefix);
             if (index != -1)
-                serialPortInfo.d_ptr->productIdentifier = s.mid(index + productIdentifierPrefix.size(), productIdentifierSize).toInt(0, 16);
+                serialPortInfo.d_ptr->productIdentifier = s.mid(index + productIdentifierPrefix.size(), productIdentifierSize)
+                                                            .toInt(&serialPortInfo.d_ptr->hasProductIdentifier, 16);
 
             serialPortInfoList.append(serialPortInfo);
         }