QBluetoothUuid: keep custom quint128 and related methods when 128-bit ints are not supported

... to retain SC with prior Qt versions.

For QBluetoothUuid::toUInt128() this is done by introducing
an extra condition to the method declaration and definition.
If the 128-bit ints are not supported, we shouldn't hide the
method under QT_BLUETOOTH_REMOVED_SINCE.

The QBluetoothUuid(quint128) c-tor is a bit more tricky,
because we need to provide a forwarding c-tor to be able to
use QUuid(quint128) c-tor. And at the same time, we need
to keep BC by keeping the constructor that takes custom
struct quint128.
This is achieved by having an unconstrained c-tor declaration
and two implementations:
* an implementation in qbluetoothuuid.cpp is only available
  when Qt supports 128-bit ints. It just forwards to the
  QUuid c-tor.
* an implementation in removed_api.cpp serves as a backup
  implementation to keep BC for the case when Qt supports
  128-bit ints. And at the same time it serves as a main
  implementation when 128-bit ints are not supported.

Also extend the unit-tests to explicitly check that both
APIs are available on all platforms.
The test additionally makes sure that QUuid::toUInt128() and
QBluetoothUuid::toUInt128() provide the result which is similar to
QUuid::toBytes(). This guarantees compatibility between platforms.

This commit amends 1e903be81f43da4e31385bb7866bb4d3f07e5eba.

Pick-to: 6.6
Change-Id: I6ba3ff6278e6db11a372b46f001429f4466520a0
Reviewed-by: Marc Mutz <marc.mutz@qt.io>

1 files changed, 17 insertions, 0 deletions

diff --git a/tests/auto/qbluetoothuuid/tst_qbluetoothuuid.cpp b/tests/auto/qbluetoothuuid/tst_qbluetoothuuid.cpp
index e31b0667..7a31300c 100644
--- a/tests/auto/qbluetoothuuid/tst_qbluetoothuuid.cpp
+++ b/tests/auto/qbluetoothuuid/tst_qbluetoothuuid.cpp
@@ -359,6 +359,23 @@ void tst_QBluetoothUuid::tst_comparison()
         for (int var = 0; var < 16; ++var) {
             QVERIFY(quuid128.toBytes().data[var] == uuid128.data[var]);
         }
+
+        // check that toUInt128() call returns the value in the same format as
+        // QUuid::Id128Bytes, no matter what version we use (it can be
+        // QUuid::toUint128() on platforms that define __SIZEOF_INT128__ or
+        // QBluetoothUuid::toUint128() on other platforms).
+        const quint128 i128 = quuid128.toUInt128();
+        static_assert(sizeof(i128) == 16); // uint128 or QUuid::Id128Bytes
+        uchar dst[16];
+        memcpy(dst, &i128, sizeof(i128));
+        for (int var = 0; var < 16; ++var)
+            QCOMPARE_EQ(dst[var], uuid128.data[var]);
+
+        // check that we always have a c-tor taking quint128
+        QBluetoothUuid other{i128};
+        const auto bytes = other.toBytes();
+        for (int var = 0; var < 16; ++var)
+            QCOMPARE_EQ(bytes.data[var], uuid128.data[var]);
     }
 }