IPC: make the two platformSafeKey functions return QNativeIpcKey

There's no need to return QString, only to create the QNativeIpcKey
elsewhere, when nothing uses this intermediary QString (those two
functions aren't used in unit tests any more, since the two "IPC: add
native key support" commits (2c286561bbc9e4e408d34e5bf43db8ad9acc0e84
and 3ae052d3bb5d7af0badf32575a5aa042cffd8243). Since they aren't used in
the tests, we can remove the Q_AUTOTEST_EXPORT macro too and the
unnecessary default argument.

I'll need the ability to return QNativeIpcKey to store the original,
legacy key inside of it.

Change-Id: Idd5e1bb52be047d7b4fffffd17506c05e4f61f79
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
(cherry picked from commit b5584ed2240abe3892fa5b0a23b3ad093ed9fec2)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
(cherry picked from commit 608b08f4d57369378b1a101b78a46202bd17c11a)

4 files changed, 51 insertions, 45 deletions

diff --git a/src/corelib/ipc/qsharedmemory.cpp b/src/corelib/ipc/qsharedmemory.cpp
index 139c1440e3..89bd4ffe0c 100644
--- a/src/corelib/ipc/qsharedmemory.cpp
+++ b/src/corelib/ipc/qsharedmemory.cpp
@@ -686,12 +686,12 @@ bool QSharedMemory::isKeyTypeSupported(QNativeIpcKey::Type type)
 
 QNativeIpcKey QSharedMemory::platformSafeKey(const QString &key, QNativeIpcKey::Type type)
 {
-    return { QtIpcCommon::platformSafeKey(key, IpcType::SharedMemory, type), type };
+    return QtIpcCommon::platformSafeKey(key, IpcType::SharedMemory, type);
 }
 
 QNativeIpcKey QSharedMemory::legacyNativeKey(const QString &key, QNativeIpcKey::Type type)
 {
-    return { legacyPlatformSafeKey(key, IpcType::SharedMemory, type), type };
+    return QtIpcCommon::legacyPlatformSafeKey(key, IpcType::SharedMemory, type);
 }
 
 #endif // QT_CONFIG(sharedmemory)
diff --git a/src/corelib/ipc/qsystemsemaphore.cpp b/src/corelib/ipc/qsystemsemaphore.cpp
index 0f59b378a3..d22e653b5d 100644
--- a/src/corelib/ipc/qsystemsemaphore.cpp
+++ b/src/corelib/ipc/qsystemsemaphore.cpp
@@ -406,12 +406,12 @@ bool QSystemSemaphore::isKeyTypeSupported(QNativeIpcKey::Type type)
 
 QNativeIpcKey QSystemSemaphore::platformSafeKey(const QString &key, QNativeIpcKey::Type type)
 {
-    return { QtIpcCommon::platformSafeKey(key, IpcType::SystemSemaphore, type), type };
+    return QtIpcCommon::platformSafeKey(key, IpcType::SystemSemaphore, type);
 }
 
 QNativeIpcKey QSystemSemaphore::legacyNativeKey(const QString &key, QNativeIpcKey::Type type)
 {
-    return { legacyPlatformSafeKey(key, IpcType::SystemSemaphore, type), type };
+    return QtIpcCommon::legacyPlatformSafeKey(key, IpcType::SystemSemaphore, type);
 }
 
 QT_END_NAMESPACE
diff --git a/src/corelib/ipc/qtipccommon.cpp b/src/corelib/ipc/qtipccommon.cpp
index f5b3561c06..190cb8c1fd 100644
--- a/src/corelib/ipc/qtipccommon.cpp
+++ b/src/corelib/ipc/qtipccommon.cpp
@@ -96,11 +96,12 @@ static QNativeIpcKey::Type stringToType(QStringView typeString)
 
     On Unix this will be a file name
 */
-QString QtIpcCommon::legacyPlatformSafeKey(const QString &key, QtIpcCommon::IpcType ipcType,
-                                           QNativeIpcKey::Type type)
+QNativeIpcKey QtIpcCommon::legacyPlatformSafeKey(const QString &key, QtIpcCommon::IpcType ipcType,
+                                                 QNativeIpcKey::Type type)
 {
+    QNativeIpcKey k(type);
     if (key.isEmpty())
-        return QString();
+        return k;
 
     QByteArray hex = QCryptographicHash::hash(key.toUtf8(), QCryptographicHash::Sha1).toHex();
 
@@ -111,13 +112,15 @@ QString QtIpcCommon::legacyPlatformSafeKey(const QString &key, QtIpcCommon::IpcT
             // to be in the form <application group identifier>/<custom identifier>.
             // Since we don't know which application group identifier the user wants
             // to apply, we instead document that requirement, and use the key directly.
-            return key;
+            k.setNativeKey(key);
+        } else {
+            // The shared memory name limit on Apple platforms is very low (30 characters),
+            // so we can't use the logic below of combining the prefix, key, and a hash,
+            // to ensure a unique and valid name. Instead we use the first part of the
+            // hash, which should still long enough to avoid collisions in practice.
+            k.setNativeKey(u'/' + QLatin1StringView(hex).left(SHM_NAME_MAX - 1));
         }
-        // The shared memory name limit on Apple platforms is very low (30 characters),
-        // so we can't use the logic below of combining the prefix, key, and a hash,
-        // to ensure a unique and valid name. Instead we use the first part of the
-        // hash, which should still long enough to avoid collisions in practice.
-        return u'/' + QLatin1StringView(hex).left(SHM_NAME_MAX - 1);
+        return k;
 #endif
     }
 
@@ -141,38 +144,41 @@ QString QtIpcCommon::legacyPlatformSafeKey(const QString &key, QtIpcCommon::IpcT
 
     switch (type) {
     case QNativeIpcKey::Type::Windows:
-        if (!isIpcSupported(ipcType, QNativeIpcKey::Type::Windows))
-            return QString();
-        return result;
+        if (isIpcSupported(ipcType, QNativeIpcKey::Type::Windows))
+            k.setNativeKey(result);
+        return k;
     case QNativeIpcKey::Type::PosixRealtime:
-        if (!isIpcSupported(ipcType, QNativeIpcKey::Type::PosixRealtime))
-            return QString();
-        return result.prepend(u'/');
+        if (isIpcSupported(ipcType, QNativeIpcKey::Type::PosixRealtime))
+            k.setNativeKey(result.prepend(u'/'));
+        return k;
     case QNativeIpcKey::Type::SystemV:
         break;
     }
-    if (!isIpcSupported(ipcType, QNativeIpcKey::Type::SystemV))
-        return QString();
-    return QStandardPaths::writableLocation(QStandardPaths::TempLocation) + u'/' + result;
+    if (isIpcSupported(ipcType, QNativeIpcKey::Type::SystemV))
+        k.setNativeKey(QStandardPaths::writableLocation(QStandardPaths::TempLocation) + u'/' + result);
+    return k;
 }
 
-QString QtIpcCommon::platformSafeKey(const QString &key, QtIpcCommon::IpcType ipcType,
-                                     QNativeIpcKey::Type type)
+QNativeIpcKey QtIpcCommon::platformSafeKey(const QString &key, QtIpcCommon::IpcType ipcType,
+                                           QNativeIpcKey::Type type)
 {
+    QNativeIpcKey k(type);
     if (key.isEmpty())
-        return key;
+        return k;
 
     switch (type) {
     case QNativeIpcKey::Type::PosixRealtime:
-        if (!isIpcSupported(ipcType, QNativeIpcKey::Type::PosixRealtime))
-            return QString();
+        if (isIpcSupported(ipcType, QNativeIpcKey::Type::PosixRealtime)) {
 #ifdef SHM_NAME_MAX
-        // The shared memory name limit on Apple platforms is very low (30
-        // characters), so we have to cut it down to avoid ENAMETOOLONG. We
-        // hope that there won't be too many collisions...
-        return u'/' + QStringView(key).left(SHM_NAME_MAX - 1);
+            // The shared memory name limit on Apple platforms is very low (30
+            // characters), so we have to cut it down to avoid ENAMETOOLONG. We
+            // hope that there won't be too many collisions...
+            k.setNativeKey(u'/' + QStringView(key).left(SHM_NAME_MAX - 1));
+#else
+            k.setNativeKey(u'/' + key);
 #endif
-        return u'/' + key;
+        }
+        return k;
 
     case QNativeIpcKey::Type::Windows:
         if (isIpcSupported(ipcType, QNativeIpcKey::Type::Windows)) {
@@ -197,22 +203,24 @@ QString QtIpcCommon::platformSafeKey(const QString &key, QtIpcCommon::IpcType ip
 #ifdef MAX_PATH
             result.truncate(MAX_PATH);
 #endif
-            return result;
+            k.setNativeKey(result);
         }
-        return QString();
+        return k;
 
     case QNativeIpcKey::Type::SystemV:
         break;
     }
 
     // System V
-    if (!isIpcSupported(ipcType, QNativeIpcKey::Type::SystemV))
-        return QString();
-    if (key.startsWith(u'/'))
-        return key;
-
-    QString baseDir = QStandardPaths::writableLocation(QStandardPaths::RuntimeLocation);
-    return baseDir + u'/' + key;
+    if (isIpcSupported(ipcType, QNativeIpcKey::Type::SystemV)) {
+        if (key.startsWith(u'/')) {
+            k.setNativeKey(key);
+        } else {
+            QString baseDir = QStandardPaths::writableLocation(QStandardPaths::RuntimeLocation);
+            k.setNativeKey(baseDir + u'/' + key);
+        }
+    }
+    return k;
 }
 
 /*!
diff --git a/src/corelib/ipc/qtipccommon_p.h b/src/corelib/ipc/qtipccommon_p.h
index 4416359820..3d6ad0903b 100644
--- a/src/corelib/ipc/qtipccommon_p.h
+++ b/src/corelib/ipc/qtipccommon_p.h
@@ -118,10 +118,8 @@ public:
     }
 };
 
-Q_AUTOTEST_EXPORT QString
-legacyPlatformSafeKey(const QString &key, IpcType ipcType,
-                      QNativeIpcKey::Type type = QNativeIpcKey::legacyDefaultTypeForOs());
-Q_AUTOTEST_EXPORT QString platformSafeKey(const QString &key, IpcType ipcType, QNativeIpcKey::Type type);
+QNativeIpcKey legacyPlatformSafeKey(const QString &key, IpcType ipcType, QNativeIpcKey::Type type);
+QNativeIpcKey platformSafeKey(const QString &key, IpcType ipcType, QNativeIpcKey::Type type);
 
 #ifdef Q_OS_UNIX
 // Convenience function to create the file if needed