Merge the multiple implementations of getting the local hostname

This commit moves the functionality from QtNetwork's QHostInfo to
QtCore. Note that due to Windows ws2_32.dll's quirky behavior of
requiring WSAStartup before calling gethostname, this change required
moving the initialization to QtCore too.

On Linux systems, gethostname() gets the name from uname(), so we bypass
the middle man and save one memcpy.

Change-Id: I27eaacb532114dd188c4ffff13d32655a6301346
Reviewed-by: Erik Verbruggen <erik.verbruggen@theqtcompany.com>
Reviewed-by: Oliver Wolff <oliver.wolff@theqtcompany.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

4 files changed, 15 insertions, 62 deletions

diff --git a/src/network/kernel/qhostinfo.cpp b/src/network/kernel/qhostinfo.cpp
index a2ac9065fd..c6c09542e7 100644
--- a/src/network/kernel/qhostinfo.cpp
+++ b/src/network/kernel/qhostinfo.cpp
@@ -415,10 +415,22 @@ void QHostInfo::setErrorString(const QString &str)
 /*!
     \fn QString QHostInfo::localHostName()
 
-    Returns the host name of this machine.
+    Returns this machine's host name, if one is configured. Note that hostnames
+    are not guaranteed to be globally unique, especially if they were
+    configured automatically.
 
-    \sa hostName()
+    This function does not guarantee the returned host name is a Fully
+    Qualified Domain Name (FQDN). For that, use fromName() to resolve the
+    returned name to an FQDN.
+
+    This function returns the same as QSysInfo::machineHostName().
+
+    \sa hostName(), localDomainName()
 */
+QString QHostInfo::localHostName()
+{
+    return QSysInfo::machineHostName();
+}
 
 /*!
     \fn QString QHostInfo::localDomainName()
diff --git a/src/network/kernel/qhostinfo_unix.cpp b/src/network/kernel/qhostinfo_unix.cpp
index 90a6f763f7..266a67771c 100644
--- a/src/network/kernel/qhostinfo_unix.cpp
+++ b/src/network/kernel/qhostinfo_unix.cpp
@@ -315,15 +315,6 @@ QHostInfo QHostInfoAgent::fromName(const QString &hostName)
     return results;
 }
 
-QString QHostInfo::localHostName()
-{
-    char hostName[512];
-    if (gethostname(hostName, sizeof(hostName)) == -1)
-        return QString();
-    hostName[sizeof(hostName) - 1] = '\0';
-    return QString::fromLocal8Bit(hostName);
-}
-
 QString QHostInfo::localDomainName()
 {
 #if !defined(Q_OS_VXWORKS) && !defined(Q_OS_ANDROID)
diff --git a/src/network/kernel/qhostinfo_win.cpp b/src/network/kernel/qhostinfo_win.cpp
index e044728198..fc65ce9fa2 100644
--- a/src/network/kernel/qhostinfo_win.cpp
+++ b/src/network/kernel/qhostinfo_win.cpp
@@ -111,7 +111,7 @@ QHostInfo QHostInfoAgent::fromName(const QString &hostName)
     QMutexLocker locker(&qPrivCEMutex);
 #endif
 
-    QWindowsSockInit winSock;
+    QSysInfo::machineHostName();        // this initializes ws2_32.dll
 
     // Load res_init on demand.
     static QBasicAtomicInt triedResolve = Q_BASIC_ATOMIC_INITIALIZER(false);
@@ -256,17 +256,6 @@ QHostInfo QHostInfoAgent::fromName(const QString &hostName)
     return results;
 }
 
-QString QHostInfo::localHostName()
-{
-    QWindowsSockInit winSock;
-
-    char hostName[512];
-    if (gethostname(hostName, sizeof(hostName)) == -1)
-        return QString();
-    hostName[sizeof(hostName) - 1] = '\0';
-    return QString::fromLocal8Bit(hostName);
-}
-
 // QString QHostInfo::localDomainName() defined in qnetworkinterface_win.cpp
 
 QT_END_NAMESPACE
diff --git a/src/network/kernel/qhostinfo_winrt.cpp b/src/network/kernel/qhostinfo_winrt.cpp
index 1a97fe0e40..3d2344726b 100644
--- a/src/network/kernel/qhostinfo_winrt.cpp
+++ b/src/network/kernel/qhostinfo_winrt.cpp
@@ -130,45 +130,6 @@ QHostInfo QHostInfoAgent::fromName(const QString &hostName)
     return results;
 }
 
-QString QHostInfo::localHostName()
-{
-    ComPtr<INetworkInformationStatics> statics;
-    GetActivationFactory(HString::MakeReference(RuntimeClass_Windows_Networking_Connectivity_NetworkInformation).Get(), &statics);
-
-    ComPtr<IVectorView<HostName *>> hostNames;
-    statics->GetHostNames(&hostNames);
-    if (!hostNames)
-        return QString();
-
-    unsigned int size;
-    hostNames->get_Size(&size);
-    if (size == 0)
-        return QString();
-
-    for (unsigned int i = 0; i < size; ++i) {
-        ComPtr<IHostName> hostName;
-        hostNames->GetAt(i, &hostName);
-        HostNameType type;
-        hostName->get_Type(&type);
-        if (type != HostNameType_DomainName)
-            continue;
-
-        HString name;
-        hostName->get_CanonicalName(name.GetAddressOf());
-        UINT32 length;
-        PCWSTR rawString = name.GetRawBuffer(&length);
-        return QString::fromWCharArray(rawString, length);
-    }
-    ComPtr<IHostName> firstHost;
-    hostNames->GetAt(0, &firstHost);
-
-    HString name;
-    firstHost->get_CanonicalName(name.GetAddressOf());
-    UINT32 length;
-    PCWSTR rawString = name.GetRawBuffer(&length);
-    return QString::fromWCharArray(rawString, length);
-}
-
 // QString QHostInfo::localDomainName() defined in qnetworkinterface_win.cpp
 
 QT_END_NAMESPACE