QEvdev: Extract Method parseSpecification()

All four manager classes contained roughly the same code in their
ctors that parsed out devices from a colon-separated string.

Extract shared code, and port the parsing to QStringRef (later to be
ported to QStringView).

Saves ~2.4KiB on optimized Linux GCC 9.1 AMD64 builds across all
.so's that link to libQtInputSupport.a.

Change-Id: I3db826ee2b422cfc02f8d49bd21985a03b6c0935
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>

src/platformsupport/input/evdevkeyboard/qevdevkeyboardmanager.cpp

@@ -39,6 +39,8 @@
 
 #include "qevdevkeyboardmanager_p.h"
 
+#include <QtInputSupport/private/qevdevutil_p.h>
+
 #include <QStringList>
 #include <QCoreApplication>
 #include <QLoggingCategory>
@@ -61,25 +63,14 @@ QEvdevKeyboardManager::QEvdevKeyboardManager(const QString &key, const QString &
     if (spec.isEmpty())
         spec = specification;
 
-    QStringList args = spec.split(QLatin1Char(':'));
-    QStringList devices;
-
-    foreach (const QString &arg, args) {
-        if (arg.startsWith(QLatin1String("/dev/"))) {
-            // if device is specified try to use it
-            devices.append(arg);
-            args.removeAll(arg);
-        }
-    }
-
-    // build new specification without /dev/ elements
-    m_spec = args.join(QLatin1Char(':'));
+    auto parsed = QEvdevUtil::parseSpecification(spec);
+    m_spec = std::move(parsed.spec);
 
     // add all keyboards for devices specified in the argument list
-    foreach (const QString &device, devices)
+    for (const QString &device : qAsConst(parsed.devices))
         addKeyboard(device);
 
-    if (devices.isEmpty()) {
+    if (parsed.devices.isEmpty()) {
         qCDebug(qLcEvdevKey, "evdevkeyboard: Using device discovery");
         m_deviceDiscovery = QDeviceDiscovery::create(QDeviceDiscovery::Device_Keyboard, this);
         if (m_deviceDiscovery) {

src/platformsupport/input/evdevmouse/qevdevmousemanager.cpp

@@ -39,6 +39,8 @@
 
 #include "qevdevmousemanager_p.h"
 
+#include <QtInputSupport/private/qevdevutil_p.h>
+
 #include <QStringList>
 #include <QGuiApplication>
 #include <QScreen>
@@ -63,29 +65,22 @@ QEvdevMouseManager::QEvdevMouseManager(const QString &key, const QString &specif
     if (spec.isEmpty())
         spec = specification;
 
-    QStringList args = spec.split(QLatin1Char(':'));
-    QStringList devices;
+    auto parsed = QEvdevUtil::parseSpecification(spec);
+    m_spec = std::move(parsed.spec);
 
-    foreach (const QString &arg, args) {
-        if (arg.startsWith(QLatin1String("/dev/"))) {
-            // if device is specified try to use it
-            devices.append(arg);
-            args.removeAll(arg);
-        } else if (arg.startsWith(QLatin1String("xoffset="))) {
+    for (const QStringRef &arg : qAsConst(parsed.args)) {
+        if (arg.startsWith(QLatin1String("xoffset="))) {
             m_xoffset = arg.mid(8).toInt();
         } else if (arg.startsWith(QLatin1String("yoffset="))) {
             m_yoffset = arg.mid(8).toInt();
         }
     }
 
-    // build new specification without /dev/ elements
-    m_spec = args.join(QLatin1Char(':'));
-
     // add all mice for devices specified in the argument list
-    foreach (const QString &device, devices)
+    for (const QString &device : qAsConst(parsed.devices))
         addMouse(device);
 
-    if (devices.isEmpty()) {
+    if (parsed.devices.isEmpty()) {
         qCDebug(qLcEvdevMouse, "evdevmouse: Using device discovery");
         m_deviceDiscovery = QDeviceDiscovery::create(QDeviceDiscovery::Device_Mouse | QDeviceDiscovery::Device_Touchpad, this);
         if (m_deviceDiscovery) {

src/platformsupport/input/evdevtablet/qevdevtabletmanager.cpp

@@ -40,6 +40,8 @@
 #include "qevdevtabletmanager_p.h"
 #include "qevdevtablethandler_p.h"
 
+#include <QtInputSupport/private/qevdevutil_p.h>
+
 #include <QStringList>
 #include <QGuiApplication>
 #include <QLoggingCategory>
@@ -65,24 +67,14 @@ QEvdevTabletManager::QEvdevTabletManager(const QString &key, const QString &spec
     if (spec.isEmpty())
         spec = specification;
 
-    QStringList args = spec.split(QLatin1Char(':'));
-    QStringList devices;
+    auto parsed = QEvdevUtil::parseSpecification(spec);
+    m_spec = std::move(parsed.spec);
 
-    foreach (const QString &arg, args) {
-        if (arg.startsWith(QLatin1String("/dev/"))) {
-            devices.append(arg);
-            args.removeAll(arg);
-        }
-    }
-
-    // build new specification without /dev/ elements
-    m_spec = args.join(QLatin1Char(':'));
-
-    foreach (const QString &device, devices)
+    for (const QString &device : qAsConst(parsed.devices))
         addDevice(device);
 
     // when no devices specified, use device discovery to scan and monitor
-    if (devices.isEmpty()) {
+    if (parsed.devices.isEmpty()) {
         qCDebug(qLcEvdevTablet, "evdevtablet: Using device discovery");
         m_deviceDiscovery = QDeviceDiscovery::create(QDeviceDiscovery::Device_Tablet, this);
         if (m_deviceDiscovery) {

src/platformsupport/input/evdevtouch/qevdevtouchmanager.cpp

@@ -40,6 +40,8 @@
 #include "qevdevtouchmanager_p.h"
 #include "qevdevtouchhandler_p.h"
 
+#include <QtInputSupport/private/qevdevutil_p.h>
+
 #include <QStringList>
 #include <QGuiApplication>
 #include <QLoggingCategory>
@@ -65,24 +67,14 @@ QEvdevTouchManager::QEvdevTouchManager(const QString &key, const QString &specif
     if (spec.isEmpty())
         spec = specification;
 
-    QStringList args = spec.split(QLatin1Char(':'));
-    QStringList devices;
+    auto parsed = QEvdevUtil::parseSpecification(spec);
+    m_spec = std::move(parsed.spec);
 
-    foreach (const QString &arg, args) {
-        if (arg.startsWith(QLatin1String("/dev/"))) {
-            devices.append(arg);
-            args.removeAll(arg);
-        }
-    }
-
-    // build new specification without /dev/ elements
-    m_spec = args.join(QLatin1Char(':'));
-
-    foreach (const QString &device, devices)
+    for (const QString &device : qAsConst(parsed.devices))
         addDevice(device);
 
     // when no devices specified, use device discovery to scan and monitor
-    if (devices.isEmpty()) {
+    if (parsed.devices.isEmpty()) {
         qCDebug(qLcEvdevTouch, "evdevtouch: Using device discovery");
         m_deviceDiscovery = QDeviceDiscovery::create(QDeviceDiscovery::Device_Touchpad | QDeviceDiscovery::Device_Touchscreen, this);
         if (m_deviceDiscovery) {

src/platformsupport/input/shared/qevdevutil.cpp

@@ -0,0 +1,70 @@
+/****************************************************************************
+**
+** Copyright (C) 2019 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Marc Mutz <marc.mutz@kdab.com>
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the plugins module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qevdevutil_p.h"
+
+QT_BEGIN_NAMESPACE
+
+namespace QEvdevUtil {
+
+ParsedSpecification parseSpecification(const QString &specification)
+{
+    ParsedSpecification result;
+
+    result.args = specification.splitRef(QLatin1Char(':'));
+
+    for (const QStringRef &arg : qAsConst(result.args)) {
+        if (arg.startsWith(QLatin1String("/dev/"))) {
+            // if device is specified try to use it
+            result.devices.append(arg.toString());
+        } else {
+            // build new specification without /dev/ elements
+            result.spec += arg + QLatin1Char(':');
+        }
+    }
+
+    if (!result.spec.isEmpty())
+        result.spec.chop(1); // remove trailing ':'
+
+    return result;
+}
+
+} // namespace QEvdevUtil
+
+QT_END_NAMESPACE

src/platformsupport/input/shared/qevdevutil_p.h

@@ -0,0 +1,76 @@
+/****************************************************************************
+**
+** Copyright (C) 2019 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Marc Mutz <marc.mutz@kdab.com>
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the plugins module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QEVDEVUTIL_P_H
+#define QEVDEVUTIL_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <QString>
+#include <QStringList>
+#include <QVector>
+#include <QStringRef>
+
+QT_BEGIN_NAMESPACE
+
+namespace QEvdevUtil {
+
+struct ParsedSpecification
+{
+    QString spec;
+    QStringList devices;
+    QVector<QStringRef> args;
+};
+
+ParsedSpecification parseSpecification(const QString &specification);
+
+}
+
+QT_END_NAMESPACE
+
+#endif // QEVDEVUTIL_P_H

src/platformsupport/input/shared/shared.pri

@@ -1,6 +1,8 @@
 HEADERS += \
     $$PWD/devicehandlerlist_p.h \
+    $$PWD/qevdevutil_p.h \
     $$PWD/qtouchoutputmapping_p.h
 
 SOURCES += \
+    $$PWD/qevdevutil.cpp \
     $$PWD/qtouchoutputmapping.cpp