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39 
40 #include "qdnd_p.h"
41 
42 #include "qguiapplication.h"
43 #include <ctype.h>
44 #include <qpa/qplatformdrag.h>
45 #include <qpa/qplatformintegration.h>
46 #include <private/qguiapplication_p.h>
47 
48 QT_BEGIN_NAMESPACE
49 
50 // the universe's only drag manager
51 QDragManager *QDragManager::m_instance = nullptr;
52 
QDragManager()53 QDragManager::QDragManager()
54     : QObject(qApp), m_currentDropTarget(nullptr),
55       m_platformDrag(QGuiApplicationPrivate::platformIntegration()->drag()),
56       m_object(nullptr)
57 {
58     Q_ASSERT(!m_instance);
59 }
60 
~QDragManager()61 QDragManager::~QDragManager()
62 {
63     m_instance = nullptr;
64 }
65 
self()66 QDragManager *QDragManager::self()
67 {
68     if (!m_instance && !QGuiApplication::closingDown())
69         m_instance = new QDragManager;
70     return m_instance;
71 }
72 
source() const73 QObject *QDragManager::source() const
74 {
75     if (m_object)
76         return m_object->source();
77     return nullptr;
78 }
79 
setCurrentTarget(QObject * target,bool dropped)80 void QDragManager::setCurrentTarget(QObject *target, bool dropped)
81 {
82     if (m_currentDropTarget == target)
83         return;
84 
85     m_currentDropTarget = target;
86     if (!dropped && m_object) {
87         m_object->d_func()->target = target;
88         emit m_object->targetChanged(target);
89     }
90 }
91 
currentTarget() const92 QObject *QDragManager::currentTarget() const
93 {
94     return m_currentDropTarget;
95 }
96 
drag(QDrag * o)97 Qt::DropAction QDragManager::drag(QDrag *o)
98 {
99     if (!o || m_object == o)
100          return Qt::IgnoreAction;
101 
102     if (!m_platformDrag || !o->source()) {
103         o->deleteLater();
104         return Qt::IgnoreAction;
105     }
106 
107     if (m_object) {
108         qWarning("QDragManager::drag in possibly invalid state");
109         return Qt::IgnoreAction;
110     }
111 
112     m_object = o;
113 
114     m_object->d_func()->target = nullptr;
115 
116     QGuiApplicationPrivate::instance()->notifyDragStarted(m_object.data());
117     const Qt::DropAction result = m_platformDrag->drag(m_object);
118     if (!m_object.isNull() && !m_platformDrag->ownsDragObject())
119         m_object->deleteLater();
120 
121     m_object.clear();
122     return result;
123 }
124 
125 QT_END_NAMESPACE
126