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21 ** GNU General Public License Usage
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40 ****************************************************************************/
42 #ifndef QDECLARATIVEACCESSORS_P_H
43 #define QDECLARATIVEACCESSORS_P_H
45 #include <QtCore/qvector.h>
46 #include <QtCore/qhash.h>
47 #include <QtCore/QReadWriteLock>
54 class QDeclarativeNotifier;
56 // QML "accessor properties" allow V4 and V8 to bypass Qt's meta system to read and, more
57 // importantly, subscribe to properties directly. Any property that is primarily read
58 // from bindings is a candidate for inclusion as an accessor property.
60 // To define accessor properties, use the QML_DECLARE_PROPERTIES() and QML_DEFINE_PROPERTIES()
61 // macros. The QML_DECLARE_PROPERTIES() macro is used to specify the properties, and the
62 // QML_DEFINE_PROPERTIES() macro to register the properties with the
63 // QDeclarativeAccessorProperties singleton.
65 // A class with accessor properties must also add the Q_CLASSINFO("qt_HasQmlAccessors", "true")
66 // tag to its declaration. This is essential for QML to maintain internal consistency,
67 // and forgetting to do so will probably cause your application to qFatal() with a
68 // helpful reminder of this requirement.
70 // It is important that QML_DEFINE_PROPERTIES() has been called before QML ever sees
71 // the type with the accessor properties. As QML_DEFINE_PROPERTIES() is idempotent, it is
72 // recommended to call it in the type's constructor as well as when the type is registered
73 // as a QML element (if it ever is). QML_DEFINE_PROPERTIES() is a very cheap operation
74 // if registration has already occurred.
76 #define QML_DECLARE_PROPERTIES(type) \
77 static volatile bool qdeclarative_accessor_properties_isregistered_ ## type = false; \
78 static QDeclarativeAccessorProperties::Property qdeclarative_accessor_properties_ ## type[] =
80 #define QML_DEFINE_PROPERTIES(type) \
82 if (!qdeclarative_accessor_properties_isregistered_ ## type) { \
83 int count = sizeof(qdeclarative_accessor_properties_ ## type) / \
84 sizeof(QDeclarativeAccessorProperties::Property); \
85 QDeclarativeAccessorProperties::registerProperties(&type::staticMetaObject, count, \
86 qdeclarative_accessor_properties_ ## type);\
87 qdeclarative_accessor_properties_isregistered_ ## type = true; \
91 #define QML_PRIVATE_ACCESSOR(clazz, cpptype, name, variable) \
92 static void clazz ## _ ## name ## Read(QObject *o, intptr_t, void *rv) \
94 clazz ## Private *d = clazz ## Private::get(static_cast<clazz *>(o)); \
95 *static_cast<cpptype *>(rv) = d->variable; \
98 #define QML_PROPERTY_NAME(name) #name, sizeof #name - 1
100 class QDeclarativeAccessors
103 void (*read)(QObject *object, intptr_t property, void *output);
104 void (*notifier)(QObject *object, intptr_t property, QDeclarativeNotifier **notifier);
107 namespace QDeclarativeAccessorProperties {
110 unsigned int nameLength;
112 QDeclarativeAccessors *accessors;
117 Properties(Property *, int);
119 bool operator==(const Properties &o) const {
120 return count == o.count && properties == o.properties;
123 inline Property *property(const char *name);
126 Property *properties;
130 Properties properties(const QMetaObject *);
131 void Q_DECLARATIVE_EXPORT registerProperties(const QMetaObject *, int, Property *);
134 QDeclarativeAccessorProperties::Property *
135 QDeclarativeAccessorProperties::Properties::property(const char *name)
140 unsigned int length = strlen(name);
144 if (nameMask & (1 << qMin(31U, length - 1))) {
146 for (int ii = 0; ii < count; ++ii) {
147 if (properties[ii].nameLength == length && 0 == qstrcmp(name, properties[ii].name))
148 return &properties[ii];
156 QDeclarativeAccessorProperties::Properties::Properties()
157 : count(0), properties(0), nameMask(0)
165 #endif // QDECLARATIVEACCESSORS_P_H