diff options
author | Jędrzej Nowacki <jedrzej.nowacki@digia.com> | 2014-06-26 13:02:54 +0200 |
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committer | Jędrzej Nowacki <jedrzej.nowacki@digia.com> | 2014-07-25 15:25:17 +0200 |
commit | 20cf632ad5f3ffe7b0fd231724c971f4e07304eb (patch) | |
tree | 6c393d91728928e5aaa33c64fea6a1797dcde7b9 /src/corelib/json/qjson_p.h | |
parent | c8edde3b833cb3d15377afed13d6fcd2e5fa5cd9 (diff) |
Reading QJsonObject property should not modify the object itself.
Before this change such code:
QJsonObject o;
o["blah"];
would create property "blah" and assign null value to it, while
this code:
const QJsonObject o;
o["blah"];
would not. The change unifies the confusing behavior. Now reading
a non-existing property, is not causing a property to be added
in any visible way.
Internally QJsonObject stores a special hash of undefined, but
referenced values. Such reference is supposed to not live long,
only to the first compacting or assignment.
Change-Id: Ib022acf74ff49bad88d45d65d7093c4281d468f1
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
Diffstat (limited to 'src/corelib/json/qjson_p.h')
-rw-r--r-- | src/corelib/json/qjson_p.h | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/src/corelib/json/qjson_p.h b/src/corelib/json/qjson_p.h index 7d0162938d..92330175ba 100644 --- a/src/corelib/json/qjson_p.h +++ b/src/corelib/json/qjson_p.h @@ -61,6 +61,8 @@ #include <qstring.h> #include <qendian.h> #include <qnumeric.h> +#include <QtCore/qhash.h> +#include <QtCore/qmutex.h> #include <limits.h> #include <limits> @@ -776,6 +778,75 @@ private: Q_DISABLE_COPY(Data) }; +struct ObjectUndefinedKeys +{ + static void insertKey(const QJsonObject *object, int index, const QString &key) + { + QMutexLocker lock(&mutex); + keys()[object][index] = key; + } + static QString takeKey(const QJsonObject *object, int index) + { + QMutexLocker lock(&mutex); + return keys()[object].take(index); + } + static void removeKeys(const QJsonObject *object) + { + QMutexLocker lock(&mutex); + keys().remove(object); + } +private: + typedef QHash<const QJsonObject*, QHash<int, QString> > KeysHash; + static KeysHash &keys() + { + static KeysHash keys; + return keys; + } + static QBasicMutex mutex; +}; + +} // namespace QJsonPrivate + +struct QJsonValueRef::UnionHelper +{ + static inline QJsonObject *untaggedPointer(QJsonObject *object) + { + const quintptr Mask = ~quintptr(0) << 2; + return reinterpret_cast<QJsonObject*>(quintptr(object) & Mask); + } + static inline QJsonObject *taggedPointer(QJsonObject *object) + { + const quintptr Mask = 1; + return reinterpret_cast<QJsonObject*>(quintptr(object) | Mask); + } + + static void setValueAt(QJsonValueRef *ref, QJsonValue value) + { + using namespace QJsonPrivate; + QJsonObject *object = untaggedPointer(ref->o); + if (ref->o != object) + object->insert(ObjectUndefinedKeys::takeKey(object, ref->index), value); + else + object->setValueAt(ref->index, value); + } + + static QJsonValue valueAt(const QJsonValueRef *ref) + { + QJsonObject *object = untaggedPointer(ref->o); + if (ref->o != object) + return QJsonValue::Undefined; + return ref->o->valueAt(ref->index); + } +}; + +/*! + \internal + Constructor that creates reference to an undefined value in \a object. +*/ +inline QJsonValueRef::QJsonValueRef(QJsonObject *object, const QString &key) + : o(UnionHelper::taggedPointer(object)), is_object(true), index(qHash(key)) +{ + QJsonPrivate::ObjectUndefinedKeys::insertKey(object, index, key); } QT_END_NAMESPACE |