1 files changed, 75 insertions, 19 deletions

diff --git a/src/corelib/json/qjsonobject.cpp b/src/corelib/json/qjsonobject.cpp
index a3ce13a99f..4ee20ef168 100644
--- a/src/corelib/json/qjsonobject.cpp
+++ b/src/corelib/json/qjsonobject.cpp
@@ -203,11 +203,54 @@ QJsonObject &QJsonObject::operator =(const QJsonObject &other)
  */
 QJsonObject QJsonObject::fromVariantMap(const QVariantMap &map)
 {
-    // ### this is implemented the trivial way, not the most efficient way
-
     QJsonObject object;
-    for (QVariantMap::const_iterator it = map.constBegin(); it != map.constEnd(); ++it)
-        object.insert(it.key(), QJsonValue::fromVariant(it.value()));
+    if (map.isEmpty())
+        return object;
+
+    object.detach2(1024);
+
+    QVector<QJsonPrivate::offset> offsets;
+    QJsonPrivate::offset currentOffset;
+    currentOffset = sizeof(QJsonPrivate::Base);
+
+    // the map is already sorted, so we can simply append one entry after the other and
+    // write the offset table at the end
+    for (QVariantMap::const_iterator it = map.constBegin(); it != map.constEnd(); ++it) {
+        QString key = it.key();
+        QJsonValue val = QJsonValue::fromVariant(it.value());
+
+        bool latinOrIntValue;
+        int valueSize = QJsonPrivate::Value::requiredStorage(val, &latinOrIntValue);
+
+        bool latinKey = QJsonPrivate::useCompressed(key);
+        int valueOffset = sizeof(QJsonPrivate::Entry) + QJsonPrivate::qStringSize(key, latinKey);
+        int requiredSize = valueOffset + valueSize;
+
+        if (!object.detach2(requiredSize + sizeof(QJsonPrivate::offset))) // offset for the new index entry
+            return QJsonObject();
+
+        QJsonPrivate::Entry *e = reinterpret_cast<QJsonPrivate::Entry *>(reinterpret_cast<char *>(object.o) + currentOffset);
+        e->value.type = val.t;
+        e->value.latinKey = latinKey;
+        e->value.latinOrIntValue = latinOrIntValue;
+        e->value.value = QJsonPrivate::Value::valueToStore(val, (char *)e - (char *)object.o + valueOffset);
+        QJsonPrivate::copyString((char *)(e + 1), key, latinKey);
+        if (valueSize)
+            QJsonPrivate::Value::copyData(val, (char *)e + valueOffset, latinOrIntValue);
+
+        offsets << currentOffset;
+        currentOffset += requiredSize;
+        object.o->size = currentOffset;
+    }
+
+    // write table
+    object.o->tableOffset = currentOffset;
+    if (!object.detach2(sizeof(QJsonPrivate::offset)*offsets.size()))
+        return QJsonObject();
+    memcpy(object.o->table(), offsets.constData(), offsets.size()*sizeof(uint));
+    object.o->length = offsets.size();
+    object.o->size = currentOffset + sizeof(QJsonPrivate::offset)*offsets.size();
+
     return object;
 }
 
@@ -276,16 +319,14 @@ QVariantHash QJsonObject::toVariantHash() const
  */
 QStringList QJsonObject::keys() const
 {
-    if (!d)
-        return QStringList();
-
     QStringList keys;
-    keys.reserve(o->length);
-    for (uint i = 0; i < o->length; ++i) {
-        QJsonPrivate::Entry *e = o->entryAt(i);
-        keys.append(e->key());
+    if (o) {
+        keys.reserve(o->length);
+        for (uint i = 0; i < o->length; ++i) {
+            QJsonPrivate::Entry *e = o->entryAt(i);
+            keys.append(e->key());
+        }
     }
-
     return keys;
 }
 
@@ -397,7 +438,8 @@ QJsonObject::iterator QJsonObject::insert(const QString &key, const QJsonValue &
     int valueOffset = sizeof(QJsonPrivate::Entry) + QJsonPrivate::qStringSize(key, latinKey);
     int requiredSize = valueOffset + valueSize;
 
-    detach(requiredSize + sizeof(QJsonPrivate::offset)); // offset for the new index entry
+    if (!detach2(requiredSize + sizeof(QJsonPrivate::offset))) // offset for the new index entry
+        return iterator();
 
     if (!o->length)
         o->tableOffset = sizeof(QJsonPrivate::Object);
@@ -441,7 +483,7 @@ void QJsonObject::remove(const QString &key)
     if (!keyExists)
         return;
 
-    detach();
+    detach2();
     o->removeItems(index, 1);
     ++d->compactionCounter;
     if (d->compactionCounter > 32u && d->compactionCounter >= unsigned(o->length) / 2u)
@@ -468,7 +510,7 @@ QJsonValue QJsonObject::take(const QString &key)
         return QJsonValue(QJsonValue::Undefined);
 
     QJsonValue v(d, o, o->entryAt(index)->value);
-    detach();
+    detach2();
     o->removeItems(index, 1);
     ++d->compactionCounter;
     if (d->compactionCounter > 32u && d->compactionCounter >= unsigned(o->length) / 2u)
@@ -562,7 +604,7 @@ QJsonObject::iterator QJsonObject::find(const QString &key)
     int index = o ? o->indexOf(key, &keyExists) : 0;
     if (!keyExists)
         return end();
-    detach();
+    detach2();
     return iterator(this, index);
 }
 
@@ -1069,21 +1111,35 @@ QJsonObject::const_iterator QJsonObject::constFind(const QString &key) const
  */
 void QJsonObject::detach(uint reserve)
 {
+    Q_UNUSED(reserve)
+    Q_ASSERT(!reserve);
+    detach2(reserve);
+}
+
+bool QJsonObject::detach2(uint reserve)
+{
     if (!d) {
+        if (reserve >= QJsonPrivate::Value::MaxSize) {
+            qWarning("QJson: Document too large to store in data structure");
+            return false;
+        }
         d = new QJsonPrivate::Data(reserve, QJsonValue::Object);
         o = static_cast<QJsonPrivate::Object *>(d->header->root());
         d->ref.ref();
-        return;
+        return true;
     }
     if (reserve == 0 && d->ref.load() == 1)
-        return;
+        return true;
 
     QJsonPrivate::Data *x = d->clone(o, reserve);
+    if (!x)
+        return false;
     x->ref.ref();
     if (!d->ref.deref())
         delete d;
     d = x;
     o = static_cast<QJsonPrivate::Object *>(d->header->root());
+    return true;
 }
 
 /*!
@@ -1094,7 +1150,7 @@ void QJsonObject::compact()
     if (!d || !d->compactionCounter)
         return;
 
-    detach();
+    detach2();
     d->compact();
     o = static_cast<QJsonPrivate::Object *>(d->header->root());
 }