Reimplement JSON support on top of Cbor

In turn, deprecate the QJsonDocument methods that deal with JSON binary
data. You should use CBOR for data serialization these days.

[ChangeLog][Deprecation Notice] The binary JSON representation is
deprecated. The CBOR format should be used instead.

Fixes: QTBUG-47629
Change-Id: Ic8b92ea36de87815b12307a9d8b1095f07166db8
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 415 insertions, 0 deletions

diff --git a/src/corelib/serialization/qbinaryjson.cpp b/src/corelib/serialization/qbinaryjson.cpp
new file mode 100644
index 0000000000..3d359f0998
--- /dev/null
+++ b/src/corelib/serialization/qbinaryjson.cpp
@@ -0,0 +1,415 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtCore 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 "qbinaryjson_p.h"
+
+#include <qjsonobject.h>
+#include <qjsonarray.h>
+
+QT_BEGIN_NAMESPACE
+
+namespace QBinaryJsonPrivate {
+
+static Q_CONSTEXPR Base emptyArray  = {
+    { qle_uint(sizeof(Base)) },
+    { 0 },
+    { qle_uint(0) }
+};
+
+static Q_CONSTEXPR Base emptyObject = {
+    { qle_uint(sizeof(Base)) },
+    { qToLittleEndian(1U) },
+    { qle_uint(0) }
+};
+
+void MutableData::compact()
+{
+    Q_STATIC_ASSERT(sizeof(Value) == sizeof(offset));
+
+    Base *base = header->root();
+    int reserve = 0;
+    if (base->is_object) {
+        auto *o = static_cast<Object *>(base);
+        for (uint i = 0; i < o->length; ++i)
+            reserve += o->entryAt(i)->usedStorage(o);
+    } else {
+        auto *a = static_cast<Array *>(base);
+        for (uint i = 0; i < a->length; ++i)
+            reserve += a->at(i)->usedStorage(a);
+    }
+
+    uint size = sizeof(Base) + reserve + base->length * sizeof(offset);
+    uint alloc = sizeof(Header) + size;
+    auto *h = reinterpret_cast<Header *>(malloc(alloc));
+    Q_CHECK_PTR(h);
+    h->tag = QJsonDocument::BinaryFormatTag;
+    h->version = 1;
+    Base *b = h->root();
+    b->size = size;
+    b->is_object = header->root()->is_object;
+    b->length = base->length;
+    b->tableOffset = reserve + sizeof(Array);
+
+    uint offset = sizeof(Base);
+    if (b->is_object) {
+        const auto *o = static_cast<const Object *>(base);
+        auto *no = static_cast<Object *>(b);
+
+        for (uint i = 0; i < o->length; ++i) {
+            no->table()[i] = offset;
+
+            const Entry *e = o->entryAt(i);
+            Entry *ne = no->entryAt(i);
+            uint s = e->size();
+            memcpy(ne, e, s);
+            offset += s;
+            uint dataSize = e->value.usedStorage(o);
+            if (dataSize) {
+                memcpy(reinterpret_cast<char *>(no) + offset, e->value.data(o), dataSize);
+                ne->value.value = offset;
+                offset += dataSize;
+            }
+        }
+    } else {
+        const auto *a = static_cast<const Array *>(base);
+        auto *na = static_cast<Array *>(b);
+
+        for (uint i = 0; i < a->length; ++i) {
+            const Value *v = a->at(i);
+            Value *nv = na->at(i);
+            *nv = *v;
+            uint dataSize = v->usedStorage(a);
+            if (dataSize) {
+                memcpy(reinterpret_cast<char *>(na) + offset, v->data(a), dataSize);
+                nv->value = offset;
+                offset += dataSize;
+            }
+        }
+    }
+    Q_ASSERT(offset == uint(b->tableOffset));
+
+    free(header);
+    header = h;
+    this->alloc = alloc;
+    compactionCounter = 0;
+}
+
+bool ConstData::isValid() const
+{
+    if (header->tag != QJsonDocument::BinaryFormatTag || header->version != 1U)
+        return false;
+
+    const Base *root = header->root();
+    const uint maxSize = alloc - sizeof(Header);
+    return root->is_object
+            ? static_cast<const Object *>(root)->isValid(maxSize)
+            : static_cast<const Array *>(root)->isValid(maxSize);
+}
+
+QJsonDocument ConstData::toJsonDocument() const
+{
+    const Base *root = header->root();
+    return root->is_object
+            ? QJsonDocument(static_cast<const Object *>(root)->toJsonObject())
+            : QJsonDocument(static_cast<const Array *>(root)->toJsonArray());
+}
+
+uint Base::reserveSpace(uint dataSize, uint posInTable, uint numItems, bool replace)
+{
+    Q_ASSERT(posInTable <= length);
+    if (size + dataSize >= Value::MaxSize) {
+        qWarning("QJson: Document too large to store in data structure %d %d %d",
+                 uint(size), dataSize, Value::MaxSize);
+        return 0;
+    }
+
+    offset off = tableOffset;
+    // move table to new position
+    if (replace) {
+        memmove(reinterpret_cast<char *>(table()) + dataSize, table(), length * sizeof(offset));
+    } else {
+        memmove(reinterpret_cast<char *>(table() + posInTable + numItems) + dataSize,
+                table() + posInTable, (length - posInTable) * sizeof(offset));
+        memmove(reinterpret_cast<char *>(table()) + dataSize, table(), posInTable * sizeof(offset));
+    }
+    tableOffset += dataSize;
+    for (uint i = 0; i < numItems; ++i)
+        table()[posInTable + i] = off;
+    size += dataSize;
+    if (!replace) {
+        length += numItems;
+        size += numItems * sizeof(offset);
+    }
+    return off;
+}
+
+uint Object::indexOf(QStringView key, bool *exists) const
+{
+    uint min = 0;
+    uint n = length;
+    while (n > 0) {
+        uint half = n >> 1;
+        uint middle = min + half;
+        if (*entryAt(middle) >= key) {
+            n = half;
+        } else {
+            min = middle + 1;
+            n -= half + 1;
+        }
+    }
+    if (min < length && *entryAt(min) == key) {
+        *exists = true;
+        return min;
+    }
+    *exists = false;
+    return min;
+}
+
+QJsonObject Object::toJsonObject() const
+{
+    QJsonObject object;
+    for (uint i = 0; i < length; ++i) {
+        const Entry *e = entryAt(i);
+        object.insert(e->key(), e->value.toJsonValue(this));
+    }
+    return object;
+}
+
+bool Object::isValid(uint maxSize) const
+{
+    if (size > maxSize || tableOffset + length * sizeof(offset) > size)
+        return false;
+
+    QString lastKey;
+    for (uint i = 0; i < length; ++i) {
+        if (table()[i] + sizeof(Entry) >= tableOffset)
+            return false;
+        const Entry *e = entryAt(i);
+        if (!e->isValid(tableOffset - table()[i]))
+            return false;
+        const QString key = e->key();
+        if (key < lastKey)
+            return false;
+        if (!e->value.isValid(this))
+            return false;
+        lastKey = key;
+    }
+    return true;
+}
+
+QJsonArray Array::toJsonArray() const
+{
+    QJsonArray array;
+    const offset *values = table();
+    for (uint i = 0; i < length; ++i)
+        array.append(reinterpret_cast<const Value *>(values + i)->toJsonValue(this));
+    return array;
+}
+
+bool Array::isValid(uint maxSize) const
+{
+    if (size > maxSize || tableOffset + length * sizeof(offset) > size)
+        return false;
+
+    const offset *values = table();
+    for (uint i = 0; i < length; ++i) {
+        if (!reinterpret_cast<const Value *>(values + i)->isValid(this))
+            return false;
+    }
+    return true;
+}
+
+uint Value::usedStorage(const Base *b) const
+{
+    uint s = 0;
+    switch (type) {
+    case QJsonValue::Double:
+        if (!latinOrIntValue)
+            s = sizeof(double);
+        break;
+    case QJsonValue::String: {
+        const char *d = data(b);
+        s = latinOrIntValue
+                ? (sizeof(ushort)
+                   + qFromLittleEndian(*reinterpret_cast<const ushort *>(d)))
+                : (sizeof(int)
+                   + sizeof(ushort) * qFromLittleEndian(*reinterpret_cast<const int *>(d)));
+        break;
+    }
+    case QJsonValue::Array:
+    case QJsonValue::Object:
+        s = base(b)->size;
+        break;
+    case QJsonValue::Null:
+    case QJsonValue::Bool:
+    default:
+        break;
+    }
+    return alignedSize(s);
+}
+
+QJsonValue Value::toJsonValue(const Base *b) const
+{
+    switch (type) {
+    case QJsonValue::Null:
+        return QJsonValue(QJsonValue::Null);
+    case QJsonValue::Bool:
+        return QJsonValue(toBoolean());
+    case QJsonValue::Double:
+        return QJsonValue(toDouble(b));
+    case QJsonValue::String:
+        return QJsonValue(toString(b));
+    case QJsonValue::Array:
+        return static_cast<const Array *>(base(b))->toJsonArray();
+    case QJsonValue::Object:
+        return static_cast<const Object *>(base(b))->toJsonObject();
+    case QJsonValue::Undefined:
+        return QJsonValue(QJsonValue::Undefined);
+    }
+    Q_UNREACHABLE();
+    return QJsonValue(QJsonValue::Undefined);
+}
+
+inline bool isValidValueOffset(uint offset, uint tableOffset)
+{
+    return offset >= sizeof(Base)
+        && offset + sizeof(uint) <= tableOffset;
+}
+
+bool Value::isValid(const Base *b) const
+{
+    switch (type) {
+    case QJsonValue::Null:
+    case QJsonValue::Bool:
+        return true;
+    case QJsonValue::Double:
+        return latinOrIntValue || isValidValueOffset(value, b->tableOffset);
+    case QJsonValue::String:
+        if (!isValidValueOffset(value, b->tableOffset))
+            return false;
+        if (latinOrIntValue)
+            return asLatin1String(b).isValid(b->tableOffset - value);
+        return asString(b).isValid(b->tableOffset - value);
+    case QJsonValue::Array:
+        return isValidValueOffset(value, b->tableOffset)
+            && static_cast<const Array *>(base(b))->isValid(b->tableOffset - value);
+    case QJsonValue::Object:
+        return isValidValueOffset(value, b->tableOffset)
+            && static_cast<const Object *>(base(b))->isValid(b->tableOffset - value);
+    default:
+        return false;
+    }
+}
+
+uint Value::requiredStorage(const QBinaryJsonValue &v, bool *compressed)
+{
+    *compressed = false;
+    switch (v.type()) {
+    case QJsonValue::Double:
+        if (QBinaryJsonPrivate::compressedNumber(v.toDouble()) != INT_MAX) {
+            *compressed = true;
+            return 0;
+        }
+        return sizeof(double);
+    case QJsonValue::String: {
+        QString s = v.toString();
+        *compressed = QBinaryJsonPrivate::useCompressed(s);
+        return QBinaryJsonPrivate::qStringSize(s, *compressed);
+    }
+    case QJsonValue::Array:
+    case QJsonValue::Object:
+        return v.base ? uint(v.base->size) : sizeof(QBinaryJsonPrivate::Base);
+    case QJsonValue::Undefined:
+    case QJsonValue::Null:
+    case QJsonValue::Bool:
+        break;
+    }
+    return 0;
+}
+
+uint Value::valueToStore(const QBinaryJsonValue &v, uint offset)
+{
+    switch (v.type()) {
+    case QJsonValue::Undefined:
+    case QJsonValue::Null:
+        break;
+    case QJsonValue::Bool:
+        return v.toBool();
+    case QJsonValue::Double: {
+        int c = QBinaryJsonPrivate::compressedNumber(v.toDouble());
+        if (c != INT_MAX)
+            return c;
+    }
+        Q_FALLTHROUGH();
+    case QJsonValue::String:
+    case QJsonValue::Array:
+    case QJsonValue::Object:
+        return offset;
+    }
+    return 0;
+}
+
+void Value::copyData(const QBinaryJsonValue &v, char *dest, bool compressed)
+{
+    switch (v.type()) {
+    case QJsonValue::Double:
+        if (!compressed)
+            qToLittleEndian(v.toDouble(), dest);
+        break;
+    case QJsonValue::String: {
+        const QString str = v.toString();
+        QBinaryJsonPrivate::copyString(dest, str, compressed);
+        break;
+    }
+    case QJsonValue::Array:
+    case QJsonValue::Object: {
+        const QBinaryJsonPrivate::Base *b = v.base;
+        if (!b)
+            b = (v.type() == QJsonValue::Array ? &emptyArray : &emptyObject);
+        memcpy(dest, b, b->size);
+        break;
+    }
+    default:
+        break;
+    }
+}
+
+} // namespace QBinaryJsonPrivate
+
+QT_END_NAMESPACE