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Diffstat (limited to 'src/corelib/serialization/qjsondocument.cpp')
| -rw-r--r-- | src/corelib/serialization/qjsondocument.cpp | 667 |
1 files changed, 667 insertions, 0 deletions
diff --git a/src/corelib/serialization/qjsondocument.cpp b/src/corelib/serialization/qjsondocument.cpp new file mode 100644 index 0000000000..9794bca60d --- /dev/null +++ b/src/corelib/serialization/qjsondocument.cpp @@ -0,0 +1,667 @@ +/**************************************************************************** +** +** 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 <qjsondocument.h> +#include <qjsonobject.h> +#include <qjsonvalue.h> +#include <qjsonarray.h> +#include <qstringlist.h> +#include <qvariant.h> +#include <qdebug.h> +#include "qjsonwriter_p.h" +#include "qjsonparser_p.h" +#include "qjson_p.h" + +QT_BEGIN_NAMESPACE + +/*! \class QJsonDocument + \inmodule QtCore + \ingroup json + \ingroup shared + \reentrant + \since 5.0 + + \brief The QJsonDocument class provides a way to read and write JSON documents. + + QJsonDocument is a class that wraps a complete JSON document and can read and + write this document both from a UTF-8 encoded text based representation as well + as Qt's own binary format. + + A JSON document can be converted from its text-based representation to a QJsonDocument + using QJsonDocument::fromJson(). toJson() converts it back to text. The parser is very + fast and efficient and converts the JSON to the binary representation used by Qt. + + Validity of the parsed document can be queried with !isNull() + + A document can be queried as to whether it contains an array or an object using isArray() + and isObject(). The array or object contained in the document can be retrieved using + array() or object() and then read or manipulated. + + A document can also be created from a stored binary representation using fromBinaryData() or + fromRawData(). + + \sa {JSON Support in Qt}, {JSON Save Game Example} +*/ + +/*! + * Constructs an empty and invalid document. + */ +QJsonDocument::QJsonDocument() + : d(0) +{ +} + +/*! + * Creates a QJsonDocument from \a object. + */ +QJsonDocument::QJsonDocument(const QJsonObject &object) + : d(0) +{ + setObject(object); +} + +/*! + * Constructs a QJsonDocument from \a array. + */ +QJsonDocument::QJsonDocument(const QJsonArray &array) + : d(0) +{ + setArray(array); +} + +/*! + \internal + */ +QJsonDocument::QJsonDocument(QJsonPrivate::Data *data) + : d(data) +{ + Q_ASSERT(d); + d->ref.ref(); +} + +/*! + Deletes the document. + + Binary data set with fromRawData is not freed. + */ +QJsonDocument::~QJsonDocument() +{ + if (d && !d->ref.deref()) + delete d; +} + +/*! + * Creates a copy of the \a other document. + */ +QJsonDocument::QJsonDocument(const QJsonDocument &other) +{ + d = other.d; + if (d) + d->ref.ref(); +} + +/*! + * Assigns the \a other document to this QJsonDocument. + * Returns a reference to this object. + */ +QJsonDocument &QJsonDocument::operator =(const QJsonDocument &other) +{ + if (d != other.d) { + if (d && !d->ref.deref()) + delete d; + d = other.d; + if (d) + d->ref.ref(); + } + + return *this; +} + +/*! + \fn QJsonDocument::QJsonDocument(QJsonDocument &&other) + \since 5.10 + + Move-constructs a QJsonDocument from \a other. +*/ + +/*! + \fn QJsonDocument &QJsonDocument::operator =(QJsonDocument &&other) + \since 5.10 + + Move-assigns \a other to this document. +*/ + +/*! + \fn void QJsonDocument::swap(QJsonDocument &other) + \since 5.10 + + Swaps the document \a other with this. This operation is very fast and never fails. +*/ + + +/*! \enum QJsonDocument::DataValidation + + This value is used to tell QJsonDocument whether to validate the binary data + when converting to a QJsonDocument using fromBinaryData() or fromRawData(). + + \value Validate Validate the data before using it. This is the default. + \value BypassValidation Bypasses data validation. Only use if you received the + data from a trusted place and know it's valid, as using of invalid data can crash + the application. + */ + +/*! + Creates a QJsonDocument that uses the first \a size bytes from + \a data. It assumes \a data contains a binary encoded JSON document. + The created document does not take ownership of \a data and the caller + has to guarantee that \a data will not be deleted or modified as long as + any QJsonDocument, QJsonObject or QJsonArray still references the data. + + \a data has to be aligned to a 4 byte boundary. + + \a validation decides whether the data is checked for validity before being used. + By default the data is validated. If the \a data is not valid, the method returns + a null document. + + Returns a QJsonDocument representing the data. + + \sa rawData(), fromBinaryData(), isNull(), DataValidation + */ +QJsonDocument QJsonDocument::fromRawData(const char *data, int size, DataValidation validation) +{ + if (quintptr(data) & 3) { + qWarning("QJsonDocument::fromRawData: data has to have 4 byte alignment"); + return QJsonDocument(); + } + + QJsonPrivate::Data *d = new QJsonPrivate::Data((char *)data, size); + d->ownsData = false; + + if (validation != BypassValidation && !d->valid()) { + delete d; + return QJsonDocument(); + } + + return QJsonDocument(d); +} + +/*! + Returns the raw binary representation of the data + \a size will contain the size of the returned data. + + This method is useful to e.g. stream the JSON document + in it's binary form to a file. + */ +const char *QJsonDocument::rawData(int *size) const +{ + if (!d) { + *size = 0; + return 0; + } + *size = d->alloc; + return d->rawData; +} + +/*! + Creates a QJsonDocument from \a data. + + \a validation decides whether the data is checked for validity before being used. + By default the data is validated. If the \a data is not valid, the method returns + a null document. + + \sa toBinaryData(), fromRawData(), isNull(), DataValidation + */ +QJsonDocument QJsonDocument::fromBinaryData(const QByteArray &data, DataValidation validation) +{ + if (data.size() < (int)(sizeof(QJsonPrivate::Header) + sizeof(QJsonPrivate::Base))) + return QJsonDocument(); + + QJsonPrivate::Header h; + memcpy(&h, data.constData(), sizeof(QJsonPrivate::Header)); + QJsonPrivate::Base root; + memcpy(&root, data.constData() + sizeof(QJsonPrivate::Header), sizeof(QJsonPrivate::Base)); + + // do basic checks here, so we don't try to allocate more memory than we can. + if (h.tag != QJsonDocument::BinaryFormatTag || h.version != 1u || + sizeof(QJsonPrivate::Header) + root.size > (uint)data.size()) + return QJsonDocument(); + + const uint size = sizeof(QJsonPrivate::Header) + root.size; + char *raw = (char *)malloc(size); + if (!raw) + return QJsonDocument(); + + memcpy(raw, data.constData(), size); + QJsonPrivate::Data *d = new QJsonPrivate::Data(raw, size); + + if (validation != BypassValidation && !d->valid()) { + delete d; + return QJsonDocument(); + } + + return QJsonDocument(d); +} + +/*! + Creates a QJsonDocument from the QVariant \a variant. + + If the \a variant contains any other type than a QVariantMap, + QVariantHash, QVariantList or QStringList, the returned document is invalid. + + \sa toVariant() + */ +QJsonDocument QJsonDocument::fromVariant(const QVariant &variant) +{ + QJsonDocument doc; + switch (variant.type()) { + case QVariant::Map: + doc.setObject(QJsonObject::fromVariantMap(variant.toMap())); + break; + case QVariant::Hash: + doc.setObject(QJsonObject::fromVariantHash(variant.toHash())); + break; + case QVariant::List: + doc.setArray(QJsonArray::fromVariantList(variant.toList())); + break; + case QVariant::StringList: + doc.setArray(QJsonArray::fromStringList(variant.toStringList())); + break; + default: + break; + } + return doc; +} + +/*! + Returns a QVariant representing the Json document. + + The returned variant will be a QVariantList if the document is + a QJsonArray and a QVariantMap if the document is a QJsonObject. + + \sa fromVariant(), QJsonValue::toVariant() + */ +QVariant QJsonDocument::toVariant() const +{ + if (!d) + return QVariant(); + + if (d->header->root()->isArray()) + return QJsonArray(d, static_cast<QJsonPrivate::Array *>(d->header->root())).toVariantList(); + else + return QJsonObject(d, static_cast<QJsonPrivate::Object *>(d->header->root())).toVariantMap(); +} + +/*! + Converts the QJsonDocument to a UTF-8 encoded JSON document. + + \sa fromJson() + */ +#if !defined(QT_JSON_READONLY) || defined(Q_CLANG_QDOC) +QByteArray QJsonDocument::toJson() const +{ + return toJson(Indented); +} +#endif + +/*! + \enum QJsonDocument::JsonFormat + + This value defines the format of the JSON byte array produced + when converting to a QJsonDocument using toJson(). + + \value Indented Defines human readable output as follows: + \code + { + "Array": [ + true, + 999, + "string" + ], + "Key": "Value", + "null": null + } + \endcode + + \value Compact Defines a compact output as follows: + \code + {"Array":[true,999,"string"],"Key":"Value","null":null} + \endcode + */ + +/*! + Converts the QJsonDocument to a UTF-8 encoded JSON document in the provided \a format. + + \sa fromJson(), JsonFormat + */ +#if !defined(QT_JSON_READONLY) || defined(Q_CLANG_QDOC) +QByteArray QJsonDocument::toJson(JsonFormat format) const +{ + QByteArray json; + if (!d) + return json; + + if (d->header->root()->isArray()) + QJsonPrivate::Writer::arrayToJson(static_cast<QJsonPrivate::Array *>(d->header->root()), json, 0, (format == Compact)); + else + QJsonPrivate::Writer::objectToJson(static_cast<QJsonPrivate::Object *>(d->header->root()), json, 0, (format == Compact)); + + return json; +} +#endif + +/*! + Parses \a json as a UTF-8 encoded JSON document, and creates a QJsonDocument + from it. + + Returns a valid (non-null) QJsonDocument if the parsing succeeds. If it fails, + the returned document will be null, and the optional \a error variable will contain + further details about the error. + + \sa toJson(), QJsonParseError, isNull() + */ +QJsonDocument QJsonDocument::fromJson(const QByteArray &json, QJsonParseError *error) +{ + QJsonPrivate::Parser parser(json.constData(), json.length()); + return parser.parse(error); +} + +/*! + Returns \c true if the document doesn't contain any data. + */ +bool QJsonDocument::isEmpty() const +{ + if (!d) + return true; + + return false; +} + +/*! + Returns a binary representation of the document. + + The binary representation is also the native format used internally in Qt, + and is very efficient and fast to convert to and from. + + The binary format can be stored on disk and interchanged with other applications + or computers. fromBinaryData() can be used to convert it back into a + JSON document. + + \sa fromBinaryData() + */ +QByteArray QJsonDocument::toBinaryData() const +{ + if (!d || !d->rawData) + return QByteArray(); + + return QByteArray(d->rawData, d->header->root()->size + sizeof(QJsonPrivate::Header)); +} + +/*! + Returns \c true if the document contains an array. + + \sa array(), isObject() + */ +bool QJsonDocument::isArray() const +{ + if (!d) + return false; + + QJsonPrivate::Header *h = (QJsonPrivate::Header *)d->rawData; + return h->root()->isArray(); +} + +/*! + Returns \c true if the document contains an object. + + \sa object(), isArray() + */ +bool QJsonDocument::isObject() const +{ + if (!d) + return false; + + QJsonPrivate::Header *h = (QJsonPrivate::Header *)d->rawData; + return h->root()->isObject(); +} + +/*! + Returns the QJsonObject contained in the document. + + Returns an empty object if the document contains an + array. + + \sa isObject(), array(), setObject() + */ +QJsonObject QJsonDocument::object() const +{ + if (d) { + QJsonPrivate::Base *b = d->header->root(); + if (b->isObject()) + return QJsonObject(d, static_cast<QJsonPrivate::Object *>(b)); + } + return QJsonObject(); +} + +/*! + Returns the QJsonArray contained in the document. + + Returns an empty array if the document contains an + object. + + \sa isArray(), object(), setArray() + */ +QJsonArray QJsonDocument::array() const +{ + if (d) { + QJsonPrivate::Base *b = d->header->root(); + if (b->isArray()) + return QJsonArray(d, static_cast<QJsonPrivate::Array *>(b)); + } + return QJsonArray(); +} + +/*! + Sets \a object as the main object of this document. + + \sa setArray(), object() + */ +void QJsonDocument::setObject(const QJsonObject &object) +{ + if (d && !d->ref.deref()) + delete d; + + d = object.d; + + if (!d) { + d = new QJsonPrivate::Data(0, QJsonValue::Object); + } else if (d->compactionCounter || object.o != d->header->root()) { + QJsonObject o(object); + if (d->compactionCounter) + o.compact(); + else + o.detach2(); + d = o.d; + d->ref.ref(); + return; + } + d->ref.ref(); +} + +/*! + Sets \a array as the main object of this document. + + \sa setObject(), array() + */ +void QJsonDocument::setArray(const QJsonArray &array) +{ + if (d && !d->ref.deref()) + delete d; + + d = array.d; + + if (!d) { + d = new QJsonPrivate::Data(0, QJsonValue::Array); + } else if (d->compactionCounter || array.a != d->header->root()) { + QJsonArray a(array); + if (d->compactionCounter) + a.compact(); + else + a.detach2(); + d = a.d; + d->ref.ref(); + return; + } + d->ref.ref(); +} + +/*! + Returns a QJsonValue representing the value for the key \a key. + + Equivalent to calling object().value(key). + + The returned QJsonValue is QJsonValue::Undefined if the key does not exist, + or if isObject() is false. + + \since 5.10 + + \sa QJsonValue, QJsonValue::isUndefined(), QJsonObject + */ +const QJsonValue QJsonDocument::operator[](const QString &key) const +{ + if (!isObject()) + return QJsonValue(QJsonValue::Undefined); + + return object().value(key); +} + +/*! + \overload + \since 5.10 +*/ +const QJsonValue QJsonDocument::operator[](QLatin1String key) const +{ + if (!isObject()) + return QJsonValue(QJsonValue::Undefined); + + return object().value(key); +} + +/*! + Returns a QJsonValue representing the value for index \a i. + + Equivalent to calling array().at(i). + + The returned QJsonValue is QJsonValue::Undefined, if \a i is out of bounds, + or if isArray() is false. + + \since 5.10 + + \sa QJsonValue, QJsonValue::isUndefined(), QJsonArray + */ +const QJsonValue QJsonDocument::operator[](int i) const +{ + if (!isArray()) + return QJsonValue(QJsonValue::Undefined); + + return array().at(i); +} + +/*! + Returns \c true if the \a other document is equal to this document. + */ +bool QJsonDocument::operator==(const QJsonDocument &other) const +{ + if (d == other.d) + return true; + + if (!d || !other.d) + return false; + + if (d->header->root()->isArray() != other.d->header->root()->isArray()) + return false; + + if (d->header->root()->isObject()) + return QJsonObject(d, static_cast<QJsonPrivate::Object *>(d->header->root())) + == QJsonObject(other.d, static_cast<QJsonPrivate::Object *>(other.d->header->root())); + else + return QJsonArray(d, static_cast<QJsonPrivate::Array *>(d->header->root())) + == QJsonArray(other.d, static_cast<QJsonPrivate::Array *>(other.d->header->root())); +} + +/*! + \fn bool QJsonDocument::operator!=(const QJsonDocument &other) const + + returns \c true if \a other is not equal to this document + */ + +/*! + returns \c true if this document is null. + + Null documents are documents created through the default constructor. + + Documents created from UTF-8 encoded text or the binary format are + validated during parsing. If validation fails, the returned document + will also be null. + */ +bool QJsonDocument::isNull() const +{ + return (d == 0); +} + +#if !defined(QT_NO_DEBUG_STREAM) && !defined(QT_JSON_READONLY) +QDebug operator<<(QDebug dbg, const QJsonDocument &o) +{ + QDebugStateSaver saver(dbg); + if (!o.d) { + dbg << "QJsonDocument()"; + return dbg; + } + QByteArray json; + if (o.d->header->root()->isArray()) + QJsonPrivate::Writer::arrayToJson(static_cast<QJsonPrivate::Array *>(o.d->header->root()), json, 0, true); + else + QJsonPrivate::Writer::objectToJson(static_cast<QJsonPrivate::Object *>(o.d->header->root()), json, 0, true); + dbg.nospace() << "QJsonDocument(" + << json.constData() // print as utf-8 string without extra quotation marks + << ')'; + return dbg; +} +#endif + +QT_END_NAMESPACE |