QAbstractProtobufSerializer Class | Qt Protobuf 6.8.0
Description: The QAbstractProtobufSerializer class is interface that represents basic functions for serialization/deserialization.

- Qt 6.8
- Qt Protobuf
- C++ Classes
- QtProtobuf (Technical Preview)
- QAbstractProtobufSerializer
- Qt 6.8.0 Reference Documentation

# QAbstractProtobufSerializer Class

The QAbstractProtobufSerializer class is interface that represents basic functions for serialization/deserialization. More...

Header: | #include <QAbstractProtobufSerializer>
CMake: | find_package(Qt6 REQUIRED COMPONENTS Protobuf) target_link_libraries(mytarget PRIVATE Qt6::Protobuf)
Since: | Qt 6.5
Inherited By: | QProtobufJsonSerializer and QProtobufSerializer
Status: | Technical Preview

- List of all members, including inherited members

Note: All functions in this class are reentrant.

## Public Types

enum | DeserializationError { NoError, InvalidHeaderError, NoDeserializerError, UnexpectedEndOfStreamError, InvalidFormatError }

## Public Functions

virtual | ~QAbstractProtobufSerializer()
bool | deserialize(QProtobufMessage *message, QByteArrayView data) const
virtual bool | deserializeEnum(QtProtobuf::int64 &value, const QMetaEnum &metaEnum) const = 0
virtual bool | deserializeEnumList(QList<QtProtobuf::int64> &value, const QMetaEnum &metaEnum) const = 0
virtual bool | deserializeListObject(QProtobufMessage *message) const = 0
virtual bool | deserializeMapPair(QVariant &key, QVariant &value) const = 0
virtual bool | deserializeObject(QProtobufMessage *message) const = 0
QByteArray | serialize(const QProtobufMessage *message) const
virtual void | serializeEnum(QtProtobuf::int64 value, const QMetaEnum &metaEnum, const QtProtobufPrivate::QProtobufPropertyOrderingInfo &fieldInfo) const = 0
virtual void | serializeEnumList(const QList<QtProtobuf::int64> &value, const QMetaEnum &metaEnum, const QtProtobufPrivate::QProtobufPropertyOrderingInfo &fieldInfo) const = 0
virtual void | serializeListObject(const QProtobufMessage *message, const QtProtobufPrivate::QProtobufPropertyOrderingInfo &fieldInfo) const = 0
virtual void | serializeMapPair(const QVariant &key, const QVariant &value, const QtProtobufPrivate::QProtobufPropertyOrderingInfo &fieldInfo) const = 0
virtual void | serializeObject(const QProtobufMessage *message, const QtProtobufPrivate::QProtobufPropertyOrderingInfo &fieldInfo) const = 0

## Protected Functions

virtual bool | deserializeMessage(QProtobufMessage *message, QByteArrayView data) const = 0
virtual QByteArray | serializeMessage(const QProtobufMessage *message) const = 0

## Macros

| Q_PROTOBUF_OBJECT

## Detailed Description

The QProtobufSerializer class registers serializers/deserializers for classes implementing a protobuf message, inheriting QProtobufMessage. These classes are generated automatically, based on a `.proto` file, using the CMake function qt_add_protobuf or by running qtprotobufgen directly.

This class should be used as a base for specific serializers. The handlers property contains all message-specific serializers and should be used while serialization/deserialization. Inherited classes should reimplement scope of virtual methods that used by registered message serialization/deserialization functions.

## Member Type Documentation

### enum QAbstractProtobufSerializer::DeserializationError

This enum contains possible errors that can occur during deserialization. When an error occurs, call deserializationErrorString() to get a human-readable error message.

Constant | Value | Description
--- | --- | ---
`QAbstractProtobufSerializer::NoError` | `0` | No error occurred.
`QAbstractProtobufSerializer::InvalidHeaderError` | `1` | Something went wrong while attempting to decode a header in the message.
`QAbstractProtobufSerializer::NoDeserializerError` | `2` | While deserializing a message, no deserializer was found for a type in the message.
`QAbstractProtobufSerializer::UnexpectedEndOfStreamError` | `3` | While deserializing a message, the stream ended unexpectedly.
`QAbstractProtobufSerializer::InvalidFormatError` | `4` | The data has invalid format. For example the JSON value doesn't match the field type.

## Member Function Documentation

### `[virtual noexcept]` QAbstractProtobufSerializer::~QAbstractProtobufSerializer()

Destroys this QAbstractProtobufSerializer.

### bool QAbstractProtobufSerializer::deserialize(QProtobufMessage *message, QByteArrayView data) const

Deserializes a registered Protobuf message message from a QByteArray data. message must not be `nullptr`. Returns `true` if deserialization was successful, otherwise `false`.

Unexpected/unknown properties in the data are skipped.

See also serialize().

### `[pure virtual]` bool QAbstractProtobufSerializer::deserializeEnum(QtProtobuf::int64 &value, const QMetaEnum &metaEnum) const

This function deserializes an enum value from a wire. metaEnum helps to decode the enum value. Returns `true` if deserialization was successful, otherwise `false`.

You should not call this function directly.

See also QAbstractProtobufSerializer::serializeEnum().

### `[pure virtual]` bool QAbstractProtobufSerializer::deserializeEnumList(QList<QtProtobuf::int64> &value, const QMetaEnum &metaEnum) const

This function deserializes a list of enum value from a wire. metaEnum helps to decode the enum value. Returns `true` if deserialization was successful, otherwise `false`.

You should not call this function directly.

See also QAbstractProtobufSerializer::serializeEnumList().

### `[pure virtual]` bool QAbstractProtobufSerializer::deserializeListObject(QProtobufMessage *message) const

Deserializes message from byte stream as part of list property from a wire. Returns `true` if deserialization was successful, otherwise `false`.

You should not call this function directly.

See also QAbstractProtobufSerializer::serializeListObject().

### `[pure virtual]` bool QAbstractProtobufSerializer::deserializeMapPair(QVariant &key, QVariant &value) const

This function deserializes a pair of key and value from a wire. Returns `true` if deserialization was successful, otherwise `false`.

You should not call this function directly.

See also QAbstractProtobufSerializer::serializeMapPair().

### `[pure virtual protected]` bool QAbstractProtobufSerializer::deserializeMessage(QProtobufMessage *message, QByteArrayView data) const

This is called by deserialize() to deserialize a registered Protobuf message from a QByteArrayView data. message can be assumed to not be `nullptr`. Returns `true` if deserialization was successful, otherwise `false`.

### `[pure virtual]` bool QAbstractProtobufSerializer::deserializeObject(QProtobufMessage *message) const

Deserializes a registered Protobuf message message. message must not be `nullptr`. Returns `true` if deserialization was successful, otherwise `false`.

You should not call this function directly.

See also QAbstractProtobufSerializer::serializeObject().

### QByteArray QAbstractProtobufSerializer::serialize(const QProtobufMessage *message) const

Serializes a registered Protobuf message message into a QByteArray. message must not be `nullptr`.

See also deserialize().

### `[pure virtual]` void QAbstractProtobufSerializer::serializeEnum(QtProtobuf::int64 value, const QMetaEnum &metaEnum, const QtProtobufPrivate::QProtobufPropertyOrderingInfo &fieldInfo) const

This function serializes value from enum associated with property fieldInfo. metaEnum helps to encode the enum value.

You should not call this function directly.

See also QAbstractProtobufSerializer::deserializeEnum().

### `[pure virtual]` void QAbstractProtobufSerializer::serializeEnumList(const QList<QtProtobuf::int64> &value, const QMetaEnum &metaEnum, const QtProtobufPrivate::QProtobufPropertyOrderingInfo &fieldInfo) const

This function serializes a list, value, for enum list associated with property fieldInfo. metaEnum helps to encode the enum value.

You should not call this function directly.

See also QAbstractProtobufSerializer::deserializeEnumList().

### `[pure virtual]` void QAbstractProtobufSerializer::serializeListObject(const QProtobufMessage *message, const QtProtobufPrivate::QProtobufPropertyOrderingInfo &fieldInfo) const

Serializes message as part of a list of messages one by one with fieldInfo.

You should not call this function directly.

See also QAbstractProtobufSerializer::deserializeListObject().

### `[pure virtual]` void QAbstractProtobufSerializer::serializeMapPair(const QVariant &key, const QVariant &value, const QtProtobufPrivate::QProtobufPropertyOrderingInfo &fieldInfo) const

This function serializes pair of key and value, that belong as a protobuf map record, according to fieldInfo.

You should not call this function directly.

See also QAbstractProtobufSerializer::deserializeMapPair().

### `[pure virtual protected]` QByteArray QAbstractProtobufSerializer::serializeMessage(const QProtobufMessage *message) const

This is called by serialize() to serialize a registered Protobuf message. message must not be `nullptr`. Returns a QByteArray containing the serialized message.

### `[pure virtual]` void QAbstractProtobufSerializer::serializeObject(const QProtobufMessage *message, const QtProtobufPrivate::QProtobufPropertyOrderingInfo &fieldInfo) const

Serializes a registered Protobuf message message with defined fieldInfo, that is recognized like an object, into a QByteArray. message must not be `nullptr`.

You should not call this function directly.

See also QAbstractProtobufSerializer::deserializeObject().

## Macro Documentation

### Q_PROTOBUF_OBJECT

Declares the propertyOrdering member in a class inheriting QProtobufMessage. This is used as part of the code generated by the qtprotobufgen tool.