Struct rdkafka_wrap::message::BorrowedMessage

pub struct BorrowedMessage<'a> { /* private fields */ }

A zero-copy Kafka message.

Provides a read-only access to headers owned by a Kafka consumer or producer or by an OwnedMessage struct.

Consumers

BorrowedMessages coming from consumers are removed from the consumer buffer once they are dropped. Holding references to too many messages will cause the memory of the consumer to fill up and the consumer to block until some of the BorrowedMessages are dropped.

Conversion to owned

To transform a BorrowedMessage into a OwnedMessage, use the detach method.

Implementations

impl<'a> BorrowedMessage<'a>

pub fn ptr(&self) -> *mut rd_kafka_message_s

Returns a pointer to the RDKafkaMessage.

pub fn topic_ptr(&self) -> *mut rd_kafka_topic_s

Returns a pointer to the message’s RDKafkaTopic

pub fn key_len(&self) -> usize

Returns the length of the key field of the message.

pub fn payload_len(&self) -> usize

Returns the length of the payload field of the message.

pub fn detach(&self) -> OwnedMessage

Clones the content of the BorrowedMessage and returns an OwnedMessage that can outlive the consumer.

This operation requires memory allocation and can be expensive.

Trait Implementations

impl<'a> Debug for BorrowedMessage<'a>

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl<'a> Message for BorrowedMessage<'a>

type Headers = BorrowedHeaders

The type of headers that this message contains.

fn key(&self) -> Option<&[u8]>

Returns the key of the message, or None if there is no key.

fn payload(&self) -> Option<&[u8]>

Returns the payload of the message, or None if there is no payload.

unsafe fn payload_mut(&mut self) -> Option<&mut [u8]>

Returns a mutable reference to the payload of the message, or None if there is no payload.

fn topic(&self) -> &str

Returns the source topic of the message.

fn partition(&self) -> i32

Returns the partition number where the message is stored.

fn offset(&self) -> i64

Returns the offset of the message within the partition.

fn timestamp(&self) -> Timestamp

Returns the message timestamp.

fn headers(&self) -> Option<&BorrowedHeaders>

Returns the headers of the message, or None if there are no headers.

fn payload_view<P>(&self) -> Option<Result<&P, <P as FromBytes>::Error>>where P: FromBytes + ?Sized,

Converts the raw bytes of the payload to a reference of the specified type, that points to the same data inside the message and without performing any memory allocation.

fn key_view<K>(&self) -> Option<Result<&K, <K as FromBytes>::Error>>where K: FromBytes + ?Sized,

Converts the raw bytes of the key to a reference of the specified type, that points to the same data inside the message and without performing any memory allocation.

impl<'a> Send for BorrowedMessage<'a>

impl<'a> Sync for BorrowedMessage<'a>