Struct mz_avro::writer::Writer

pub struct Writer<W> {
    schema: Schema,
    writer: W,
    buffer: Vec<u8>,
    num_values: usize,
    codec: Option<Codec>,
    marker: [u8; 16],
    has_header: bool,
}

Main interface for writing Avro Object Container Files.

Fields

schema: Schema

writer: W

buffer: Vec<u8>

num_values: usize

codec: Option<Codec>

marker: [u8; 16]

has_header: bool

Implementations

impl<W: Write> Writer<W>

pub fn new(schema: Schema, writer: W) -> Writer<W>

Creates a Writer for the Schema and something implementing the std::io::Write trait to write to.

This uses the no-compression Codec::Null when appending records.

pub fn with_codec(schema: Schema, writer: W, codec: Codec) -> Writer<W>

Creates a Writer given a Schema and a specific compression Codec

pub fn with_codec_opt( schema: Schema, writer: W, codec: Option<Codec>, ) -> Writer<W>

Create a Writer with the given parameters.

All parameters have the same meaning as with_codec, but if codec is None then no compression will be used and the avro.codec field in the header will be omitted.

pub fn append_to(file: W) -> Result<Writer<W>, Error>

where W: AvroRead + Seek + Unpin + Send,

Creates a Writer that appends to an existing OCF file.

pub fn schema(&self) -> &Schema

Get a reference to the Schema associated to a Writer.

pub fn append<T: ToAvro>(&mut self, value: T) -> Result<usize, Error>

Append a compatible value (implementing the ToAvro trait) to a Writer, also performing schema validation.

Return the number of bytes written (it might be 0, see below).

NOTE This function is not guaranteed to perform any actual write, since it relies on internal buffering for performance reasons. If you want to be sure the value has been written, then call flush.

pub fn append_value_ref(&mut self, value: &Value) -> Result<usize, Error>

Append a compatible value to a Writer, also performing schema validation.

Return the number of bytes written (it might be 0, see below).

NOTE This function is not guaranteed to perform any actual write, since it relies on internal buffering for performance reasons. If you want to be sure the value has been written, then call flush.

pub fn extend<I, T: ToAvro>(&mut self, values: I) -> Result<usize, Error>

where I: IntoIterator<Item = T>,

Extend a Writer with an Iterator of compatible values (implementing the ToAvro trait), also performing schema validation.

Return the number of bytes written.

NOTE This function forces the written data to be flushed (an implicit call to flush is performed).

pub fn extend_from_slice(&mut self, values: &[Value]) -> Result<usize, Error>

Extend a Writer by appending each Value from a slice, while also performing schema validation on each value appended.

Return the number of bytes written.

NOTE This function forces the written data to be flushed (an implicit call to flush is performed).

pub fn flush(&mut self) -> Result<usize, Error>

Flush the content appended to a Writer. Call this function to make sure all the content has been written before releasing the Writer.

Return the number of bytes written.

pub fn into_inner(self) -> W

Return what the Writer is writing to, consuming the Writer itself.

NOTE This function doesn’t guarantee that everything gets written before consuming the buffer. Please call flush before.

fn append_marker(&mut self) -> Result<usize, Error>

Generate and append synchronization marker to the payload.

fn append_raw(&mut self, value: &Value, schema: &Schema) -> Result<usize, Error>

Append a raw Avro Value to the payload avoiding to encode it again.

fn append_bytes(&mut self, bytes: &[u8]) -> Result<usize, Error>

Append pure bytes to the payload.

fn header(&self) -> Result<Vec<u8>, Error>

Create an Avro header based on schema, codec and sync marker.