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use std::convert::TryFrom;
use crate::{FlightData, SchemaResult};
use arrow::array::ArrayRef;
use arrow::datatypes::{Schema, SchemaRef};
use arrow::error::{ArrowError, Result};
use arrow::ipc::{convert, reader, writer, writer::EncodedData, writer::IpcWriteOptions};
use arrow::record_batch::RecordBatch;
pub fn flight_data_from_arrow_batch(
batch: &RecordBatch,
options: &IpcWriteOptions,
) -> (Vec<FlightData>, FlightData) {
let data_gen = writer::IpcDataGenerator::default();
let mut dictionary_tracker = writer::DictionaryTracker::new(false);
let (encoded_dictionaries, encoded_batch) = data_gen
.encoded_batch(batch, &mut dictionary_tracker, &options)
.expect("DictionaryTracker configured above to not error on replacement");
let flight_dictionaries = encoded_dictionaries.into_iter().map(Into::into).collect();
let flight_batch = encoded_batch.into();
(flight_dictionaries, flight_batch)
}
impl From<EncodedData> for FlightData {
fn from(data: EncodedData) -> Self {
FlightData {
data_header: data.ipc_message,
data_body: data.arrow_data,
..Default::default()
}
}
}
pub fn flight_schema_from_arrow_schema(
schema: &Schema,
options: &IpcWriteOptions,
) -> SchemaResult {
SchemaResult {
schema: flight_schema_as_flatbuffer(schema, options),
}
}
pub fn flight_data_from_arrow_schema(
schema: &Schema,
options: &IpcWriteOptions,
) -> FlightData {
let data_header = flight_schema_as_flatbuffer(schema, options);
FlightData {
data_header,
..Default::default()
}
}
pub fn ipc_message_from_arrow_schema(
arrow_schema: &Schema,
options: &IpcWriteOptions,
) -> Result<Vec<u8>> {
let encoded_data = flight_schema_as_encoded_data(arrow_schema, options);
let mut schema = vec![];
arrow::ipc::writer::write_message(&mut schema, encoded_data, options)?;
Ok(schema)
}
fn flight_schema_as_flatbuffer(
arrow_schema: &Schema,
options: &IpcWriteOptions,
) -> Vec<u8> {
let encoded_data = flight_schema_as_encoded_data(arrow_schema, options);
encoded_data.ipc_message
}
fn flight_schema_as_encoded_data(
arrow_schema: &Schema,
options: &IpcWriteOptions,
) -> EncodedData {
let data_gen = writer::IpcDataGenerator::default();
data_gen.schema_to_bytes(arrow_schema, options)
}
impl TryFrom<&FlightData> for Schema {
type Error = ArrowError;
fn try_from(data: &FlightData) -> Result<Self> {
convert::schema_from_bytes(&data.data_header[..]).map_err(|err| {
ArrowError::ParseError(format!(
"Unable to convert flight data to Arrow schema: {}",
err
))
})
}
}
impl TryFrom<&SchemaResult> for Schema {
type Error = ArrowError;
fn try_from(data: &SchemaResult) -> Result<Self> {
convert::schema_from_bytes(&data.schema[..]).map_err(|err| {
ArrowError::ParseError(format!(
"Unable to convert schema result to Arrow schema: {}",
err
))
})
}
}
pub fn flight_data_to_arrow_batch(
data: &FlightData,
schema: SchemaRef,
dictionaries_by_field: &[Option<ArrayRef>],
) -> Result<RecordBatch> {
let message = arrow::ipc::root_as_message(&data.data_header[..]).map_err(|err| {
ArrowError::ParseError(format!("Unable to get root as message: {:?}", err))
})?;
message
.header_as_record_batch()
.ok_or_else(|| {
ArrowError::ParseError(
"Unable to convert flight data header to a record batch".to_string(),
)
})
.map(|batch| {
reader::read_record_batch(
&data.data_body,
batch,
schema,
&dictionaries_by_field,
)
})?
}