Trait AsyncFileReader

pub trait AsyncFileReader: Send {
    // Required methods
    fn get_bytes(&mut self, range: Range<usize>) -> BoxFuture<'_, Result<Bytes>>;
    fn get_metadata<'a>(
        &'a mut self,
        options: Option<&'a ArrowReaderOptions>,
    ) -> BoxFuture<'a, Result<Arc<ParquetMetaData>>>;

    // Provided method
    fn get_byte_ranges(
        &mut self,
        ranges: Vec<Range<usize>>,
    ) -> BoxFuture<'_, Result<Vec<Bytes>>> { ... }
}

The asynchronous interface used by ParquetRecordBatchStream to read parquet files

Notes:

1. There is a default implementation for types that implement [AsyncRead] and [AsyncSeek], for example tokio::fs::File.

2. ParquetObjectReader, available when the object_store crate feature is enabled, implements this interface for ObjectStore.

Required Methods

fn get_bytes(&mut self, range: Range<usize>) -> BoxFuture<'_, Result<Bytes>>

Retrieve the bytes in range

fn get_metadata<'a>( &'a mut self, options: Option<&'a ArrowReaderOptions>, ) -> BoxFuture<'a, Result<Arc<ParquetMetaData>>>

Provides asynchronous access to the ParquetMetaData of a parquet file, allowing fine-grained control over how metadata is sourced, in particular allowing for caching, pre-fetching, catalog metadata, etc… ArrowReaderOptions may be provided to supply decryption parameters

Provided Methods

fn get_byte_ranges( &mut self, ranges: Vec<Range<usize>>, ) -> BoxFuture<'_, Result<Vec<Bytes>>>

Retrieve multiple byte ranges. The default implementation will call get_bytes sequentially

Trait Implementations

impl AsyncFileReader for Box<dyn AsyncFileReader + '_>

This allows Box<dyn AsyncFileReader + ’_> to be used as an AsyncFileReader,

fn get_bytes(&mut self, range: Range<usize>) -> BoxFuture<'_, Result<Bytes>>

Retrieve the bytes in range

fn get_byte_ranges( &mut self, ranges: Vec<Range<usize>>, ) -> BoxFuture<'_, Result<Vec<Bytes>>>

Retrieve multiple byte ranges. The default implementation will call get_bytes sequentially

fn get_metadata<'a>( &'a mut self, options: Option<&'a ArrowReaderOptions>, ) -> BoxFuture<'a, Result<Arc<ParquetMetaData>>>

Provides asynchronous access to the ParquetMetaData of a parquet file, allowing fine-grained control over how metadata is sourced, in particular allowing for caching, pre-fetching, catalog metadata, etc… ArrowReaderOptions may be provided to supply decryption parameters

Implementations on Foreign Types

impl AsyncFileReader for Box<dyn AsyncFileReader + '_>

This allows Box<dyn AsyncFileReader + ’_> to be used as an AsyncFileReader,

fn get_bytes(&mut self, range: Range<usize>) -> BoxFuture<'_, Result<Bytes>>

fn get_byte_ranges( &mut self, ranges: Vec<Range<usize>>, ) -> BoxFuture<'_, Result<Vec<Bytes>>>

fn get_metadata<'a>( &'a mut self, options: Option<&'a ArrowReaderOptions>, ) -> BoxFuture<'a, Result<Arc<ParquetMetaData>>>

Implementors

impl AsyncFileReader for ParquetObjectReader

impl<T: AsyncRead + AsyncSeek + Unpin + Send> AsyncFileReader for T