pub trait PageReader: Iterator<Item = Result<Page>> + Send {
// Required methods
fn get_next_page(&mut self) -> Result<Option<Page>>;
fn peek_next_page(&mut self) -> Result<Option<PageMetadata>>;
fn skip_next_page(&mut self) -> Result<()>;
// Provided method
fn at_record_boundary(&mut self) -> Result<bool> { ... }
}Expand description
API for reading pages from a column chunk. This offers a iterator like API to get the next page.
Required Methods§
Sourcefn get_next_page(&mut self) -> Result<Option<Page>>
fn get_next_page(&mut self) -> Result<Option<Page>>
Gets the next page in the column chunk associated with this reader.
Returns None if there are no pages left.
Sourcefn peek_next_page(&mut self) -> Result<Option<PageMetadata>>
fn peek_next_page(&mut self) -> Result<Option<PageMetadata>>
Gets metadata about the next page, returns an error if no column index information
Sourcefn skip_next_page(&mut self) -> Result<()>
fn skip_next_page(&mut self) -> Result<()>
Skips reading the next page, returns an error if no column index information
Provided Methods§
Sourcefn at_record_boundary(&mut self) -> Result<bool>
fn at_record_boundary(&mut self) -> Result<bool>
Returns true if the next page can be assumed to contain the start of a new record
Prior to parquet V2 the specification was ambiguous as to whether a single record
could be split across multiple pages, and prior to (#4327) the Rust writer would do
this in certain situations. However, correctly interpreting the offset index relies on
this assumption holding (#4943), and so this mechanism is provided for a PageReader
to signal this to the calling context