Struct ScanRequest 

pub struct ScanRequest<'a> {
    pub row_start: u64,
    pub row_count: u64,
    pub flags: u64,
    pub projection: Projection<'a>,
    pub filter: &'a [u8],
}

The host asking the decoder for a run of rows.

Fields

row_start: u64

The first row wanted, counting from zero.

This is 64 bits because a row count that fits in 32 bits is a limit somebody will hit, and the whole point of the exercise is not to build limits into a format that ossifies.

row_count: u64

How many rows are wanted. u64::MAX means “everything from row_start on”.

flags: u64

Flags, all currently reserved and required to be zero.

projection: Projection<'a>

Which columns are wanted.

filter: &'a [u8]

A filter for the decoder to apply, in a form the decoder and the host have agreed on separately. Empty means no filter.

Implementations

impl<'a> ScanRequest<'a>

pub const VERSION: u16 = 1

The layout version of this record.

pub const fn everything() -> Self

A request for every row and every column.

pub fn encode(&self, w: &mut Writer<'_>) -> Result<()>

Writes the record.

Errors

Returns Error::BufferFull if the buffer runs out.

pub fn decode(version: u16, p: &mut Reader<'a>) -> Result<Self>

Reads the record from its payload.

Errors

Returns Error::UnsupportedVersion if the layout version is not one this build knows, Error::Truncated if the payload ends early, or Error::Malformed if the projection is not a whole number of column indices.

Trait Implementations

impl<'a> Clone for ScanRequest<'a>

fn clone(&self) -> ScanRequest<'a>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<'a> Copy for ScanRequest<'a>

impl<'a> Debug for ScanRequest<'a>

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

Formats the value using the given formatter.

impl<'a> Eq for ScanRequest<'a>

impl<'a> PartialEq for ScanRequest<'a>

fn eq(&self, other: &ScanRequest<'a>) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl<'a> StructuralPartialEq for ScanRequest<'a>