Struct Blob 

pub struct Blob { /* private fields */ }

Binary blob.

Can be used to read and write to a blob. Reads and writes are buffered.

Created by Connection::open_blob.

Example

use futures::AsyncWriteExt;

let id = conn.insert("INSERT INTO my_table (column) VALUES (?);",
    asqlite::params!(asqlite::ZeroBlob(4096))).await?;
let mut blob = conn.open_blob(
    "main",
    "my_table",
    "column",
    id,
    asqlite::BlobOpenMode::ReadWrite,
).await?;
blob.write_all(b"example").await?;
blob.flush().await?;

Implementations

impl Blob

pub fn poll_read( &mut self, cx: &mut Context<'_>, bytes: &mut [u8], ) -> Poll<Result<usize>>

Read some bytes into bytes.

See also: read.

pub fn poll_write( &mut self, cx: &mut Context<'_>, bytes: &[u8], ) -> Poll<Result<usize>>

Write some bytes into buffer.

See also: write.

pub fn poll_flush(&mut self, cx: &mut Context<'_>) -> Poll<Result<()>>

Flush written bytes to the database.

See also: flush.

pub fn poll_fill_buf(&mut self, cx: &mut Context<'_>) -> Poll<Result<&[u8]>>

Read the content of the internal buffer, filling it if empty.

See also: fill_buf.

pub fn consume(&mut self, bytes: usize)

Consume the internal buffer.

This function is a lower-level call that should be paired with poll_fill_buf to work properly.

pub fn seek(&mut self, position: SeekFrom) -> Result<u64>

Seek to an offset.

pub fn size(&self) -> u64

Return the size of the binary blob.

pub async fn read(&mut self, bytes: &mut [u8]) -> Result<usize>

Read some bytes into buffer.

Returns the number of bytes read, or 0 when the EOF is reached.

pub async fn write(&mut self, bytes: &[u8]) -> Result<usize>

Write some bytes into buffer.

Returns amount of bytes written.

pub async fn flush(&mut self) -> Result<()>

Flush written bytes to the database.

pub async fn fill_buf(&mut self) -> Result<&[u8]>

Read the content of the internal buffer, filling it if empty.

This function is a lower-level call that should be paired with consume to work properly.

pub async fn reopen(&mut self, row: i64) -> Result<()>

Move the blob to another row, reopening the blob at the selected row.

Trait Implementations

impl AsyncBufRead for Blob

fn poll_fill_buf( self: Pin<&mut Self>, cx: &mut Context<'_>, ) -> Poll<Result<&[u8]>>

Attempt to return the contents of the internal buffer, filling it with more data from the inner reader if it is empty.

fn consume(self: Pin<&mut Self>, bytes: usize)

Tells this buffer that amt bytes have been consumed from the buffer, so they should no longer be returned in calls to poll_read.

impl AsyncRead for Blob

fn poll_read( self: Pin<&mut Self>, cx: &mut Context<'_>, buf: &mut [u8], ) -> Poll<Result<usize>>

Attempt to read from the AsyncRead into buf.

fn poll_read_vectored( self: Pin<&mut Self>, cx: &mut Context<'_>, bufs: &mut [IoSliceMut<'_>], ) -> Poll<Result<usize, Error>>

Attempt to read from the AsyncRead into bufs using vectored IO operations.

impl AsyncSeek for Blob

fn poll_seek( self: Pin<&mut Self>, _: &mut Context<'_>, pos: SeekFrom, ) -> Poll<Result<u64>>

Attempt to seek to an offset, in bytes, in a stream.

impl AsyncWrite for Blob

fn poll_write( self: Pin<&mut Self>, cx: &mut Context<'_>, buf: &[u8], ) -> Poll<Result<usize>>

Attempt to write bytes from buf into the object.

fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>>

Attempt to flush the object, ensuring that any buffered data reach their destination.

fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>>

Attempt to close the object.

fn poll_write_vectored( self: Pin<&mut Self>, cx: &mut Context<'_>, bufs: &[IoSlice<'_>], ) -> Poll<Result<usize, Error>>

Attempt to write bytes from bufs into the object using vectored IO operations.

impl Debug for Blob

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

Formats the value using the given formatter.

impl Drop for Blob

fn drop(&mut self)

Executes the destructor for this type.