Struct Reader

pub struct Reader { /* private fields */ }

File handle for reading data asynchronously.

Make sure to call .check() when done reading to verify that the extracted data passes integrity verification.

Implementations

impl Reader

pub fn check(self) -> Result<Algorithm>

Checks that data read from disk passes integrity checks. Returns the algorithm that was used verified the data. Should be called only after all data has been read from disk.

This check is very cheap, since most of the verification is done on the fly. This simply finalizes verification, and is always synchronous.

Example

use async_std::prelude::*;
use async_attributes;

#[async_attributes::main]
async fn main() -> cacache::Result<()> {
    let mut fd = cacache::Reader::open("./my-cache", "my-key").await?;
    let mut str = String::new();
    fd.read_to_string(&mut str).await.expect("Failed to read to string");
    // Remember to check that the data you got was correct!
    fd.check()?;
    Ok(())
}

pub async fn open<P, K>(cache: P, key: K) -> Result<Reader>

where P: AsRef<Path>, K: AsRef<str>,

Opens a new file handle into the cache, looking it up in the index using key.

Example

use async_std::prelude::*;
use async_attributes;

#[async_attributes::main]
async fn main() -> cacache::Result<()> {
    let mut fd = cacache::Reader::open("./my-cache", "my-key").await?;
    let mut str = String::new();
    fd.read_to_string(&mut str).await.expect("Failed to read to string");
    // Remember to check that the data you got was correct!
    fd.check()?;
    Ok(())
}

pub async fn open_hash<P>(cache: P, sri: Integrity) -> Result<Reader>

where P: AsRef<Path>,

Opens a new file handle into the cache, based on its integrity address.

Example

use async_std::prelude::*;
use async_attributes;

#[async_attributes::main]
async fn main() -> cacache::Result<()> {
    let sri = cacache::write("./my-cache", "key", b"hello world").await?;
    let mut fd = cacache::Reader::open_hash("./my-cache", sri).await?;
    let mut str = String::new();
    fd.read_to_string(&mut str).await.expect("Failed to read to string");
    // Remember to check that the data you got was correct!
    fd.check()?;
    Ok(())
}

Trait Implementations

impl AsyncRead for Reader

fn poll_read( self: Pin<&mut Self>, cx: &mut TaskContext<'_>, 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.