Question

我有<代码>Vec<Bytes>,希望将其用作<代码>Any:decode(。

由于<代码>Any:decode() s case is a Buf trait that does not need a contiguous memory, theoryly, Vec<Bytes> can be used withoutplicaing memory.

然而,由于<代码>Vec<Bytes>没有实施Buf trait,需要将其转化为不同的东西。

While this scenario seems somewhat common, I failed to find an existing solution.

我如何能够做到这一点?

For Bytes and Buf, see https://docs.rs/bytes/1.5.0/bytes/
For Any, see https://docs.rs/prost-types/latest/prost_types/struct.Any.html
(However, familiarity with Any is not necessary. all I want to know is how to use Vec<Bytes> as a Buf.)

Answer 1

如果两种类型(Vec<Bytes>)和海峡(Buf)均为外国,即目前图书馆没有申报,那么你就无法对此类类型实施海峡。 https://github.com/Ixrec/rust-orphan-rules” rel=“nofollow noreferer”

To workaround this limitation, you use something called a newtype pattern.

NewType Pattern

你可以简单地宣布你自己的习俗类型,以总结外国的类型。现在,你可以简单地为你的新习俗而执行外国海峡。

pub struct MyCustomBuf(Vec<Bytes>);

impl Buf for MyCustomBuf {
// ... impl the functions
}

// now any function that takes `impl Buf` or `T: Buf` will accept your MyCustomBuf

Answer 2

Maybe chunked-bytes 有用:

use bytes::{Buf, Bytes};
use chunked_bytes::ChunkedBytes;

pub fn chain_noncopying(f: Vec<Bytes>) -> ChunkedBytes {
    f.into_iter().fold(ChunkedBytes::new(), |mut acc, b| {
        acc.put_bytes(b);
        
        acc
    })
}

旧答案:

How about re-collecting into Bytes?:

pub fn flatten_bytes_seq(bytes_collection: Vec<Bytes>) -> Bytes {
    bytes_collection.into_iter().flatten().collect()
}

NewType Pattern

友情链接