如何使用 zbus 列出块设备？

Question

我想使用名为 zbus 的 dbus 实现列出系统中所有可用的块设备。

UDisks2 documentation 提到了调用 org.freedesktop.UDisks2.Manager 接口的方法调用 GetBlockDevices，它接受 IN a{sv} options, OUT ao block_objects 作为方法参数。

使用zbus，我写：

use std::error::Error;
use std::result::Result;
use zbus::{Connection, Proxy};

fn main() -> Result<(), Box<dyn Error>> {
    let connection = Connection::new_system()?;
    let p = Proxy::new(
        &connection,
        "org.freedesktop.UDisks2",
        "/org/freedesktop/UDisks2/Manager",
        "org.freedesktop.UDisks2.Manager",
    )?;
    let resp: Vec<zvariant::ObjectPath> = p.call("GetBlockDevices", &std::collections::HashMap::<String, zvariant::Value>::new())?;
    dbg!(resp);
    Ok(())
}

据我了解，zvariant Values 代表一个 DBus 变体。但是我收到以下错误：

error: implementation of `serde::de::Deserialize` is not general enough
   --> src/main.rs:13:45
    |
13  |       let resp: Vec<zvariant::ObjectPath> = p.call("GetBlockDevices", &std::collections::HashMap::<String, zvariant::Value>::new())?;
    |                                               ^^^^ implementation of `serde::de::Deserialize` is not general enough
    | 
   ::: /home/adnan338/.cargo/registry/src/github.com-1ecc6299db9ec823/serde-1.0.115/src/de/mod.rs:531:1
    |
531 | / pub trait Deserialize<'de>: Sized {
532 | |     /// Deserialize this value from the given Serde deserializer.
533 | |     ///
534 | |     /// See the [Implementing `Deserialize`][impl-deserialize] section of the
...   |
569 | |     }
570 | | }
    | |_- trait `serde::de::Deserialize` defined here
    |
    = note: `std::vec::Vec<zvariant::object_path::ObjectPath<'_>>` must implement `serde::de::Deserialize<'0>`, for any lifetime `'0`...
    = note: ...but `std::vec::Vec<zvariant::object_path::ObjectPath<'_>>` actually implements `serde::de::Deserialize<'1>`, for some specific lifetime `'1`

这是什么原因造成的，我该如何避免这个错误？

Answer 1

首先，感谢您试用我们的箱子。问题是 zbus::Proxy::call 期望 return 值是一个拥有的值，而您正在反序列化为一个无主类型。以下两项工作：

// OwnedObjectPath require zvariant >= 2.2.0
let resp: Vec<zvariant::OwnedObjectPath> = p.call(
    "GetBlockDevices",
    &std::collections::HashMap::<String, zvariant::Value>::new(),
)?;

let resp = p.call_method(
    "GetBlockDevices",
    &std::collections::HashMap::<String, zvariant::Value>::new(),
)?; 
let resp: Vec<zvariant::ObjectPath> = resp.body()?;

如何使用 zbus 列出块设备？

How to use zbus to list block devices?

dbus

rust

freedesktop.org

udisks