Re: [pdm-devel] [PATCH proxmox 3/3] section-config: add lookup and convert_to_typed_array helpers

[Wolfgang Bumiller <w.bumiller@proxmox.com>]

On Mon, Apr 14, 2025 at 02:00:45PM +0200, Gabriel Goller wrote:
> These helpers exist on the untyped SectionConfigData struct, but not on
> the typed one. To facilitate the migration to the typed
> SectionConfigData<T> add these as macros.
> 
> These can be used to simply lookup an item with a specific type by
> passing the type, e.g.:
> 
>     lookup!(config, "root", UserSectionConfig::User)
> 
> or retrieve a vector with the sections that correspond to the passed
> type, e.g.:
> 
>     convert_to_typed_array!(config, UserSectionConfig::ApiToken)
> 
> Also add some simple unit-tests to test them.
> 
> Signed-off-by: Gabriel Goller <g.goller@proxmox.com>
> ---
>  proxmox-section-config/Cargo.toml   |   3 +
>  proxmox-section-config/src/typed.rs | 125 ++++++++++++++++++++++++++++
>  2 files changed, 128 insertions(+)
> 
> diff --git a/proxmox-section-config/Cargo.toml b/proxmox-section-config/Cargo.toml
> index 4796a6bff5e6..eb456a3bb3e6 100644
> --- a/proxmox-section-config/Cargo.toml
> +++ b/proxmox-section-config/Cargo.toml
> @@ -19,3 +19,6 @@ serde_json.workspace = true
>  proxmox-schema.workspace = true
>  # FIXME: remove!
>  proxmox-lang.workspace = true
> +
> +[dev-dependencies]
> +serde = { workspace = true, features = ["derive"] }
> diff --git a/proxmox-section-config/src/typed.rs b/proxmox-section-config/src/typed.rs
> index 14a8d87e3425..c13e2338461d 100644
> --- a/proxmox-section-config/src/typed.rs
> +++ b/proxmox-section-config/src/typed.rs
> @@ -207,6 +207,37 @@ impl<T> SectionConfigData<T> {
>      }
>  }
>  
> +#[macro_export]
> +macro_rules! lookup {
> +    ($map:expr, $key:expr, $variant:path) => {
> +        $map.get($key).and_then(|value| {
> +            if let $variant(inner) = value {
> +                Some(inner)
> +            } else {
> +                None
> +            }
> +        })

^ You could shorten this by matching on the nested structure here:

    match $map.get($key) {
        Some($variant(inner)) => Some(inner),
        _ => None,
    }

> +    };
> +}
> +
> +#[macro_export]
> +macro_rules! convert_to_typed_array {
> +    ($map:expr, $variant:path) => {
> +        $map.values()
> +            .filter_map(|value| {
> +                if let $variant(inner) = value {
> +                    Some(inner)
> +                } else {
> +                    None
> +                }

^ (rustfmt puts a `match` here on the `filter_map` line, so that would
be much shorter ;-) )

> +            })
> +            .collect::<Vec<_>>()
> +    };
> +}
> +
> +pub use lookup;
> +pub use convert_to_typed_array;

If, for now, you intend for these to be used via the `typed` module
instead of at the top level you should mark these re-exports with
`#[doc(inline)]` and the macros above with `#[doc(hidden)]`.

Otherwise the documentation shows them at the top level, with the ones
in `typed` as re-exports.

> +
>  impl<T: ApiSectionDataEntry + DeserializeOwned> TryFrom<RawSectionConfigData>
>      for SectionConfigData<T>
>  {
> @@ -367,6 +398,7 @@ mod test {
>      use std::sync::OnceLock;
>  
>      use proxmox_schema::{ApiStringFormat, EnumEntry, ObjectSchema, Schema, StringSchema};
> +    use serde::{Deserialize, Serialize};
>  
>      use crate::{SectionConfig, SectionConfigPlugin};
>  
> @@ -508,4 +540,97 @@ mod test {
>              .expect("failed to write out section config");
>          assert_eq!(written, raw);
>      }
> +
> +    #[derive(Deserialize, Serialize, Debug, PartialEq, Eq, PartialOrd, Ord)]
> +    struct User {
> +        user_id: String,
> +    }
> +
> +    #[derive(Deserialize, Serialize, Debug, PartialEq, Eq, PartialOrd, Ord)]
> +    struct Token {
> +        token: String,
> +    }
> +
> +    #[derive(Deserialize, Serialize)]
> +    enum UserSectionConfig {
> +        #[serde(rename="user")]
> +        User(User),
> +        #[serde(rename="token")]
> +        Token(Token)
> +    }
> +
> +    const USER_PROPERTIES: ObjectSchema = ObjectSchema::new(
> +        "User",
> +        &[
> +            ("user_id", false, &StringSchema::new("Some id.").schema()),
> +        ],
> +    );
> +
> +    const TOKEN_PROPERTIES: ObjectSchema = ObjectSchema::new(
> +        "Token",
> +        &[
> +            ("token", false, &StringSchema::new("Some token.").schema()),
> +        ],
> +    );
> +
> +    impl ApiSectionDataEntry for UserSectionConfig {
> +        fn section_config() -> &'static SectionConfig {
> +            static SC: OnceLock<SectionConfig> = OnceLock::new();
> +
> +            SC.get_or_init(|| {
> +                let mut config = SectionConfig::new(&ID_SCHEMA);
> +                config.register_plugin(SectionConfigPlugin::new(
> +                    "user".to_string(),
> +                    None,
> +                    &USER_PROPERTIES,
> +                ));
> +                config.register_plugin(SectionConfigPlugin::new(
> +                    "token".to_string(),
> +                    None,
> +                    &TOKEN_PROPERTIES,
> +                ));
> +                config
> +            })
> +        }
> +
> +        fn section_type(&self) -> &'static str {
> +            match self {
> +                UserSectionConfig::User(_) => "user",
> +                UserSectionConfig::Token(_) => "token",
> +            }
> +        }
> +    }
> +
> +    #[test]
> +    fn test_macros() {
> +        let filename = "sync.cfg";
> +        let raw = "\
> +            token: first\n\
> +                \ttoken 1\n\
> +            \n\
> +            user: second\n\
> +                \tuser_id 2\n\
> +            \n\
> +            user: third\n\
> +                \tuser_id 4\n\
> +        ";
> +
> +        let parsed = UserSectionConfig::section_config()
> +            .parse(filename, raw)
> +            .expect("failed to parse");
> +        let config: SectionConfigData<UserSectionConfig> = parsed.try_into().expect("failed to convert");
> +
> +        let token = lookup!(config, "first", UserSectionConfig::Token);
> +        assert_eq!(token.unwrap().token, "1");
> +        let user = lookup!(config, "second", UserSectionConfig::User);
> +        assert_eq!(user.unwrap().user_id, "2");
> +
> +        let mut tokens = convert_to_typed_array!(config, UserSectionConfig::Token);
> +        tokens.sort();
> +        assert_eq!(tokens, vec![&Token{token: "1".to_owned()}]);
> +
> +        let mut users = convert_to_typed_array!(config, UserSectionConfig::User);
> +        users.sort();
> +        assert_eq!(users, vec![&User{user_id: "2".to_owned()}, &User{user_id: "4".to_owned()}]);
> +    }
>  }
> -- 
> 2.39.5


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