zlink-macros 0.7.0

//! Types used in service macro processing.

use syn::{FnArg, Ident, LitStr, Pat, Type};

/// Information about a method parameter.
#[derive(Clone)]
pub(super) struct ParamInfo {
    /// The parameter name.
    pub name: Ident,
    /// The parameter type.
    pub ty: Type,
    /// The serialized name (from `#[zlink(rename = "...")]`). The literal is kept, not just its
    /// value, so a bad wire name can be reported against the span the user wrote it at.
    pub serialized_name: Option<LitStr>,
    /// Whether this parameter is marked with `#[zlink(connection)]`.
    pub is_connection: bool,
    /// Whether this parameter is marked with `#[zlink(fds)]`.
    pub is_fds: bool,
    /// Whether this is the `more` parameter for streaming methods.
    pub is_more: bool,
}

impl ParamInfo {
    /// The parameter name used on the wire (and in the IDL).
    ///
    /// This is the explicit `#[zlink(rename = "...")]` name if provided, the unraw'd Rust
    /// parameter name otherwise. Unrawing is what keeps the IDL and the wire in agreement: serde
    /// unraws the name it deserializes, so an `r#`-prefixed IDL name would advertise a parameter
    /// the method could never accept.
    pub(super) fn wire_name(&self) -> String {
        match &self.serialized_name {
            Some(name) => name.value(),
            None => crate::naming::unraw(&self.name),
        }
    }

    /// Extract parameter information from a function argument.
    pub(super) fn from_fn_arg(arg: &FnArg) -> Option<Self> {
        let FnArg::Typed(pat_type) = arg else {
            return None;
        };
        let Pat::Ident(pat_ident) = &*pat_type.pat else {
            return None;
        };

        Some(Self {
            name: pat_ident.ident.clone(),
            ty: (*pat_type.ty).clone(),
            serialized_name: None,
            is_connection: false,
            is_fds: false,
            is_more: false,
        })
    }
}