Function compute_struct_fingerprint

rust/fory-derive/src/object/util.rs:779–826

Computes struct fingerprint string at compile time (during proc-macro execution). Fingerprint Format:** ` , , , [ ];` Tagged fields are sorted by numeric ID. Untagged fields are sorted by name lexicographically.

(fields: &[&Field])

/// **Fingerprint Format:** `<field_name_or_id>,<type_id>,<ref>,<nullable>[<child...>];`
/// Tagged fields are sorted by numeric ID. Untagged fields are sorted by name lexicographically.
fn compute_struct_fingerprint(fields: &[&Field]) -> String {
    use super::field_meta::parse_field_meta;
    use std::cmp::Ordering;

    let mut field_infos: Vec<FieldFingerprintInfo> = Vec::with_capacity(fields.len());

    for (idx, field) in fields.iter().enumerate() {
        let meta = parse_field_meta(field).unwrap_or_default();
        if meta.skip {
            continue;
        }

        let name = get_field_name(field, idx);
        let field_id = meta.effective_id();
        let name_or_id = if field_id >= 0 {
            field_id.to_string()
        } else {
            to_snake_case(&name)
        };

        field_infos.push(FieldFingerprintInfo {
            field_id,
            name_or_id,
            type_fingerprint: build_type_fingerprint(&field.ty, &meta, true, true),
        });
    }

    field_infos.sort_by(|a, b| match (a.field_id >= 0, b.field_id >= 0) {
        (true, true) => a
            .field_id
            .cmp(&b.field_id)
            .then_with(|| a.name_or_id.cmp(&b.name_or_id)),
        (true, false) => Ordering::Less,
        (false, true) => Ordering::Greater,
        (false, false) => a.name_or_id.cmp(&b.name_or_id),
    });

    // Build fingerprint string
    let mut fingerprint = String::new();
    for info in &field_infos {
        fingerprint.push_str(&info.name_or_id);
        fingerprint.push(',');
        fingerprint.push_str(&info.type_fingerprint);
        fingerprint.push(';');
    }

    fingerprint
}

/// Generates TokenStream for struct version hash (computed at compile time).
pub(crate) fn gen_struct_version_hash_ts(fields: &[&Field]) -> TokenStream {