serde-lite-derive 0.1.0

Implementation of #[derive(Deserialize, Serialize, Update)] for serde-lite
Documentation 
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use syn::{Attribute, Field, Lit, Meta, NestedMeta, Variant};

/// Get the rename attribute for a given field or the field name.
pub fn get_field_name(field: &Field) -> String {
    if let Some(v) = get_attr_value(&field.attrs, "rename") {
        if let Lit::Str(n) = v {
            return n.value();
        } else {
            panic!("invalid rename attribute");
        }
    }

    field.ident.as_ref().unwrap().to_string()
}

/// Get the skip_serializing_if path for a given field (if present).
pub fn get_skip_field_serializing_if(field: &Field) -> Option<String> {
    if let Some(v) = get_attr_value(&field.attrs, "skip_serializing_if") {
        if let Lit::Str(n) = v {
            Some(n.value())
        } else {
            panic!("invalid skip_serializing_if attribute");
        }
    } else {
        None
    }
}

/// Get enum tag attribute (if present).
pub fn get_enum_tag(attrs: &[Attribute]) -> Option<String> {
    if let Some(v) = get_attr_value(attrs, "tag") {
        if let Lit::Str(n) = v {
            Some(n.value())
        } else {
            panic!("invalid tag attribute");
        }
    } else {
        None
    }
}

/// Get enum content attribute (if present).
pub fn get_enum_content(attrs: &[Attribute]) -> Option<String> {
    if let Some(v) = get_attr_value(attrs, "content") {
        if let Lit::Str(n) = v {
            Some(n.value())
        } else {
            panic!("invalid content attribute");
        }
    } else {
        None
    }
}

/// Get the rename attribute for a given enum variant or the variant name.
pub fn get_variant_name(variant: &Variant) -> String {
    if let Some(v) = get_attr_value(&variant.attrs, "rename") {
        if let Lit::Str(n) = v {
            return n.value();
        } else {
            panic!("invalid rename attribute");
        }
    }

    variant.ident.to_string()
}

/// Get value of a given attribute.
pub fn get_attr_value(attrs: &[Attribute], name: &str) -> Option<Lit> {
    for attr in attrs {
        if attr.path.is_ident("serde") {
            if let Ok(Meta::List(meta)) = attr.parse_meta() {
                for nested in meta.nested {
                    if let NestedMeta::Meta(Meta::NameValue(a)) = nested {
                        if a.path.is_ident(name) {
                            return Some(a.lit);
                        }
                    }
                }
            }
        }
    }

    None
}

/// Check if a given attribute flag is present.
pub fn has_flag(attrs: &[Attribute], name: &str) -> bool {
    for attr in attrs {
        if attr.path.is_ident("serde") {
            if let Ok(Meta::List(meta)) = attr.parse_meta() {
                for nested in meta.nested {
                    if let NestedMeta::Meta(Meta::Path(a)) = nested {
                        if a.is_ident(name) {
                            return true;
                        }
                    }
                }
            }
        }
    }

    false
}