Function json_value_expr

avro_derive/src/utils.rs:73–130

Convert a `Value` into a `TokenStream`. The `Value` is constructed, not parsed from a JSON string.

(value: Value)

/// Convert a `Value` into a `TokenStream`.
///
/// The `Value` is constructed, not parsed from a JSON string.
pub fn json_value_expr(value: Value) -> TokenStream {
    match value {
        Value::Null => quote! {
            ::serde_json::Value::Null
        },
        Value::Bool(bool) => quote! {
            ::serde_json::Value::Bool(#bool)
        },
        Value::Number(number) => {
            if let Some(n) = number.as_u64() {
                quote! {
                    ::serde_json::Value::Number(::serde_json::Number::from(#n))
                }
            } else if let Some(n) = number.as_i64() {
                quote! {
                    ::serde_json::Value::Number(::serde_json::Number::from(#n))
                }
            } else if let Some(n) = number.as_f64() {
                quote! {
                    ::serde_json::Value::Number(::serde_json::Number::from_f64(#n).expect("Unreachable, f64 is finite"))
                }
            } else {
                // This is needed when the arbitrary-precision feature flag is enabled on serde_json
                let s = number.to_string();
                quote! {
                    ::serde_json::Value::Number(#s.parse().expect(concat!("This was a valid number at compile time: ", #s)))
                }
            }
        }
        Value::String(string) => quote! {
            ::serde_json::Value::String(::std::string::String::from(#string))
        },
        Value::Array(array) => {
            let array = array.into_iter().map(json_value_expr);
            quote! {
                ::serde_json::Value::Array(vec![#(#array),*])
            }
        }
        Value::Object(object) => {
            let len = object.len();

            let mut keys = Vec::with_capacity(len);
            let mut values = Vec::with_capacity(len);
            for (key, value) in object {
                keys.push(key);
                values.push(json_value_expr(value));
            }

            quote! {
                ::serde_json::Value::Object({
                    let mut map = ::serde_json::Map::with_capacity(#len);
                    #(map.insert(::std::string::String::from(#keys), #values);)*
                    map
                })
            }
        }