lgwks_std 0.5.1

//! `json` owns JSON encoding and decoding for external interfaces.
//! Built on serde_json for correctness and interoperability. For
//! internal binary wire format, use [`crate::wire`].
//!
//! INV-JSON-UTF8: all output is valid UTF-8. Input is validated as
//! UTF-8 during deserialization.

// ── Re-exports ──────────────────────────────────────────────────────────────

pub use serde::{self, Deserialize, Serialize};
pub use serde_json::{Error, Map, Number, Value};

// ── Encoding ────────────────────────────────────────────────────────────────

/// Serialize `value` to a compact JSON string (no whitespace, no newlines).
pub fn to_string<T: Serialize>(value: &T) -> Result<String, Error> {
    serde_json::to_string(value)
}

/// Serialize `value` to a pretty-printed JSON string with indentation.
pub fn to_string_pretty<T: Serialize>(value: &T) -> Result<String, Error> {
    serde_json::to_string_pretty(value)
}

/// Serialize `value` to a byte vector (compact JSON).
pub fn to_vec<T: Serialize>(value: &T) -> Result<Vec<u8>, Error> {
    serde_json::to_vec(value)
}

/// Serialize `value` to a writer.
pub fn to_writer<W: std::io::Write, T: Serialize>(writer: W, value: &T) -> Result<(), Error> {
    serde_json::to_writer(writer, value)
}

// ── Decoding ────────────────────────────────────────────────────────────────

/// Deserialize a JSON string into the requested type.
pub fn from_str<T: serde::de::DeserializeOwned>(s: &str) -> Result<T, Error> {
    serde_json::from_str(s)
}

/// Deserialize a JSON byte slice into the requested type.
pub fn from_slice<T: serde::de::DeserializeOwned>(bytes: &[u8]) -> Result<T, Error> {
    serde_json::from_slice(bytes)
}

/// Deserialize from a reader.
pub fn from_reader<R: std::io::Read, T: serde::de::DeserializeOwned>(
    reader: R,
) -> Result<T, Error> {
    serde_json::from_reader(reader)
}

/// Deserialize a [`Value`] into the requested type.
pub fn from_value<T: serde::de::DeserializeOwned>(value: Value) -> Result<T, Error> {
    serde_json::from_value(value)
}

/// Serialize a value into a [`Value`].
pub fn to_value<T: Serialize>(value: &T) -> Result<Value, Error> {
    serde_json::to_value(value)
}

// ── Tests ───────────────────────────────────────────────────────────────────

#[cfg(test)]
mod tests {
    use super::*;
    use serde::Deserialize;

    #[derive(Serialize, Deserialize, Debug, PartialEq, Eq)]
    struct Point {
        x: i32,
        y: i32,
    }

    #[test]
    fn roundtrips_through_string() {
        let p = Point { x: 1, y: 2 };
        let s = to_string(&p).unwrap();
        let q: Point = from_str(&s).unwrap();
        assert_eq!(p, q);
    }

    #[test]
    fn compact_output_has_no_whitespace() {
        let p = Point { x: 1, y: 2 };
        let s = to_string(&p).unwrap();
        assert!(!s.contains('\n'));
        assert!(!s.contains("  "));
    }

    #[test]
    fn pretty_output_has_indentation() {
        let p = Point { x: 1, y: 2 };
        let s = to_string_pretty(&p).unwrap();
        assert!(s.contains('\n'));
    }

    #[test]
    fn from_str_rejects_invalid() {
        let result: Result<Point, _> = from_str("{");
        assert!(result.is_err());
    }
}