qubit_codec/value/
json_string_value_encoder.rs

1// =============================================================================
2//    Copyright (c) 2026 Haixing Hu.
3//
4//    SPDX-License-Identifier: Apache-2.0
5//
6//    Licensed under the Apache License, Version 2.0.
7// =============================================================================
8//! Serde JSON string encoder for one owned value.
9
10use core::marker::PhantomData;
11
12use serde::Serialize;
13use serde_json::Error as JsonError;
14use serde_json::to_string;
15
16use super::ValueEncoder;
17
18/// Encodes one serializable value into a UTF-8 JSON string via `serde_json`.
19/// Its stateless marker implements `Clone`, `Copy`, and `Default` without
20/// requiring those traits on `T`.
21///
22/// # Type Parameters
23///
24/// - `T`: Source value type serialized through Serde.
25///
26/// # Examples
27///
28/// ```rust
29/// use qubit_codec::{JsonStringValueEncoder, ValueEncoder};
30/// use serde::Serialize;
31///
32/// #[derive(Serialize)]
33/// struct Point {
34///     x: i32,
35///     y: i32,
36/// }
37///
38/// let mut encoder = JsonStringValueEncoder::<Point>::new();
39/// let json = encoder.encode(&Point { x: 1, y: 2 }).unwrap();
40/// assert_eq!(json, r#"{"x":1,"y":2}"#);
41/// ```
42#[must_use]
43#[derive(Debug)]
44pub struct JsonStringValueEncoder<T> {
45    /// Associates the encoder with `T` without retaining a source value.
46    _marker: PhantomData<T>,
47}
48
49impl<T> Copy for JsonStringValueEncoder<T> {}
50
51impl<T> Clone for JsonStringValueEncoder<T> {
52    /// Copies the stateless encoder marker without requiring `T: Clone`.
53    #[inline]
54    fn clone(&self) -> Self {
55        *self
56    }
57}
58
59impl<T> Default for JsonStringValueEncoder<T> {
60    /// Creates the stateless encoder through its const constructor.
61    #[inline]
62    fn default() -> Self {
63        Self::new()
64    }
65}
66
67impl<T> JsonStringValueEncoder<T> {
68    /// Creates a JSON string encoder for values of type `T`.
69    ///
70    /// # Returns
71    ///
72    /// Returns a stateless encoder without allocating an output string.
73    #[inline]
74    pub const fn new() -> Self {
75        Self { _marker: PhantomData }
76    }
77}
78
79impl<T> ValueEncoder<T> for JsonStringValueEncoder<T>
80where
81    T: Serialize,
82{
83    /// JSON serialization error returned when `T` cannot be serialized.
84    type Error = JsonError;
85    /// UTF-8 JSON text owned by the caller.
86    type Output = String;
87
88    /// Serializes `input` into a compact JSON string.
89    ///
90    /// # Parameters
91    /// - `input`: Value to serialize.
92    ///
93    /// # Returns
94    /// The serialized JSON text as an owned UTF-8 string.
95    ///
96    /// # Errors
97    /// Returns the `serde_json` error if serialization fails, such as when a
98    /// custom serializer reports an error or the value contains unsupported
99    /// data.
100    #[inline]
101    fn encode(&mut self, input: &T) -> Result<Self::Output, Self::Error> {
102        to_string(input)
103    }
104}
qubit_codec/value/json_string_value_encoder.rs

qubit_codec/value/
json_string_value_encoder.rs
