qubit_json/
json_top_level_kind.rs

1/*******************************************************************************
2 *
3 *    Copyright (c) 2026 Haixing Hu.
4 *
5 *    SPDX-License-Identifier: Apache-2.0
6 *
7 *    Licensed under the Apache License, Version 2.0.
8 *
9 ******************************************************************************/
10//! Defines the coarse top-level JSON kinds used by constrained decode methods.
11//!
12
13use std::{fmt, str::FromStr};
14
15use serde_json::Value;
16
17/// Represents the top-level kind of a parsed JSON value.
18///
19/// The decoder uses this type to report whether the parsed value is an object,
20/// an array, or any other scalar-like JSON value.
21#[non_exhaustive]
22#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
23pub enum JsonTopLevelKind {
24    /// Indicates that the parsed top-level value is a JSON object.
25    Object,
26    /// Indicates that the parsed top-level value is a JSON array.
27    Array,
28    /// Indicates that the parsed top-level value is neither an object nor an
29    /// array.
30    Other,
31}
32
33impl JsonTopLevelKind {
34    /// Classifies the top-level kind of `value`.
35    ///
36    /// This helper is used internally by constrained decode methods and may
37    /// also be useful to callers inspecting decoded [`Value`] instances.
38    #[inline]
39    #[must_use]
40    pub fn of(value: &Value) -> Self {
41        match value {
42            Value::Object(_) => Self::Object,
43            Value::Array(_) => Self::Array,
44            _ => Self::Other,
45        }
46    }
47}
48
49impl From<&Value> for JsonTopLevelKind {
50    #[inline]
51    fn from(value: &Value) -> Self {
52        Self::of(value)
53    }
54}
55
56impl fmt::Display for JsonTopLevelKind {
57    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
58        let name = match self {
59            Self::Object => "object",
60            Self::Array => "array",
61            Self::Other => "other",
62        };
63        f.write_str(name)
64    }
65}
66
67impl FromStr for JsonTopLevelKind {
68    type Err = &'static str;
69
70    fn from_str(value: &str) -> Result<Self, Self::Err> {
71        if value.eq_ignore_ascii_case("object") {
72            Ok(Self::Object)
73        } else if value.eq_ignore_ascii_case("array") {
74            Ok(Self::Array)
75        } else if value.eq_ignore_ascii_case("other") {
76            Ok(Self::Other)
77        } else {
78            Err("unknown JsonTopLevelKind")
79        }
80    }
81}
qubit_json/json_top_level_kind.rs

qubit_json/
json_top_level_kind.rs
