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::{
14    fmt,
15    str::FromStr,
16};
17
18use serde_json::Value;
19
20/// Represents the top-level kind of a parsed JSON value.
21///
22/// The decoder uses this type to report whether the parsed value is an object,
23/// an array, or any other scalar-like JSON value.
24#[non_exhaustive]
25#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
26pub enum JsonTopLevelKind {
27    /// Indicates that the parsed top-level value is a JSON object.
28    Object,
29    /// Indicates that the parsed top-level value is a JSON array.
30    Array,
31    /// Indicates that the parsed top-level value is neither an object nor an
32    /// array.
33    Other,
34}
35
36impl JsonTopLevelKind {
37    /// Classifies the top-level kind of `value`.
38    ///
39    /// This helper is used internally by constrained decode methods and may
40    /// also be useful to callers inspecting decoded [`Value`] instances.
41    #[inline]
42    #[must_use]
43    pub fn of(value: &Value) -> Self {
44        match value {
45            Value::Object(_) => Self::Object,
46            Value::Array(_) => Self::Array,
47            _ => Self::Other,
48        }
49    }
50}
51
52impl From<&Value> for JsonTopLevelKind {
53    #[inline]
54    fn from(value: &Value) -> Self {
55        Self::of(value)
56    }
57}
58
59impl fmt::Display for JsonTopLevelKind {
60    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
61        let name = match self {
62            Self::Object => "object",
63            Self::Array => "array",
64            Self::Other => "other",
65        };
66        f.write_str(name)
67    }
68}
69
70impl FromStr for JsonTopLevelKind {
71    type Err = &'static str;
72
73    fn from_str(value: &str) -> Result<Self, Self::Err> {
74        if value.eq_ignore_ascii_case("object") {
75            Ok(Self::Object)
76        } else if value.eq_ignore_ascii_case("array") {
77            Ok(Self::Array)
78        } else if value.eq_ignore_ascii_case("other") {
79            Ok(Self::Other)
80        } else {
81            Err("unknown JsonTopLevelKind")
82        }
83    }
84}
qubit_json/json_top_level_kind.rs

qubit_json/
json_top_level_kind.rs
