workshop_rs/gameplay/
data.rs

1//! Embedded gameplay data with a pinned source identity.
2//!
3//! The data file is a checked-in projection of the user-provided
4//! `workshop-data` export. This module owns parsing, schema validation, and
5//! dataset-digest verification; query and calculation APIs remain separate.
6
7use sha2::{Digest, Sha256};
8use std::sync::OnceLock;
9
10use crate::gameplay::{GameplayCatalog, GameplayDataError, GameplayDatasetIdentity, Hero};
11
12/// The canonical gameplay dataset embedded in the crate.
13pub const GAMEPLAY_DATA: &str = include_str!("gameplay.json");
14
15const SCHEMA_VERSION: u32 = 2;
16
17#[derive(serde::Deserialize)]
18#[serde(rename_all = "camelCase")]
19struct GameplaySchema {
20    schema_version: u32,
21}
22
23#[derive(serde::Deserialize)]
24#[serde(rename_all = "camelCase")]
25struct GameplayFile {
26    schema_version: u32,
27    identity: GameplayDatasetIdentity,
28    heroes: Vec<Hero>,
29}
30
31fn probe_schema_version(json: &str) -> Result<u32, GameplayDataError> {
32    let schema: GameplaySchema = serde_json::from_str(json)
33        .map_err(|error| GameplayDataError::Malformed(error.to_string()))?;
34    if schema.schema_version != SCHEMA_VERSION {
35        return Err(GameplayDataError::UnsupportedSchema(schema.schema_version));
36    }
37    Ok(schema.schema_version)
38}
39
40/// Load and validate a gameplay dataset from its JSON representation.
41pub fn load(json: &str) -> Result<GameplayCatalog, GameplayDataError> {
42    let schema_version = probe_schema_version(json)?;
43
44    let file: GameplayFile = serde_json::from_str(json)
45        .map_err(|error| GameplayDataError::Malformed(error.to_string()))?;
46    if file.schema_version != schema_version {
47        return Err(GameplayDataError::UnsupportedSchema(file.schema_version));
48    }
49
50    let computed = content_digest(json)?;
51    if file.identity.digest != computed {
52        return Err(GameplayDataError::DigestMismatch {
53            declared: file.identity.digest,
54            computed,
55        });
56    }
57
58    GameplayCatalog::new(file.identity, file.heroes)
59}
60
61/// Load the checked-in gameplay dataset.
62pub fn builtin() -> Result<GameplayCatalog, GameplayDataError> {
63    builtin_ref().cloned().map_err(Clone::clone)
64}
65
66/// The checked-in gameplay dataset, loaded and validated once per process.
67pub fn builtin_ref() -> Result<&'static GameplayCatalog, &'static GameplayDataError> {
68    static DATA: OnceLock<Result<GameplayCatalog, GameplayDataError>> = OnceLock::new();
69    match DATA.get_or_init(|| load(GAMEPLAY_DATA)) {
70        Ok(catalog) => Ok(catalog),
71        Err(error) => Err(error),
72    }
73}
74
75/// Compute the deterministic SHA-256 identity of a gameplay dataset.
76///
77/// The self-referential `identity.digest` field is excluded before the JSON
78/// value is serialized with sorted object keys. Whitespace and source key
79/// ordering therefore do not change the dataset identity.
80pub fn content_digest(json: &str) -> Result<String, GameplayDataError> {
81    let mut value: serde_json::Value = serde_json::from_str(json)
82        .map_err(|error| GameplayDataError::Malformed(error.to_string()))?;
83    let identity = value
84        .as_object_mut()
85        .and_then(|root| root.get_mut("identity"))
86        .and_then(serde_json::Value::as_object_mut)
87        .ok_or_else(|| GameplayDataError::Malformed("missing identity object".to_string()))?;
88    identity
89        .remove("digest")
90        .ok_or_else(|| GameplayDataError::Malformed("missing identity.digest".to_string()))?;
91
92    let canonical = serde_json::to_string(&value)
93        .map_err(|error| GameplayDataError::Malformed(error.to_string()))?;
94    Ok(format!("sha256:{:x}", Sha256::digest(canonical.as_bytes())))
95}
workshop_rs/gameplay/data.rs

workshop_rs/gameplay/
data.rs
