lemma/
limits.rs

1use crate::error::Error;
2use crate::parsing::source::Source;
3
4pub const MAX_SPEC_NAME_LENGTH: usize = 128;
5pub const MAX_DATA_NAME_LENGTH: usize = 256;
6pub const MAX_RULE_NAME_LENGTH: usize = 256;
7
8/// Maximum significant digits in a number string. rust_decimal supports at most 28;
9/// more can panic or overflow in parse or arithmetic.
10pub const MAX_NUMBER_DIGITS: usize = 28;
11
12/// Maximum character length for a text value (data/runtime input).
13pub const MAX_TEXT_VALUE_LENGTH: usize = 1024;
14
15/// Validate that a name does not exceed the given character limit.
16/// `kind` is a human-readable noun like "spec", "data", "rule", or "type".
17pub fn check_max_length(
18    name: &str,
19    limit: usize,
20    kind: &str,
21    source: Option<Source>,
22) -> Result<(), Error> {
23    if name.len() > limit {
24        return Err(Error::resource_limit_exceeded(
25            format!("max_{kind}_name_length"),
26            format!("{limit} characters"),
27            format!("{} characters", name.len()),
28            format!("Shorten the {kind} name to at most {limit} characters"),
29            source,
30            None,
31            None,
32        ));
33    }
34    Ok(())
35}
36
37/// Limits to prevent abuse and enable predictable resource usage
38///
39/// These limits protect against malicious inputs while being generous enough
40/// for all legitimate use cases.
41#[derive(Debug, Clone)]
42pub struct ResourceLimits {
43    /// Maximum file size in bytes
44    /// Real usage: ~5KB, Limit: 5MB (1000x)
45    pub max_file_size_bytes: usize,
46
47    /// Maximum expression nesting depth
48    /// Real usage: ~3 levels, Limit: 7. Deeper logic via rule composition.
49    pub max_expression_depth: usize,
50
51    /// Maximum expression nodes per file (parser-level)
52    /// Quick-reject for pathological single files.
53    pub max_expression_count: usize,
54
55    /// Maximum total expression nodes across all files (engine-level)
56    /// The real capacity ceiling. pi (~3.1M) — generous for national-scale
57    /// regulatory systems while bounding total engine workload.
58    pub max_total_expression_count: usize,
59
60    /// Maximum size of a single data value in bytes
61    /// Real usage: ~100 bytes, Limit: 1KB (10x)
62    /// Enables server pre-allocation for zero-allocation evaluation
63    pub max_data_value_bytes: usize,
64
65    /// Maximum total bytes to read in a single load_from_paths call (and/or in-memory size of loaded specs)
66    pub max_loaded_bytes: usize,
67
68    /// Maximum number of .lemma files to load in a single load_from_paths call
69    pub max_files: usize,
70}
71
72impl Default for ResourceLimits {
73    fn default() -> Self {
74        Self {
75            max_file_size_bytes: 5 * 1024 * 1024, // 5 MB
76            max_expression_depth: 7,
77            max_expression_count: 4096,
78            max_total_expression_count: 3_141_592,
79            max_data_value_bytes: 1024,         // 1 KB
80            max_loaded_bytes: 50 * 1024 * 1024, // 50 MB
81            max_files: 4096,
82        }
83    }
84}
lemma/limits.rs

lemma/
limits.rs
