lemma/
limits.rs

1use crate::error::Error;
2use crate::parsing::source::Source;
3
4pub const MAX_SPEC_NAME_LENGTH: usize = 128;
5pub const MAX_FACT_NAME_LENGTH: usize = 256;
6pub const MAX_RULE_NAME_LENGTH: usize = 256;
7pub const MAX_TYPE_NAME_LENGTH: usize = 256;
8
9/// Maximum significant digits in a number string. rust_decimal supports at most 28;
10/// more can panic or overflow in parse or arithmetic.
11pub const MAX_NUMBER_DIGITS: usize = 28;
12
13/// Maximum character length for a text value (fact/runtime input).
14pub const MAX_TEXT_VALUE_LENGTH: usize = 1024;
15
16/// Validate that a name does not exceed the given character limit.
17/// `kind` is a human-readable noun like "spec", "fact", "rule", or "type".
18pub fn check_max_length(
19    name: &str,
20    limit: usize,
21    kind: &str,
22    source: Option<Source>,
23) -> Result<(), Error> {
24    if name.len() > limit {
25        return Err(Error::resource_limit_exceeded(
26            format!("max_{kind}_name_length"),
27            format!("{limit} characters"),
28            format!("{} characters", name.len()),
29            format!("Shorten the {kind} name to at most {limit} characters"),
30            source,
31            None,
32            None,
33        ));
34    }
35    Ok(())
36}
37
38/// Limits to prevent abuse and enable predictable resource usage
39///
40/// These limits protect against malicious inputs while being generous enough
41/// for all legitimate use cases.
42#[derive(Debug, Clone)]
43pub struct ResourceLimits {
44    /// Maximum file size in bytes
45    /// Real usage: ~5KB, Limit: 5MB (1000x)
46    pub max_file_size_bytes: usize,
47
48    /// Maximum expression nesting depth
49    /// Real usage: ~3 levels, Limit: 7. Deeper logic via rule composition.
50    pub max_expression_depth: usize,
51
52    /// Maximum expression nodes per file (parser-level)
53    /// Quick-reject for pathological single files.
54    pub max_expression_count: usize,
55
56    /// Maximum total expression nodes across all files (engine-level)
57    /// The real capacity ceiling. pi (~3.1M) — generous for national-scale
58    /// regulatory systems while bounding total engine workload.
59    pub max_total_expression_count: usize,
60
61    /// Maximum size of a single fact value in bytes
62    /// Real usage: ~100 bytes, Limit: 1KB (10x)
63    /// Enables server pre-allocation for zero-allocation evaluation
64    pub max_fact_value_bytes: usize,
65
66    /// Maximum total bytes to read in a single load_from_paths call (and/or in-memory size of loaded specs)
67    pub max_loaded_bytes: usize,
68
69    /// Maximum number of .lemma files to load in a single load_from_paths call
70    pub max_files: usize,
71}
72
73impl Default for ResourceLimits {
74    fn default() -> Self {
75        Self {
76            max_file_size_bytes: 5 * 1024 * 1024, // 5 MB
77            max_expression_depth: 7,
78            max_expression_count: 4096,
79            max_total_expression_count: 3_141_592,
80            max_fact_value_bytes: 1024,         // 1 KB
81            max_loaded_bytes: 50 * 1024 * 1024, // 50 MB
82            max_files: 4096,
83        }
84    }
85}
lemma/limits.rs

lemma/
limits.rs
