molframe_core/io/input/
limits.rs

1//! Hostile-input ceilings shared by readers and decoders.
2
3use crate::diagnostic::{Code, Diagnostic};
4
5const DEFAULT_DECOMPRESSED_BYTES: u64 = u64::MAX;
6const DEFAULT_COMPRESSION_RATIO: u64 = 1_000;
7const DEFAULT_NESTING_DEPTH: u32 = 64;
8
9/// Ceilings that turn hostile input into diagnostics rather than exhaustion.
10#[derive(Clone, Copy, PartialEq, Eq, Debug)]
11pub struct Limits {
12    /// Largest accepted size after decompression, in bytes.
13    ///
14    /// Unbounded by default. The ceiling exists to stop a small compressed
15    /// input expanding without limit, and that job is done by
16    /// [`Self::compression_ratio`], which bounds expansion against the bytes
17    /// actually supplied. An absolute ceiling additionally refuses large
18    /// *uncompressed* input, where there is nothing to defend against: the
19    /// file is already that size, and reading it cannot multiply it.
20    ///
21    /// A caller who wants an absolute ceiling sets one.
22    pub decompressed_bytes: u64,
23    /// Largest accepted ratio of decompressed to compressed size.
24    pub compression_ratio: u64,
25    /// Largest accepted declared row count for one category.
26    pub rows_per_category: u64,
27    /// Deepest accepted nesting.
28    pub nesting_depth: u32,
29    /// Largest accepted identifier dictionary.
30    pub dictionary_entries: u32,
31}
32
33impl Default for Limits {
34    fn default() -> Self {
35        Self {
36            decompressed_bytes: DEFAULT_DECOMPRESSED_BYTES,
37            compression_ratio: DEFAULT_COMPRESSION_RATIO,
38            rows_per_category: u64::MAX,
39            nesting_depth: DEFAULT_NESTING_DEPTH,
40            dictionary_entries: u32::MAX - 1,
41        }
42    }
43}
44
45impl Limits {
46    /// Builds the registered finding for a violated ceiling.
47    #[must_use]
48    pub fn exceeded(limit: &'static str, value: impl std::fmt::Display) -> Diagnostic {
49        Diagnostic::new(Code::E1901)
50            .with_context("limit", limit)
51            .with_context("value", value.to_string())
52    }
53}
molframe_core/io/input/limits.rs

molframe_core/io/input/
limits.rs
