alint_rules/
file_header.rs

1//! `file_header` — first N lines of each file in scope must match a pattern.
2
3use alint_core::{Context, Error, Level, Result, Rule, RuleSpec, Scope, Violation};
4use regex::Regex;
5use serde::Deserialize;
6
7#[derive(Debug, Deserialize)]
8struct Options {
9    pattern: String,
10    #[serde(default = "default_lines")]
11    lines: usize,
12}
13
14fn default_lines() -> usize {
15    20
16}
17
18#[derive(Debug)]
19pub struct FileHeaderRule {
20    id: String,
21    level: Level,
22    policy_url: Option<String>,
23    message: Option<String>,
24    scope: Scope,
25    pattern_src: String,
26    pattern: Regex,
27    lines: usize,
28}
29
30impl Rule for FileHeaderRule {
31    fn id(&self) -> &str {
32        &self.id
33    }
34    fn level(&self) -> Level {
35        self.level
36    }
37    fn policy_url(&self) -> Option<&str> {
38        self.policy_url.as_deref()
39    }
40
41    fn evaluate(&self, ctx: &Context<'_>) -> Result<Vec<Violation>> {
42        let mut violations = Vec::new();
43        for entry in ctx.index.files() {
44            if !self.scope.matches(&entry.path) {
45                continue;
46            }
47            let full = ctx.root.join(&entry.path);
48            let bytes = match std::fs::read(&full) {
49                Ok(b) => b,
50                Err(e) => {
51                    violations.push(
52                        Violation::new(format!("could not read file: {e}")).with_path(&entry.path),
53                    );
54                    continue;
55                }
56            };
57            let Ok(text) = std::str::from_utf8(&bytes) else {
58                violations.push(
59                    Violation::new("file is not valid UTF-8; cannot match header")
60                        .with_path(&entry.path),
61                );
62                continue;
63            };
64            let header: String = text.split_inclusive('\n').take(self.lines).collect();
65            if !self.pattern.is_match(&header) {
66                let msg = self.message.clone().unwrap_or_else(|| {
67                    format!(
68                        "first {} line(s) do not match required header /{}/",
69                        self.lines, self.pattern_src
70                    )
71                });
72                violations.push(
73                    Violation::new(msg)
74                        .with_path(&entry.path)
75                        .with_location(1, 1),
76                );
77            }
78        }
79        Ok(violations)
80    }
81}
82
83pub fn build(spec: &RuleSpec) -> Result<Box<dyn Rule>> {
84    let Some(paths) = &spec.paths else {
85        return Err(Error::rule_config(
86            &spec.id,
87            "file_header requires a `paths` field",
88        ));
89    };
90    let opts: Options = spec
91        .deserialize_options()
92        .map_err(|e| Error::rule_config(&spec.id, format!("invalid options: {e}")))?;
93    if opts.lines == 0 {
94        return Err(Error::rule_config(
95            &spec.id,
96            "file_header `lines` must be > 0",
97        ));
98    }
99    let pattern = Regex::new(&opts.pattern)
100        .map_err(|e| Error::rule_config(&spec.id, format!("invalid pattern: {e}")))?;
101    Ok(Box::new(FileHeaderRule {
102        id: spec.id.clone(),
103        level: spec.level,
104        policy_url: spec.policy_url.clone(),
105        message: spec.message.clone(),
106        scope: Scope::from_paths_spec(paths)?,
107        pattern_src: opts.pattern,
108        pattern,
109        lines: opts.lines,
110    }))
111}
alint_rules/file_header.rs

alint_rules/
file_header.rs
