rusty_grep/
lib.rs

1use std::env;
2use std::error::Error;
3use std::fs;
4
5pub struct Config {
6    pub query: String,
7    pub file_path: String,
8    pub ignore_case: bool,
9}
10
11impl Config {
12    pub fn build(mut args: impl Iterator<Item = String>) -> Result<Config, &'static str> {
13        args.next();
14
15        let query = match args.next() {
16            Some(arg) => arg,
17            None => return Err("Didn't get a query string"),
18        };
19
20        let file_path = match args.next() {
21            Some(arg) => arg,
22            None => return Err("Didn't get a file path"),
23        };
24
25        let ignore_case = env::var("IGNORE_CASE").is_ok();
26
27        Ok(Config {
28            query,
29            file_path,
30            ignore_case,
31        })
32    }
33}
34
35pub fn run(config: Config) -> Result<(), Box<dyn Error>> {
36    let contents = fs::read_to_string(config.file_path)?;
37
38    let results = if config.ignore_case {
39        search_case_insensitive(&config.query, &contents)
40    } else {
41        search(&config.query, &contents)
42    };
43
44    for line in results {
45        println!("{line}");
46    }
47
48    Ok(())
49}
50
51pub fn search<'a>(query: &str, contents: &'a str) -> Vec<&'a str> {
52    contents
53        .lines()
54        .filter(|line| line.contains(query))
55        .collect()
56}
57
58pub fn search_case_insensitive<'a>(query: &str, contents: &'a str) -> Vec<&'a str> {
59    let query = query.to_lowercase();
60    let mut results = Vec::new();
61
62    for line in contents.lines() {
63        if line.to_lowercase().contains(&query) {
64            results.push(line);
65        }
66    }
67
68    results
69}
70
71#[cfg(test)]
72mod tests {
73    use super::*;
74
75    #[test]
76    fn case_sensitive() {
77        let query = "duct";
78        let contents = "\
79Rust:
80safe, fast, productive.
81Pick three.
82Duct tape.";
83
84        assert_eq!(vec!["safe, fast, productive."], search(query, contents));
85    }
86
87    #[test]
88    fn case_insensitive() {
89        let query = "rUsT";
90        let contents = "\
91Rust:
92safe, fast, productive.
93Pick three.
94Trust me.";
95
96        assert_eq!(
97            vec!["Rust:", "Trust me."],
98            search_case_insensitive(query, contents)
99        );
100    }
101}
rusty_grep/lib.rs

rusty_grep/
lib.rs
