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