100 lines
2.1 KiB
Rust
100 lines
2.1 KiB
Rust
use std::env;
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use std::error::Error;
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use std::fs;
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pub struct Config {
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pub query: String,
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pub filename: String,
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pub case_sensitive: bool,
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}
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impl Config {
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pub fn new(mut args: std::env::Args) -> Result<Config, &'static str> {
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args.next(); // Skip the program's name
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let query = match args.next() {
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Some(arg) => arg,
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None => return Err("Didn't get a query string"),
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};
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let filename = match args.next() {
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Some(arg) => arg,
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None => return Err("Didn't get a file name"),
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};
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let case_sensitive = env::var("CASE_INSENSITIVE").is_err();
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Ok(Config { query, filename, case_sensitive })
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}
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}
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pub fn run(config: Config) -> Result<(), Box<dyn Error>> {
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// The ? operator passes the error back to the caller.
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let contents = fs::read_to_string(config.filename)?;
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let results = if config.case_sensitive {
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search(&config.query, &contents)
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} else {
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search_case_insensitive(&config.query, &contents)
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};
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for line in results {
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println!("{}", line);
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}
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Ok(())
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}
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fn search<'a>(query: &str, contents: &'a str) -> Vec<&'a str> {
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contents.lines()
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.filter(|line| line.contains(query))
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.collect()
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}
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fn search_case_insensitive<'a>(query: &str, contents: &'a str) -> Vec<&'a str> {
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let query = query.to_lowercase();
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contents.lines()
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.filter(|line| {
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line.to_lowercase()
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.as_str()
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.contains(query.as_str())
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})
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.collect()
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn case_sensitive() {
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let query = "duct";
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let contents = "\
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Rust:
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safe, fast, productive.
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Pick three.
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Duct tape.";
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assert_eq!(
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vec!["safe, fast, productive."],
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search(query, contents)
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);
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}
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#[test]
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fn case_insensitive() {
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let query = "rUsT";
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let contents = "\
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Rust:
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safe, fast, productive.
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Pick three.
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Trust me.";
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assert_eq!(
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vec!["Rust:", "Trust me."],
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search_case_insensitive(query, contents)
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);
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}
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}
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