rust_learning/minigrep/src/lib.rs

111 lines
2.4 KiB
Rust

use std::error::Error;
use std::fs;
use std::env;
pub struct Config {
pub query: String,
pub filename: String,
pub case_sensitive: bool,
}
impl Config {
pub fn new(mut args: env::Args) -> Result<Config, &'static str> {
args.next();
let query = match args.next() {
Some(arg) => arg,
None => return Err("Didn't get a query string"),
};
let filename = match args.next() {
Some(arg) => arg,
None => return Err("Didn't get a file name"),
};
let case_sensitive = env::var("CASE_INSENSITIVE").is_err();
Ok(Config { query, filename, case_sensitive })
}
}
fn search<'a>(query: &str, contents: &'a str) -> Vec<&'a str> {
contents
.lines()
.filter(|line| line.contains(query))
.collect()
}
fn search_case_insensitive<'a>(query: &str, contents: &'a str) -> Vec<&'a str> {
let query = query.to_lowercase();
contents
.lines()
.filter(|line| line.to_lowercase().contains(&query))
.collect()
}
pub fn run(config: Config) -> Result<(), Box<dyn Error>> {
let contents = fs::read_to_string(config.filename)?;
let results = if config.case_sensitive {
search(&config.query, &contents)
} else {
search_case_insensitive(&config.query, &contents)
};
for line in results {
println!("{}", line);
}
Ok(())
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn search_case_sensitive() {
let query = "duct";
let contents = "\
Rust:
safe, fast, productive.
Pick three.
Duct tape.";
assert_eq!(vec!["safe, fast, productive."], search(query, contents));
}
#[test]
fn case_insensitive() {
let query = "rUsT";
let contents = "\
Rust:
safe, fast, productive.
Pick three.
Trust me.";
assert_eq!(
vec!["Rust:", "Trust me."],
search_case_insensitive(query, contents)
);
}
#[test]
fn run_valid_file() {
assert!(run(Config {
query: String::from("test"),
filename: String::from("poem.txt"),
case_sensitive: true,
}).is_ok());
}
#[test]
fn run_invalid_file() {
assert!(run(Config {
query: String::from("test"),
filename: String::from("134857320592.txt"),
case_sensitive: true,
}).is_err());
}
}