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extern crate rand; // <1>
use rand::Rng; // <2>
fn one_in(n: u32) -> bool { // <3>
rand::thread_rng().gen_weighted_bool(n)
}
#[derive(Debug)]
struct File {
name: String,
data: Vec<u8>,
}
impl File {
fn new(name: &str) -> File {
File { name: String::from(name), data: Vec::new() } // <4>
}
fn new_with_data(name: &str, data: &Vec<u8>) -> File {
let mut f = File::new(name);
f.data = data.clone();
f
}
fn read(self: &File, save_to: &mut Vec<u8>) -> Result<usize, String> { // <5>
let mut tmp = self.data.clone();
let read_length = tmp.len();
save_to.reserve(read_length);
save_to.append(&mut tmp);
Ok(read_length) // <6>
}
}
fn open(f: File) -> Result<File, String> {
if one_in(10_000) { // <7>
let err_msg = String::from("Permission denied");
return Err(err_msg);
}
Ok(f)
}
fn close(f: File) -> Result<File, String> {
if one_in(100_000) { // <8>
let err_msg = String::from("Interrupted by signal!");
return Err(err_msg);
}
Ok(f)
}
fn main() {
let f4_data: Vec<u8> = vec![114, 117, 115, 116, 33];
let mut f4 = File::new_with_data("4.txt", &f4_data);
let mut buffer: Vec<u8> = vec![];
f4 = open(f4).unwrap(); // <9>
let f4_length = f4.read(&mut buffer).unwrap(); // <9>
f4 = close(f4).unwrap(); // <9>
let text = String::from_utf8_lossy(&buffer);
println!("{:?}", f4);
println!("{} is {} bytes long", &f4.name, f4_length);
println!("{}", text);
}
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