mirror of https://github.com/rwf2/Rocket.git
58 lines
1.7 KiB
Rust
58 lines
1.7 KiB
Rust
use std::fmt;
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use std::borrow::Cow;
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use rocket::request::FromParam;
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use rocket::http::RawStr;
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use rand::{self, Rng};
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/// Table to retrieve base62 values from.
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const BASE62: &'static [u8] = b"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
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/// A _probably_ unique paste ID.
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pub struct PasteID<'a>(Cow<'a, str>);
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impl<'a> PasteID<'a> {
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/// Generate a _probably_ unique ID with `size` characters. For readability,
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/// the characters used are from the sets [0-9], [A-Z], [a-z]. The
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/// probability of a collision depends on the value of `size` and the number
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/// of IDs generated thus far.
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pub fn new(size: usize) -> PasteID<'static> {
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let mut id = String::with_capacity(size);
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let mut rng = rand::thread_rng();
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for _ in 0..size {
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id.push(BASE62[rng.gen::<usize>() % 62] as char);
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}
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PasteID(Cow::Owned(id))
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}
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}
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impl<'a> fmt::Display for PasteID<'a> {
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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write!(f, "{}", self.0)
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}
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}
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/// Returns `true` if `id` is a valid paste ID and `false` otherwise.
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fn valid_id(id: &str) -> bool {
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id.chars().all(|c| {
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(c >= 'a' && c <= 'z')
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|| (c >= 'A' && c <= 'Z')
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|| (c >= '0' && c <= '9')
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})
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}
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/// Returns an instance of `PasteID` if the path segment is a valid ID.
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/// Otherwise returns the invalid ID as the `Err` value.
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impl<'a> FromParam<'a> for PasteID<'a> {
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type Error = &'a RawStr;
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fn from_param(param: &'a RawStr) -> Result<PasteID<'a>, &'a RawStr> {
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match valid_id(param) {
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true => Ok(PasteID(Cow::Borrowed(param))),
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false => Err(param)
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}
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}
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}
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