contact_tracing/
rpi.rs

1use std::fmt;
2
3#[cfg(feature = "chrono")]
4use chrono::{DateTime, Utc};
5use derive_more::{Display, Error};
6
7use crate::utils::Base64DebugFmtHelper;
8
9#[cfg(feature = "chrono")]
10use crate::utils::tin_for_timestamp;
11
12/// A Rolling Proximity Identifier.
13#[derive(Default, Copy, Clone, PartialEq, Eq, Ord, PartialOrd, Hash)]
14pub struct Rpi {
15    bytes: [u8; 16],
16}
17
18impl fmt::Debug for Rpi {
19    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
20        f.debug_tuple("Rpi")
21            .field(&Base64DebugFmtHelper(self))
22            .finish()
23    }
24}
25
26impl Rpi {
27    /// Returns the RPI for a timestamp directly from a tracing key.
28    #[cfg(feature = "chrono")]
29    pub fn for_timestamp(tk: &crate::tkey::TracingKey, timestamp: &DateTime<Utc>) -> Rpi {
30        let dtkey = crate::dtkey::DailyTracingKey::for_timestamp(tk, timestamp);
31        dtkey.get_rpi_for_tin(tin_for_timestamp(timestamp)).unwrap()
32    }
33
34    /// Returns the RPI that is for the current time interval.
35    #[cfg(feature = "chrono")]
36    pub fn for_now(tk: &crate::tkey::TracingKey) -> Rpi {
37        Rpi::for_timestamp(tk, &Utc::now())
38    }
39
40    /// Creates a RPI from raw bytes.
41    pub fn from_bytes(b: &[u8]) -> Result<Rpi, InvalidRpi> {
42        if b.len() != 16 {
43            return Err(InvalidRpi);
44        }
45        let mut bytes = [0u8; 16];
46        bytes.copy_from_slice(b);
47        Ok(Rpi { bytes })
48    }
49
50    /// Returns the bytes behind the RPI
51    pub fn as_bytes(&self) -> &[u8] {
52        &self.bytes
53    }
54}
55
56/// Raised if a RPI is invalid.
57#[derive(Error, Display, Debug)]
58#[display(fmt = "invalid rpi")]
59pub struct InvalidRpi;
60
61#[cfg(feature = "base64")]
62mod base64_impl {
63    use super::*;
64    use std::{fmt, str};
65
66    impl str::FromStr for Rpi {
67        type Err = InvalidRpi;
68
69        fn from_str(value: &str) -> Result<Rpi, InvalidRpi> {
70            let mut bytes = [0u8; 16];
71            if value.len() != 22 {
72                return Err(InvalidRpi);
73            }
74            base64_::decode_config_slice(value, base64_::URL_SAFE_NO_PAD, &mut bytes[..])
75                .map_err(|_| InvalidRpi)?;
76            Ok(Rpi { bytes })
77        }
78    }
79
80    impl fmt::Display for Rpi {
81        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
82            let mut buf = [0u8; 50];
83            let len = base64_::encode_config_slice(self.bytes, base64_::URL_SAFE_NO_PAD, &mut buf);
84            f.write_str(unsafe { std::str::from_utf8_unchecked(&buf[..len]) })
85        }
86    }
87}
88
89#[cfg(feature = "serde")]
90mod serde_impl {
91    pub use super::*;
92
93    use serde_::de::Deserializer;
94    use serde_::ser::Serializer;
95    use serde_::{Deserialize, Serialize};
96
97    impl Serialize for Rpi {
98        fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
99        where
100            S: Serializer,
101        {
102            if serializer.is_human_readable() {
103                serializer.serialize_str(&self.to_string())
104            } else {
105                serializer.serialize_bytes(self.as_bytes())
106            }
107        }
108    }
109
110    impl<'de> Deserialize<'de> for Rpi {
111        fn deserialize<D>(deserializer: D) -> Result<Rpi, D::Error>
112        where
113            D: Deserializer<'de>,
114        {
115            use serde_::de::Error;
116            if deserializer.is_human_readable() {
117                let s = String::deserialize(deserializer).map_err(D::Error::custom)?;
118                s.parse().map_err(D::Error::custom)
119            } else {
120                let buf = Vec::<u8>::deserialize(deserializer).map_err(D::Error::custom)?;
121                Rpi::from_bytes(&buf).map_err(D::Error::custom)
122            }
123        }
124    }
125}
contact_tracing/rpi.rs

contact_tracing/
rpi.rs
