matrix_sdk_crypto/
utilities.rs

1// Copyright 2020 The Matrix.org Foundation C.I.C.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15use std::num::NonZeroU8;
16
17use ruma::MilliSecondsSinceUnixEpoch;
18use time::{
19    format_description::well_known::{iso8601, Iso8601},
20    OffsetDateTime,
21};
22
23#[cfg(test)]
24pub(crate) fn json_convert<T, U>(value: &T) -> serde_json::Result<U>
25where
26    T: serde::Serialize,
27    U: serde::de::DeserializeOwned,
28{
29    let json = serde_json::to_string(value)?;
30    serde_json::from_str(&json)
31}
32
33const ISO8601_WITH_MILLIS: iso8601::EncodedConfig = iso8601::Config::DEFAULT
34    .set_time_precision(iso8601::TimePrecision::Second { decimal_digits: NonZeroU8::new(3) })
35    .encode();
36
37/// Format the given timestamp into a human-readable timestamp.
38///
39/// # Returns
40///
41/// Provided the timestamp fits within an `OffsetDateTime` (ie, it is on or
42/// before year 9999), a string that looks like `1970-01-01T00:00:00.000Z`.
43/// Otherwise, `None`.
44pub fn timestamp_to_iso8601(ts: MilliSecondsSinceUnixEpoch) -> Option<String> {
45    let nanos_since_epoch = i128::from(ts.get()) * 1_000_000;
46
47    // OffsetDateTime has a max year of 9999, whereas MilliSecondsSinceUnixEpoch has
48    // a max year of 285427, so `from_unix_timestamp_nanos` can overflow for very
49    // large timestamps. (The Y10K problem!)
50    let dt = OffsetDateTime::from_unix_timestamp_nanos(nanos_since_epoch).ok()?;
51
52    // SAFETY: `format` can fail if:
53    //   * The input lacks information on a component we have asked it to format
54    //     (eg, it is given a `Time` and we ask it for a date), or
55    //   * The input contains an invalid component (eg 30th February), or
56    //   * An `io::Error` is raised internally.
57    //
58    // The first two cannot occur because we know we are giving it a valid
59    // OffsetDateTime that has all the components we are asking it to print.
60    //
61    // The third should not occur because we are formatting a short string to an
62    // in-memory buffer.
63
64    Some(dt.format(&Iso8601::<ISO8601_WITH_MILLIS>).unwrap())
65}
66
67#[cfg(test)]
68pub(crate) mod tests {
69    use ruma::{MilliSecondsSinceUnixEpoch, UInt};
70
71    use super::timestamp_to_iso8601;
72
73    #[test]
74    fn test_timestamp_to_iso8601() {
75        assert_eq!(
76            timestamp_to_iso8601(MilliSecondsSinceUnixEpoch(UInt::new_saturating(0))),
77            Some("1970-01-01T00:00:00.000Z".to_owned())
78        );
79        assert_eq!(
80            timestamp_to_iso8601(MilliSecondsSinceUnixEpoch(UInt::new_saturating(1709657033012))),
81            Some("2024-03-05T16:43:53.012Z".to_owned())
82        );
83        assert_eq!(timestamp_to_iso8601(MilliSecondsSinceUnixEpoch(UInt::MAX)), None);
84    }
85}
matrix_sdk_crypto/utilities.rs

matrix_sdk_crypto/
utilities.rs
