qlog/
reader.rs

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26
27use crate::QlogSeq;
28
29/// Represents the format of the read event.
30#[allow(clippy::large_enum_variant)]
31#[derive(Clone, Debug)]
32pub enum Event {
33    /// A native qlog event type.
34    Qlog(crate::events::Event),
35
36    // An extended JSON event type.
37    Json(crate::events::JsonEvent),
38}
39
40/// A helper object specialized for reading JSON-SEQ qlog from a [`BufRead`]
41/// trait.
42///
43/// [`BufRead`]: https://doc.rust-lang.org/std/io/trait.BufRead.html
44pub struct QlogSeqReader<'a> {
45    pub qlog: QlogSeq,
46    reader: Box<dyn std::io::BufRead + Send + Sync + 'a>,
47}
48
49impl<'a> QlogSeqReader<'a> {
50    pub fn new(
51        mut reader: Box<dyn std::io::BufRead + Send + Sync + 'a>,
52    ) -> Result<Self, Box<dyn std::error::Error>> {
53        // "null record" skip it
54        Self::read_record(reader.as_mut());
55
56        let header = Self::read_record(reader.as_mut()).ok_or_else(|| {
57            std::io::Error::other("error reading file header bytes")
58        })?;
59
60        let res: Result<QlogSeq, serde_json::Error> =
61            serde_json::from_slice(&header);
62        match res {
63            Ok(qlog) => Ok(Self { qlog, reader }),
64
65            Err(e) => Err(e.into()),
66        }
67    }
68
69    fn read_record(
70        reader: &mut (dyn std::io::BufRead + Send + Sync),
71    ) -> Option<Vec<u8>> {
72        let mut buf = Vec::<u8>::new();
73        let size = reader.read_until(b'', &mut buf).unwrap();
74        if size <= 1 {
75            return None;
76        }
77
78        buf.truncate(buf.len() - 1);
79
80        Some(buf)
81    }
82}
83
84impl Iterator for QlogSeqReader<'_> {
85    type Item = Event;
86
87    #[inline]
88    fn next(&mut self) -> Option<Self::Item> {
89        // Attempt to deserialize events but skip them if that fails for any
90        // reason, ensuring we always read all bytes in the reader.
91        while let Some(bytes) = Self::read_record(&mut self.reader) {
92            let r: serde_json::Result<crate::events::Event> =
93                serde_json::from_slice(&bytes);
94
95            if let Ok(event) = r {
96                return Some(Event::Qlog(event));
97            }
98
99            let r: serde_json::Result<crate::events::JsonEvent> =
100                serde_json::from_slice(&bytes);
101
102            if let Ok(event) = r {
103                return Some(Event::Json(event));
104            }
105        }
106
107        None
108    }
109}
qlog/reader.rs

qlog/
reader.rs
