vendor/tracing-subscriber/src/field/display.rs

   1 //! `MakeVisitor` wrappers for working with `fmt::Display` fields.
   2 use super::{MakeVisitor, VisitFmt, VisitOutput};
   3 use tracing_core::field::{Field, Visit};
   4
   5 use core::fmt;
   6
   7 /// A visitor wrapper that ensures any strings named "message" are formatted
   8 /// using `fmt::Display`
   9 #[derive(Debug, Clone)]
  10 pub struct Messages<V>(V);
  11
  12 // TODO(eliza): When `error` as a primitive type is stable, add a
  13 // `DisplayErrors` wrapper...
  14
  15 // === impl Messages ===
  16 //
  17 impl<V> Messages<V> {
  18     /// Returns a new [`MakeVisitor`] implementation that will wrap `inner` so
  19     /// that any strings named `message` are formatted using `fmt::Display`.
  20     ///
  21     /// [`MakeVisitor`]: super::MakeVisitor
  22     pub fn new(inner: V) -> Self {
  23         Messages(inner)
  24     }
  25 }
  26
  27 impl<T, V> MakeVisitor<T> for Messages<V>
  28 where
  29     V: MakeVisitor<T>,
  30 {
  31     type Visitor = Messages<V::Visitor>;
  32
  33     #[inline]
  34     fn make_visitor(&self, target: T) -> Self::Visitor {
  35         Messages(self.0.make_visitor(target))
  36     }
  37 }
  38
  39 impl<V> Visit for Messages<V>
  40 where
  41     V: Visit,
  42 {
  43     #[inline]
  44     fn record_f64(&mut self, field: &Field, value: f64) {
  45         self.0.record_f64(field, value)
  46     }
  47
  48     #[inline]
  49     fn record_i64(&mut self, field: &Field, value: i64) {
  50         self.0.record_i64(field, value)
  51     }
  52
  53     #[inline]
  54     fn record_u64(&mut self, field: &Field, value: u64) {
  55         self.0.record_u64(field, value)
  56     }
  57
  58     #[inline]
  59     fn record_bool(&mut self, field: &Field, value: bool) {
  60         self.0.record_bool(field, value)
  61     }
  62
  63     /// Visit a string value.
  64     fn record_str(&mut self, field: &Field, value: &str) {
  65         if field.name() == "message" {
  66             self.0.record_debug(field, &format_args!("{}", value))
  67         } else {
  68             self.0.record_str(field, value)
  69         }
  70     }
  71
  72     // TODO(eliza): add RecordError when stable
  73     // fn record_error(&mut self, field: &Field, value: &(dyn std::error::Error + 'static)) {
  74     //     self.record_debug(field, &format_args!("{}", value))
  75     // }
  76
  77     #[inline]
  78     fn record_debug(&mut self, field: &Field, value: &dyn fmt::Debug) {
  79         self.0.record_debug(field, value)
  80     }
  81 }
  82
  83 impl<V, O> VisitOutput<O> for Messages<V>
  84 where
  85     V: VisitOutput<O>,
  86 {
  87     #[inline]
  88     fn finish(self) -> O {
  89         self.0.finish()
  90     }
  91 }
  92
  93 feature! {
  94     #![feature = "std"]
  95     use super::VisitWrite;
  96     use std::io;
  97
  98     impl<V> VisitWrite for Messages<V>
  99     where
 100         V: VisitWrite,
 101     {
 102         #[inline]
 103         fn writer(&mut self) -> &mut dyn io::Write {
 104             self.0.writer()
 105         }
 106     }
 107 }
 108
 109 impl<V> VisitFmt for Messages<V>
 110 where
 111     V: VisitFmt,
 112 {
 113     #[inline]
 114     fn writer(&mut self) -> &mut dyn fmt::Write {
 115         self.0.writer()
 116     }
 117 }