sofie_core/
show.rs

1use std::fmt::Display;
2
3use serde_json::{Map, Number};
4
5use crate::{Instant, Timestamp, Uuid, Value};
6
7/// What a screen reads of a value: borrowed from it, so reading allocates nothing.
8#[derive(Clone, Copy)]
9pub enum Shown<'a> {
10    Null,
11    Bool(bool),
12    Integer(i64),
13    Float(f64),
14    Number(&'a Number),
15    Text(&'a str),
16    /// Hex digits and hyphens only, so a page writes it without escaping or percent-encoding.
17    Uuid(Uuid),
18    /// Typed, so a screen tells it from text written like one.
19    Instant(Instant),
20    Formatted(&'a dyn Display),
21    List(&'a dyn Items),
22    Record(&'a dyn Fields),
23}
24
25pub trait Show {
26    fn show(&self) -> Shown<'_>;
27}
28
29pub trait Items {
30    fn item(&self, index: usize) -> Option<Shown<'_>>;
31}
32
33/// Named and ordered as the type's JSON; `#[derive(ReadModel)]` writes them for a read model.
34pub trait Fields {
35    fn name(&self, index: usize) -> Option<&str>;
36
37    fn get(&self, name: &str) -> Option<Shown<'_>>;
38
39    /// Overridden where `name(index)` walks from the start, so a walk over all fields stays linear.
40    fn names(&self) -> Box<dyn Iterator<Item = &str> + '_> {
41        Box::new((0..).map_while(|index| self.name(index)))
42    }
43}
44
45impl<V: Value> Show for V
46where
47    V::Inner: Show,
48{
49    fn show(&self) -> Shown<'_> {
50        self.inner().show()
51    }
52}
53
54impl Show for serde_json::Value {
55    fn show(&self) -> Shown<'_> {
56        match self {
57            Self::Null => Shown::Null,
58            Self::Bool(flag) => Shown::Bool(*flag),
59            Self::Number(number) => Shown::Number(number),
60            Self::String(text) => Shown::Text(text),
61            Self::Array(items) => Shown::List(items),
62            Self::Object(fields) => Shown::Record(fields),
63        }
64    }
65}
66
67impl Fields for Map<String, serde_json::Value> {
68    fn name(&self, index: usize) -> Option<&str> {
69        self.keys().nth(index).map(String::as_str)
70    }
71
72    fn get(&self, name: &str) -> Option<Shown<'_>> {
73        self.get(name).map(Show::show)
74    }
75
76    fn names(&self) -> Box<dyn Iterator<Item = &str> + '_> {
77        Box::new(self.keys().map(String::as_str))
78    }
79}
80
81impl<T: Show> Items for Vec<T> {
82    fn item(&self, index: usize) -> Option<Shown<'_>> {
83        self.get(index).map(Show::show)
84    }
85}
86
87impl<T: Show> Show for Vec<T> {
88    fn show(&self) -> Shown<'_> {
89        Shown::List(self)
90    }
91}
92
93impl<T: Show> Show for Option<T> {
94    fn show(&self) -> Shown<'_> {
95        self.as_ref().map_or(Shown::Null, Show::show)
96    }
97}
98
99macro_rules! show {
100    ($($type:ty => |$value:ident| $shown:expr),* $(,)?) => {
101        $(impl Show for $type { fn show(&self) -> Shown<'_> { let $value = self; $shown } })*
102    };
103}
104
105show! {
106    bool => |flag| Shown::Bool(*flag), String => |text| Shown::Text(text),
107    i64 => |number| Shown::Integer(*number), i32 => |number| Shown::Integer(i64::from(*number)),
108    u64 => |number| i64::try_from(*number).map_or(Shown::Formatted(number), Shown::Integer),
109    f64 => |number| Shown::Float(*number), Uuid => |uuid| Shown::Uuid(*uuid),
110    Timestamp => |timestamp| Shown::Instant(Instant::from(*timestamp)), jiff::civil::Date => |day| Shown::Formatted(day),
111}
sofie_core/show.rs

sofie_core/
show.rs
