logo
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
use std::ops::BitOr;

/// Information about a [`Fairing`](crate::fairing::Fairing).
///
/// The `name` field is an arbitrary name for a fairing. The `kind` field is a
/// is an `or`d set of [`Kind`] structures. Rocket uses the values set in `Kind`
/// to determine which callbacks from a given `Fairing` implementation to
/// actually call.
///
/// # Example
///
/// A simple `Info` structure that can be used for a `Fairing` that implements
/// all callbacks:
///
/// ```
/// use rocket::fairing::{Info, Kind};
///
/// # let _unused_info =
/// Info {
///     name: "Example Fairing",
///     kind: Kind::Ignite | Kind::Liftoff | Kind::Request | Kind::Response | Kind::Shutdown
/// }
/// # ;
/// ```
#[derive(Debug, Copy, Clone)]
pub struct Info {
    /// The name of the fairing.
    pub name: &'static str,
    /// A set representing the callbacks the fairing wishes to receive.
    pub kind: Kind,
}

/// A bitset representing the kinds of callbacks a
/// [`Fairing`](crate::fairing::Fairing) wishes to receive.
///
/// A fairing can request any combination of any of the following kinds of
/// callbacks:
///
///   * Ignite
///   * Liftoff
///   * Request
///   * Response
///   * Shutdown
///
/// Two `Kind` structures can be `or`d together to represent a combination. For
/// instance, to represent a fairing that is both an ignite and request fairing,
/// use `Kind::Ignite | Kind::Request`. Similarly, to represent a fairing that
/// is only an ignite fairing, use `Kind::Ignite`.
///
/// Additionally, a fairing can request to be treated as a
/// [singleton](crate::fairing::Fairing#singletons) by specifying the
/// `Singleton` kind.
#[derive(Debug, Clone, Copy)]
pub struct Kind(usize);

#[allow(non_upper_case_globals)]
impl Kind {
    /// `Kind` flag representing a request for a 'ignite' callback.
    pub const Ignite: Kind = Kind(1 << 0);

    /// `Kind` flag representing a request for a 'liftoff' callback.
    pub const Liftoff: Kind = Kind(1 << 1);

    /// `Kind` flag representing a request for a 'request' callback.
    pub const Request: Kind = Kind(1 << 2);

    /// `Kind` flag representing a request for a 'response' callback.
    pub const Response: Kind = Kind(1 << 3);

    /// `Kind` flag representing a request for a 'shutdown' callback.
    pub const Shutdown: Kind = Kind(1 << 4);

    /// `Kind` flag representing a
    /// [singleton](crate::fairing::Fairing#singletons) fairing.
    pub const Singleton: Kind = Kind(1 << 5);

    /// Returns `true` if `self` is a superset of `other`. In other words,
    /// returns `true` if all of the kinds in `other` are also in `self`.
    ///
    /// # Example
    ///
    /// ```rust
    /// use rocket::fairing::Kind;
    ///
    /// let ignite_and_req = Kind::Ignite | Kind::Request;
    /// assert!(ignite_and_req.is(Kind::Ignite | Kind::Request));
    ///
    /// assert!(ignite_and_req.is(Kind::Ignite));
    /// assert!(ignite_and_req.is(Kind::Request));
    ///
    /// assert!(!ignite_and_req.is(Kind::Liftoff));
    /// assert!(!ignite_and_req.is(Kind::Response));
    /// assert!(!ignite_and_req.is(Kind::Ignite | Kind::Response));
    /// assert!(!ignite_and_req.is(Kind::Ignite | Kind::Request | Kind::Response));
    /// ```
    #[inline]
    pub fn is(self, other: Kind) -> bool {
        (other.0 & self.0) == other.0
    }

    /// Returns `true` if `self` is exactly `other`.
    ///
    /// # Example
    ///
    /// ```rust
    /// use rocket::fairing::Kind;
    ///
    /// let ignite_and_req = Kind::Ignite | Kind::Request;
    /// assert!(ignite_and_req.is_exactly(Kind::Ignite | Kind::Request));
    ///
    /// assert!(!ignite_and_req.is_exactly(Kind::Ignite));
    /// assert!(!ignite_and_req.is_exactly(Kind::Request));
    /// assert!(!ignite_and_req.is_exactly(Kind::Response));
    /// assert!(!ignite_and_req.is_exactly(Kind::Ignite | Kind::Response));
    /// ```
    #[inline]
    pub fn is_exactly(self, other: Kind) -> bool {
        self.0 == other.0
    }
}

impl BitOr for Kind {
    type Output = Self;

    #[inline(always)]
    fn bitor(self, rhs: Self) -> Self {
        Kind(self.0 | rhs.0)
    }
}

impl std::fmt::Display for Kind {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        let mut is_first = true;
        let mut write = |string, kind| {
            if self.is(kind) {
                if !is_first { f.write_str(", ")?; }
                f.write_str(string)?;
                is_first = false;
            }

            Ok(())
        };

        write("ignite", Kind::Ignite)?;
        write("liftoff", Kind::Liftoff)?;
        write("request", Kind::Request)?;
        write("response", Kind::Response)?;
        write("shutdown", Kind::Shutdown)?;
        write("singleton", Kind::Singleton)
    }
}