1use std::fmt;
2
3/// HTTP/2 error codes.
4///
5/// Error codes are used in `RST_STREAM` and `GOAWAY` frames to convey the
6/// reasons for the stream or connection error. For example,
7/// [`SendStream::send_reset`] takes a `Reason` argument. Also, the `Error` type
8/// may contain a `Reason`.
9///
10/// Error codes share a common code space. Some error codes apply only to
11/// streams, others apply only to connections, and others may apply to either.
12/// See [RFC 7540] for more information.
13///
14/// See [Error Codes in the spec][spec].
15///
16/// [spec]: http://httpwg.org/specs/rfc7540.html#ErrorCodes
17/// [`SendStream::send_reset`]: struct.SendStream.html#method.send_reset
18#[derive(PartialEq, Eq, Clone, Copy)]
19pub struct Reason(u32);
20
21impl Reason {
22 /// The associated condition is not a result of an error.
23 ///
24 /// For example, a GOAWAY might include this code to indicate graceful
25 /// shutdown of a connection.
26 pub const NO_ERROR: Reason = Reason(0);
27 /// The endpoint detected an unspecific protocol error.
28 ///
29 /// This error is for use when a more specific error code is not available.
30 pub const PROTOCOL_ERROR: Reason = Reason(1);
31 /// The endpoint encountered an unexpected internal error.
32 pub const INTERNAL_ERROR: Reason = Reason(2);
33 /// The endpoint detected that its peer violated the flow-control protocol.
34 pub const FLOW_CONTROL_ERROR: Reason = Reason(3);
35 /// The endpoint sent a SETTINGS frame but did not receive a response in
36 /// a timely manner.
37 pub const SETTINGS_TIMEOUT: Reason = Reason(4);
38 /// The endpoint received a frame after a stream was half-closed.
39 pub const STREAM_CLOSED: Reason = Reason(5);
40 /// The endpoint received a frame with an invalid size.
41 pub const FRAME_SIZE_ERROR: Reason = Reason(6);
42 /// The endpoint refused the stream prior to performing any application
43 /// processing.
44 pub const REFUSED_STREAM: Reason = Reason(7);
45 /// Used by the endpoint to indicate that the stream is no longer needed.
46 pub const CANCEL: Reason = Reason(8);
47 /// The endpoint is unable to maintain the header compression context for
48 /// the connection.
49 pub const COMPRESSION_ERROR: Reason = Reason(9);
50 /// The connection established in response to a CONNECT request was reset
51 /// or abnormally closed.
52 pub const CONNECT_ERROR: Reason = Reason(10);
53 /// The endpoint detected that its peer is exhibiting a behavior that might
54 /// be generating excessive load.
55 pub const ENHANCE_YOUR_CALM: Reason = Reason(11);
56 /// The underlying transport has properties that do not meet minimum
57 /// security requirements.
58 pub const INADEQUATE_SECURITY: Reason = Reason(12);
59 /// The endpoint requires that HTTP/1.1 be used instead of HTTP/2.
60 pub const HTTP_1_1_REQUIRED: Reason = Reason(13);
61
62 /// Get a string description of the error code.
63 pub fn description(&self) -> &str {
64 match self.0 {
65 0 => "not a result of an error",
66 1 => "unspecific protocol error detected",
67 2 => "unexpected internal error encountered",
68 3 => "flow-control protocol violated",
69 4 => "settings ACK not received in timely manner",
70 5 => "received frame when stream half-closed",
71 6 => "frame with invalid size",
72 7 => "refused stream before processing any application logic",
73 8 => "stream no longer needed",
74 9 => "unable to maintain the header compression context",
75 10 => {
76 "connection established in response to a CONNECT request was reset or abnormally \
77 closed"
78 }
79 11 => "detected excessive load generating behavior",
80 12 => "security properties do not meet minimum requirements",
81 13 => "endpoint requires HTTP/1.1",
82 _ => "unknown reason",
83 }
84 }
85}
86
87impl From<u32> for Reason {
88 fn from(src: u32) -> Reason {
89 Reason(src)
90 }
91}
92
93impl From<Reason> for u32 {
94 fn from(src: Reason) -> u32 {
95 src.0
96 }
97}
98
99impl fmt::Debug for Reason {
100 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
101 let name: &'static str = match self.0 {
102 0 => "NO_ERROR",
103 1 => "PROTOCOL_ERROR",
104 2 => "INTERNAL_ERROR",
105 3 => "FLOW_CONTROL_ERROR",
106 4 => "SETTINGS_TIMEOUT",
107 5 => "STREAM_CLOSED",
108 6 => "FRAME_SIZE_ERROR",
109 7 => "REFUSED_STREAM",
110 8 => "CANCEL",
111 9 => "COMPRESSION_ERROR",
112 10 => "CONNECT_ERROR",
113 11 => "ENHANCE_YOUR_CALM",
114 12 => "INADEQUATE_SECURITY",
115 13 => "HTTP_1_1_REQUIRED",
116 other: u32 => return f.debug_tuple(name:"Reason").field(&Hex(other)).finish(),
117 };
118 f.write_str(data:name)
119 }
120}
121
122struct Hex(u32);
123
124impl fmt::Debug for Hex {
125 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
126 fmt::LowerHex::fmt(&self.0, f)
127 }
128}
129
130impl fmt::Display for Reason {
131 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
132 write!(fmt, "{}", self.description())
133 }
134}
135