http/uri/
scheme.rs

1use std::convert::TryFrom;
2use std::fmt;
3use std::hash::{Hash, Hasher};
4use std::str::FromStr;
5
6use bytes::Bytes;
7
8use super::{ErrorKind, InvalidUri};
9use crate::byte_str::ByteStr;
10
11/// Represents the scheme component of a URI
12#[derive(Clone)]
13pub struct Scheme {
14    pub(super) inner: Scheme2,
15}
16
17#[derive(Clone, Debug)]
18pub(super) enum Scheme2<T = Box<ByteStr>> {
19    None,
20    Standard(Protocol),
21    Other(T),
22}
23
24#[derive(Copy, Clone, Debug)]
25pub(super) enum Protocol {
26    Http,
27    Https,
28}
29
30impl Scheme {
31    /// HTTP protocol scheme
32    pub const HTTP: Scheme = Scheme {
33        inner: Scheme2::Standard(Protocol::Http),
34    };
35
36    /// HTTP protocol over TLS.
37    pub const HTTPS: Scheme = Scheme {
38        inner: Scheme2::Standard(Protocol::Https),
39    };
40
41    pub(super) fn empty() -> Self {
42        Scheme {
43            inner: Scheme2::None,
44        }
45    }
46
47    /// Return a str representation of the scheme
48    ///
49    /// # Examples
50    ///
51    /// ```
52    /// # use http::uri::*;
53    /// let scheme: Scheme = "http".parse().unwrap();
54    /// assert_eq!(scheme.as_str(), "http");
55    /// ```
56    #[inline]
57    pub fn as_str(&self) -> &str {
58        use self::Protocol::*;
59        use self::Scheme2::*;
60
61        match self.inner {
62            Standard(Http) => "http",
63            Standard(Https) => "https",
64            Other(ref v) => &v[..],
65            None => unreachable!(),
66        }
67    }
68}
69
70impl<'a> TryFrom<&'a [u8]> for Scheme {
71    type Error = InvalidUri;
72    #[inline]
73    fn try_from(s: &'a [u8]) -> Result<Self, Self::Error> {
74        use self::Scheme2::*;
75
76        match Scheme2::parse_exact(s)? {
77            None => Err(ErrorKind::InvalidScheme.into()),
78            Standard(p) => Ok(Standard(p).into()),
79            Other(_) => {
80                let bytes = Bytes::copy_from_slice(s);
81
82                // Safety: postcondition on parse_exact() means that s and
83                // hence bytes are valid UTF-8.
84                let string = unsafe { ByteStr::from_utf8_unchecked(bytes) };
85
86                Ok(Other(Box::new(string)).into())
87            }
88        }
89    }
90}
91
92impl<'a> TryFrom<&'a str> for Scheme {
93    type Error = InvalidUri;
94    #[inline]
95    fn try_from(s: &'a str) -> Result<Self, Self::Error> {
96        TryFrom::try_from(s.as_bytes())
97    }
98}
99
100impl FromStr for Scheme {
101    type Err = InvalidUri;
102
103    fn from_str(s: &str) -> Result<Self, Self::Err> {
104        TryFrom::try_from(s)
105    }
106}
107
108impl fmt::Debug for Scheme {
109    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
110        fmt::Debug::fmt(self.as_str(), f)
111    }
112}
113
114impl fmt::Display for Scheme {
115    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
116        f.write_str(self.as_str())
117    }
118}
119
120impl AsRef<str> for Scheme {
121    #[inline]
122    fn as_ref(&self) -> &str {
123        self.as_str()
124    }
125}
126
127impl PartialEq for Scheme {
128    fn eq(&self, other: &Scheme) -> bool {
129        use self::Protocol::*;
130        use self::Scheme2::*;
131
132        match (&self.inner, &other.inner) {
133            (&Standard(Http), &Standard(Http)) => true,
134            (&Standard(Https), &Standard(Https)) => true,
135            (Other(a), Other(b)) => a.eq_ignore_ascii_case(b),
136            (&None, _) | (_, &None) => unreachable!(),
137            _ => false,
138        }
139    }
140}
141
142impl Eq for Scheme {}
143
144/// Case-insensitive equality
145///
146/// # Examples
147///
148/// ```
149/// # use http::uri::Scheme;
150/// let scheme: Scheme = "HTTP".parse().unwrap();
151/// assert_eq!(scheme, *"http");
152/// ```
153impl PartialEq<str> for Scheme {
154    fn eq(&self, other: &str) -> bool {
155        self.as_str().eq_ignore_ascii_case(other)
156    }
157}
158
159/// Case-insensitive equality
160impl PartialEq<Scheme> for str {
161    fn eq(&self, other: &Scheme) -> bool {
162        other == self
163    }
164}
165
166/// Case-insensitive hashing
167impl Hash for Scheme {
168    fn hash<H>(&self, state: &mut H)
169    where
170        H: Hasher,
171    {
172        match self.inner {
173            Scheme2::None => (),
174            Scheme2::Standard(Protocol::Http) => state.write_u8(1),
175            Scheme2::Standard(Protocol::Https) => state.write_u8(2),
176            Scheme2::Other(ref other) => {
177                other.len().hash(state);
178                for &b in other.as_bytes() {
179                    state.write_u8(b.to_ascii_lowercase());
180                }
181            }
182        }
183    }
184}
185
186impl<T> Scheme2<T> {
187    pub(super) fn is_none(&self) -> bool {
188        matches!(*self, Scheme2::None)
189    }
190}
191
192// Require the scheme to not be too long in order to enable further
193// optimizations later.
194const MAX_SCHEME_LEN: usize = 64;
195
196// scheme = ALPHA *( ALPHA / DIGIT / "+" / "-" / "." )
197//
198// SCHEME_CHARS is a table of valid characters in the scheme part of a URI.  An
199// entry in the table is 0 for invalid characters. For valid characters the
200// entry is itself (i.e.  the entry for 43 is b'+' because b'+' == 43u8). An
201// important characteristic of this table is that all entries above 127 are
202// invalid. This makes all of the valid entries a valid single-byte UTF-8 code
203// point. This means that a slice of such valid entries is valid UTF-8.
204#[rustfmt::skip]
205const SCHEME_CHARS: [u8; 256] = [
206    //  0      1      2      3      4      5      6      7      8      9
207        0,     0,     0,     0,     0,     0,     0,     0,     0,     0, //   x
208        0,     0,     0,     0,     0,     0,     0,     0,     0,     0, //  1x
209        0,     0,     0,     0,     0,     0,     0,     0,     0,     0, //  2x
210        0,     0,     0,     0,     0,     0,     0,     0,     0,     0, //  3x
211        0,     0,     0,  b'+',     0,  b'-',  b'.',     0,  b'0',  b'1', //  4x
212     b'2',  b'3',  b'4',  b'5',  b'6',  b'7',  b'8',  b'9',  b':',     0, //  5x
213        0,     0,     0,     0,     0,  b'A',  b'B',  b'C',  b'D',  b'E', //  6x
214     b'F',  b'G',  b'H',  b'I',  b'J',  b'K',  b'L',  b'M',  b'N',  b'O', //  7x
215     b'P',  b'Q',  b'R',  b'S',  b'T',  b'U',  b'V',  b'W',  b'X',  b'Y', //  8x
216     b'Z',     0,     0,     0,     0,     0,     0,  b'a',  b'b',  b'c', //  9x
217     b'd',  b'e',  b'f',  b'g',  b'h',  b'i',  b'j',  b'k',  b'l',  b'm', // 10x
218     b'n',  b'o',  b'p',  b'q',  b'r',  b's',  b't',  b'u',  b'v',  b'w', // 11x
219     b'x',  b'y',  b'z',     0,     0,     0,  b'~',     0,     0,     0, // 12x
220        0,     0,     0,     0,     0,     0,     0,     0,     0,     0, // 13x
221        0,     0,     0,     0,     0,     0,     0,     0,     0,     0, // 14x
222        0,     0,     0,     0,     0,     0,     0,     0,     0,     0, // 15x
223        0,     0,     0,     0,     0,     0,     0,     0,     0,     0, // 16x
224        0,     0,     0,     0,     0,     0,     0,     0,     0,     0, // 17x
225        0,     0,     0,     0,     0,     0,     0,     0,     0,     0, // 18x
226        0,     0,     0,     0,     0,     0,     0,     0,     0,     0, // 19x
227        0,     0,     0,     0,     0,     0,     0,     0,     0,     0, // 20x
228        0,     0,     0,     0,     0,     0,     0,     0,     0,     0, // 21x
229        0,     0,     0,     0,     0,     0,     0,     0,     0,     0, // 22x
230        0,     0,     0,     0,     0,     0,     0,     0,     0,     0, // 23x
231        0,     0,     0,     0,     0,     0,     0,     0,     0,     0, // 24x
232        0,     0,     0,     0,     0,     0                              // 25x
233];
234
235impl Scheme2<usize> {
236    // Postcondition: On all Ok() returns, s is valid UTF-8
237    fn parse_exact(s: &[u8]) -> Result<Scheme2<()>, InvalidUri> {
238        match s {
239            b"http" => Ok(Protocol::Http.into()),
240            b"https" => Ok(Protocol::Https.into()),
241            _ => {
242                if s.len() > MAX_SCHEME_LEN {
243                    return Err(ErrorKind::SchemeTooLong.into());
244                }
245
246                // check that each byte in s is a SCHEME_CHARS which implies
247                // that it is a valid single byte UTF-8 code point.
248                for &b in s {
249                    match SCHEME_CHARS[b as usize] {
250                        b':' => {
251                            // Don't want :// here
252                            return Err(ErrorKind::InvalidScheme.into());
253                        }
254                        0 => {
255                            return Err(ErrorKind::InvalidScheme.into());
256                        }
257                        _ => {}
258                    }
259                }
260
261                Ok(Scheme2::Other(()))
262            }
263        }
264    }
265
266    pub(super) fn parse(s: &[u8]) -> Result<Scheme2<usize>, InvalidUri> {
267        if s.len() >= 7 {
268            // Check for HTTP
269            if s[..7].eq_ignore_ascii_case(b"http://") {
270                // Prefix will be striped
271                return Ok(Protocol::Http.into());
272            }
273        }
274
275        if s.len() >= 8 {
276            // Check for HTTPs
277            if s[..8].eq_ignore_ascii_case(b"https://") {
278                return Ok(Protocol::Https.into());
279            }
280        }
281
282        if s.len() > 3 {
283            for i in 0..s.len() {
284                let b = s[i];
285
286                match SCHEME_CHARS[b as usize] {
287                    b':' => {
288                        // Not enough data remaining
289                        if s.len() < i + 3 {
290                            break;
291                        }
292
293                        // Not a scheme
294                        if &s[i + 1..i + 3] != b"//" {
295                            break;
296                        }
297
298                        if i > MAX_SCHEME_LEN {
299                            return Err(ErrorKind::SchemeTooLong.into());
300                        }
301
302                        // Return scheme
303                        return Ok(Scheme2::Other(i));
304                    }
305                    // Invalid scheme character, abort
306                    0 => break,
307                    _ => {}
308                }
309            }
310        }
311
312        Ok(Scheme2::None)
313    }
314}
315
316impl Protocol {
317    pub(super) fn len(&self) -> usize {
318        match *self {
319            Protocol::Http => 4,
320            Protocol::Https => 5,
321        }
322    }
323}
324
325impl<T> From<Protocol> for Scheme2<T> {
326    fn from(src: Protocol) -> Self {
327        Scheme2::Standard(src)
328    }
329}
330
331#[doc(hidden)]
332impl From<Scheme2> for Scheme {
333    fn from(src: Scheme2) -> Self {
334        Scheme { inner: src }
335    }
336}
337
338#[cfg(test)]
339mod test {
340    use super::*;
341
342    #[test]
343    fn scheme_eq_to_str() {
344        assert_eq!(&scheme("http"), "http");
345        assert_eq!(&scheme("https"), "https");
346        assert_eq!(&scheme("ftp"), "ftp");
347        assert_eq!(&scheme("my+funky+scheme"), "my+funky+scheme");
348    }
349
350    #[test]
351    fn invalid_scheme_is_error() {
352        Scheme::try_from("my_funky_scheme").expect_err("Unexpectedly valid Scheme");
353
354        // Invalid UTF-8
355        Scheme::try_from([0xC0].as_ref()).expect_err("Unexpectedly valid Scheme");
356    }
357
358    fn scheme(s: &str) -> Scheme {
359        s.parse().expect(&format!("Invalid scheme: {}", s))
360    }
361}
http/uri/scheme.rs

http/uri/
scheme.rs
