mirror of
https://github.com/actix/actix-extras.git
synced 2024-11-26 08:45:12 +01:00
231 lines
8.3 KiB
Rust
231 lines
8.3 KiB
Rust
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use std::str::FromStr;
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use std::fmt::{self, Display, Write};
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use header::{http, Writer, IntoHeaderValue};
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/// check that each char in the slice is either:
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/// 1. `%x21`, or
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/// 2. in the range `%x23` to `%x7E`, or
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/// 3. above `%x80`
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fn check_slice_validity(slice: &str) -> bool {
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slice.bytes().all(|c|
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c == b'\x21' || (c >= b'\x23' && c <= b'\x7e') | (c >= b'\x80'))
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}
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/// An entity tag, defined in [RFC7232](https://tools.ietf.org/html/rfc7232#section-2.3)
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///
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/// An entity tag consists of a string enclosed by two literal double quotes.
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/// Preceding the first double quote is an optional weakness indicator,
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/// which always looks like `W/`. Examples for valid tags are `"xyzzy"` and `W/"xyzzy"`.
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///
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/// # ABNF
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///
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/// ```text
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/// entity-tag = [ weak ] opaque-tag
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/// weak = %x57.2F ; "W/", case-sensitive
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/// opaque-tag = DQUOTE *etagc DQUOTE
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/// etagc = %x21 / %x23-7E / obs-text
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/// ; VCHAR except double quotes, plus obs-text
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/// ```
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///
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/// # Comparison
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/// To check if two entity tags are equivalent in an application always use the `strong_eq` or
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/// `weak_eq` methods based on the context of the Tag. Only use `==` to check if two tags are
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/// identical.
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///
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/// The example below shows the results for a set of entity-tag pairs and
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/// both the weak and strong comparison function results:
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///
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/// | `ETag 1`| `ETag 2`| Strong Comparison | Weak Comparison |
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/// |---------|---------|-------------------|-----------------|
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/// | `W/"1"` | `W/"1"` | no match | match |
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/// | `W/"1"` | `W/"2"` | no match | no match |
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/// | `W/"1"` | `"1"` | no match | match |
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/// | `"1"` | `"1"` | match | match |
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#[derive(Clone, Debug, Eq, PartialEq)]
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pub struct EntityTag {
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/// Weakness indicator for the tag
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pub weak: bool,
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/// The opaque string in between the DQUOTEs
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tag: String
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}
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impl EntityTag {
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/// Constructs a new EntityTag.
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/// # Panics
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/// If the tag contains invalid characters.
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pub fn new(weak: bool, tag: String) -> EntityTag {
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assert!(check_slice_validity(&tag), "Invalid tag: {:?}", tag);
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EntityTag { weak, tag }
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}
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/// Constructs a new weak EntityTag.
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/// # Panics
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/// If the tag contains invalid characters.
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pub fn weak(tag: String) -> EntityTag {
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EntityTag::new(true, tag)
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}
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/// Constructs a new strong EntityTag.
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/// # Panics
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/// If the tag contains invalid characters.
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pub fn strong(tag: String) -> EntityTag {
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EntityTag::new(false, tag)
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}
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/// Get the tag.
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pub fn tag(&self) -> &str {
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self.tag.as_ref()
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}
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/// Set the tag.
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/// # Panics
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/// If the tag contains invalid characters.
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pub fn set_tag(&mut self, tag: String) {
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assert!(check_slice_validity(&tag), "Invalid tag: {:?}", tag);
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self.tag = tag
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}
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/// For strong comparison two entity-tags are equivalent if both are not weak and their
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/// opaque-tags match character-by-character.
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pub fn strong_eq(&self, other: &EntityTag) -> bool {
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!self.weak && !other.weak && self.tag == other.tag
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}
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/// For weak comparison two entity-tags are equivalent if their
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/// opaque-tags match character-by-character, regardless of either or
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/// both being tagged as "weak".
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pub fn weak_eq(&self, other: &EntityTag) -> bool {
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self.tag == other.tag
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}
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/// The inverse of `EntityTag.strong_eq()`.
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pub fn strong_ne(&self, other: &EntityTag) -> bool {
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!self.strong_eq(other)
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}
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/// The inverse of `EntityTag.weak_eq()`.
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pub fn weak_ne(&self, other: &EntityTag) -> bool {
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!self.weak_eq(other)
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}
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}
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impl Display for EntityTag {
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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if self.weak {
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write!(f, "W/\"{}\"", self.tag)
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} else {
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write!(f, "\"{}\"", self.tag)
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}
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}
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}
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impl FromStr for EntityTag {
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type Err = ::error::ParseError;
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fn from_str(s: &str) -> Result<EntityTag, ::error::ParseError> {
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let length: usize = s.len();
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let slice = &s[..];
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// Early exits if it doesn't terminate in a DQUOTE.
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if !slice.ends_with('"') || slice.len() < 2 {
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return Err(::error::ParseError::Header);
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}
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// The etag is weak if its first char is not a DQUOTE.
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if slice.len() >= 2 && slice.starts_with('"')
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&& check_slice_validity(&slice[1..length-1]) {
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// No need to check if the last char is a DQUOTE,
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// we already did that above.
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return Ok(EntityTag { weak: false, tag: slice[1..length-1].to_owned() });
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} else if slice.len() >= 4 && slice.starts_with("W/\"")
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&& check_slice_validity(&slice[3..length-1]) {
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return Ok(EntityTag { weak: true, tag: slice[3..length-1].to_owned() });
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}
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Err(::error::ParseError::Header)
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}
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}
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impl IntoHeaderValue for EntityTag {
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type Error = http::InvalidHeaderValueBytes;
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fn try_into(self) -> Result<http::HeaderValue, Self::Error> {
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let mut wrt = Writer::new();
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write!(wrt, "{}", self).unwrap();
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unsafe{Ok(http::HeaderValue::from_shared_unchecked(wrt.take()))}
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}
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}
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#[cfg(test)]
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mod tests {
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use super::EntityTag;
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#[test]
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fn test_etag_parse_success() {
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// Expected success
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assert_eq!("\"foobar\"".parse::<EntityTag>().unwrap(),
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EntityTag::strong("foobar".to_owned()));
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assert_eq!("\"\"".parse::<EntityTag>().unwrap(),
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EntityTag::strong("".to_owned()));
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assert_eq!("W/\"weaktag\"".parse::<EntityTag>().unwrap(),
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EntityTag::weak("weaktag".to_owned()));
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assert_eq!("W/\"\x65\x62\"".parse::<EntityTag>().unwrap(),
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EntityTag::weak("\x65\x62".to_owned()));
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assert_eq!("W/\"\"".parse::<EntityTag>().unwrap(), EntityTag::weak("".to_owned()));
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}
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#[test]
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fn test_etag_parse_failures() {
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// Expected failures
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assert!("no-dquotes".parse::<EntityTag>().is_err());
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assert!("w/\"the-first-w-is-case-sensitive\"".parse::<EntityTag>().is_err());
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assert!("".parse::<EntityTag>().is_err());
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assert!("\"unmatched-dquotes1".parse::<EntityTag>().is_err());
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assert!("unmatched-dquotes2\"".parse::<EntityTag>().is_err());
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assert!("matched-\"dquotes\"".parse::<EntityTag>().is_err());
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}
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#[test]
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fn test_etag_fmt() {
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assert_eq!(format!("{}", EntityTag::strong("foobar".to_owned())), "\"foobar\"");
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assert_eq!(format!("{}", EntityTag::strong("".to_owned())), "\"\"");
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assert_eq!(format!("{}", EntityTag::weak("weak-etag".to_owned())), "W/\"weak-etag\"");
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assert_eq!(format!("{}", EntityTag::weak("\u{0065}".to_owned())), "W/\"\x65\"");
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assert_eq!(format!("{}", EntityTag::weak("".to_owned())), "W/\"\"");
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}
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#[test]
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fn test_cmp() {
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// | ETag 1 | ETag 2 | Strong Comparison | Weak Comparison |
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// |---------|---------|-------------------|-----------------|
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// | `W/"1"` | `W/"1"` | no match | match |
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// | `W/"1"` | `W/"2"` | no match | no match |
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// | `W/"1"` | `"1"` | no match | match |
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// | `"1"` | `"1"` | match | match |
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let mut etag1 = EntityTag::weak("1".to_owned());
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let mut etag2 = EntityTag::weak("1".to_owned());
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assert!(!etag1.strong_eq(&etag2));
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assert!(etag1.weak_eq(&etag2));
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assert!(etag1.strong_ne(&etag2));
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assert!(!etag1.weak_ne(&etag2));
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etag1 = EntityTag::weak("1".to_owned());
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etag2 = EntityTag::weak("2".to_owned());
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assert!(!etag1.strong_eq(&etag2));
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assert!(!etag1.weak_eq(&etag2));
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assert!(etag1.strong_ne(&etag2));
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assert!(etag1.weak_ne(&etag2));
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etag1 = EntityTag::weak("1".to_owned());
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etag2 = EntityTag::strong("1".to_owned());
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assert!(!etag1.strong_eq(&etag2));
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assert!(etag1.weak_eq(&etag2));
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assert!(etag1.strong_ne(&etag2));
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assert!(!etag1.weak_ne(&etag2));
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etag1 = EntityTag::strong("1".to_owned());
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etag2 = EntityTag::strong("1".to_owned());
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assert!(etag1.strong_eq(&etag2));
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assert!(etag1.weak_eq(&etag2));
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assert!(!etag1.strong_ne(&etag2));
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assert!(!etag1.weak_ne(&etag2));
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}
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}
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