1 files changed, 156 insertions, 0 deletions
diff --git a/third_party/rust/semver/src/impls.rs b/third_party/rust/semver/src/impls.rs
new file mode 100644
index 0000000000..c3b6c60133
--- /dev/null
+++ b/third_party/rust/semver/src/impls.rs
@@ -0,0 +1,156 @@
+use crate::backport::*;
+use crate::identifier::Identifier;
+use crate::{BuildMetadata, Comparator, Prerelease, VersionReq};
+use core::cmp::Ordering;
+use core::hash::{Hash, Hasher};
+use core::iter::FromIterator;
+use core::ops::Deref;
+
+impl Default for Identifier {
+    fn default() -> Self {
+        Identifier::empty()
+    }
+}
+
+impl Eq for Identifier {}
+
+impl Hash for Identifier {
+    fn hash<H: Hasher>(&self, hasher: &mut H) {
+        self.as_str().hash(hasher);
+    }
+}
+
+impl Deref for Prerelease {
+    type Target = str;
+
+    fn deref(&self) -> &Self::Target {
+        self.identifier.as_str()
+    }
+}
+
+impl Deref for BuildMetadata {
+    type Target = str;
+
+    fn deref(&self) -> &Self::Target {
+        self.identifier.as_str()
+    }
+}
+
+impl PartialOrd for Prerelease {
+    fn partial_cmp(&self, rhs: &Self) -> Option<Ordering> {
+        Some(Ord::cmp(self, rhs))
+    }
+}
+
+impl PartialOrd for BuildMetadata {
+    fn partial_cmp(&self, rhs: &Self) -> Option<Ordering> {
+        Some(Ord::cmp(self, rhs))
+    }
+}
+
+impl Ord for Prerelease {
+    fn cmp(&self, rhs: &Self) -> Ordering {
+        match self.is_empty() {
+            true if rhs.is_empty() => return Ordering::Equal,
+            // A real release compares greater than prerelease.
+            true => return Ordering::Greater,
+            // Prerelease compares less than the real release.
+            false if rhs.is_empty() => return Ordering::Less,
+            false => {}
+        }
+
+        let lhs = self.as_str().split('.');
+        let mut rhs = rhs.as_str().split('.');
+
+        for lhs in lhs {
+            let rhs = match rhs.next() {
+                // Spec: "A larger set of pre-release fields has a higher
+                // precedence than a smaller set, if all of the preceding
+                // identifiers are equal."
+                None => return Ordering::Greater,
+                Some(rhs) => rhs,
+            };
+
+            let string_cmp = || Ord::cmp(lhs, rhs);
+            let is_ascii_digit = |b: u8| b.is_ascii_digit();
+            let ordering = match (
+                lhs.bytes().all(is_ascii_digit),
+                rhs.bytes().all(is_ascii_digit),
+            ) {
+                // Respect numeric ordering, for example 99 < 100. Spec says:
+                // "Identifiers consisting of only digits are compared
+                // numerically."
+                (true, true) => Ord::cmp(&lhs.len(), &rhs.len()).then_with(string_cmp),
+                // Spec: "Numeric identifiers always have lower precedence than
+                // non-numeric identifiers."
+                (true, false) => return Ordering::Less,
+                (false, true) => return Ordering::Greater,
+                // Spec: "Identifiers with letters or hyphens are compared
+                // lexically in ASCII sort order."
+                (false, false) => string_cmp(),
+            };
+
+            if ordering != Ordering::Equal {
+                return ordering;
+            }
+        }
+
+        if rhs.next().is_none() {
+            Ordering::Equal
+        } else {
+            Ordering::Less
+        }
+    }
+}
+
+impl Ord for BuildMetadata {
+    fn cmp(&self, rhs: &Self) -> Ordering {
+        let lhs = self.as_str().split('.');
+        let mut rhs = rhs.as_str().split('.');
+
+        for lhs in lhs {
+            let rhs = match rhs.next() {
+                None => return Ordering::Greater,
+                Some(rhs) => rhs,
+            };
+
+            let is_ascii_digit = |b: u8| b.is_ascii_digit();
+            let ordering = match (
+                lhs.bytes().all(is_ascii_digit),
+                rhs.bytes().all(is_ascii_digit),
+            ) {
+                (true, true) => {
+                    // 0 < 00 < 1 < 01 < 001 < 2 < 02 < 002 < 10
+                    let lhval = lhs.trim_start_matches('0');
+                    let rhval = rhs.trim_start_matches('0');
+                    Ord::cmp(&lhval.len(), &rhval.len())
+                        .then_with(|| Ord::cmp(lhval, rhval))
+                        .then_with(|| Ord::cmp(&lhs.len(), &rhs.len()))
+                }
+                (true, false) => return Ordering::Less,
+                (false, true) => return Ordering::Greater,
+                (false, false) => Ord::cmp(lhs, rhs),
+            };
+
+            if ordering != Ordering::Equal {
+                return ordering;
+            }
+        }
+
+        if rhs.next().is_none() {
+            Ordering::Equal
+        } else {
+            Ordering::Less
+        }
+    }
+}
+
+impl FromIterator<Comparator> for VersionReq {
+    fn from_iter<I>(iter: I) -> Self
+    where
+        I: IntoIterator<Item = Comparator>,
+    {
+        let comparators = Vec::from_iter(iter);
+        VersionReq { comparators }
+    }
+}