Add is_compatible_with function to distant-protocol

CHANGELOG.md

@@ -13,6 +13,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   when executing `distant spawn` in order to run the command within a shell
   rather than directly
 - `semver` crate to be used for version information in protocol and manager
+- `is_compatible_with` function to root of `distant-protocol` crate that checks
+  if a provided version is compatible with the protocol
 
 ### Changed
 

distant-protocol/src/lib.rs

@@ -26,3 +26,83 @@ pub const PROTOCOL_VERSION: semver::Version = semver::Version::new(
     const_str::parse!(env!("CARGO_PKG_VERSION_MINOR"), u64),
     const_str::parse!(env!("CARGO_PKG_VERSION_PATCH"), u64),
 );
+
+/// Comparators used to indicate the [lower, upper) bounds of supported protocol versions.
+const PROTOCOL_VERSION_COMPAT: (semver::Comparator, semver::Comparator) = (
+    semver::Comparator {
+        op: semver::Op::GreaterEq,
+        major: const_str::parse!(env!("CARGO_PKG_VERSION_MAJOR"), u64),
+        minor: Some(const_str::parse!(env!("CARGO_PKG_VERSION_MINOR"), u64)),
+        patch: Some(const_str::parse!(env!("CARGO_PKG_VERSION_PATCH"), u64)),
+        pre: semver::Prerelease::EMPTY,
+    },
+    semver::Comparator {
+        op: semver::Op::Less,
+        major: {
+            let major = const_str::parse!(env!("CARGO_PKG_VERSION_MAJOR"), u64);
+
+            // If we have a version like 0.20, then the upper bound is 0.21,
+            // otherwise if we have a version like 1.2, then the upper bound is 2.0
+            //
+            // So only increment the major if it is greater than 0
+            if major > 0 {
+                major + 1
+            } else {
+                major
+            }
+        },
+        minor: {
+            let major = const_str::parse!(env!("CARGO_PKG_VERSION_MAJOR"), u64);
+            let minor = const_str::parse!(env!("CARGO_PKG_VERSION_MINOR"), u64);
+
+            // If we have a version like 0.20, then the upper bound is 0.21,
+            // otherwise if we have a version like 1.2, then the upper bound is 2.0
+            //
+            // So only increment the minor if major is 0
+            if major > 0 {
+                None
+            } else {
+                Some(minor + 1)
+            }
+        },
+        patch: None,
+        pre: semver::Prerelease::EMPTY,
+    },
+);
+
+/// Returns true if the provided version is compatible with the protocol version.
+///
+/// ```
+/// use distant_protocol::{is_compatible_with, PROTOCOL_VERSION};
+/// use distant_protocol::semver::Version;
+///
+/// // The current protocol version tied to this crate is always compatible
+/// assert!(is_compatible_with(&PROTOCOL_VERSION));
+///
+/// // Major bumps in distant's protocol version are always considered incompatible
+/// assert!(!is_compatible_with(&Version::new(
+///     PROTOCOL_VERSION.major + 1,
+///     PROTOCOL_VERSION.minor,
+///     PROTOCOL_VERSION.patch,
+/// )));
+///
+/// // While distant's protocol is being stabilized, minor version bumps
+/// // are also considered incompatible!
+/// assert!(!is_compatible_with(&Version::new(
+///     PROTOCOL_VERSION.major,
+///     PROTOCOL_VERSION.minor + 1,
+///     PROTOCOL_VERSION.patch,
+/// )));
+///
+/// // Patch bumps in distant's protocol are always considered compatible
+/// assert!(is_compatible_with(&Version::new(
+///     PROTOCOL_VERSION.major,
+///     PROTOCOL_VERSION.minor,
+///     PROTOCOL_VERSION.patch + 1,
+/// )));
+/// ```
+pub fn is_compatible_with(version: &semver::Version) -> bool {
+    let (lower, upper) = PROTOCOL_VERSION_COMPAT;
+
+    lower.matches(version) && upper.matches(version)
+}