From 44116e49074b398a652671bf829267fa53738fbd Mon Sep 17 00:00:00 2001
From: Dave Hrycyszyn <futurechimp@users.noreply.github.com>
Date: Wed, 22 Jan 2020 16:17:35 +0000
Subject: [PATCH] common: adding a version-checker crate

---
 Cargo.lock                        |  8 +++++
 common/version-checker/.gitignore |  3 ++
 common/version-checker/Cargo.toml | 10 ++++++
 common/version-checker/src/lib.rs | 51 +++++++++++++++++++++++++++++++
 4 files changed, 72 insertions(+)
 create mode 100644 common/version-checker/.gitignore
 create mode 100644 common/version-checker/Cargo.toml
 create mode 100644 common/version-checker/src/lib.rs

diff --git a/Cargo.lock b/Cargo.lock
index 66d9693e54..5aec0f39d0 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2422,6 +2422,7 @@ dependencies = [
  "rand 0.7.2",
  "serde",
  "sphinx",
+ "version-checker",
 ]
 
 [[package]]
@@ -2557,6 +2558,13 @@ version = "0.8.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "05c78687fb1a80548ae3250346c3db86a80a7cdd77bda190189f2d0a0987c81a"
 
+[[package]]
+name = "version-checker"
+version = "0.1.0"
+dependencies = [
+ "semver",
+]
+
 [[package]]
 name = "version_check"
 version = "0.1.5"
diff --git a/common/version-checker/.gitignore b/common/version-checker/.gitignore
new file mode 100644
index 0000000000..693699042b
--- /dev/null
+++ b/common/version-checker/.gitignore
@@ -0,0 +1,3 @@
+/target
+**/*.rs.bk
+Cargo.lock
diff --git a/common/version-checker/Cargo.toml b/common/version-checker/Cargo.toml
new file mode 100644
index 0000000000..80c97fb349
--- /dev/null
+++ b/common/version-checker/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "version-checker"
+version = "0.1.0"
+authors = ["Dave Hrycyszyn <futurechimp@users.noreply.github.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+semver = "0.9.0"
\ No newline at end of file
diff --git a/common/version-checker/src/lib.rs b/common/version-checker/src/lib.rs
new file mode 100644
index 0000000000..d6ae38d19e
--- /dev/null
+++ b/common/version-checker/src/lib.rs
@@ -0,0 +1,51 @@
+use semver::Version;
+use semver::VersionReq;
+
+/// Checks whether given `version` is compatible with a given semantic
+/// version requirement `req` according to major-minor semver rules.
+/// The semantic version requirement can be passed as a full, concrete version
+/// number, because that's what we'll have in our Cargo.toml files (e.g. 0.3.2).
+/// The patch number in the requirement will be dropped and replaced with a wildcard (0.3.*) as all minor versions should be compatible with each other.
+pub fn is_compatible(version: &str, req: &str) -> bool {
+    let version = Version::parse(version).unwrap();
+    let tmp = Version::parse(req).unwrap();
+    let wildcard = format!("{}.{}.*", tmp.major, tmp.minor).to_string();
+    let semver_requirement = VersionReq::parse(&wildcard).unwrap();
+
+    semver_requirement.matches(&version)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn version_0_3_0_is_compatible_with_requirement_0_3_x() {
+        assert!(is_compatible("0.3.0", "0.3.2"));
+    }
+
+    #[test]
+    fn version_0_3_1_is_compatible_with_minimum_requirement_0_3_x() {
+        assert!(is_compatible("0.3.1", "0.3.2"));
+    }
+
+    #[test]
+    fn version_0_3_2_is_compatible_with_minimum_requirement_0_3_x() {
+        assert!(is_compatible("0.3.2", "0.3.0"));
+    }
+
+    #[test]
+    fn version_0_2_0_is_not_compatible_with_requirement_0_3_x() {
+        assert!(!is_compatible("0.2.0", "0.3.2"));
+    }
+
+    #[test]
+    fn version_0_4_0_is_not_compatible_with_requirement_0_3_x() {
+        assert!(!is_compatible("0.4.0", "0.3.2"));
+    }
+
+    #[test]
+    fn version_1_3_2_is_not_compatible_with_requirement_0_3_x() {
+        assert!(!is_compatible("1.3.2", "0.3.2"));
+    }
+}