Factor vergen stuff to a build-info crate

build-info/src/lib.rs

@@ -0,0 +1,203 @@
+use time::format_description::well_known::Iso8601;
+
+#[derive(Debug, Clone)]
+pub struct BuildInfo {
+    pub branch: Option<&'static str>,
+    pub describe: Option<DescribeResult>,
+    pub commit_sha1: Option<&'static str>,
+    pub commit_msg: Option<&'static str>,
+    pub commit_timestamp: Option<time::OffsetDateTime>,
+}
+
+impl BuildInfo {
+    pub fn from_build() -> Self {
+        let branch: Option<&'static str> = option_env!("VERGEN_GIT_BRANCH");
+        let describe = DescribeResult::from_build();
+        let commit_sha1 = option_env!("VERGEN_GIT_SHA");
+        let commit_msg = option_env!("VERGEN_GIT_COMMIT_MESSAGE");
+        let commit_timestamp = option_env!("VERGEN_GIT_COMMIT_TIMESTAMP");
+
+        let commit_timestamp = commit_timestamp.and_then(|commit_timestamp| {
+            time::OffsetDateTime::parse(commit_timestamp, &Iso8601::DEFAULT).ok()
+        });
+
+        Self { branch, describe, commit_sha1, commit_msg, commit_timestamp }
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub enum DescribeResult {
+    Prototype { name: &'static str },
+    Release { version: &'static str, major: u64, minor: u64, patch: u64 },
+    Prerelease { version: &'static str, major: u64, minor: u64, patch: u64, rc: u64 },
+    NotATag { describe: &'static str },
+}
+
+impl DescribeResult {
+    pub fn new(describe: &'static str) -> Self {
+        if let Some(name) = prototype_name(describe) {
+            Self::Prototype { name }
+        } else if let Some(release) = release_version(describe) {
+            release
+        } else if let Some(prerelease) = prerelease_version(describe) {
+            prerelease
+        } else {
+            Self::NotATag { describe }
+        }
+    }
+
+    pub fn from_build() -> Option<Self> {
+        let describe: &'static str = option_env!("VERGEN_GIT_DESCRIBE")?;
+        Some(Self::new(describe))
+    }
+
+    pub fn as_tag(&self) -> Option<&'static str> {
+        match self {
+            DescribeResult::Prototype { name } => Some(name),
+            DescribeResult::Release { version, .. } => Some(version),
+            DescribeResult::Prerelease { version, .. } => Some(version),
+            DescribeResult::NotATag { describe: _ } => None,
+        }
+    }
+
+    pub fn as_prototype(&self) -> Option<&'static str> {
+        match self {
+            DescribeResult::Prototype { name } => Some(name),
+            DescribeResult::Release { .. }
+            | DescribeResult::Prerelease { .. }
+            | DescribeResult::NotATag { .. } => None,
+        }
+    }
+}
+
+/// Parses the input as a prototype name.
+///
+/// Returns `Some(prototype_name)` if the following conditions are met on this value:
+///
+/// 1. starts with `prototype-`,
+/// 2. ends with `-<some_number>`,
+/// 3. does not end with `<some_number>-<some_number>`.
+///
+/// Otherwise, returns `None`.
+fn prototype_name(describe: &'static str) -> Option<&'static str> {
+    if !describe.starts_with("prototype-") {
+        return None;
+    }
+
+    let mut rsplit_prototype = describe.rsplit('-');
+    // last component MUST be a number
+    rsplit_prototype.next()?.parse::<u64>().ok()?;
+    // before than last component SHALL NOT be a number
+    rsplit_prototype.next()?.parse::<u64>().err()?;
+
+    Some(describe)
+}
+
+fn release_version(describe: &'static str) -> Option<DescribeResult> {
+    if !describe.starts_with('v') {
+        return None;
+    }
+
+    // full release version don't contain a `-`
+    if describe.contains('-') {
+        return None;
+    }
+
+    // full release version parse as vX.Y.Z, with X, Y, Z numbers.
+    let mut dots = describe[1..].split('.');
+    let major: u64 = dots.next()?.parse().ok()?;
+    let minor: u64 = dots.next()?.parse().ok()?;
+    let patch: u64 = dots.next()?.parse().ok()?;
+
+    if dots.next().is_some() {
+        return None;
+    }
+
+    Some(DescribeResult::Release { version: describe, major, minor, patch })
+}
+
+fn prerelease_version(describe: &'static str) -> Option<DescribeResult> {
+    // prerelease version is in the shape vM.N.P-rc.C
+    let mut hyphen = describe.rsplit('-');
+    let prerelease = hyphen.next()?;
+    if !prerelease.starts_with("rc.") {
+        return None;
+    }
+
+    let rc: u64 = prerelease[3..].parse().ok()?;
+
+    let release = hyphen.next()?;
+
+    let DescribeResult::Release { version: _, major, minor, patch } = release_version(release)?
+    else {
+        return None;
+    };
+
+    Some(DescribeResult::Prerelease { version: describe, major, minor, patch, rc })
+}
+
+#[cfg(test)]
+mod test {
+    use super::DescribeResult;
+
+    fn assert_not_a_tag(describe: &'static str) {
+        assert_eq!(DescribeResult::NotATag { describe }, DescribeResult::new(describe))
+    }
+
+    fn assert_proto(describe: &'static str) {
+        assert_eq!(DescribeResult::Prototype { name: describe }, DescribeResult::new(describe))
+    }
+
+    fn assert_release(describe: &'static str, major: u64, minor: u64, patch: u64) {
+        assert_eq!(
+            DescribeResult::Release { version: describe, major, minor, patch },
+            DescribeResult::new(describe)
+        )
+    }
+
+    fn assert_prerelease(describe: &'static str, major: u64, minor: u64, patch: u64, rc: u64) {
+        assert_eq!(
+            DescribeResult::Prerelease { version: describe, major, minor, patch, rc },
+            DescribeResult::new(describe)
+        )
+    }
+
+    #[test]
+    fn not_a_tag() {
+        assert_not_a_tag("whatever-fuzzy");
+        assert_not_a_tag("whatever-fuzzy-5-ggg-dirty");
+        assert_not_a_tag("whatever-fuzzy-120-ggg-dirty");
+
+        // technically a tag, but not a proto nor a version, so not parsed as a tag
+        assert_not_a_tag("whatever");
+
+        // dirty version
+        assert_not_a_tag("v1.7.0-1-ggga-dirty");
+        assert_not_a_tag("v1.7.0-rc.1-1-ggga-dirty");
+
+        // after version
+        assert_not_a_tag("v1.7.0-1-ggga");
+        assert_not_a_tag("v1.7.0-rc.1-1-ggga");
+
+        // after proto
+        assert_not_a_tag("protoype-tag-0-1-ggga");
+        assert_not_a_tag("protoype-tag-0-1-ggga-dirty");
+    }
+
+    #[test]
+    fn prototype() {
+        assert_proto("prototype-tag-0");
+        assert_proto("prototype-tag-10");
+        assert_proto("prototype-long-name-tag-10");
+    }
+
+    #[test]
+    fn release() {
+        assert_release("v1.7.2", 1, 7, 2);
+    }
+
+    #[test]
+    fn prerelease() {
+        assert_prerelease("v1.7.2-rc.3", 1, 7, 2, 3);
+    }
+}