move contents of taskchampion repo to tc/

rust/taskchampion/src/depmap.rs

@@ -0,0 +1,81 @@
+use uuid::Uuid;
+
+/// DependencyMap stores information on task dependencies between pending tasks.
+///
+/// This information requires a scan of the working set to generate, so it is
+/// typically calculated once and re-used.
+#[derive(Debug, PartialEq)]
+pub struct DependencyMap {
+    /// Edges of the dependency graph.  If (a, b) is in this array, then task a depends on tsak b.
+    edges: Vec<(Uuid, Uuid)>,
+}
+
+impl DependencyMap {
+    /// Create a new, empty DependencyMap.
+    pub(super) fn new() -> Self {
+        Self { edges: Vec::new() }
+    }
+
+    /// Add a dependency of a on b.
+    pub(super) fn add_dependency(&mut self, a: Uuid, b: Uuid) {
+        self.edges.push((a, b));
+    }
+
+    /// Return an iterator of Uuids on which task `deps_of` depends.  This is equivalent to
+    /// `task.get_dependencies()`.
+    pub fn dependencies(&self, dep_of: Uuid) -> impl Iterator<Item = Uuid> + '_ {
+        self.edges
+            .iter()
+            .filter_map(move |(a, b)| if a == &dep_of { Some(*b) } else { None })
+    }
+
+    /// Return an iterator of Uuids of tasks that depend on `dep_on`
+    /// `task.get_dependencies()`.
+    pub fn dependents(&self, dep_on: Uuid) -> impl Iterator<Item = Uuid> + '_ {
+        self.edges
+            .iter()
+            .filter_map(move |(a, b)| if b == &dep_on { Some(*a) } else { None })
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use pretty_assertions::assert_eq;
+    use std::collections::HashSet;
+
+    #[test]
+    fn dependencies() {
+        let t = Uuid::new_v4();
+        let uuid1 = Uuid::new_v4();
+        let uuid2 = Uuid::new_v4();
+        let mut dm = DependencyMap::new();
+
+        dm.add_dependency(t, uuid1);
+        dm.add_dependency(t, uuid2);
+        dm.add_dependency(Uuid::new_v4(), t);
+        dm.add_dependency(Uuid::new_v4(), uuid1);
+        dm.add_dependency(uuid2, Uuid::new_v4());
+
+        assert_eq!(
+            dm.dependencies(t).collect::<HashSet<_>>(),
+            set![uuid1, uuid2]
+        );
+    }
+
+    #[test]
+    fn dependents() {
+        let t = Uuid::new_v4();
+        let uuid1 = Uuid::new_v4();
+        let uuid2 = Uuid::new_v4();
+        let mut dm = DependencyMap::new();
+
+        dm.add_dependency(uuid1, t);
+        dm.add_dependency(uuid2, t);
+        dm.add_dependency(t, Uuid::new_v4());
+        dm.add_dependency(Uuid::new_v4(), uuid1);
+        dm.add_dependency(uuid2, Uuid::new_v4());
+
+        assert_eq!(dm.dependents(t).collect::<HashSet<_>>(), set![uuid1, uuid2]);
+    }
+}