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