1 files changed, 83 insertions, 0 deletions
diff --git a/development/tools/cargo-workspace2/src/query/executor.rs b/development/tools/cargo-workspace2/src/query/executor.rs
new file mode 100644
index 000000000000..da67324de4c0
--- /dev/null
+++ b/development/tools/cargo-workspace2/src/query/executor.rs
@@ -0,0 +1,83 @@
+use super::{Constraint, DepConstraint};
+use crate::models::{CrateId, DepGraph};
+use std::collections::BTreeSet;
+
+/// Execute a simple set query
+pub(crate) fn set(crates: &Vec<String>, g: &DepGraph) -> Vec<CrateId> {
+    crates
+        .iter()
+        .filter_map(|name| match g.find_crate(name) {
+            None => {
+                eprintln!("[ERROR]: Unable to find crate: `{}`", name);
+                None
+            }
+            some => some,
+        })
+        .collect()
+}
+
+/// Execute a search query on the dependency graph
+pub(crate) fn deps(mut deps: Vec<DepConstraint>, g: &DepGraph) -> Vec<CrateId> {
+    // Parse the anchor point (first crate)
+    let DepConstraint {
+        ref _crate,
+        ref constraint,
+    } = deps.remove(0);
+    let init_id = get_crate_error(_crate, g);
+
+    // Get it's dependents
+    let mut dependents: BTreeSet<_> = match constraint {
+        Constraint::Initial(true) => g.get_dependents(init_id).into_iter().collect(),
+        Constraint::Initial(false) => g
+            .get_all()
+            .iter()
+            .filter(|c| c.has_dependency(init_id))
+            .map(|c| c.id)
+            .collect(),
+        _ => {
+            eprintln!("Invalid initial constraint! Only `<` and `!<` are allowed!");
+            std::process::exit(2);
+        }
+    };
+
+    // Then loop over all other constraints and subtract crates from
+    // the dependents set until all constraints are met.
+    deps.reverse();
+    while let Some(dc) = deps.pop() {
+        let DepConstraint {
+            ref _crate,
+            ref constraint,
+        } = dc;
+
+        let id = get_crate_error(_crate, g);
+        let ldeps = g.get_dependents(id);
+        dependents = apply_constraint(dependents, ldeps, constraint);
+    }
+
+    dependents.into_iter().collect()
+}
+
+fn get_crate_error(_crate: &String, g: &DepGraph) -> CrateId {
+    match g.find_crate(&_crate.trim().to_string()) {
+        Some(id) => id,
+        None => {
+            eprintln!("[ERROR]: Crate `{}` not found in workspace!", _crate);
+            std::process::exit(2);
+        }
+    }
+}
+
+fn apply_constraint(
+    init: BTreeSet<CrateId>,
+    cmp: Vec<CrateId>,
+    cnd: &Constraint,
+) -> BTreeSet<CrateId> {
+    let cmp: BTreeSet<CrateId> = cmp.into_iter().collect();
+    let init = init.into_iter();
+    match cnd {
+        Constraint::And(true) => init.filter(|id| cmp.contains(id)).collect(),
+        Constraint::And(false) => init.filter(|id| !cmp.contains(id)).collect(),
+        Constraint::Or => init.chain(cmp.into_iter()).collect(),
+        _ => todo!(),
+    }
+}