setup meson to allow building multiple fuzzers easily

fuzz/atom/parser/gencorpus.rs

@@ -0,0 +1,64 @@
+use std::{
+    env,
+    error::Error,
+    fs::{self, OpenOptions},
+    io::Write,
+    path::PathBuf,
+};
+
+use gentoo_utils::{
+    atom::Atom,
+    ebuild::{Depend, repo::Repo},
+};
+
+fn main() -> Result<(), Box<dyn Error>> {
+    let corpus_dir = PathBuf::from(
+        env::args()
+            .nth(1)
+            .expect("expected corpus directory as first argument"),
+    );
+
+    fs::create_dir_all(&corpus_dir)?;
+
+    let repo = Repo::new("/var/db/repos/gentoo");
+    let mut atoms = Vec::new();
+
+    for category in repo.categories()? {
+        for ebuild in category?.ebuilds()? {
+            let depend = ebuild?.depend().to_vec();
+
+            for expr in depend {
+                walk_expr(&mut atoms, &expr);
+            }
+        }
+    }
+
+    for (i, atom) in atoms.iter().enumerate() {
+        let path = corpus_dir.as_path().join(i.to_string());
+        let mut file = OpenOptions::new()
+            .write(true)
+            .truncate(true)
+            .create(true)
+            .open(path)?;
+
+        write!(file, "{atom}")?;
+    }
+
+    Ok(())
+}
+
+fn walk_expr(atoms: &mut Vec<Atom>, depend: &Depend<Atom>) {
+    match depend {
+        Depend::Element(atom) => {
+            atoms.push(atom.clone());
+        }
+        Depend::AllOf(exprs)
+        | Depend::OneOf(exprs)
+        | Depend::AnyOf(exprs)
+        | Depend::ConditionalGroup(_, exprs) => {
+            for expr in exprs {
+                walk_expr(atoms, expr);
+            }
+        }
+    }
+}