onepass diff

Author: addisoncrump

fuzz/Cargo.toml

@@ -75,6 +75,10 @@ path = "fuzz_targets/ast_diff_default.rs"
 name = "ast_diff_dense_dfa"
 path = "fuzz_targets/ast_diff_dense_dfa.rs"
 
+[[bin]]
+name = "ast_diff_onepass_dfa"
+path = "fuzz_targets/ast_diff_onepass_dfa.rs"
+
 [[bin]]
 name = "ast_diff_sparse_dfa"
 path = "fuzz_targets/ast_diff_sparse_dfa.rs"

fuzz/fuzz_targets/ast_diff_onepass_dfa.rs

@@ -0,0 +1,82 @@
+#![no_main]
+
+use {
+    libfuzzer_sys::{fuzz_target, Corpus},
+    regex_automata::{
+        dfa::{onepass::Builder as RegexBuilder, onepass::DFA},
+        nfa::thompson::{pikevm::PikeVM as NfaRegex, NFA},
+    },
+    regex_syntax::ast::Ast,
+};
+
+#[derive(Eq, PartialEq, arbitrary::Arbitrary)]
+struct FuzzData {
+    ast: Ast,
+    haystack: String,
+}
+
+impl std::fmt::Debug for FuzzData {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let mut builder = f.debug_struct("FuzzData");
+        builder.field("ast", &format!("{}", self.ast));
+        builder.field("haystack", &self.haystack);
+        builder.finish()
+    }
+}
+
+fn do_fuzz(data: FuzzData) -> Corpus {
+    let _ = env_logger::try_init();
+
+    let pattern = format!("{}", data.ast);
+    let config = NFA::config().nfa_size_limit(Some(1 << 20));
+    let Ok(nfa) = NFA::compiler().configure(config).build(&pattern) else {
+        return Corpus::Reject;
+    };
+    let Ok(baseline) = NfaRegex::new_from_nfa(nfa) else {
+        return Corpus::Reject;
+    };
+    let mut baseline_cache = baseline.create_cache();
+
+    let config = DFA::config().size_limit(Some(1 << 20));
+    let Ok(re) = RegexBuilder::new().configure(config).build(&pattern) else {
+        return Corpus::Reject;
+    };
+    let mut onepass_cache = re.create_cache();
+
+    assert_eq!(
+        re.is_match(&mut onepass_cache, &data.haystack),
+        baseline.is_match(&mut baseline_cache, &data.haystack)
+    );
+    let found1 = re.find(&mut onepass_cache, &data.haystack);
+    let found2 = baseline.find(&mut baseline_cache, &data.haystack);
+    if let Some(found1) = found1 {
+        let found2 = found2.expect("Found in target, but not in baseline!");
+        assert_eq!(found1.start(), found2.start());
+        assert_eq!(found1.end(), found2.end());
+    }
+
+    let mut onepass_captures = re.create_captures();
+    re.captures(&mut onepass_cache, &data.haystack, &mut onepass_captures);
+
+    let mut baseline_captures = baseline.create_captures();
+    baseline.captures(
+        &mut baseline_cache,
+        &data.haystack,
+        &mut baseline_captures,
+    );
+    drop(baseline_cache);
+    assert_eq!(onepass_captures.group_len(), baseline_captures.group_len());
+    for (c1, c2) in onepass_captures.iter().zip(baseline_captures.iter()) {
+        if let Some(c1) = c1 {
+            let c2 = c2.expect("Matched in target, but not baseline!");
+            assert_eq!(c1.start, c2.start);
+            assert_eq!(c1.end, c2.end);
+        } else {
+            assert!(c2.is_none(), "Matched in baseline, but not target!");
+        }
+    }
+
+    Corpus::Keep
+}
+
+fuzz_target!(|data: FuzzData| -> Corpus { do_fuzz(data) });