1 files changed, 197 insertions, 0 deletions
diff --git a/third_party/rust/regex-automata/tests/dfa/onepass/suite.rs b/third_party/rust/regex-automata/tests/dfa/onepass/suite.rs
new file mode 100644
index 0000000000..20bd6965c8
--- /dev/null
+++ b/third_party/rust/regex-automata/tests/dfa/onepass/suite.rs
@@ -0,0 +1,197 @@
+use {
+    anyhow::Result,
+    regex_automata::{
+        dfa::onepass::{self, DFA},
+        nfa::thompson,
+        util::{iter, syntax},
+    },
+    regex_test::{
+        CompiledRegex, Match, RegexTest, SearchKind, Span, TestResult,
+        TestRunner,
+    },
+};
+
+use crate::{create_input, suite, testify_captures, untestify_kind};
+
+const EXPANSIONS: &[&str] = &["is_match", "find", "captures"];
+
+/// Tests the default configuration of the hybrid NFA/DFA.
+#[test]
+fn default() -> Result<()> {
+    let builder = DFA::builder();
+    TestRunner::new()?
+        .expand(EXPANSIONS, |t| t.compiles())
+        .test_iter(suite()?.iter(), compiler(builder))
+        .assert();
+    Ok(())
+}
+
+/// Tests the hybrid NFA/DFA when 'starts_for_each_pattern' is enabled for all
+/// tests.
+#[test]
+fn starts_for_each_pattern() -> Result<()> {
+    let mut builder = DFA::builder();
+    builder.configure(DFA::config().starts_for_each_pattern(true));
+    TestRunner::new()?
+        .expand(EXPANSIONS, |t| t.compiles())
+        .test_iter(suite()?.iter(), compiler(builder))
+        .assert();
+    Ok(())
+}
+
+/// Tests the hybrid NFA/DFA when byte classes are disabled.
+///
+/// N.B. Disabling byte classes doesn't avoid any indirection at search time.
+/// All it does is cause every byte value to be its own distinct equivalence
+/// class.
+#[test]
+fn no_byte_classes() -> Result<()> {
+    let mut builder = DFA::builder();
+    builder.configure(DFA::config().byte_classes(false));
+    TestRunner::new()?
+        .expand(EXPANSIONS, |t| t.compiles())
+        .test_iter(suite()?.iter(), compiler(builder))
+        .assert();
+    Ok(())
+}
+
+fn compiler(
+    mut builder: onepass::Builder,
+) -> impl FnMut(&RegexTest, &[String]) -> Result<CompiledRegex> {
+    move |test, regexes| {
+        // Check if our regex contains things that aren't supported by DFAs.
+        // That is, Unicode word boundaries when searching non-ASCII text.
+        if !configure_onepass_builder(test, &mut builder) {
+            return Ok(CompiledRegex::skip());
+        }
+        let re = match builder.build_many(&regexes) {
+            Ok(re) => re,
+            Err(err) => {
+                let msg = err.to_string();
+                // This is pretty gross, but when a regex fails to compile as
+                // a one-pass regex, then we want to be OK with that and just
+                // skip the test. But we have to be careful to only skip it
+                // when the expected result is that the regex compiles. If
+                // the test is specifically checking that the regex does not
+                // compile, then we should bubble up that error and allow the
+                // test to pass.
+                //
+                // Since our error types are all generally opaque, we just
+                // look for an error string. Not great, but not the end of the
+                // world.
+                if test.compiles() && msg.contains("not one-pass") {
+                    return Ok(CompiledRegex::skip());
+                }
+                return Err(err.into());
+            }
+        };
+        let mut cache = re.create_cache();
+        Ok(CompiledRegex::compiled(move |test| -> TestResult {
+            run_test(&re, &mut cache, test)
+        }))
+    }
+}
+
+fn run_test(
+    re: &DFA,
+    cache: &mut onepass::Cache,
+    test: &RegexTest,
+) -> TestResult {
+    let input = create_input(test);
+    match test.additional_name() {
+        "is_match" => {
+            TestResult::matched(re.is_match(cache, input.earliest(true)))
+        }
+        "find" => match test.search_kind() {
+            SearchKind::Earliest | SearchKind::Leftmost => {
+                let input =
+                    input.earliest(test.search_kind() == SearchKind::Earliest);
+                let mut caps = re.create_captures();
+                let it = iter::Searcher::new(input)
+                    .into_matches_iter(|input| {
+                        re.try_search(cache, input, &mut caps)?;
+                        Ok(caps.get_match())
+                    })
+                    .infallible()
+                    .take(test.match_limit().unwrap_or(std::usize::MAX))
+                    .map(|m| Match {
+                        id: m.pattern().as_usize(),
+                        span: Span { start: m.start(), end: m.end() },
+                    });
+                TestResult::matches(it)
+            }
+            SearchKind::Overlapping => {
+                // The one-pass DFA does not support any kind of overlapping
+                // search. This is not just a matter of not having the API.
+                // It's fundamentally incompatible with the one-pass concept.
+                // If overlapping matches were possible, then the one-pass DFA
+                // would fail to build.
+                TestResult::skip()
+            }
+        },
+        "captures" => match test.search_kind() {
+            SearchKind::Earliest | SearchKind::Leftmost => {
+                let input =
+                    input.earliest(test.search_kind() == SearchKind::Earliest);
+                let it = iter::Searcher::new(input)
+                    .into_captures_iter(re.create_captures(), |input, caps| {
+                        re.try_search(cache, input, caps)
+                    })
+                    .infallible()
+                    .take(test.match_limit().unwrap_or(std::usize::MAX))
+                    .map(|caps| testify_captures(&caps));
+                TestResult::captures(it)
+            }
+            SearchKind::Overlapping => {
+                // The one-pass DFA does not support any kind of overlapping
+                // search. This is not just a matter of not having the API.
+                // It's fundamentally incompatible with the one-pass concept.
+                // If overlapping matches were possible, then the one-pass DFA
+                // would fail to build.
+                TestResult::skip()
+            }
+        },
+        name => TestResult::fail(&format!("unrecognized test name: {}", name)),
+    }
+}
+
+/// Configures the given regex builder with all relevant settings on the given
+/// regex test.
+///
+/// If the regex test has a setting that is unsupported, then this returns
+/// false (implying the test should be skipped).
+fn configure_onepass_builder(
+    test: &RegexTest,
+    builder: &mut onepass::Builder,
+) -> bool {
+    if !test.anchored() {
+        return false;
+    }
+    let match_kind = match untestify_kind(test.match_kind()) {
+        None => return false,
+        Some(k) => k,
+    };
+
+    let config = DFA::config().match_kind(match_kind);
+    builder
+        .configure(config)
+        .syntax(config_syntax(test))
+        .thompson(config_thompson(test));
+    true
+}
+
+/// Configuration of a Thompson NFA compiler from a regex test.
+fn config_thompson(test: &RegexTest) -> thompson::Config {
+    let mut lookm = regex_automata::util::look::LookMatcher::new();
+    lookm.set_line_terminator(test.line_terminator());
+    thompson::Config::new().utf8(test.utf8()).look_matcher(lookm)
+}
+
+/// Configuration of the regex parser from a regex test.
+fn config_syntax(test: &RegexTest) -> syntax::Config {
+    syntax::Config::new()
+        .case_insensitive(test.case_insensitive())
+        .unicode(test.unicode())
+        .utf8(test.utf8())
+        .line_terminator(test.line_terminator())
+}