From e8eb3c5d5a1e7eb2f7c61f27dee659bfe00d7e6a Mon Sep 17 00:00:00 2001
From: Douglas Creager <dcreager@dcreager.net>
Date: Tue, 27 Apr 2021 09:21:38 -0400
Subject: [PATCH] binding_web: Add Query.didExceedMatchLimit

This lets wasm clients check whether a query exceeded its maximum number
of in-progress matches.
---
 lib/binding_web/binding.c          |  7 +++++++
 lib/binding_web/binding.js         |  4 ++++
 lib/binding_web/exports.json       |  1 +
 lib/binding_web/test/query-test.js | 20 ++++++++++++++++++++
 4 files changed, 32 insertions(+)

diff --git a/lib/binding_web/binding.c b/lib/binding_web/binding.c
index d020da7c..c605731e 100644
--- a/lib/binding_web/binding.c
+++ b/lib/binding_web/binding.c
@@ -670,3 +670,10 @@ void ts_query_captures_wasm(
   TRANSFER_BUFFER[0] = (const void *)(capture_count);
   TRANSFER_BUFFER[1] = result.contents;
 }
+
+bool ts_query_did_exceed_match_limit_wasm(
+  const TSQuery *self
+) {
+  if (!scratch_query_cursor) return false;
+  return ts_query_cursor_did_exceed_match_limit(scratch_query_cursor);
+}
diff --git a/lib/binding_web/binding.js b/lib/binding_web/binding.js
index 62b147f1..a51a7aea 100644
--- a/lib/binding_web/binding.js
+++ b/lib/binding_web/binding.js
@@ -1048,6 +1048,10 @@ class Query {
   predicatesForPattern(patternIndex) {
     return this.predicates[patternIndex]
   }
+
+  didExceedMatchLimit() {
+    return C._ts_query_did_exceed_match_limit_wasm(this[0]);
+  }
 }
 
 function getText(tree, startIndex, endIndex) {
diff --git a/lib/binding_web/exports.json b/lib/binding_web/exports.json
index b2b4449d..7e73a11a 100644
--- a/lib/binding_web/exports.json
+++ b/lib/binding_web/exports.json
@@ -76,6 +76,7 @@
   "_ts_query_capture_name_for_id",
   "_ts_query_captures_wasm",
   "_ts_query_delete",
+  "_ts_query_did_exceed_match_limit_wasm",
   "_ts_query_matches_wasm",
   "_ts_query_new",
   "_ts_query_pattern_count",
diff --git a/lib/binding_web/test/query-test.js b/lib/binding_web/test/query-test.js
index 77937a45..b7b2e053 100644
--- a/lib/binding_web/test/query-test.js
+++ b/lib/binding_web/test/query-test.js
@@ -238,6 +238,26 @@ describe("Query", () => {
           refutedProperties: { bar: "baz" },
         },
       ]);
+      assert.ok(!query.didExceedMatchLimit());
+    });
+
+    it("detects queries with too many permutations to track", () => {
+      tree = parser.parse(`
+        [
+          hello, hello, hello, hello, hello, hello, hello, hello, hello, hello,
+          hello, hello, hello, hello, hello, hello, hello, hello, hello, hello,
+          hello, hello, hello, hello, hello, hello, hello, hello, hello, hello,
+          hello, hello, hello, hello, hello, hello, hello, hello, hello, hello,
+          hello, hello, hello, hello, hello, hello, hello, hello, hello, hello,
+        ];
+      `);
+
+      query = JavaScript.query(`
+        (array (identifier) @pre (identifier) @post)
+      `);
+
+      const captures = query.captures(tree.rootNode);
+      assert.ok(query.didExceedMatchLimit());
     });
   });