chore: import upstream snapshot with attribution

2026-07-13 13:32:57 +08:00
commit cd420f9332
4811 changed files with 884702 additions and 0 deletions
@@ -0,0 +1,82 @@
+/**
+ * Detects unpaired UTF-16 surrogate escape sequences in JSON-encoded text.
+ *
+ * Returns true if the input contains a `\uD8XX`/`\uD9XX`/`\uDAXX`/`\uDBXX`
+ * high-surrogate escape not immediately followed by a `\uDC..`–`\uDF..` low
+ * surrogate, or a `\uDC..`–`\uDF..` low surrogate not immediately preceded by
+ * a high surrogate. Strict JSON parsers (e.g. ClickHouse `JSONEachRow`)
+ * reject input containing such sequences.
+ *
+ * Surrogate hex ranges (case-insensitive — inputs from `JSON.stringify` are
+ * lowercase):
+ *   - High surrogate (U+D800–U+DBFF):  `\uD[8-B][0-9A-F][0-9A-F]`
+ *   - Low surrogate  (U+DC00–U+DFFF):  `\uD[C-F][0-9A-F][0-9A-F]`
+ */
+export function detectBadJsonStrings(jsonString: string): boolean {
+  // Fast path: skip everything if no \u
+  let idx = jsonString.indexOf("\\u");
+  if (idx === -1) return false;
+
+  // Use a more efficient scanning strategy
+  const length = jsonString.length;
+
+  while (idx !== -1 && idx < length - 5) {
+    // Only check if we have enough characters left
+    if (idx + 6 > length) break;
+
+    if (jsonString[idx + 1] === "u" && jsonString[idx + 2] === "d") {
+      const third = jsonString[idx + 3];
+
+      // High surrogate check — third nibble is 8, 9, a, or b (U+D800–U+DBFF)
+      if (
+        /[89ab]/.test(third) &&
+        /[0-9a-f]/.test(jsonString[idx + 4]) &&
+        /[0-9a-f]/.test(jsonString[idx + 5])
+      ) {
+        // Check for low surrogate after (need at least 6 more chars)
+        if (idx + 12 > length) {
+          return true; // Incomplete high surrogate (not enough chars left)
+        }
+
+        if (
+          jsonString[idx + 6] !== "\\" ||
+          jsonString[idx + 7] !== "u" ||
+          jsonString[idx + 8] !== "d" ||
+          !/[c-f]/.test(jsonString[idx + 9]) ||
+          !/[0-9a-f]/.test(jsonString[idx + 10]) ||
+          !/[0-9a-f]/.test(jsonString[idx + 11])
+        ) {
+          return true; // Incomplete high surrogate
+        }
+      }
+
+      // Low surrogate check — third nibble is c, d, e, or f (U+DC00–U+DFFF)
+      if (
+        /[c-f]/.test(third) &&
+        /[0-9a-f]/.test(jsonString[idx + 4]) &&
+        /[0-9a-f]/.test(jsonString[idx + 5])
+      ) {
+        // Check for high surrogate before (need at least 6 chars before)
+        if (idx < 6) {
+          return true; // Incomplete low surrogate (not enough chars before)
+        }
+
+        if (
+          jsonString[idx - 6] !== "\\" ||
+          jsonString[idx - 5] !== "u" ||
+          jsonString[idx - 4] !== "d" ||
+          !/[89ab]/.test(jsonString[idx - 3]) ||
+          !/[0-9a-f]/.test(jsonString[idx - 2]) ||
+          !/[0-9a-f]/.test(jsonString[idx - 1])
+        ) {
+          return true; // Incomplete low surrogate
+        }
+      }
+    }
+
+    // More efficient next search - skip ahead by 2 to avoid overlapping matches
+    idx = jsonString.indexOf("\\u", idx + 2);
+  }
+
+  return false;
+}