Function safeRegexTest

src/LiveQuery/QueryTools.js:23–48

(pattern, flags, input)

// IMPORTANT: This function must remain synchronous. See vmContext comment above.
function safeRegexTest(pattern, flags, input) {
  try {
    if (!regexTimeout) {
      var re = new RegExp(pattern, flags);
      return re.test(input);
    }
    var cacheKey = flags + ':' + pattern;
    var script = scriptCache.get(cacheKey);
    if (!script) {
      if (scriptCache.size >= SCRIPT_CACHE_MAX) { scriptCache.clear(); }
      script = new vm.Script('new RegExp(pattern, flags).test(input)');
      scriptCache.set(cacheKey, script);
    }
    vmContext.pattern = pattern;
    vmContext.flags = flags;
    vmContext.input = input;
    return script.runInContext(vmContext, { timeout: regexTimeout });
  } catch (e) {
    if (e.code === 'ERR_SCRIPT_EXECUTION_TIMEOUT') {
      logger.warn(`Regex timeout: pattern "${pattern}" with flags "${flags}" exceeded ${regexTimeout}ms limit`);
    } else {
      logger.warn(`Invalid regex: pattern "${pattern}" with flags "${flags}": ${e.message}`);
    }
    return false;
  }
}

/**
 * Query Hashes are deterministic hashes for Parse Queries.