crypto,tls: perf improvements for crypto and tls getCiphers

Improve performance of crypto.getCiphers, getHashes, getCurves
and tls.getCiphers by consolidating filterDuplicates logic, adding
caching of output, and streamlining filterDuplicates implementation.

Benchmarks:

crypto.getCiphers n=1    v6.2.1 = 2559.3, new = 15890 ...... -83.89%
crypto.getCiphers n=5000 v6.2.1 = 3516.3, new = 24203000 ... -99.99%

tls.getCiphers    n=1    v6.2.1 = 3405.3, new = 14877 ...... -77.11%
tls.getCiphers    n=5000 v6.2.1 = 6074.4, new = 24202000 ... -99.97%

PR-URL: https://github.com/nodejs/node/pull/7225
Reviewed-By: Fedor Indutny <fedor.indutny@gmail.com>
Reviewed-By: Brian White <mscdex@mscdex.net>

1 files changed, 5 insertions, 11 deletions

diff --git a/lib/tls.js b/lib/tls.js
index 80ea0d76977..695edd8c5a6 100644
--- a/lib/tls.js
+++ b/lib/tls.js
@@ -1,6 +1,7 @@
 'use strict';
 
-require('internal/util').assertCrypto(exports);
+const internalUtil = require('internal/util');
+internalUtil.assertCrypto(exports);
 
 const net = require('net');
 const url = require('url');
@@ -21,16 +22,9 @@ exports.DEFAULT_CIPHERS =
 
 exports.DEFAULT_ECDH_CURVE = 'prime256v1';
 
-exports.getCiphers = function() {
-  const names = binding.getSSLCiphers();
-  // Drop all-caps names in favor of their lowercase aliases,
-  var ctx = {};
-  names.forEach(function(name) {
-    if (/^[0-9A-Z\-]+$/.test(name)) name = name.toLowerCase();
-    ctx[name] = true;
-  });
-  return Object.getOwnPropertyNames(ctx).sort();
-};
+exports.getCiphers = internalUtil.cachedResult(() => {
+  return internalUtil.filterDuplicateStrings(binding.getSSLCiphers(), true);
+});
 
 // Convert protocols array into valid OpenSSL protocols list
 // ("\x06spdy/2\x08http/1.1\x08http/1.0")