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, 9 insertions, 27 deletions

diff --git a/lib/crypto.js b/lib/crypto.js
index 4bce371701..9ffff06f7f 100644
--- a/lib/crypto.js
+++ b/lib/crypto.js
@@ -632,41 +632,23 @@ exports.randomBytes = exports.pseudoRandomBytes = randomBytes;
 
 exports.rng = exports.prng = randomBytes;
 
-exports.getCiphers = function() {
-  return filterDuplicates(getCiphers());
-};
-
-
-exports.getHashes = function() {
-  return filterDuplicates(getHashes());
-};
+exports.getCiphers = internalUtil.cachedResult(() => {
+  return internalUtil.filterDuplicateStrings(getCiphers());
+});
 
+exports.getHashes = internalUtil.cachedResult(() => {
+  return internalUtil.filterDuplicateStrings(getHashes());
+});
 
-exports.getCurves = function() {
-  return filterDuplicates(getCurves());
-};
+exports.getCurves = internalUtil.cachedResult(() => {
+  return internalUtil.filterDuplicateStrings(getCurves());
+});
 
 Object.defineProperty(exports, 'fips', {
   get: getFipsCrypto,
   set: setFipsCrypto
 });
 
-function filterDuplicates(names) {
-  // Drop all-caps names in favor of their lowercase aliases,
-  // for example, 'sha1' instead of 'SHA1'.
-  var ctx = {};
-  names.forEach(function(name) {
-    var key = name;
-    if (/^[0-9A-Z\-]+$/.test(key)) key = key.toLowerCase();
-    if (!ctx.hasOwnProperty(key) || ctx[key] < name)
-      ctx[key] = name;
-  });
-
-  return Object.getOwnPropertyNames(ctx).map(function(key) {
-    return ctx[key];
-  }).sort();
-}
-
 // Legacy API
 Object.defineProperty(exports, 'createCredentials', {
   configurable: true,