Update: replace MD5 hashing of cache files with MurmurHash (fixes esl…

…int#5522)
michaelficarra · Mar 13, 2016 · 7ef1d07 · 7ef1d07
1 parent a05394a
commit 7ef1d07
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Showing 4 changed files with 44 additions and 39 deletions.
diff --git a/lib/cli-engine.js b/lib/cli-engine.js
@@ -36,8 +36,8 @@ var fs = require("fs"),
     SourceCodeFixer = require("./util/source-code-fixer"),
     validator = require("./config/config-validator"),
     stringify = require("json-stable-stringify"),
+    hash = require("./util/hash"),
 
-    crypto = require( "crypto" ),
     pkg = require("../package.json");
 
 
@@ -262,17 +262,6 @@ function isErrorMessage(message) {
     return message.severity === 2;
 }
 
-/**
- * create a md5Hash of a given string
- * @param  {string} str the string to calculate the hash for
- * @returns {string}    the calculated hash
- */
-function md5Hash(str) {
-    return crypto
-        .createHash("md5")
-        .update(str, "utf8")
-        .digest("hex");
-}
 
 /**
  * return the cacheFile to be used by eslint, based on whether the provided parameter is
@@ -298,7 +287,7 @@ function getCacheFile(cacheFile, cwd) {
      * @returns {string} the resolved path to the cacheFile
      */
     function getCacheFileForDirectory() {
-        return path.join(resolvedCacheFile, ".cache_" + md5Hash(cwd));
+        return path.join(resolvedCacheFile, ".cache_" + hash(cwd));
     }
 
     var fileStats;
@@ -531,7 +520,7 @@ CLIEngine.prototype = {
 
                 var eslintVersion = pkg.version;
 
-                prevConfig.hash = md5Hash(eslintVersion + "_" + stringify(config));
+                prevConfig.hash = hash(eslintVersion + "_" + stringify(config));
             }
 
             return prevConfig.hash;

diff --git a/lib/util/hash.js b/lib/util/hash.js
@@ -0,0 +1,37 @@
+/**
+ * @fileoverview Defining the hashing function in one place.
+ * @author Michael Ficarra
+ * @copyright 2016 Michael Ficarra. All rights reserved.
+ * See LICENSE file in root directory for full license.
+ */
+
+"use strict";
+
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+var murmur = require("imurmurhash");
+
+//------------------------------------------------------------------------------
+// Helpers
+//------------------------------------------------------------------------------
+
+//------------------------------------------------------------------------------
+// Private
+//------------------------------------------------------------------------------
+
+/**
+ * hash the given string
+ * @param  {string} str the string to hash
+ * @returns {string}    the hash
+ */
+function hash(str) {
+    return murmur(str).result().toString(36);
+}
+
+//------------------------------------------------------------------------------
+// Public Interface
+//------------------------------------------------------------------------------
+
+module.exports = hash;
diff --git a/package.json b/package.json
@@ -49,6 +49,7 @@
     "glob": "^6.0.4",
     "globals": "^8.18.0",
     "ignore": "^2.2.19",
+    "imurmurhash": "^0.1.4",
     "inquirer": "^0.12.0",
     "is-my-json-valid": "^2.10.0",
     "is-resolvable": "^1.0.0",

diff --git a/tests/lib/cli-engine.js b/tests/lib/cli-engine.js
@@ -20,7 +20,7 @@ var assert = require("chai").assert,
     Plugins = require("../../lib/config/plugins"),
     fs = require("fs"),
     os = require("os"),
-    crypto = require("crypto");
+    hash = require("../../lib/util/hash");
 
 require("shelljs/global");
 proxyquire = proxyquire.noCallThru().noPreserveCache();
@@ -1309,17 +1309,6 @@ describe("CLIEngine", function() {
                 it("should create the cache file inside the provided directory", function() {
                     assert.isFalse(fs.existsSync(path.resolve("./tmp/.cacheFileDir/.cache_hashOfCurrentWorkingDirectory")), "the cache for eslint does not exist");
 
-                    sandbox.stub(crypto, "createHash", function() {
-                        return {
-                            update: function() {
-                                return this;
-                            },
-                            digest: function() {
-                                return "hashOfCurrentWorkingDirectory";
-                            }
-                        };
-                    });
-
                     engine = new CLIEngine({
                         useEslintrc: false,
                         // specifying cache true the cache will be created
@@ -1337,7 +1326,7 @@ describe("CLIEngine", function() {
 
                     engine.executeOnFiles([file]);
 
-                    assert.isTrue(fs.existsSync(path.resolve("./tmp/.cacheFileDir/.cache_hashOfCurrentWorkingDirectory")), "the cache for eslint was created");
+                    assert.isTrue(fs.existsSync(path.resolve("./tmp/.cacheFileDir/.cache_" + hash(process.cwd()))), "the cache for eslint was created");
 
                     sandbox.restore();
                 });
@@ -1346,17 +1335,6 @@ describe("CLIEngine", function() {
             it("should create the cache file inside the provided directory using the cacheLocation option", function() {
                 assert.isFalse(fs.existsSync(path.resolve("./tmp/.cacheFileDir/.cache_hashOfCurrentWorkingDirectory")), "the cache for eslint does not exist");
 
-                sandbox.stub(crypto, "createHash", function() {
-                    return {
-                        update: function() {
-                            return this;
-                        },
-                        digest: function() {
-                            return "hashOfCurrentWorkingDirectory";
-                        }
-                    };
-                });
-
                 engine = new CLIEngine({
                     useEslintrc: false,
                     // specifying cache true the cache will be created
@@ -1374,7 +1352,7 @@ describe("CLIEngine", function() {
 
                 engine.executeOnFiles([file]);
 
-                assert.isTrue(fs.existsSync(path.resolve("./tmp/.cacheFileDir/.cache_hashOfCurrentWorkingDirectory")), "the cache for eslint was created");
+                assert.isTrue(fs.existsSync(path.resolve("./tmp/.cacheFileDir/.cache_" + hash(process.cwd()))), "the cache for eslint was created");
 
                 sandbox.restore();
             });