From 2efed5995739837ec3863e1a6f568faf10da6c2a Mon Sep 17 00:00:00 2001
From: Juan Cruz Viotti <jv@jviotti.com>
Date: Mon, 1 Oct 2018 11:31:53 +0100
Subject: [PATCH] Retry unlocking if EPERM

See: https://github.com/electron-userland/electron-json-storage/issues/116
Signed-off-by: Juan Cruz Viotti <jv@jviotti.com>
---
 lib/lock.js    | 87 ++++++++++++++++++++++++++++++++++++++++++++++++++
 lib/storage.js | 21 +++---------
 2 files changed, 92 insertions(+), 16 deletions(-)
 create mode 100644 lib/lock.js

diff --git a/lib/lock.js b/lib/lock.js
new file mode 100644
index 0000000..a38a84a
--- /dev/null
+++ b/lib/lock.js
@@ -0,0 +1,87 @@
+/*
+ * The MIT License
+ *
+ * Copyright (c) 2018 Juan Cruz Viotti. https://github.com/jviotti
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+'use strict';
+
+const lockFile = require('lockfile');
+
+/**
+ * @summary Lock options
+ * @type {Object}
+ * @private
+ */
+const lockOptions = {
+  stale: 10000,
+  retries: Infinity,
+  retryWait: 50
+};
+
+/**
+ * @summary Create a lock file
+ * @function
+ * @public
+ *
+ * @param {String} file - lock file
+ * @param {Function} callback - callback (error)
+ *
+ * @example
+ * lock.lock('foo.lock', function(error) {
+ *   if (error) {
+ *     throw error;
+ *   }
+ * })
+ */
+exports.lock = function(file, callback) {
+  lockFile.lock(file, lockOptions, callback);
+};
+
+/**
+ * @summary Unlock a lock file
+ * @function
+ * @public
+ *
+ * @param {String} file - lock file
+ * @param {Function} callback - callback (error)
+ *
+ * @example
+ * lock.unlock('foo.lock', function(error) {
+ *   if (error) {
+ *     throw error;
+ *   }
+ * })
+ */
+exports.unlock = function(file, callback, times) {
+  times = times || 0;
+
+  lockFile.unlock(file, function(error) {
+    if (error && error.code === 'EPERM' && times < 10) {
+      setTimeout(function() {
+        exports.unlock(file, callback, times + 1);
+      }, 1000);
+      return;
+    }
+
+    return callback(error);
+  });
+};
diff --git a/lib/storage.js b/lib/storage.js
index ff08aa4..8828cd0 100644
--- a/lib/storage.js
+++ b/lib/storage.js
@@ -35,18 +35,7 @@ const rimraf = require('rimraf');
 const mkdirp = require('mkdirp');
 const path = require('path');
 const utils = require('./utils');
-const lockFile = require('lockfile');
-
-/**
- * @summary Lock options
- * @type {Object}
- * @private
- */
-const lockOptions = {
-  stale: 10000,
-  retries: Infinity,
-  retryWait: 50
-};
+const lock = require('./lock');
 
 /**
  * @summary Get the default data path
@@ -143,7 +132,7 @@ exports.get = function(key, options, callback) {
       mkdirp(path.dirname(fileName), callback);
     },
     function(made, next) {
-      lockFile.lock(utils.getLockFileName(fileName), lockOptions, function(error) {
+      lock.lock(utils.getLockFileName(fileName), function(error) {
         if (error && error.code === 'EEXIST') {
           return exports.get(key, options, callback);
         }
@@ -176,7 +165,7 @@ exports.get = function(key, options, callback) {
       return callback(null, objectJSON);
     }
   ], function(error, result) {
-    lockFile.unlock(utils.getLockFileName(fileName), function(lockError) {
+    lock.unlock(utils.getLockFileName(fileName), function(lockError) {
       if (error) {
         return callback(error);
       }
@@ -319,7 +308,7 @@ exports.set = function(key, json, options, callback) {
       });
     },
     function(data, next) {
-      lockFile.lock(utils.getLockFileName(fileName), lockOptions, function(error) {
+      lock.lock(utils.getLockFileName(fileName), function(error) {
         if (error && error.code === 'EEXIST') {
           return exports.set(key, json, options, callback);
         }
@@ -331,7 +320,7 @@ exports.set = function(key, json, options, callback) {
       fs.writeFile(fileName, data, callback);
     }
   ], function(error) {
-    lockFile.unlock(utils.getLockFileName(fileName), function(lockError) {
+    lock.unlock(utils.getLockFileName(fileName), function(lockError) {
       if (error) {
         return callback(error);
       }