fix: attach queue to fs module in addition to global

PR-URL: #184
Credit: @SimenB
Close: #184
Fixes: #183
Reviewed-by: @coreyfarrell

graceful-fs.js

@@ -21,6 +21,14 @@ if (typeof Symbol === 'function' && typeof Symbol.for === 'function') {
 
 function noop () {}
 
+function publishQueue(context, queue) {
+  Object.defineProperty(context, gracefulQueue, {
+    get: function() {
+      return queue
+    }
+  })
+}
+
 var debug = noop
 if (util.debuglog)
   debug = util.debuglog('gfs4')
@@ -32,14 +40,10 @@ else if (/\bgfs4\b/i.test(process.env.NODE_DEBUG || ''))
   }
 
 // Once time initialization
-if (!global[gracefulQueue]) {
+if (!fs[gracefulQueue]) {
   // This queue can be shared by multiple loaded instances
-  var queue = []
-  Object.defineProperty(global, gracefulQueue, {
-    get: function() {
-      return queue
-    }
-  })
+  var queue = global[gracefulQueue] || []
+  publishQueue(fs, queue)
 
   // Patch fs.close/closeSync to shared queue version, because we need
   // to retry() whenever a close happens *anywhere* in the program.
@@ -79,12 +83,16 @@ if (!global[gracefulQueue]) {
 
   if (/\bgfs4\b/i.test(process.env.NODE_DEBUG || '')) {
     process.on('exit', function() {
-      debug(global[gracefulQueue])
-      require('assert').equal(global[gracefulQueue].length, 0)
+      debug(fs[gracefulQueue])
+      require('assert').equal(fs[gracefulQueue].length, 0)
     })
   }
 }
 
+if (!global[gracefulQueue]) {
+  publishQueue(global, fs[gracefulQueue]);
+}
+
 module.exports = patch(clone(fs))
 if (process.env.TEST_GRACEFUL_FS_GLOBAL_PATCH && !fs.__patched) {
     module.exports = patch(fs)
@@ -334,11 +342,11 @@ function patch (fs) {
 
 function enqueue (elem) {
   debug('ENQUEUE', elem[0].name, elem[1])
-  global[gracefulQueue].push(elem)
+  fs[gracefulQueue].push(elem)
 }
 
 function retry () {
-  var elem = global[gracefulQueue].shift()
+  var elem = fs[gracefulQueue].shift()
   if (elem) {
     debug('RETRY', elem[0].name, elem[1])
     elem[0].apply(null, elem[1])