Various small improvements

CHANGELOG.md

@@ -4,6 +4,11 @@ All notable changes to this project will be documented in this file
 automatically by Versionist. DO NOT EDIT THIS FILE MANUALLY!
 This project adheres to [Semantic Versioning](http://semver.org/).
 
+## v4.1.1 - 2017-12-11
+
+* Refactor read stream logic to improve clarity & error handling #32 [Tim Perry]
+* Update Bluebird to v3 #32 [Tim Perry]
+
 ## v4.1.0 - 2017-11-21
 
 * Upgrade partitioninfo so we can read GPT partition tables too #31 [Tim Perry]

build/imagefs.js

@@ -104,18 +104,24 @@ read = function(disk, partition, path) {
     readStream = null;
     outputStream = new stream.PassThrough();
     startReadStream = function() {
-      outputStream.removeListener('newListener', startReadStream);
-      return process.nextTick(function() {
+      var e;
+      try {
         readStream = fs_.createReadStream(path, {
           autoClose: false
         });
-        readStream.on('error', function(err) {
-          return outputStream.emit('error', err);
-        });
-        return readStream.pipe(outputStream);
+      } catch (_error) {
+        e = _error;
+        outputStream.emit('error', e);
+        return;
+      }
+      readStream.on('error', function(err) {
+        return outputStream.emit('error', err);
       });
+      return readStream.pipe(outputStream);
     };
-    outputStream.on('newListener', startReadStream);
+    outputStream.once('newListener', function() {
+      return process.nextTick(startReadStream);
+    });
     return Promise.resolve(outputStream).disposer(function(stream) {
       outputStream.end();
       if ((readStream != null) && readStream.closeAsync) {

lib/imagefs.coffee

@@ -90,18 +90,21 @@ read = (disk, partition, path) ->
 			readStream = null
 			outputStream = new stream.PassThrough()
 
-			# We don't start the stream until somebody else starts listening
 			startReadStream = ->
-				outputStream.removeListener('newListener', startReadStream)
-
-				# This is triggered _before_ the listener is added, so wait briefly
-				process.nextTick ->
+				try
 					readStream = fs_.createReadStream(path, autoClose: false)
-					readStream.on 'error', (err) ->
-						outputStream.emit('error', err)
-					readStream.pipe(outputStream)
+				catch e
+					outputStream.emit('error', e)
+					return
+
+				readStream.on 'error', (err) ->
+					outputStream.emit('error', err)
 
-			outputStream.on('newListener', startReadStream)
+				readStream.pipe(outputStream)
+
+			# We don't start the stream until somebody else starts listening
+			# Delayed slightly, as this event fires _before_ the listener is added
+			outputStream.once('newListener', -> process.nextTick(startReadStream))
 
 			Promise.resolve(outputStream)
 			.disposer (stream) ->

package.json

@@ -1,6 +1,6 @@
 {
   "name": "resin-image-fs",
-  "version": "4.1.0",
+  "version": "4.1.1",
   "description": "Resin.io image filesystem manipulation utilities",
   "main": "build/imagefs.js",
   "homepage": "https://github.com/resin-io/resin-image-fs",
@@ -44,7 +44,7 @@
     "wary": "^1.0.0"
   },
   "dependencies": {
-    "bluebird": "^2.9.32",
+    "bluebird": "^3.5.1",
     "ext2fs": "^0.1.0",
     "fatfs": "^0.10.6",
     "file-disk": "^1.0.1",