extract Windows PowerShell operations from squirrel-update

spec/squirrel-update-spec.coffee

@@ -4,6 +4,7 @@ path = require 'path'
 temp = require 'temp'
 SquirrelUpdate = require '../src/browser/squirrel-update'
 Spawner = require '../src/browser/spawner'
+WinPowerShell = require '../src/browser/win-powershell'
 WinRegistry = require '../src/browser/win-registry'
 
 # Run passed callback as Spawner.spawn() would do
@@ -12,7 +13,7 @@ invokeCallback = (callback) ->
   stdout = ''
   callback?(error, stdout)
 
-fdescribe "Windows Squirrel Update", ->
+describe "Windows Squirrel Update", ->
   tempHomeDirectory = null
 
   beforeEach ->

src/browser/squirrel-update.coffee

@@ -2,6 +2,7 @@ fs = require 'fs-plus'
 path = require 'path'
 Spawner = require './spawner'
 WinRegistry = require './win-registry'
+WinPowerShell = require './win-powershell'
 
 appFolder = path.resolve(process.execPath, '..')
 rootAtomFolder = path.resolve(appFolder, '..')
@@ -11,28 +12,10 @@ exeName = path.basename(process.execPath)
 
 if process.env.SystemRoot
   system32Path = path.join(process.env.SystemRoot, 'System32')
-  powershellPath = path.join(system32Path, 'WindowsPowerShell', 'v1.0', 'powershell.exe')
   setxPath = path.join(system32Path, 'setx.exe')
 else
-  powershellPath = 'powershell.exe'
   setxPath = 'setx.exe'
 
-# Spawn powershell.exe and callback when it completes
-spawnPowershell = (args, callback) ->
-  # set encoding and execute the command, capture the output, and return it via .NET's console in order to have consistent UTF-8 encoding
-  # http://stackoverflow.com/questions/22349139/utf-8-output-from-powershell
-  # to address https://github.com/atom/atom/issues/5063
-  args[0] = """
-    [Console]::OutputEncoding=[System.Text.Encoding]::UTF8
-    $output=#{args[0]}
-    [Console]::WriteLine($output)
-  """
-  args.unshift('-command')
-  args.unshift('RemoteSigned')
-  args.unshift('-ExecutionPolicy')
-  args.unshift('-noprofile')
-  Spawner.spawn(powershellPath, args, callback)
-
 # Spawn setx.exe and callback when it completes
 spawnSetx = (args, callback) ->
   Spawner.spawn(setxPath, args, callback)
@@ -42,15 +25,6 @@ spawnSetx = (args, callback) ->
 spawnUpdate = (args, callback) ->
   Spawner.spawn(updateDotExe, args, callback)
 
-# Get the user's PATH environment variable registry value.
-getPath = (callback) ->
-  spawnPowershell ['[environment]::GetEnvironmentVariable(\'Path\',\'User\')'], (error, stdout) ->
-    if error?
-      return callback(error)
-
-    pathOutput = stdout.replace(/^\s+|\s+$/g, '')
-    callback(null, pathOutput)
-
 # Add atom and apm to the PATH
 #
 # This is done by adding .cmd shims to the root bin folder in the Atom
@@ -88,7 +62,7 @@ addCommandsToPath = (callback) ->
   installCommands (error) ->
     return callback(error) if error?
 
-    getPath (error, pathEnv) ->
+    WinPowerShell.getPath (error, pathEnv) ->
       return callback(error) if error?
 
       pathSegments = pathEnv.split(/;+/).filter (pathSegment) -> pathSegment
@@ -99,7 +73,7 @@ addCommandsToPath = (callback) ->
 
 # Remove atom and apm from the PATH
 removeCommandsFromPath = (callback) ->
-  getPath (error, pathEnv) ->
+  WinPowerShell.getPath (error, pathEnv) ->
     return callback(error) if error?
 
     pathSegments = pathEnv.split(/;+/).filter (pathSegment) ->

src/browser/win-powershell.coffee

@@ -0,0 +1,39 @@
+path = require 'path'
+Spawner = require './spawner'
+
+if process.env.SystemRoot
+  system32Path = path.join(process.env.SystemRoot, 'System32')
+  powershellPath = path.join(system32Path, 'WindowsPowerShell', 'v1.0', 'powershell.exe')
+else
+  powershellPath = 'powershell.exe'
+
+# Spawn powershell.exe and callback when it completes
+spawnPowershell = (args, callback) ->
+  # Set encoding and execute the command, capture the output, and return it 
+  # via .NET's console in order to have consistent UTF-8 encoding.
+  # See http://stackoverflow.com/questions/22349139/utf-8-output-from-powershell
+  # to address https://github.com/atom/atom/issues/5063
+  args[0] = """
+    [Console]::OutputEncoding=[System.Text.Encoding]::UTF8
+    $output=#{args[0]}
+    [Console]::WriteLine($output)
+  """
+  args.unshift('-command')
+  args.unshift('RemoteSigned')
+  args.unshift('-ExecutionPolicy')
+  args.unshift('-noprofile')
+  Spawner.spawn(powershellPath, args, callback)
+
+# Get the user's PATH environment variable registry value.
+#
+# * `callback` The {Function} to call after registry operation is done.
+#   It will be invoked with the same arguments provided by {Spawner.spawn}.
+#
+# Returns the user's path {String}.
+exports.getPath = (callback) ->
+  spawnPowershell ['[environment]::GetEnvironmentVariable(\'Path\',\'User\')'], (error, stdout) ->
+    if error?
+      return callback(error)
+
+    pathOutput = stdout.replace(/^\s+|\s+$/g, '')
+    callback(null, pathOutput)