Reload user stylesheet when changed

spec/theme-manager-spec.coffee

@@ -1,5 +1,7 @@
 path = require 'path'
+
 {$, $$, fs, WorkspaceView} = require 'atom'
+temp = require 'temp'
 
 ThemeManager = require '../src/theme-manager'
 AtomPackage = require '../src/atom-package'
@@ -155,3 +157,29 @@ describe "ThemeManager", ->
       expect($(".editor").css("padding-top")).toBe "150px"
       expect($(".editor").css("padding-right")).toBe "150px"
       expect($(".editor").css("padding-bottom")).toBe "150px"
+
+  describe "when the user stylesheet changes", ->
+    it "reloads it", ->
+      userStylesheetPath = path.join(temp.mkdirSync("atom"), 'user.css')
+      fs.writeFileSync(userStylesheetPath, 'body {border-style: dotted !important;}')
+
+      spyOn(themeManager, 'getUserStylesheetPath').andReturn userStylesheetPath
+      themeManager.activateThemes()
+
+      expect($(document.body).css('border-style')).toBe 'dotted'
+      spyOn(themeManager, 'loadUserStylesheet').andCallThrough()
+
+      fs.writeFileSync(userStylesheetPath, 'body {border-style: dashed}')
+
+      waitsFor ->
+        themeManager.loadUserStylesheet.callCount is 1
+
+      runs ->
+        expect($(document.body).css('border-style')).toBe 'dashed'
+        fs.removeSync(userStylesheetPath)
+
+      waitsFor ->
+        themeManager.loadUserStylesheet.callCount is 2
+
+      runs ->
+        expect($(document.body).css('border-style')).toBe 'none'

src/theme-manager.coffee

@@ -4,6 +4,7 @@ _ = require 'underscore-plus'
 {Emitter} = require 'emissary'
 fs = require 'fs-plus'
 
+File = require './file'
 Package = require './package'
 AtomPackage = require './atom-package'
 {$} = require './space-pen-extensions'
@@ -71,7 +72,7 @@ class ThemeManager
 
   # Internal-only:
   deactivateThemes: ->
-    @removeStylesheet(@userStylesheetPath) if @userStylesheetPath?
+    @unwatchUserStylesheet()
     @packageManager.deactivatePackage(pack.name) for pack in @getActiveThemes()
     null
 
@@ -106,12 +107,23 @@ class ThemeManager
     else
       null
 
+  #Private:
+  unwatchUserStylesheet: ->
+    @userStylesheetFile?.off()
+    @removeStylesheet(@userStylesheetPath) if @userStylesheetPath?
+
   # Private:
   loadUserStylesheet: ->
-    if userStylesheetPath = @getUserStylesheetPath()
-      @userStylesheetPath = userStylesheetPath
-      userStylesheetContents = @loadStylesheet(userStylesheetPath)
-      @applyStylesheet(userStylesheetPath, userStylesheetContents, 'userTheme')
+    @unwatchUserStylesheet()
+    userStylesheetPath = @getUserStylesheetPath()
+    return unless fs.isFileSync(userStylesheetPath)
+
+    @userStylesheetPath = userStylesheetPath
+    @userStylesheetFile = new File(userStylesheetPath)
+    @userStylesheetFile.on 'contents-changed moved removed', =>
+      @loadUserStylesheet()
+    userStylesheetContents = @loadStylesheet(userStylesheetPath)
+    @applyStylesheet(userStylesheetPath, userStylesheetContents, 'userTheme')
 
   # Internal-only:
   loadBaseStylesheets: ->
@@ -178,8 +190,7 @@ class ThemeManager
 
   # Internal-only:
   removeStylesheet: (stylesheetPath) ->
-    unless fullPath = @resolveStylesheet(stylesheetPath)
-      throw new Error("Could not find a file at path '#{stylesheetPath}'")
+    fullPath = @resolveStylesheet(stylesheetPath) ? stylesheetPath
     @stylesheetElementForId(@stringToId(fullPath)).remove()
 
   # Internal-only: