From 1fe1147901e0268a28da9fb2e65fce19f9b2786f Mon Sep 17 00:00:00 2001
From: Nathan Sobo <nathan@github.com>
Date: Mon, 13 Oct 2014 12:43:36 -0600
Subject: [PATCH] Add group parameter to StyleManager::addStyleSheet

This can be used to sequence style elements at the correct location in
the cascade even if they are loaded later than elements in a subsequent
group.
---
 spec/style-manager-spec.coffee | 12 ++++++++++++
 src/style-manager.coffee       | 17 ++++++++++++++---
 2 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/spec/style-manager-spec.coffee b/spec/style-manager-spec.coffee
index d7f0b0e97..3b70e7ad4 100644
--- a/spec/style-manager-spec.coffee
+++ b/spec/style-manager-spec.coffee
@@ -56,3 +56,15 @@ describe "StyleManager", ->
         expect(addEvents.length).toBe 1
         expect(addEvents[0].sourcePath).toBe '/foo/bar'
         expect(addEvents[0].styleElement.textContent).toBe "a {color: yellow;}"
+
+    describe "when a group parameter is specified", ->
+      it "inserts the stylesheet at the end of any existing stylesheets for the same group", ->
+        manager.addStyleSheet("a {color: red}", group: 'a')
+        manager.addStyleSheet("a {color: blue}", group: 'b')
+        manager.addStyleSheet("a {color: green}", group: 'a')
+
+        expect(manager.getStyleElements().map (elt) -> elt.textContent).toEqual [
+          "a {color: red}"
+          "a {color: green}"
+          "a {color: blue}"
+        ]
diff --git a/src/style-manager.coffee b/src/style-manager.coffee
index cd4604f8e..cf3be51c9 100644
--- a/src/style-manager.coffee
+++ b/src/style-manager.coffee
@@ -21,20 +21,31 @@ class StyleManager
 
   addStyleSheet: (source, params) ->
     sourcePath = params?.sourcePath
+    group = params?.group
+
     if sourcePath? and styleElement = @styleElementsBySourcePath[sourcePath]
       updated = true
     else
       styleElement = document.createElement('style')
+      styleElement.group = group if group?
 
     styleElement.textContent = source
 
-    @styleElements.push(styleElement)
+    if group?
+      for existingElement, index in @styleElements
+        if existingElement.group is group
+          insertIndex = index + 1
+        else
+          break if insertIndex?
+    insertIndex ?= @styleElements.length
+
+    @styleElements.splice(insertIndex, 0, styleElement)
     @styleElementsBySourcePath[sourcePath] ?= styleElement if sourcePath?
 
     if updated
-      @emitter.emit 'did-update-style-sheet', {styleElement, sourcePath}
+      @emitter.emit 'did-update-style-sheet', {styleElement, sourcePath, group}
     else
-      @emitter.emit 'did-add-style-sheet', {styleElement, sourcePath}
+      @emitter.emit 'did-add-style-sheet', {styleElement, sourcePath, group}
 
     new Disposable => @removeStyleElement(styleElement, params)