From b91c353d2b551c4978962b8079949694b012e10b Mon Sep 17 00:00:00 2001
From: Kevin Sawicki & Nathan Sobo <kevin+nathan@github.com>
Date: Fri, 14 Dec 2012 11:08:18 -0800
Subject: [PATCH] Add `View#observeConfig` as a space-pen extension

---
 spec/stdlib/space-pen-extensions-spec.coffee  | 41 +++++++++++++++++++
 src/app/config.coffee                         |  5 ++-
 src/app/window.coffee                         |  1 +
 src/extensions/tree-view/src/tree-view.coffee |  2 +-
 src/stdlib/space-pen-extensions.coffee        | 19 +++++++++
 5 files changed, 66 insertions(+), 2 deletions(-)
 create mode 100644 spec/stdlib/space-pen-extensions-spec.coffee
 create mode 100644 src/stdlib/space-pen-extensions.coffee

diff --git a/spec/stdlib/space-pen-extensions-spec.coffee b/spec/stdlib/space-pen-extensions-spec.coffee
new file mode 100644
index 000000000..fecda73fa
--- /dev/null
+++ b/spec/stdlib/space-pen-extensions-spec.coffee
@@ -0,0 +1,41 @@
+{View, $$} = require 'space-pen'
+
+describe "SpacePen extensions", ->
+  class TestView extends View
+    @content: -> @div()
+
+  [view, parent, observeHandler] = []
+
+  beforeEach ->
+    view = new TestView
+    parent = $$ -> @div()
+    parent.append(view)
+    observeHandler = jasmine.createSpy("observeHandler")
+    view.observeConfig "foo.bar", observeHandler
+    expect(view.hasParent()).toBeTruthy()
+
+  describe "View#observeConfig(keyPath, callback)", ->
+    it "observes the keyPath and destroys the subscription when unsubscribe is called", ->
+      expect(observeHandler).toHaveBeenCalledWith(undefined)
+      observeHandler.reset()
+
+      config.foo = { bar: "hello" }
+      config.update()
+
+      expect(observeHandler).toHaveBeenCalledWith("hello")
+      observeHandler.reset()
+
+      view.unsubscribe()
+
+      config.foo.bar = "goodbye"
+      config.update()
+
+      expect(observeHandler).not.toHaveBeenCalled()
+
+    it "unsubscribes on remove", ->
+      observeHandler.reset()
+      view.remove()
+      expect(view.hasParent()).toBeFalsy()
+      config.foo = { bar: "hello" }
+      config.update()
+      expect(observeHandler).not.toHaveBeenCalled()
diff --git a/src/app/config.coffee b/src/app/config.coffee
index 610f3e216..e0908173e 100644
--- a/src/app/config.coffee
+++ b/src/app/config.coffee
@@ -50,11 +50,14 @@ class Config
   observe: (keyPathString, callback) ->
     keyPath = keyPathString.split('.')
     value = @valueAtKeyPath(keyPath)
-    @on 'update', =>
+    updateCallback = =>
       newValue = @valueAtKeyPath(keyPath)
       unless newValue == value
         value = newValue
         callback(value)
+    subscription = { destroy: => @off 'update', updateCallback  }
+    @on 'update', updateCallback
     callback(value)
+    subscription
 
 _.extend Config.prototype, EventEmitter
diff --git a/src/app/window.coffee b/src/app/window.coffee
index 115dd6ba1..c507c10e7 100644
--- a/src/app/window.coffee
+++ b/src/app/window.coffee
@@ -13,6 +13,7 @@ RootView = require 'root-view'
 Pasteboard = require 'pasteboard'
 require 'jquery-extensions'
 require 'underscore-extensions'
+require 'space-pen-extensions'
 
 windowAdditions =
   rootViewParentSelector: 'body'
diff --git a/src/extensions/tree-view/src/tree-view.coffee b/src/extensions/tree-view/src/tree-view.coffee
index 2d868e62d..fc7b27e9c 100644
--- a/src/extensions/tree-view/src/tree-view.coffee
+++ b/src/extensions/tree-view/src/tree-view.coffee
@@ -65,7 +65,7 @@ class TreeView extends ScrollView
     @rootView.command 'tree-view:reveal-active-file', => @revealActiveFile()
     @rootView.on 'active-editor-path-change', => @selectActiveFile()
     @rootView.project.on 'path-change', => @updateRoot()
-    config.observe 'core.hideGitIgnoredFiles', => @updateRoot()
+    @observeConfig 'core.hideGitIgnoredFiles', => @updateRoot()
 
     @selectEntry(@root) if @root
 
diff --git a/src/stdlib/space-pen-extensions.coffee b/src/stdlib/space-pen-extensions.coffee
new file mode 100644
index 000000000..211eb845a
--- /dev/null
+++ b/src/stdlib/space-pen-extensions.coffee
@@ -0,0 +1,19 @@
+_ = require 'underscore'
+{View} = require 'space-pen'
+
+originalRemove = View.prototype.remove
+
+_.extend View.prototype,
+  observeConfig: (keyPath, callback) ->
+    @subscribe(config.observe(keyPath, callback))
+
+  subscribe: (subscription) ->
+    @subscriptions ?= []
+    @subscriptions.push(subscription)
+
+  unsubscribe: ->
+    subscription.destroy() for subscription in @subscriptions ? []
+
+  remove: (args...) ->
+    @unsubscribe()
+    originalRemove.apply(this, args)