Support activation events in package manifest

These events will load the package's main module
when first triggered.  The go-to-line package has been
migrated to use this new option.

src/app/atom-package.coffee

@@ -1,5 +1,6 @@
 Package = require 'package'
 fs = require 'fs'
+_ = require 'underscore'
 
 module.exports =
 class AtomPackage extends Package
@@ -16,12 +17,34 @@ class AtomPackage extends Package
       @loadMetadata()
       @loadKeymaps()
       @loadStylesheets() if @autoloadStylesheets
-      if packageMain = @getPackageMain()
-        rootView?.activatePackage(@name, packageMain)
+      if activationEvents = @getActivationEvents()
+        @subscribeToActivationEvents(activationEvents)
+      else
+        @activatePackageMain()
     catch e
       console.warn "Failed to load package named '#{@name}'", e.stack
     this
 
+  subscribeToActivationEvents: (activationEvents) ->
+    if _.isArray(activationEvents)
+      activateHandler = =>
+        @activatePackageMain()
+        for event in activationEvents
+          rootView.off event, activateHandler
+      for event in activationEvents
+        rootView.command event, activateHandler
+    else
+      activateHandler = =>
+        @activatePackageMain()
+        for event, selector of activationEvents
+          rootView.off event, selector, activateHandler
+      for event, selector of activationEvents
+        rootView.command event, selector, activateHandler
+
+  activatePackageMain: ->
+    if packageMain = @getPackageMain()
+      rootView?.activatePackage(@name, packageMain)
+
   getPackageMain: ->
     mainPath = require.resolve(@metadata.main) if @metadata.main
     if mainPath
@@ -29,6 +52,8 @@ class AtomPackage extends Package
     else if require.resolve(@path)
       this
 
+  getActivationEvents: -> @metadata.activationEvents
+
   loadMetadata: ->
     if metadataPath = fs.resolveExtension(fs.join(@path, "package"), ['cson', 'json'])
       @metadata = fs.readObject(metadataPath)

src/packages/go-to-line/index.coffee

@@ -1,12 +0,0 @@
-DeferredAtomPackage = require 'deferred-atom-package'
-
-module.exports =
-class GoToLinePackage extends DeferredAtomPackage
-
-  loadEvents:
-    'editor:go-to-line': '.editor'
-
-  instanceClass: 'go-to-line/lib/go-to-line-view'
-
-  onLoadEvent: (event, instance) ->
-    instance.toggle(event.currentTargetView())

src/packages/go-to-line/lib/go-to-line-view.coffee

@@ -6,7 +6,7 @@ Point = require 'point'
 module.exports =
 class GoToLineView extends View
 
-  @activate: (rootView) -> new GoToLineView(rootView)
+  @activate: (rootView) -> new GoToLineView(rootView).attach()
 
   @content: ->
     @div class: 'go-to-line overlay from-top mini', =>
@@ -14,6 +14,7 @@ class GoToLineView extends View
       @div class: 'message', outlet: 'message'
 
   initialize: (@rootView) ->
+    @rootView.command 'editor:go-to-line', '.editor', => @toggle()
     @miniEditor.on 'focusout', => @detach()
     @on 'core:confirm', => @confirm()
     @on 'core:cancel', => @detach()

src/packages/go-to-line/package.cson

@@ -0,0 +1,3 @@
+'activationEvents':
+  'editor:go-to-line': '.editor'
+'main': 'go-to-line/lib/go-to-line-view'

src/packages/go-to-line/spec/go-to-line-spec.coffee

@@ -6,8 +6,11 @@ describe 'GoToLine', ->
   beforeEach ->
     rootView = new RootView(require.resolve('fixtures/sample.js'))
     rootView.enableKeymap()
-    goToLine = atom.loadPackage("go-to-line").getInstance()
+    atom.loadPackage("go-to-line")
     editor = rootView.getActiveEditor()
+    editor.trigger 'editor:go-to-line'
+    goToLine = rootView.find('.go-to-line').view()
+    editor.trigger 'editor:go-to-line'
     editor.setCursorBufferPosition([1,0])
 
   afterEach ->