Support launching the app directly with a URL

In this case there will be no paths to open and so editor windows
should be created.

This will allow sessions to be joined when Atom isn't currently running
but a session link is clicked from within another application.

src/atom-application.coffee

@@ -39,7 +39,7 @@ class AtomApplication
   installUpdate: null
   version: null
 
-  constructor: ({@resourcePath, pathsToOpen, @version, test, pidToKillWhenClosed, @dev, newWindow}) ->
+  constructor: ({@resourcePath, pathsToOpen, urlsToOpen, @version, test, pidToKillWhenClosed, @dev, newWindow}) ->
     global.atomApplication = this
 
     @pidsToOpenWindows = {}
@@ -57,6 +57,8 @@ class AtomApplication
       @runSpecs({exitWhenDone: true, @resourcePath})
     else if pathsToOpen.length > 0
       @openPaths({pathsToOpen, pidToKillWhenClosed, newWindow})
+    else if urlsToOpen.length > 0
+      @openUrl(urlToOpen) for urlToOpen in urlsToOpen
     else
       # Always open a editor window if this is the first instance of Atom.
       @openPath({pidToKillWhenClosed, newWindow})
@@ -174,13 +176,7 @@ class AtomApplication
 
     app.on 'open-url', (event, urlToOpen) =>
       event.preventDefault()
-
-      parsedUrl = url.parse(urlToOpen)
-      if parsedUrl.host is 'session'
-        sessionId = parsedUrl.path.split('/')[1]
-        if sessionId
-          bootstrapScript = 'collaboration/lib/bootstrap'
-          new AtomWindow({bootstrapScript, @resourcePath, sessionId})
+      @openUrl(urlToOpen)
 
     autoUpdater.on 'ready-for-update-on-quit', (event, version, quitAndUpdate) =>
       event.preventDefault()
@@ -251,6 +247,14 @@ class AtomApplication
             console.log("Killing process #{pid} failed: #{error.code}")
         delete @pidsToOpenWindows[pid]
 
+  openUrl: (urlToOpen) ->
+    parsedUrl = url.parse(urlToOpen)
+    if parsedUrl.host is 'session'
+      sessionId = parsedUrl.path.split('/')[1]
+      if sessionId
+        bootstrapScript = 'collaboration/lib/bootstrap'
+        new AtomWindow({bootstrapScript, @resourcePath, sessionId})
+
   openConfig: ->
     if @configWindow
       @configWindow.focus()

src/main.coffee

@@ -18,11 +18,21 @@ require 'coffee-script'
 delegate.browserMainParts.preMainMessageLoopRun = ->
   args = parseCommandLine()
 
-  addPathToOpen = (event, filePath) ->
+  addPathToOpen = (event, pathToOpen) ->
     event.preventDefault()
-    args.pathsToOpen.push(filePath)
+    args.pathsToOpen.push(pathToOpen)
+
+  args.urlsToOpen = []
+  addUrlToOpen = (event, urlToOpen) ->
+    event.preventDefault()
+    args.urlsToOpen.push(urlToOpen)
+
+  app.on 'open-url', (event, urlToOpen) ->
+    event.preventDefault()
+    args.urlsToOpen.push(urlToOpen)
 
   app.on 'open-file', addPathToOpen
+  app.on 'open-url', addUrlToOpen
 
   app.on 'will-finish-launching', ->
     setupCrashReporter()
@@ -30,6 +40,7 @@ delegate.browserMainParts.preMainMessageLoopRun = ->
 
   app.on 'finish-launching', ->
     app.removeListener 'open-file', addPathToOpen
+    app.removeListener 'open-url', addUrlToOpen
 
     args.pathsToOpen = args.pathsToOpen.map (pathToOpen) ->
       path.resolve(args.executedFrom ? process.cwd(), pathToOpen)