Hook up package URL handlers

src/package-manager.js

@@ -648,6 +648,10 @@ module.exports = class PackageManager {
     })
   }
 
+  registerUrlHandlerForPackage (packageName, handler) {
+    return this.urlHandlerRegistry.registerHostHandler(packageName, handler)
+  }
+
   // another type of package manager can handle other package types.
   // See ThemeManager
   registerPackageActivator (activator, types) {

src/package.coffee

@@ -84,6 +84,7 @@ class Package
     @loadMenus()
     @registerDeserializerMethods()
     @activateCoreStartupServices()
+    @registerUrlHandler()
     @configSchemaRegisteredOnLoad = @registerConfigSchemaFromMetadata()
     @requireMainModule()
     @settingsPromise = @loadSettings()
@@ -114,6 +115,7 @@ class Package
         @loadStylesheets()
         @registerDeserializerMethods()
         @activateCoreStartupServices()
+        @registerUrlHandler()
         @registerTranspilerConfig()
         @configSchemaRegisteredOnLoad = @registerConfigSchemaFromMetadata()
         @settingsPromise = @loadSettings()
@@ -318,6 +320,21 @@ class Package
           @activationDisposables.add @packageManager.serviceHub.consume(name, version, @mainModule[methodName].bind(@mainModule))
     return
 
+  registerUrlHandler: ->
+    handlerConfig = @getUrlHandler()
+    if methodName = handlerConfig?.method
+      @urlHandlerSubscription = @packageManager.registerUrlHandlerForPackage @name, (url) =>
+        @handleUrl(url, methodName)
+
+  unregisterUrlHandler: ->
+    @urlHandlerSubscription?.dispose()
+
+  handleUrl: (url, methodName) ->
+    @activate().then =>
+      @mainModule[methodName]?(url)
+    unless @mainActivated
+      @activateNow()
+
   registerTranspilerConfig: ->
     if @metadata.atomTranspilers
       CompileCache.addTranspilerConfigForPath(@path, @name, @metadata, @metadata.atomTranspilers)
@@ -595,7 +612,7 @@ class Package
       @mainModulePath = fs.resolveExtension(mainModulePath, ["", CompileCache.supportedExtensions...])
 
   activationShouldBeDeferred: ->
-    @hasActivationCommands() or @hasActivationHooks()
+    @hasActivationCommands() or @hasActivationHooks() or @hasDeferredUrlHandler()
 
   hasActivationHooks: ->
     @getActivationHooks()?.length > 0
@@ -605,6 +622,9 @@ class Package
       return true if commands.length > 0
     false
 
+  hasDeferredUrlHandler: ->
+    @getUrlHandler() and @getUrlHandler().deferActivation isnt false
+
   subscribeToDeferredActivation: ->
     @subscribeToActivationCommands()
     @subscribeToActivationHooks()
@@ -673,6 +693,9 @@ class Package
 
     @activationHooks = _.uniq(@activationHooks)
 
+  getUrlHandler: ->
+    @metadata?.urlHandler
+
   # Does the given module path contain native code?
   isNativeModule: (modulePath) ->
     try