From a160891a27ddfa7ad68860ed45a61300f2ef2c5e Mon Sep 17 00:00:00 2001
From: Paul Betts <paul@paulbetts.org>
Date: Wed, 21 Oct 2015 12:29:00 -0700
Subject: [PATCH] If a user calls makeSingleInstance more than once, just
 ignore it

---
 atom/browser/api/atom_api_app.cc | 14 +++++++-------
 atom/browser/browser.cc          |  7 ++++---
 atom/browser/browser.h           |  2 +-
 3 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/atom/browser/api/atom_api_app.cc b/atom/browser/api/atom_api_app.cc
index b16e346065..96f1ce0253 100644
--- a/atom/browser/api/atom_api_app.cc
+++ b/atom/browser/api/atom_api_app.cc
@@ -271,15 +271,15 @@ v8::Local<v8::Value> App::DefaultSession(v8::Isolate* isolate) {
 
 bool App::MakeSingleInstance(v8::Local<v8::Function> callback) {
   auto browser = Browser::Get();
-  single_instance_callback_ = callback;
+  if (browser->InitializeSingleInstance()) {
+    single_instance_callback_ = callback;
 
-  browser->InitializeSingleInstance();
+    ProcessSingleton::NotificationCallback cb;
+    mate::Converter<ProcessSingleton::NotificationCallback>::FromV8(
+        isolate(), single_instance_callback_, &cb);
 
-  ProcessSingleton::NotificationCallback cb;
-  mate::Converter<ProcessSingleton::NotificationCallback>::FromV8(
-      isolate(), single_instance_callback_, &cb);
-
-  browser->SetSingleInstanceCallback(cb);
+    browser->SetSingleInstanceCallback(cb);
+  }
 
   switch (browser->GetSingleInstanceResult()) {
     case ProcessSingleton::NotifyResult::PROCESS_NONE:
diff --git a/atom/browser/browser.cc b/atom/browser/browser.cc
index c8d6104bea..6bfeae3c56 100644
--- a/atom/browser/browser.cc
+++ b/atom/browser/browser.cc
@@ -165,7 +165,7 @@ bool Browser::HandleBeforeQuit() {
   return !prevent_default;
 }
 
-void Browser::InitializeSingleInstance() {
+bool Browser::InitializeSingleInstance() {
   base::FilePath userDir;
   PathService::Get(brightray::DIR_USER_DATA, &userDir);
 
@@ -174,11 +174,12 @@ void Browser::InitializeSingleInstance() {
     userDir,
     base::Bind(&Browser::OnProcessSingletonNotification, no_refcount_this)));
 
-  process_notify_result_ = process_singleton_->NotifyOtherProcessOrCreate();
-
   if (is_ready_) {
     process_singleton_->Unlock();
   }
+
+  process_notify_result_ = process_singleton_->NotifyOtherProcessOrCreate();
+  return true;
 }
 
 ProcessSingleton::NotifyResult Browser::GetSingleInstanceResult() {
diff --git a/atom/browser/browser.h b/atom/browser/browser.h
index 1ac4d03e09..f9b86b6924 100644
--- a/atom/browser/browser.h
+++ b/atom/browser/browser.h
@@ -66,7 +66,7 @@ class Browser : public WindowListObserver {
   // Clear the recent documents list.
   void ClearRecentDocuments();
 
-  void InitializeSingleInstance();
+  bool InitializeSingleInstance();
   ProcessSingleton::NotifyResult GetSingleInstanceResult();
   void SetSingleInstanceCallback(
       ProcessSingleton::NotificationCallback callback);