From cd407d1c3fa9096e370577d4bf37eddcf0e5a403 Mon Sep 17 00:00:00 2001
From: Birunthan Mohanathas <birunthan@mohanathas.com>
Date: Thu, 19 Apr 2018 12:39:17 +0200
Subject: [PATCH] Stop overwriting prevent_default if default wasn't prevented

This didn't actually cause any issues because there is only one listener
for the affected methods right now. Should we have added more, the last
called observer would have overwritten `prevent_default`. Lets only set
it when necessary to avoid this footgun in the future.
---
 atom/browser/api/atom_api_app.cc              | 24 ++++++++++++++-----
 atom/browser/api/atom_api_top_level_window.cc |  4 +++-
 2 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/atom/browser/api/atom_api_app.cc b/atom/browser/api/atom_api_app.cc
index 07e82b3e0fb3..f644cda83cb3 100644
--- a/atom/browser/api/atom_api_app.cc
+++ b/atom/browser/api/atom_api_app.cc
@@ -551,11 +551,15 @@ App::~App() {
 }
 
 void App::OnBeforeQuit(bool* prevent_default) {
-  *prevent_default = Emit("before-quit");
+  if (Emit("before-quit")) {
+    *prevent_default = true;
+  }
 }
 
 void App::OnWillQuit(bool* prevent_default) {
-  *prevent_default = Emit("will-quit");
+  if (Emit("will-quit")) {
+    *prevent_default = true;
+  }
 }
 
 void App::OnWindowAllClosed() {
@@ -573,7 +577,9 @@ void App::OnQuit() {
 }
 
 void App::OnOpenFile(bool* prevent_default, const std::string& file_path) {
-  *prevent_default = Emit("open-file", file_path);
+  if (Emit("open-file", file_path)) {
+    *prevent_default = true;
+  }
 }
 
 void App::OnOpenURL(const std::string& url) {
@@ -611,7 +617,9 @@ void App::OnAccessibilitySupportChanged() {
 #if defined(OS_MACOSX)
 void App::OnWillContinueUserActivity(bool* prevent_default,
                                      const std::string& type) {
-  *prevent_default = Emit("will-continue-activity", type);
+  if (Emit("will-continue-activity", type)) {
+    *prevent_default = true;
+  }
 }
 
 void App::OnDidFailToContinueUserActivity(const std::string& type,
@@ -622,7 +630,9 @@ void App::OnDidFailToContinueUserActivity(const std::string& type,
 void App::OnContinueUserActivity(bool* prevent_default,
                                  const std::string& type,
                                  const base::DictionaryValue& user_info) {
-  *prevent_default = Emit("continue-activity", type, user_info);
+  if (Emit("continue-activity", type, user_info)) {
+    *prevent_default = true;
+  }
 }
 
 void App::OnUserActivityWasContinued(const std::string& type,
@@ -633,7 +643,9 @@ void App::OnUserActivityWasContinued(const std::string& type,
 void App::OnUpdateUserActivityState(bool* prevent_default,
                                     const std::string& type,
                                     const base::DictionaryValue& user_info) {
-  *prevent_default = Emit("update-activity-state", type, user_info);
+  if (Emit("update-activity-state", type, user_info)) {
+    *prevent_default = true;
+  }
 }
 
 void App::OnNewWindowForTab() {
diff --git a/atom/browser/api/atom_api_top_level_window.cc b/atom/browser/api/atom_api_top_level_window.cc
index 87cc03540edd..99d24e0e4026 100644
--- a/atom/browser/api/atom_api_top_level_window.cc
+++ b/atom/browser/api/atom_api_top_level_window.cc
@@ -135,7 +135,9 @@ void TopLevelWindow::InitWith(v8::Isolate* isolate,
 }
 
 void TopLevelWindow::WillCloseWindow(bool* prevent_default) {
-  *prevent_default = Emit("close");
+  if (Emit("close")) {
+    *prevent_default = true;
+  }
 }
 
 void TopLevelWindow::OnWindowClosed() {