From a52fbfcff7274d55c57e40267cfc28627a1235c6 Mon Sep 17 00:00:00 2001
From: "Unknown W. Brackets" <checkins@unknownbrackets.org>
Date: Sun, 11 Sep 2016 11:26:35 -0700
Subject: [PATCH] UI: Lock input while mutating views/screens.

This way we can't get an axis event while switching screens and crash.
---
 UI/ControlMappingScreen.cpp | 6 ------
 UI/ControlMappingScreen.h   | 3 ---
 ext/native/ui/screen.cpp    | 9 +++++++++
 ext/native/ui/screen.h      | 3 +++
 ext/native/ui/ui_screen.cpp | 2 ++
 5 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/UI/ControlMappingScreen.cpp b/UI/ControlMappingScreen.cpp
index 8086cf59d6..63734d1dd1 100644
--- a/UI/ControlMappingScreen.cpp
+++ b/UI/ControlMappingScreen.cpp
@@ -439,8 +439,6 @@ bool AnalogTestScreen::key(const KeyInput &key) {
 		return true;
 	}
 
-	lock_guard guard(eventLock_);
-
 	char buf[512];
 	snprintf(buf, sizeof(buf), "Keycode: %d Device ID: %d [%s%s%s%s]", key.keyCode, key.deviceId,
 		(key.flags & KEY_IS_REPEAT) ? "REP" : "",
@@ -461,8 +459,6 @@ bool AnalogTestScreen::axis(const AxisInput &axis) {
 	// a controller would be confusing for the user.
 	char buf[512];
 
-	lock_guard guard(eventLock_);
-
 	if (IgnoreAxisForMapping(axis.axisId))
 		return false;
 
@@ -482,8 +478,6 @@ bool AnalogTestScreen::axis(const AxisInput &axis) {
 void AnalogTestScreen::CreateViews() {
 	using namespace UI;
 
-	lock_guard guard(eventLock_);
-
 	I18NCategory *di = GetI18NCategory("Dialog");
 
 	root_ = new LinearLayout(ORIENT_VERTICAL);
diff --git a/UI/ControlMappingScreen.h b/UI/ControlMappingScreen.h
index 69fd34e73a..b971839906 100644
--- a/UI/ControlMappingScreen.h
+++ b/UI/ControlMappingScreen.h
@@ -19,7 +19,6 @@
 
 #include <vector>
 #include "base/functional.h"
-#include "base/mutex.h"
 #include "ui/view.h"
 #include "ui/ui_screen.h"
 
@@ -81,6 +80,4 @@ protected:
 
 	UI::TextView *lastKeyEvent_;
 	UI::TextView *lastLastKeyEvent_;
-
-	recursive_mutex eventLock_;
 };
diff --git a/ext/native/ui/screen.cpp b/ext/native/ui/screen.cpp
index 6cb9fa0a5f..e745d8cff9 100644
--- a/ext/native/ui/screen.cpp
+++ b/ext/native/ui/screen.cpp
@@ -47,6 +47,7 @@ void ScreenManager::update(InputState &input) {
 }
 
 void ScreenManager::switchToNext() {
+	lock_guard guard(inputLock_);
 	if (!nextScreen_) {
 		ELOG("switchToNext: No nextScreen_!");
 	}
@@ -66,6 +67,7 @@ void ScreenManager::switchToNext() {
 }
 
 bool ScreenManager::touch(const TouchInput &touch) {
+	lock_guard guard(inputLock_);
 	if (!stack_.empty()) {
 		return stack_.back().screen->touch(touch);
 	} else {
@@ -74,6 +76,7 @@ bool ScreenManager::touch(const TouchInput &touch) {
 }
 
 bool ScreenManager::key(const KeyInput &key) {
+	lock_guard guard(inputLock_);
 	if (!stack_.empty()) {
 		return stack_.back().screen->key(key);
 	} else {
@@ -82,6 +85,7 @@ bool ScreenManager::key(const KeyInput &key) {
 }
 
 bool ScreenManager::axis(const AxisInput &axis) {
+	lock_guard guard(inputLock_);
 	if (!stack_.empty()) {
 		return stack_.back().screen->axis(axis);
 	} else {
@@ -90,6 +94,7 @@ bool ScreenManager::axis(const AxisInput &axis) {
 }
 
 void ScreenManager::resized() {
+	lock_guard guard(inputLock_);
 	// Have to notify the whole stack, otherwise there will be problems when going back
 	// to non-top screens.
 	for (auto iter = stack_.begin(); iter != stack_.end(); ++iter) {
@@ -163,6 +168,7 @@ Screen *ScreenManager::topScreen() const {
 }
 
 void ScreenManager::shutdown() {
+	lock_guard guard(inputLock_);
 	for (auto x = stack_.begin(); x != stack_.end(); x++)
 		delete x->screen;
 	stack_.clear();
@@ -171,6 +177,7 @@ void ScreenManager::shutdown() {
 }
 
 void ScreenManager::push(Screen *screen, int layerFlags) {
+	lock_guard guard(inputLock_);
 	if (nextScreen_ && stack_.empty()) {
 		// we're during init, this is OK
 		switchToNext();
@@ -185,6 +192,7 @@ void ScreenManager::push(Screen *screen, int layerFlags) {
 }
 
 void ScreenManager::pop() {
+	lock_guard guard(inputLock_);
 	if (stack_.size()) {
 		delete stack_.back().screen;
 		stack_.pop_back();
@@ -215,6 +223,7 @@ void ScreenManager::finishDialog(Screen *dialog, DialogResult result) {
 
 void ScreenManager::processFinishDialog() {
 	if (dialogFinished_) {
+		lock_guard guard(inputLock_);
 		// Another dialog may have been pushed before the render, so search for it.
 		Screen *caller = 0;
 		for (size_t i = 0; i < stack_.size(); ++i) {
diff --git a/ext/native/ui/screen.h b/ext/native/ui/screen.h
index 248f9f5f50..f8f7282c9e 100644
--- a/ext/native/ui/screen.h
+++ b/ext/native/ui/screen.h
@@ -17,6 +17,7 @@
 
 #include "base/basictypes.h"
 #include "base/logging.h"
+#include "base/mutex.h"
 #include "base/NativeApp.h"
 
 namespace UI {
@@ -126,6 +127,8 @@ public:
 
 	Screen *topScreen() const;
 
+	recursive_mutex inputLock_;
+
 private:
 	void pop();
 	void switchToNext();
diff --git a/ext/native/ui/ui_screen.cpp b/ext/native/ui/ui_screen.cpp
index 3914296e89..399b668190 100644
--- a/ext/native/ui/ui_screen.cpp
+++ b/ext/native/ui/ui_screen.cpp
@@ -19,6 +19,8 @@ UIScreen::~UIScreen() {
 }
 
 void UIScreen::DoRecreateViews() {
+	lock_guard guard(screenManager()->inputLock_);
+
 	if (recreateViews_) {
 		UI::PersistMap persisted;
 		bool persisting = root_ != nullptr;