From 1e29c281c6fbb8bed67f8e3bf4acc1c733e7cb6c Mon Sep 17 00:00:00 2001
From: Hans-Christoph Steiner <hans@eds.org>
Date: Fri, 5 Jul 2019 23:47:15 +0200
Subject: [PATCH] catch random NullPointerExceptions related to WifiApControl

java.lang.NullPointerException: Attempt to read from field 'boolean android.net.wifi.WifiConfiguration.hiddenSSID' on a null object reference
at org.fdroid.fdroid.nearby.WifiStateChangeService.setSsid(WifiStateChangeService.java:252)
at org.fdroid.fdroid.nearby.WifiStateChangeService.access$100(WifiStateChangeService.java:59)
at org.fdroid.fdroid.nearby.WifiStateChangeService$WifiInfoThread.run(WifiStateChangeService.java:174)


java.lang.NullPointerException: null receiver
	at java.lang.reflect.Method.invoke(Native Method)
	at cc.mvdan.accesspoint.WifiApControl.invokeQuietly(WifiApControl.java:178)
	at cc.mvdan.accesspoint.WifiApControl.isWifiApEnabled(WifiApControl.java:189)
	at cc.mvdan.accesspoint.WifiApControl.isEnabled(WifiApControl.java:198)
	at org.fdroid.fdroid.nearby.WifiStateChangeService.setSsid(WifiStateChangeService.java:249)
	at org.fdroid.fdroid.nearby.WifiStateChangeService.access$100(WifiStateChangeService.java:59)
	at org.fdroid.fdroid.nearby.WifiStateChangeService$WifiInfoThread.run(WifiStateChangeService.java:133)

java.lang.NullPointerException: Attempt to invoke virtual method 'int android.app.AppOpsManager.checkOpNoThrow(int, int, java.lang.String)' on a null object reference
 at android.provider.Settings.isCallingPackageAllowedToPerformAppOpsProtectedOperation(Settings.java:13730)
 at android.provider.Settings.isCallingPackageAllowedToWriteSettings(Settings.java:13634)
 at android.provider.Settings$System.canWrite(Settings.java:4793)
 at cc.mvdan.accesspoint.WifiApControl.getInstance(WifiApControl.java:122)
 at org.fdroid.fdroid.nearby.WifiStateChangeService.setSsid(WifiStateChangeService.java:240)
 at org.fdroid.fdroid.nearby.WifiStateChangeService.access$100(WifiStateChangeService.java:59)
 at org.fdroid.fdroid.nearby.WifiStateChangeService$WifiInfoThread.run(WifiStateChangeService.java:133)
---
 .../fdroid/fdroid/nearby/WifiStateChangeService.java | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/app/src/full/java/org/fdroid/fdroid/nearby/WifiStateChangeService.java b/app/src/full/java/org/fdroid/fdroid/nearby/WifiStateChangeService.java
index 4d2636b99..cf255d93a 100644
--- a/app/src/full/java/org/fdroid/fdroid/nearby/WifiStateChangeService.java
+++ b/app/src/full/java/org/fdroid/fdroid/nearby/WifiStateChangeService.java
@@ -237,7 +237,13 @@ public class WifiStateChangeService extends IntentService {
             }
             FDroidApp.bssid = wifiInfo.getBSSID();
         } else {
-            WifiApControl wifiApControl = WifiApControl.getInstance(this);
+            WifiApControl wifiApControl = null;
+            try {
+                wifiApControl = WifiApControl.getInstance(this);
+                wifiApControl.isEnabled();
+            } catch (NullPointerException e) {
+                wifiApControl = null;
+            }
             Utils.debugLog(TAG, "WifiApControl: " + wifiApControl);
             if (wifiApControl == null && FDroidApp.ipAddressString != null) {
                 wifiInfo = wifiManager.getConnectionInfo();
@@ -249,7 +255,9 @@ public class WifiStateChangeService extends IntentService {
             } else if (wifiApControl != null && wifiApControl.isEnabled()) {
                 WifiConfiguration wifiConfiguration = wifiApControl.getConfiguration();
                 Utils.debugLog(TAG, "WifiConfiguration: " + wifiConfiguration);
-                if (wifiConfiguration.hiddenSSID) {
+                if (wifiConfiguration == null) {
+                    FDroidApp.ssid = getString(R.string.swap_active_hotspot, "");
+                } else if (wifiConfiguration.hiddenSSID) {
                     FDroidApp.ssid = getString(R.string.swap_hidden_wifi_ssid);
                 } else {
                     FDroidApp.ssid = wifiConfiguration.SSID;