[WifiTrackerLib] Make WifiEntry scan result lists thread safe

The scan result lists of each WifiEntry is modified by the worker thread,
but clients on the main thread may need to iterate on the lists to
generate the verbose log. This may result in concurrent modification
exceptions, so we need to put locks on these lists.

Bug: 150978717
Test: build
Change-Id: Ice9f653b0496b20d87470ef0af1eda22a2d2fe9c

3 files changed, 45 insertions, 21 deletions

diff --git a/libs/WifiTrackerLib/src/com/android/wifitrackerlib/OsuWifiEntry.java b/libs/WifiTrackerLib/src/com/android/wifitrackerlib/OsuWifiEntry.java
index 9aaf346d7..b3b99e0b9 100644
--- a/libs/WifiTrackerLib/src/com/android/wifitrackerlib/OsuWifiEntry.java
+++ b/libs/WifiTrackerLib/src/com/android/wifitrackerlib/OsuWifiEntry.java
@@ -35,6 +35,7 @@ import android.os.Handler;
 import android.text.TextUtils;
 import android.util.Pair;
 
+import androidx.annotation.GuardedBy;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.annotation.WorkerThread;
@@ -50,6 +51,9 @@ import java.util.Map;
 class OsuWifiEntry extends WifiEntry {
     static final String KEY_PREFIX = "OsuWifiEntry:";
 
+    private final Object mLock = new Object();
+    // Scan result list must be thread safe for generating the verbose scan summary
+    @GuardedBy("mLock")
     @NonNull private final List<ScanResult> mCurrentScanResults = new ArrayList<>();
 
     @NonNull private final String mKey;
@@ -265,10 +269,12 @@ class OsuWifiEntry extends WifiEntry {
             throws IllegalArgumentException {
         if (scanResults == null) scanResults = new ArrayList<>();
 
-        mCurrentScanResults.clear();
-        mCurrentScanResults.addAll(scanResults);
+        synchronized (mLock) {
+            mCurrentScanResults.clear();
+            mCurrentScanResults.addAll(scanResults);
+        }
 
-        final ScanResult bestScanResult = getBestScanResultByLevel(mCurrentScanResults);
+        final ScanResult bestScanResult = getBestScanResultByLevel(scanResults);
         if (bestScanResult == null) {
             mLevel = WIFI_LEVEL_UNREACHABLE;
         } else {
diff --git a/libs/WifiTrackerLib/src/com/android/wifitrackerlib/PasspointWifiEntry.java b/libs/WifiTrackerLib/src/com/android/wifitrackerlib/PasspointWifiEntry.java
index b26d035da..e7ed15362 100644
--- a/libs/WifiTrackerLib/src/com/android/wifitrackerlib/PasspointWifiEntry.java
+++ b/libs/WifiTrackerLib/src/com/android/wifitrackerlib/PasspointWifiEntry.java
@@ -40,6 +40,7 @@ import android.net.wifi.hotspot2.PasspointConfiguration;
 import android.os.Handler;
 import android.text.TextUtils;
 
+import androidx.annotation.GuardedBy;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.annotation.WorkerThread;
@@ -57,7 +58,11 @@ import java.util.StringJoiner;
 public class PasspointWifiEntry extends WifiEntry {
     static final String KEY_PREFIX = "PasspointWifiEntry:";
 
+    private final Object mLock = new Object();
+    // Scan result list must be thread safe for generating the verbose scan summary
+    @GuardedBy("mLock")
     private final List<ScanResult> mCurrentHomeScanResults = new ArrayList<>();
+    @GuardedBy("mLock")
     private final List<ScanResult> mCurrentRoamingScanResults = new ArrayList<>();
 
     @NonNull private final String mKey;
@@ -405,13 +410,15 @@ public class PasspointWifiEntry extends WifiEntry {
             throws IllegalArgumentException {
         mIsRoaming = false;
         mWifiConfig = wifiConfig;
-        mCurrentHomeScanResults.clear();
-        mCurrentRoamingScanResults.clear();
-        if (homeScanResults != null) {
-            mCurrentHomeScanResults.addAll(homeScanResults);
-        }
-        if (roamingScanResults != null) {
-            mCurrentRoamingScanResults.addAll(roamingScanResults);
+        synchronized (mLock) {
+            mCurrentHomeScanResults.clear();
+            mCurrentRoamingScanResults.clear();
+            if (homeScanResults != null) {
+                mCurrentHomeScanResults.addAll(homeScanResults);
+            }
+            if (roamingScanResults != null) {
+                mCurrentRoamingScanResults.addAll(roamingScanResults);
+            }
         }
         if (mWifiConfig != null) {
             mSecurity = getSecurityTypeFromWifiConfiguration(wifiConfig);
diff --git a/libs/WifiTrackerLib/src/com/android/wifitrackerlib/StandardWifiEntry.java b/libs/WifiTrackerLib/src/com/android/wifitrackerlib/StandardWifiEntry.java
index 642313a2b..fcf127721 100644
--- a/libs/WifiTrackerLib/src/com/android/wifitrackerlib/StandardWifiEntry.java
+++ b/libs/WifiTrackerLib/src/com/android/wifitrackerlib/StandardWifiEntry.java
@@ -46,6 +46,7 @@ import android.os.Handler;
 import android.os.SystemClock;
 import android.text.TextUtils;
 
+import androidx.annotation.GuardedBy;
 import androidx.annotation.IntDef;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
@@ -98,7 +99,10 @@ public class StandardWifiEntry extends WifiEntry {
     private static final int PSK_WPA_WPA2 = 2;
     private static final int PSK_UNKNOWN = 3;
 
-    private final List<ScanResult> mCurrentScanResults = new ArrayList<>();
+    private final Object mLock = new Object();
+    // Scan result list must be thread safe for generating the verbose scan summary
+    @GuardedBy("mLock")
+    @NonNull private final List<ScanResult> mCurrentScanResults = new ArrayList<>();
 
     @NonNull private final String mKey;
     @NonNull private final String mSsid;
@@ -616,10 +620,12 @@ public class StandardWifiEntry extends WifiEntry {
             }
         }
 
-        mCurrentScanResults.clear();
-        mCurrentScanResults.addAll(scanResults);
+        synchronized (mLock) {
+            mCurrentScanResults.clear();
+            mCurrentScanResults.addAll(scanResults);
+        }
 
-        final ScanResult bestScanResult = getBestScanResultByLevel(mCurrentScanResults);
+        final ScanResult bestScanResult = getBestScanResultByLevel(scanResults);
         if (bestScanResult == null) {
             mLevel = WIFI_LEVEL_UNREACHABLE;
         } else {
@@ -731,8 +737,10 @@ public class StandardWifiEntry extends WifiEntry {
 
     @Override
     String getScanResultDescription() {
-        if (mCurrentScanResults.size() == 0) {
-            return "";
+        synchronized (mLock) {
+            if (mCurrentScanResults.size() == 0) {
+                return "";
+            }
         }
 
         final StringBuilder description = new StringBuilder();
@@ -745,11 +753,14 @@ public class StandardWifiEntry extends WifiEntry {
     }
 
     private String getScanResultDescription(int minFrequency, int maxFrequency) {
-        final List<ScanResult> scanResults = mCurrentScanResults.stream()
-                .filter(scanResult -> scanResult.frequency >= minFrequency
-                        && scanResult.frequency <= maxFrequency)
-                .sorted(Comparator.comparingInt(scanResult -> -1 * scanResult.level))
-                .collect(Collectors.toList());
+        final List<ScanResult> scanResults;
+        synchronized (mLock) {
+            scanResults = mCurrentScanResults.stream()
+                    .filter(scanResult -> scanResult.frequency >= minFrequency
+                            && scanResult.frequency <= maxFrequency)
+                    .sorted(Comparator.comparingInt(scanResult -> -1 * scanResult.level))
+                    .collect(Collectors.toList());
+        }
 
         final int scanResultCount = scanResults.size();
         if (scanResultCount == 0) {