Merge "Made AccessPoint's scan result list thread safe" into qt-dev

am: 8e13ea659e

Change-Id: I88d3d604a5679972b9e6652ebd185fe3c11544b9

packages/SettingsLib/src/com/android/settingslib/wifi/AccessPoint.java

@@ -55,6 +55,7 @@ import android.util.ArraySet;
 import android.util.Log;
 import android.util.Pair;
 
+import androidx.annotation.GuardedBy;
 import androidx.annotation.NonNull;
 
 import com.android.internal.annotations.VisibleForTesting;
@@ -108,6 +109,14 @@ public class AccessPoint implements Comparable<AccessPoint> {
     /** The key which identifies this AccessPoint grouping. */
     private String mKey;
 
+    /**
+     * Synchronization lock for managing concurrency between main and worker threads.
+     *
+     * <p>This lock should be held for all modifications to {@link #mScanResults} and
+     * {@link #mExtraScanResults}.
+     */
+    private final Object mLock = new Object();
+
     @IntDef({Speed.NONE, Speed.SLOW, Speed.MODERATE, Speed.FAST, Speed.VERY_FAST})
     @Retention(RetentionPolicy.SOURCE)
     public @interface Speed {
@@ -134,12 +143,14 @@ public class AccessPoint implements Comparable<AccessPoint> {
     }
 
     /** The underlying set of scan results comprising this AccessPoint. */
+    @GuardedBy("mLock")
     private final ArraySet<ScanResult> mScanResults = new ArraySet<>();
 
     /**
      * Extra set of unused scan results corresponding to this AccessPoint for verbose logging
      * purposes, such as a set of Passpoint roaming scan results when home scans are available.
      */
+    @GuardedBy("mLock")
     private final ArraySet<ScanResult> mExtraScanResults = new ArraySet<>();
 
     /**
@@ -489,9 +500,11 @@ public class AccessPoint implements Comparable<AccessPoint> {
 
         if (isVerboseLoggingEnabled()) {
             builder.append(",rssi=").append(mRssi);
+            synchronized (mLock) {
                 builder.append(",scan cache size=").append(mScanResults.size()
                         + mExtraScanResults.size());
             }
+        }
 
         return builder.append(')').toString();
     }
@@ -532,6 +545,7 @@ public class AccessPoint implements Comparable<AccessPoint> {
      */
     private boolean updateScores(WifiNetworkScoreCache scoreCache, long maxScoreCacheAgeMillis) {
         long nowMillis = SystemClock.elapsedRealtime();
+        synchronized (mLock) {
             for (ScanResult result : mScanResults) {
                 ScoredNetwork score = scoreCache.getScoredNetwork(result);
                 if (score == null) {
@@ -546,6 +560,7 @@ public class AccessPoint implements Comparable<AccessPoint> {
                     timedScore.update(score, nowMillis);
                 }
             }
+        }
 
         // Remove old cached networks
         long evictionCutoff = nowMillis - maxScoreCacheAgeMillis;
@@ -619,6 +634,7 @@ public class AccessPoint implements Comparable<AccessPoint> {
                 mIsScoredNetworkMetered |= score.meteredHint;
             }
         } else {
+            synchronized (mLock) {
                 for (ScanResult result : mScanResults) {
                     ScoredNetwork score = scoreCache.getScoredNetwork(result);
                     if (score == null) {
@@ -627,6 +643,7 @@ public class AccessPoint implements Comparable<AccessPoint> {
                     mIsScoredNetworkMetered |= score.meteredHint;
                 }
             }
+        }
         return oldMetering == mIsScoredNetworkMetered;
     }
 
@@ -741,8 +758,10 @@ public class AccessPoint implements Comparable<AccessPoint> {
      */
     public Set<ScanResult> getScanResults() {
         Set<ScanResult> allScans = new ArraySet<>();
+        synchronized (mLock) {
             allScans.addAll(mScanResults);
             allScans.addAll(mExtraScanResults);
+        }
         return allScans;
     }
 
@@ -766,12 +785,14 @@ public class AccessPoint implements Comparable<AccessPoint> {
 
         ScanResult bestResult = null;
         int bestRssi = UNREACHABLE_RSSI;
+        synchronized (mLock) {
             for (ScanResult result : mScanResults) {
                 if (result.level > bestRssi) {
                     bestRssi = result.level;
                     bestResult = result;
                 }
             }
+        }
 
         // Set the rssi to the average of the current rssi and the previous rssi.
         if (bestRssi != UNREACHABLE_RSSI && mRssi != UNREACHABLE_RSSI) {
@@ -1210,9 +1231,11 @@ public class AccessPoint implements Comparable<AccessPoint> {
         savedState.putInt(KEY_EAPTYPE, mEapType);
         if (mConfig != null) savedState.putParcelable(KEY_CONFIG, mConfig);
         savedState.putParcelable(KEY_WIFIINFO, mInfo);
+        synchronized (mLock) {
             savedState.putParcelableArray(KEY_SCANRESULTS,
                     mScanResults.toArray(new Parcelable[mScanResults.size()
                             + mExtraScanResults.size()]));
+        }
         savedState.putParcelableArrayList(KEY_SCOREDNETWORKCACHE,
                 new ArrayList<>(mScoredNetworkCache.values()));
         if (mNetworkInfo != null) {
@@ -1291,8 +1314,10 @@ public class AccessPoint implements Comparable<AccessPoint> {
         }
 
         int oldLevel = getLevel();
+        synchronized (mLock) {
             mScanResults.clear();
             mScanResults.addAll(scanResults);
+        }
         updateBestRssiInfo();
         int newLevel = getLevel();
 
@@ -1323,18 +1348,20 @@ public class AccessPoint implements Comparable<AccessPoint> {
     void setScanResultsPasspoint(
             @Nullable Collection<ScanResult> homeScans,
             @Nullable Collection<ScanResult> roamingScans) {
+        synchronized (mLock) {
             mExtraScanResults.clear();
             if (!CollectionUtils.isEmpty(homeScans)) {
+                mIsRoaming = false;
                 if (!CollectionUtils.isEmpty(roamingScans)) {
                     mExtraScanResults.addAll(roamingScans);
                 }
-            mIsRoaming = false;
                 setScanResults(homeScans);
             } else if (!CollectionUtils.isEmpty(roamingScans)) {
                 mIsRoaming = true;
                 setScanResults(roamingScans);
             }
         }
+    }
 
     /**
      * Attempt to update the AccessPoint with the current connection info.