Merge "Increase ScanResult cache eviction timeout for failed/aborted scans" (95f28cf1) · Commits · e / os / android_frameworks_base

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

+17 −3

Original line number	Diff line number	Diff line
		@@ -84,7 +84,7 @@ public class WifiTracker implements LifecycleObserver, OnStart, OnStop, OnDestro
		private static final long DEFAULT_MAX_CACHED_SCORE_AGE_MILLIS = 20 * DateUtils.MINUTE_IN_MILLIS;

		/ Maximum age of scan results to hold onto while actively scanning. /
		private static final long MAX_SCAN_RESULT_AGE_MILLIS = 15000;
		@VisibleForTesting static final long MAX_SCAN_RESULT_AGE_MILLIS = 15000;

		private static final String TAG = "WifiTracker";
		private static final boolean DBG() {
		@@ -142,6 +142,13 @@ public class WifiTracker implements LifecycleObserver, OnStart, OnStop, OnDestro
		*/
		private boolean mStaleScanResults = true;

		/**
		* Tracks whether the latest SCAN_RESULTS_AVAILABLE_ACTION contained new scans. If not, then
		* we treat the last scan as an aborted scan and increase the eviction timeout window to avoid
		* completely flushing the AP list before the next successful scan completes.
		*/
		private boolean mLastScanSucceeded = true;

		// Does not need to be locked as it only updated on the worker thread, with the exception of
		// during onStart, which occurs before the receiver is registered on the work handler.
		private final HashMap<String, ScanResult> mScanResultCache = new HashMap<>();
		@@ -478,17 +485,22 @@ public class WifiTracker implements LifecycleObserver, OnStart, OnStop, OnDestro
		}

		/**
		* Remove old scan results from the cache.
		* Remove old scan results from the cache. If {@link #mLastScanSucceeded} is false, then
		* increase the timeout window to avoid completely flushing the AP list before the next
		* successful scan completes.
		*
		* <p>Should only ever be invoked from {@link #updateScanResultCache(List)} when
		* {@link #mStaleScanResults} is false.
		*/
		private void evictOldScans() {
		long evictionTimeoutMillis = mLastScanSucceeded ? MAX_SCAN_RESULT_AGE_MILLIS
		: MAX_SCAN_RESULT_AGE_MILLIS * 2;

		long nowMs = SystemClock.elapsedRealtime();
		for (Iterator<ScanResult> iter = mScanResultCache.values().iterator(); iter.hasNext(); ) {
		ScanResult result = iter.next();
		// result timestamp is in microseconds
		if (nowMs - result.timestamp / 1000 > MAX_SCAN_RESULT_AGE_MILLIS) {
		if (nowMs - result.timestamp / 1000 > evictionTimeoutMillis) {
		iter.remove();
		}
		}
		@@ -840,6 +852,8 @@ public class WifiTracker implements LifecycleObserver, OnStart, OnStop, OnDestro
		WifiManager.WIFI_STATE_UNKNOWN));
		} else if (WifiManager.SCAN_RESULTS_AVAILABLE_ACTION.equals(action)) {
		mStaleScanResults = false;
		mLastScanSucceeded =
		intent.getBooleanExtra(WifiManager.EXTRA_RESULTS_UPDATED, true);

		fetchScansAndConfigsAndUpdateAccessPoints();
		} else if (WifiManager.CONFIGURED_NETWORKS_CHANGED_ACTION.equals(action)

packages/SettingsLib/tests/integ/src/com/android/settingslib/wifi/WifiTrackerTest.java

+37 −4

Original line number	Diff line number	Diff line
		@@ -270,7 +270,7 @@ public class WifiTrackerTest {
		SystemClock.elapsedRealtime() * 1000 /* microsecond timestamp */);
		}

		private static ScanResult buildStaleScanResult() {
		private static ScanResult buildScanResultWithTimestamp(long timestampMillis) {
		return new ScanResult(
		WifiSsid.createFromAsciiEncoded(SSID_3),
		BSSID_3,
		@@ -280,7 +280,7 @@ public class WifiTrackerTest {
		"", // capabilities
		RSSI_3,
		0, // frequency
		0 /* microsecond timestamp */);
		timestampMillis * 1000 /* microsecond timestamp */);
		}

		private static WifiConfiguration buildPasspointConfiguration(String fqdn, String friendlyName) {
		@@ -379,6 +379,12 @@ public class WifiTrackerTest {
		tracker.mReceiver.onReceive(mContext, i);
		}

		private void sendFailedScanResults(WifiTracker tracker) throws InterruptedException {
		Intent i = new Intent(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION);
		i.putExtra(WifiManager.EXTRA_RESULTS_UPDATED, false);
		tracker.mReceiver.onReceive(mContext, i);
		}

		private void sendUpdatedScores() throws InterruptedException {
		Bundle attr1 = new Bundle();
		attr1.putParcelable(ScoredNetwork.ATTRIBUTES_KEY_BADGING_CURVE, mockBadgeCurve1);
		@@ -982,8 +988,8 @@ public class WifiTrackerTest {

		@Test
		public void onStart_updateScanResults_evictOldScanResult() {
		when(mockWifiManager.getScanResults()).thenReturn(
		Arrays.asList(buildScanResult1(), buildScanResult2(), buildStaleScanResult()));
		when(mockWifiManager.getScanResults()).thenReturn(Arrays.asList(
		buildScanResult1(), buildScanResult2(), buildScanResultWithTimestamp(0)));
		WifiTracker tracker = createMockedWifiTracker();

		tracker.forceUpdate();
		@@ -994,6 +1000,33 @@ public class WifiTrackerTest {
		assertThat(tracker.getAccessPoints().get(1).getBssid()).isEqualTo(BSSID_2);
		}

		/**
		* Verifies that a failed scan reported on SCAN_RESULTS_AVAILABLE_ACTION should increase the
		* ScanResult eviction timeout to twice the default.
		*/
		@Test
		public void failedScan_increasesEvictionTimeout() throws InterruptedException {
		when(mockWifiManager.getScanResults()).thenReturn(Arrays.asList(
		buildScanResult1(), buildScanResult2(), buildScanResultWithTimestamp(
		SystemClock.elapsedRealtime() - WifiTracker.MAX_SCAN_RESULT_AGE_MILLIS)));
		WifiTracker tracker = createMockedWifiTracker();

		sendFailedScanResults(tracker);

		// Failed scan increases timeout window to include the stale scan
		assertThat(tracker.getAccessPoints()).hasSize(3);
		assertThat(tracker.getAccessPoints().get(0).getBssid()).isEqualTo(BSSID_1);
		assertThat(tracker.getAccessPoints().get(1).getBssid()).isEqualTo(BSSID_2);
		assertThat(tracker.getAccessPoints().get(2).getBssid()).isEqualTo(BSSID_3);

		sendScanResults(tracker);

		// Successful scan resets the timeout window to remove the stale scan
		assertThat(tracker.getAccessPoints()).hasSize(2);
		assertThat(tracker.getAccessPoints().get(0).getBssid()).isEqualTo(BSSID_1);
		assertThat(tracker.getAccessPoints().get(1).getBssid()).isEqualTo(BSSID_2);
		}

		/**
		* Verifies that updatePasspointAccessPoints will only return AccessPoints whose
		* isPasspoint() evaluates as true.