Add new WifiManager API to calculate signal levels

New calculateSignalLevel() overload allows RSSI level
thresholds to be potentially overlaid.

Bug: 140781184
Test: compiles
Change-Id: Ic6c84885dbe17ca39600dc8d8eb5aeff641a0ad3

api/current.txt

@@ -30059,7 +30059,8 @@ package android.net.wifi {
     method public void addOrUpdatePasspointConfiguration(android.net.wifi.hotspot2.PasspointConfiguration);
     method @RequiresPermission(android.Manifest.permission.ACCESS_WIFI_STATE) public void addScanResultsListener(@NonNull java.util.concurrent.Executor, @NonNull android.net.wifi.WifiManager.ScanResultsListener);
     method @RequiresPermission(allOf={android.Manifest.permission.ACCESS_FINE_LOCATION, android.Manifest.permission.ACCESS_WIFI_STATE}) public void addSuggestionConnectionStatusListener(@NonNull java.util.concurrent.Executor, @NonNull android.net.wifi.WifiManager.SuggestionConnectionStatusListener);
-    method public static int calculateSignalLevel(int, int);
+    method @Deprecated public static int calculateSignalLevel(int, int);
+    method public int calculateSignalLevel(int);
     method @Deprecated public void cancelWps(android.net.wifi.WifiManager.WpsCallback);
     method public static int compareSignalLevel(int, int);
     method public android.net.wifi.WifiManager.MulticastLock createMulticastLock(String);
@@ -30072,6 +30073,7 @@ package android.net.wifi {
     method public android.net.wifi.WifiInfo getConnectionInfo();
     method public android.net.DhcpInfo getDhcpInfo();
     method public int getMaxNumberOfNetworkSuggestionsPerApp();
+    method public int getMaxSignalLevel();
     method @NonNull @RequiresPermission(android.Manifest.permission.ACCESS_WIFI_STATE) public java.util.List<android.net.wifi.WifiNetworkSuggestion> getNetworkSuggestions();
     method @Deprecated @RequiresPermission(anyOf={"android.permission.NETWORK_SETTINGS", "android.permission.NETWORK_SETUP_WIZARD"}) public java.util.List<android.net.wifi.hotspot2.PasspointConfiguration> getPasspointConfigurations();
     method public java.util.List<android.net.wifi.ScanResult> getScanResults();

wifi/java/android/net/wifi/IWifiManager.aidl

@@ -242,4 +242,6 @@ interface IWifiManager
     void registerSuggestionConnectionStatusListener(in IBinder binder, in ISuggestionConnectionStatusListener listener, int listenerIdentifier, String packageName, String featureId);
 
     void unregisterSuggestionConnectionStatusListener(int listenerIdentifier, String packageName);
+
+    int calculateSignalLevel(int rssi);
 }

wifi/java/android/net/wifi/WifiManager.java

@@ -1153,8 +1153,6 @@ public class WifiManager {
      * @hide
      */
     @UnsupportedAppUsage
-    // TODO(b/140781184): need to support custom number of RSSI levels, as well as levels that are
-    //  not evenly spaced
     public static final int RSSI_LEVELS = 5;
 
     /**
@@ -2782,11 +2780,13 @@ public class WifiManager {
      * is being shown.
      *
      * @param rssi The power of the signal measured in RSSI.
-     * @param numLevels The number of levels to consider in the calculated
-     *            level.
-     * @return A level of the signal, given in the range of 0 to numLevels-1
-     *         (both inclusive).
+     * @param numLevels The number of levels to consider in the calculated level.
+     * @return A level of the signal, given in the range of 0 to numLevels-1 (both inclusive).
+     * @deprecated Callers should use {@link #calculateSignalLevel(int)} instead to get the
+     * signal level using the system default RSSI thresholds, or otherwise compute the RSSI level
+     * themselves using their own formula.
      */
+    @Deprecated
     public static int calculateSignalLevel(int rssi, int numLevels) {
         if (rssi <= MIN_RSSI) {
             return 0;
@@ -2799,6 +2799,34 @@ public class WifiManager {
         }
     }
 
+    /**
+     * Given a raw RSSI, return the RSSI signal quality rating using the system default RSSI
+     * quality rating thresholds.
+     * @param rssi a raw RSSI value, in dBm, usually between -55 and -90
+     * @return the RSSI signal quality rating, in the range
+     * [0, {@link #getMaxSignalLevel()}], where 0 is the lowest (worst signal) RSSI
+     * rating and {@link #getMaxSignalLevel()} is the highest (best signal) RSSI rating.
+     */
+    public int calculateSignalLevel(int rssi) {
+        try {
+            IWifiManager iWifiManager = getIWifiManager();
+            if (iWifiManager == null) {
+                throw new RemoteException("Wifi service is not running");
+            }
+            return iWifiManager.calculateSignalLevel(rssi);
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+
+    /**
+     * Get the system default maximum signal level.
+     * This is the maximum RSSI level returned by {@link #calculateSignalLevel(int)}.
+     */
+    public int getMaxSignalLevel() {
+        return calculateSignalLevel(Integer.MAX_VALUE);
+    }
+
     /**
      * Compares two signal strengths.
      *

wifi/java/com/android/server/wifi/BaseWifiService.java

@@ -42,7 +42,6 @@ import android.net.wifi.hotspot2.IProvisioningCallback;
 import android.net.wifi.hotspot2.OsuProvider;
 import android.net.wifi.hotspot2.PasspointConfiguration;
 import android.os.IBinder;
-import android.os.Messenger;
 import android.os.RemoteException;
 import android.os.ResultReceiver;
 import android.os.WorkSource;
@@ -537,4 +536,9 @@ public class BaseWifiService extends IWifiManager.Stub {
             String packageName) {
         throw new UnsupportedOperationException();
     }
+
+    @Override
+    public int calculateSignalLevel(int rssi) {
+        throw new UnsupportedOperationException();
+    }
 }

wifi/tests/src/android/net/wifi/WifiManagerTest.java

@@ -1899,8 +1899,25 @@ public class WifiManagerTest {
      */
     @Test
     public void testRemoveSuggestionConnectionListener() throws Exception {
-
         mWifiManager.removeSuggestionConnectionStatusListener(mListener);
         verify(mWifiService).unregisterSuggestionConnectionStatusListener(anyInt(), anyString());
     }
+
+    /** Test {@link WifiManager#calculateSignalLevel(int)} */
+    @Test
+    public void testCalculateSignalLevel() throws Exception {
+        when(mWifiService.calculateSignalLevel(anyInt())).thenReturn(3);
+        int actual = mWifiManager.calculateSignalLevel(-60);
+        verify(mWifiService).calculateSignalLevel(-60);
+        assertEquals(3, actual);
+    }
+
+    /** Test {@link WifiManager#getMaxSignalLevel()} */
+    @Test
+    public void testGetMaxSignalLevel() throws Exception {
+        when(mWifiService.calculateSignalLevel(anyInt())).thenReturn(4);
+        int actual = mWifiManager.getMaxSignalLevel();
+        verify(mWifiService).calculateSignalLevel(Integer.MAX_VALUE);
+        assertEquals(4, actual);
+    }
 }