Use MessageUtils instead of hardcoded strings in policyNameOf.

This makes the code easier to maintain because we do not need to
manually add string representations, and because it will throw at
static initialization time if the clas contains duplicate
POLICY_xxx values. The memory overhead is likely negligible.

Bug: 216567577
Test: new coverage in FullScoreTest
Change-Id: Iab23d414c8e28ff7f26060ad44fa996f277d361f

service/src/com/android/server/connectivity/FullScore.java

@@ -21,8 +21,6 @@ import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_METERED;
 import static android.net.NetworkCapabilities.NET_CAPABILITY_VALIDATED;
 import static android.net.NetworkCapabilities.TRANSPORT_VPN;
 import static android.net.NetworkScore.KEEP_CONNECTED_NONE;
-import static android.net.NetworkScore.POLICY_EXITING;
-import static android.net.NetworkScore.POLICY_TRANSPORT_PRIMARY;
 import static android.net.NetworkScore.POLICY_YIELD_TO_BAD_WIFI;
 
 import android.annotation.IntDef;
@@ -31,8 +29,10 @@ import android.net.NetworkAgentConfig;
 import android.net.NetworkCapabilities;
 import android.net.NetworkScore;
 import android.net.NetworkScore.KeepConnectedReason;
+import android.util.SparseArray;
 
 import com.android.internal.annotations.VisibleForTesting;
+import com.android.internal.util.MessageUtils;
 
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
@@ -112,21 +112,14 @@ public class FullScore {
     private static final long EXTERNAL_POLICIES_MASK =
             0x00000000FFFFFFFFL & ~(1L << POLICY_YIELD_TO_BAD_WIFI);
 
+    private static SparseArray<String> sMessageNames = MessageUtils.findMessageNames(
+            new Class[]{FullScore.class, NetworkScore.class}, new String[]{"POLICY_"});
+
     @VisibleForTesting
     static @NonNull String policyNameOf(final int policy) {
-        switch (policy) {
+        final String name = sMessageNames.get(policy);
-            case POLICY_IS_VALIDATED: return "IS_VALIDATED";
+        if (name == null) throw new IllegalArgumentException("Unknown policy: " + policy);
-            case POLICY_IS_VPN: return "IS_VPN";
+        return name.substring("POLICY_".length());
-            case POLICY_EVER_USER_SELECTED: return "EVER_USER_SELECTED";
-            case POLICY_ACCEPT_UNVALIDATED: return "ACCEPT_UNVALIDATED";
-            case POLICY_IS_UNMETERED: return "IS_UNMETERED";
-            case POLICY_YIELD_TO_BAD_WIFI: return "YIELD_TO_BAD_WIFI";
-            case POLICY_TRANSPORT_PRIMARY: return "TRANSPORT_PRIMARY";
-            case POLICY_EXITING: return "EXITING";
-            case POLICY_IS_INVINCIBLE: return "INVINCIBLE";
-            case POLICY_EVER_VALIDATED_NOT_AVOIDED_WHEN_BAD: return "EVER_VALIDATED";
-        }
-        throw new IllegalArgumentException("Unknown policy : " + policy);
     }
 
     // Bitmask of all the policies applied to this score.

tests/unit/java/com/android/server/connectivity/FullScoreTest.kt

@@ -26,6 +26,7 @@ import androidx.test.filters.SmallTest
 import com.android.server.connectivity.FullScore.MAX_CS_MANAGED_POLICY
 import com.android.server.connectivity.FullScore.POLICY_ACCEPT_UNVALIDATED
 import com.android.server.connectivity.FullScore.POLICY_EVER_USER_SELECTED
+import com.android.server.connectivity.FullScore.POLICY_IS_UNMETERED
 import com.android.server.connectivity.FullScore.POLICY_IS_VALIDATED
 import com.android.server.connectivity.FullScore.POLICY_IS_VPN
 import com.android.testutils.DevSdkIgnoreRule
@@ -101,6 +102,7 @@ class FullScoreTest {
         assertFailsWith<IllegalArgumentException> {
             FullScore.policyNameOf(MAX_CS_MANAGED_POLICY + 1)
         }
+        assertEquals("IS_UNMETERED", FullScore.policyNameOf(POLICY_IS_UNMETERED))
     }
 
     fun getAllPolicies() = Regex("POLICY_.*").let { nameRegex ->