Refactor SubscriptionManager caching code

Create a genericized class to use for SubscriptionManager caching calls
in order to avoid duplicating logic that fetches values from ISub.

Bug: 151953109
Test: atest android.telephony.cts.SubscriptionManagerTest

Merged-In: I6682ded8aec8cb3e50521584c177df6d5dae8c49
Change-Id: I6682ded8aec8cb3e50521584c177df6d5dae8c49

Android.bp

@@ -1121,6 +1121,7 @@ filegroup {
         "core/java/com/android/internal/os/SomeArgs.java",
         "core/java/com/android/internal/util/BitwiseInputStream.java",
         "core/java/com/android/internal/util/BitwiseOutputStream.java",
+        "core/java/com/android/internal/util/FunctionalUtils.java",
         "core/java/com/android/internal/util/HexDump.java",
         "core/java/com/android/internal/util/IndentingPrintWriter.java",
         "core/java/com/android/internal/util/Preconditions.java",

telephony/java/android/telephony/SubscriptionManager.java

@@ -63,6 +63,7 @@ import com.android.internal.telephony.ISetOpportunisticDataCallback;
 import com.android.internal.telephony.ISub;
 import com.android.internal.telephony.PhoneConstants;
 import com.android.internal.telephony.util.HandlerExecutor;
+import com.android.internal.util.FunctionalUtils;
 import com.android.internal.util.Preconditions;
 import com.android.telephony.Rlog;
 
@@ -149,21 +150,49 @@ public class SubscriptionManager {
 
     private static final int MAX_CACHE_SIZE = 4;
 
-    private static PropertyInvalidatedCache<Void, Integer> sDefaultSubIdCache =
+    private static class SubscriptionPropertyInvalidatedCache<T>
-            new PropertyInvalidatedCache<Void, Integer>(
+            extends PropertyInvalidatedCache<Void, T> {
-                    MAX_CACHE_SIZE, CACHE_KEY_DEFAULT_SUB_ID_PROPERTY) {
+        private final FunctionalUtils.ThrowingFunction<ISub, T> mSubscriptionInterfaceMethod;
-            @Override
+        private final String mCacheKeyProperty;
-            protected Integer recompute(Void query) {
+        private final T mDefaultValue;
-                return getDefaultSubscriptionIdInternal();
-            }};
 
-    private static PropertyInvalidatedCache<Void, Integer> sDefaultDataSubIdCache =
+        SubscriptionPropertyInvalidatedCache(
-            new PropertyInvalidatedCache<Void, Integer>(
+                FunctionalUtils.ThrowingFunction<ISub, T> subscriptionInterfaceMethod,
-                    MAX_CACHE_SIZE, CACHE_KEY_DEFAULT_DATA_SUB_ID_PROPERTY) {
+                String cacheKeyProperty,
-            @Override
+                T defaultValue) {
-            protected Integer recompute(Void query) {
+            super(MAX_CACHE_SIZE, cacheKeyProperty);
-                return getDefaultDataSubscriptionIdInternal();
+            mSubscriptionInterfaceMethod = subscriptionInterfaceMethod;
-            }};
+            mCacheKeyProperty = cacheKeyProperty;
+            mDefaultValue = defaultValue;
+        }
+
+        @Override
+        protected T recompute(Void aVoid) {
+            T result = mDefaultValue;
+
+            try {
+                ISub iSub = TelephonyManager.getSubscriptionService();
+                if (iSub != null) {
+                    result = mSubscriptionInterfaceMethod.applyOrThrow(iSub);
+                }
+            } catch (Exception ex) {
+                Rlog.w(LOG_TAG, "Failed to recompute cache key for " + mCacheKeyProperty);
+            }
+
+            if (VDBG) logd("recomputing " + mCacheKeyProperty + ", result = " + result);
+            return result;
+        }
+    }
+
+    private static SubscriptionPropertyInvalidatedCache<Integer> sDefaultSubIdCache =
+            new SubscriptionPropertyInvalidatedCache<>(ISub::getDefaultSubId,
+                    CACHE_KEY_DEFAULT_SUB_ID_PROPERTY,
+                    INVALID_SUBSCRIPTION_ID);
+
+    private static SubscriptionPropertyInvalidatedCache<Integer> sDefaultDataSubIdCache =
+            new SubscriptionPropertyInvalidatedCache<>(ISub::getDefaultDataSubId,
+                    CACHE_KEY_DEFAULT_DATA_SUB_ID_PROPERTY,
+                    INVALID_SUBSCRIPTION_ID);
 
     private static PropertyInvalidatedCache<Void, Integer> sDefaultSmsSubIdCache =
             new SubscriptionPropertyInvalidatedCache<>(ISub::getDefaultSmsSubId,
@@ -1888,22 +1917,6 @@ public class SubscriptionManager {
         return sDefaultSubIdCache.query(null);
     }
 
-    private static int getDefaultSubscriptionIdInternal() {
-        int subId = INVALID_SUBSCRIPTION_ID;
-
-        try {
-            ISub iSub = TelephonyManager.getSubscriptionService();
-            if (iSub != null) {
-                subId = iSub.getDefaultSubId();
-            }
-        } catch (RemoteException ex) {
-            // ignore it
-        }
-
-        if (VDBG) logd("getDefaultSubId=" + subId);
-        return subId;
-    }
-
     /**
      * Returns the system's default voice subscription id.
      *
@@ -2045,22 +2058,6 @@ public class SubscriptionManager {
         return sDefaultDataSubIdCache.query(null);
     }
 
-    private static int getDefaultDataSubscriptionIdInternal() {
-        int subId = INVALID_SUBSCRIPTION_ID;
-
-        try {
-            ISub iSub = TelephonyManager.getSubscriptionService();
-            if (iSub != null) {
-                subId = iSub.getDefaultDataSubId();
-            }
-        } catch (RemoteException ex) {
-            // ignore it
-        }
-
-        if (VDBG) logd("getDefaultDataSubscriptionId, sub id = " + subId);
-        return subId;
-    }
-
     /**
      * Set the subscription which will be used by default for data, with the subscription which
      * the supplied subscription ID corresponds to; or throw a RuntimeException if the supplied