3 files changed, 55 insertions, 4 deletions

diff --git a/api/current.txt b/api/current.txt
index 00d4cb5f97dd..e626f29881a9 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -44778,6 +44778,9 @@ package android.telephony {
   public static abstract class TelephonyManager.CellInfoCallback {
     ctor public TelephonyManager.CellInfoCallback();
     method public abstract void onCellInfo(java.util.List<android.telephony.CellInfo>);
+    method public void onError(int, java.lang.Throwable);
+    field public static final int ERROR_MODEM_ERROR = 2; // 0x2
+    field public static final int ERROR_TIMEOUT = 1; // 0x1
   }
 
   public static abstract class TelephonyManager.UssdResponseCallback {
diff --git a/telephony/java/android/telephony/ICellInfoCallback.aidl b/telephony/java/android/telephony/ICellInfoCallback.aidl
index 7fb62682703a..ee3c1b1be6d9 100644
--- a/telephony/java/android/telephony/ICellInfoCallback.aidl
+++ b/telephony/java/android/telephony/ICellInfoCallback.aidl
@@ -16,6 +16,7 @@
 
 package android.telephony;
 
+import android.os.ParcelableException;
 import android.telephony.CellInfo;
 
 import java.util.List;
@@ -27,4 +28,5 @@ import java.util.List;
 oneway interface ICellInfoCallback
 {
     void onCellInfo(in List<CellInfo> state);
+    void onError(in int errorCode, in ParcelableException detail);
 }
diff --git a/telephony/java/android/telephony/TelephonyManager.java b/telephony/java/android/telephony/TelephonyManager.java
index b48a1ced61a4..7f7d5e7faae5 100644
--- a/telephony/java/android/telephony/TelephonyManager.java
+++ b/telephony/java/android/telephony/TelephonyManager.java
@@ -4898,19 +4898,53 @@ public class TelephonyManager {
     /** Callback for providing asynchronous {@link CellInfo} on request */
     public abstract static class CellInfoCallback {
         /**
-         * Response to
+         * Success response to
          * {@link android.telephony.TelephonyManager#requestCellInfoUpdate requestCellInfoUpdate()}.
          *
-         * <p>Invoked when there is a response to
+         * Invoked when there is a response to
          * {@link android.telephony.TelephonyManager#requestCellInfoUpdate requestCellInfoUpdate()}
          * to provide a list of {@link CellInfo}. If no {@link CellInfo} is available then an empty
-         * list will be provided. If an error occurs, null will be provided.
+         * list will be provided. If an error occurs, null will be provided unless the onError
+         * callback is overridden.
          *
          * @param cellInfo a list of {@link CellInfo}, an empty list, or null.
          *
          * {@see android.telephony.TelephonyManager#getAllCellInfo getAllCellInfo()}
          */
-        public abstract void onCellInfo(List<CellInfo> cellInfo);
+        public abstract void onCellInfo(@NonNull List<CellInfo> cellInfo);
+
+        /** @hide */
+        @Retention(RetentionPolicy.SOURCE)
+        @IntDef(prefix = {"ERROR_"}, value = {ERROR_TIMEOUT, ERROR_MODEM_ERROR})
+        public @interface CellInfoCallbackError {}
+
+        /**
+         * The system timed out waiting for a response from the Radio.
+         */
+        public static final int ERROR_TIMEOUT = 1;
+
+        /**
+         * The modem returned a failure.
+         */
+        public static final int ERROR_MODEM_ERROR = 2;
+
+        /**
+         * Error response to
+         * {@link android.telephony.TelephonyManager#requestCellInfoUpdate requestCellInfoUpdate()}.
+         *
+         * Invoked when an error condition prevents updated {@link CellInfo} from being fetched
+         * and returned from the modem. Callers of requestCellInfoUpdate() should override this
+         * function to receive detailed status information in the event of an error. By default,
+         * this function will invoke onCellInfo() with null.
+         *
+         * @param errorCode an error code indicating the type of failure.
+         * @param detail a Throwable object with additional detail regarding the failure if
+         *     available, otherwise null.
+         */
+        public void onError(@CellInfoCallbackError int errorCode, @Nullable Throwable detail) {
+            // By default, simply invoke the success callback with an empty list.
+            onCellInfo(new ArrayList<CellInfo>());
+        }
     };
 
     /**
@@ -4937,6 +4971,12 @@ public class TelephonyManager {
                             Binder.withCleanCallingIdentity(() ->
                                     executor.execute(() -> callback.onCellInfo(cellInfo)));
                         }
+
+                        public void onError(int errorCode, android.os.ParcelableException detail) {
+                            Binder.withCleanCallingIdentity(() ->
+                                    executor.execute(() -> callback.onError(
+                                            errorCode, detail.getCause())));
+                        }
                     }, getOpPackageName());
 
         } catch (RemoteException ex) {
@@ -4971,6 +5011,12 @@ public class TelephonyManager {
                             Binder.withCleanCallingIdentity(() ->
                                     executor.execute(() -> callback.onCellInfo(cellInfo)));
                         }
+
+                        public void onError(int errorCode, android.os.ParcelableException detail) {
+                            Binder.withCleanCallingIdentity(() ->
+                                    executor.execute(() -> callback.onError(
+                                            errorCode, detail.getCause())));
+                        }
                     }, getOpPackageName(), workSource);
         } catch (RemoteException ex) {
         }