Fixed how FillEventHistory is reset and clarified javadoc.

Test: existing CtsAutoFillServiceTestCases pass
Test: checkFillSelectionIsResetAfterReturningNull()
Test: checkFillSelectionIsResetAfterReturningError()
Test: checkFillSelectionIsResetAfterTimeout()

Bug: 62802026

Change-Id: I389d95fc13c08f1056960e5f67e131c8dc306401

core/java/android/service/autofill/AutofillService.java

@@ -215,12 +215,22 @@ public abstract class AutofillService extends Service {
     }
 
     /**
-     * Returns the {@link FillEventHistory.Event events} since the last {@link FillResponse} was
-     * returned.
+     * Gets the events that happened after the last
+     * {@link AutofillService#onFillRequest(FillRequest, android.os.CancellationSignal, FillCallback)}
+     * call.
      *
-     * <p>The history is not persisted over reboots.
+     * <p>This method is typically used to keep track of previous user actions to optimize further
+     * requests. For example, the service might return email addresses in alphabetical order by
+     * default, but change that order based on the address the user picked on previous requests.
      *
-     * @return The history or {@code null} if there are not events.
+     * <p>The history is not persisted over reboots, and it's cleared every time the service
+     * replies to a {@link #onFillRequest(FillRequest, CancellationSignal, FillCallback)} by calling
+     * {@link FillCallback#onSuccess(FillResponse)} or {@link FillCallback#onFailure(CharSequence)}
+     * (if the service doesn't call any of these methods, the history will clear out after some
+     * pre-defined time). Hence, the service should call {@link #getFillEventHistory()} before
+     * finishing the {@link FillCallback}.
+     *
+     * @return The history or {@code null} if there are no events.
      */
     @Nullable public final FillEventHistory getFillEventHistory() {
         AutofillManager afm = getSystemService(AutofillManager.class);

core/java/android/service/autofill/FillEventHistory.java

@@ -33,7 +33,20 @@ import java.util.ArrayList;
 import java.util.List;
 
 /**
- * Describes what happened after the latest call to {@link FillCallback#onSuccess(FillResponse)}.
+ * Describes what happened after the last
+ * {@link AutofillService#onFillRequest(FillRequest, android.os.CancellationSignal, FillCallback)}
+ * call.
+ *
+ * <p>This history is typically used to keep track of previous user actions to optimize further
+ * requests. For example, the service might return email addresses in alphabetical order by
+ * default, but change that order based on the address the user picked on previous requests.
+ *
+ * <p>The history is not persisted over reboots, and it's cleared every time the service
+ * replies to a
+ * {@link AutofillService#onFillRequest(FillRequest, android.os.CancellationSignal, FillCallback)}
+ * by calling {@link FillCallback#onSuccess(FillResponse)} or
+ * {@link FillCallback#onFailure(CharSequence)} (if the service doesn't call any of these methods,
+ * the history will clear out after some pre-defined time).
  */
 public final class FillEventHistory implements Parcelable {
     /**
@@ -56,9 +69,11 @@ public final class FillEventHistory implements Parcelable {
     }
 
     /**
-     * Returns the client state of the {@link FillResponse}.
+     * Returns the client state set in the previous {@link FillResponse}.
      *
-     * @return The client state set by the last {@link FillResponse}
+     * <p><b>NOTE: </b>the state is associated with the app that was autofilled in the previous
+     * {@link AutofillService#onFillRequest(FillRequest, android.os.CancellationSignal, FillCallback)}
+     * , which is not necessary the same app being autofilled now.
      */
     @Nullable public Bundle getClientState() {
         return mClientState;

services/autofill/java/com/android/server/autofill/AutofillManagerServiceImpl.java

@@ -495,11 +495,24 @@ final class AutofillManagerServiceImpl {
         }
     }
 
+    /**
+     * Resets the last fill selection.
+     */
+    void resetLastResponse() {
+        synchronized (mLock) {
+            mEventHistory = null;
+        }
+    }
+
     /**
      * Updates the last fill selection when an authentication was selected.
      */
     void setAuthenticationSelected() {
         synchronized (mLock) {
+            if (mEventHistory == null) {
+                Slog.w(TAG, "setAuthenticationSelected(): ignored when history is null");
+                return;
+            }
             mEventHistory.addEvent(new Event(Event.TYPE_AUTHENTICATION_SELECTED, null));
         }
     }
@@ -509,6 +522,10 @@ final class AutofillManagerServiceImpl {
      */
     void setDatasetAuthenticationSelected(@Nullable String selectedDataset) {
         synchronized (mLock) {
+            if (mEventHistory == null) {
+                Slog.w(TAG, "setDatasetAuthenticationSelected(): ignored when history is null");
+                return;
+            }
             mEventHistory.addEvent(
                     new Event(Event.TYPE_DATASET_AUTHENTICATION_SELECTED, selectedDataset));
         }
@@ -519,6 +536,10 @@ final class AutofillManagerServiceImpl {
      */
     void setSaveShown() {
         synchronized (mLock) {
+            if (mEventHistory == null) {
+                Slog.w(TAG, "setSaveShown(): ignored when history is null");
+                return;
+            }
             mEventHistory.addEvent(new Event(Event.TYPE_SAVE_SHOWN, null));
         }
     }
@@ -528,6 +549,10 @@ final class AutofillManagerServiceImpl {
      */
     void setDatasetSelected(@Nullable String selectedDataset) {
         synchronized (mLock) {
+            if (mEventHistory == null) {
+                Slog.w(TAG, "setDatasetSelected(): ignored when history is null");
+                return;
+            }
             mEventHistory.addEvent(new Event(Event.TYPE_DATASET_SELECTED, selectedDataset));
         }
     }

services/autofill/java/com/android/server/autofill/RemoteFillService.java

@@ -427,6 +427,7 @@ final class RemoteFillService implements DeathRecipient {
                     mCompleted = true;
                 }
 
+                Slog.w(LOG_TAG, getClass().getSimpleName() + " timed out");
                 final RemoteFillService remoteService = mWeakService.get();
                 if (remoteService != null) {
                     fail(remoteService);

services/autofill/java/com/android/server/autofill/Session.java

@@ -407,6 +407,7 @@ final class Session implements RemoteFillService.FillServiceCallbacks, ViewState
             if ((requestFlags & FLAG_MANUAL_REQUEST) != 0) {
                 getUiForShowing().showError(R.string.autofill_error_cannot_autofill, this);
             }
+            mService.resetLastResponse();
             // Nothing to be done, but need to notify client.
             notifyUnavailableToClient();
             removeSelf();
@@ -444,6 +445,7 @@ final class Session implements RemoteFillService.FillServiceCallbacks, ViewState
                         + id + " destroyed");
                 return;
             }
+            mService.resetLastResponse();
         }
         LogMaker log = (new LogMaker(MetricsEvent.AUTOFILL_REQUEST))
                 .setType(MetricsEvent.TYPE_FAILURE)