Merge "Add CredentialDescription get impl."
diff --git a/services/credentials/java/com/android/server/credentials/CredentialDescriptionRegistry.java b/services/credentials/java/com/android/server/credentials/CredentialDescriptionRegistry.java
index fbdcc44..3d504ef 100644
--- a/services/credentials/java/com/android/server/credentials/CredentialDescriptionRegistry.java
+++ b/services/credentials/java/com/android/server/credentials/CredentialDescriptionRegistry.java
@@ -19,35 +19,72 @@
 import android.credentials.CredentialDescription;
 import android.credentials.RegisterCredentialDescriptionRequest;
 import android.credentials.UnregisterCredentialDescriptionRequest;
+import android.service.credentials.CredentialEntry;
 import android.util.SparseArray;
 
+import com.android.internal.annotations.GuardedBy;
+
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.concurrent.locks.ReentrantLock;
 
 /** Contains information on what CredentialProvider has what provisioned Credential. */
-public class CredentialDescriptionRegistry {
+public final class CredentialDescriptionRegistry {
 
     private static final int MAX_ALLOWED_CREDENTIAL_DESCRIPTIONS = 128;
     private static final int MAX_ALLOWED_ENTRIES_PER_PROVIDER = 16;
-    private static SparseArray<CredentialDescriptionRegistry> sCredentialDescriptionSessionPerUser;
+    @GuardedBy("sLock")
+    private static final SparseArray<CredentialDescriptionRegistry>
+            sCredentialDescriptionSessionPerUser;
+    private static final ReentrantLock sLock;
 
     static {
         sCredentialDescriptionSessionPerUser = new SparseArray<>();
+        sLock = new ReentrantLock();
     }
 
-    // TODO(b/265992655): add a way to update CredentialRegistry when a user is removed.
-    /** Get and/or create a {@link  CredentialDescription} for the given user id. */
-    public static CredentialDescriptionRegistry forUser(int userId) {
-        CredentialDescriptionRegistry session =
-                sCredentialDescriptionSessionPerUser.get(userId, null);
+    /** Represents the results of a given query into the registry. */
+    public static final class FilterResult {
+        final String mPackageName;
+        final List<CredentialEntry> mCredentialEntries;
 
-        if (session == null) {
-            session = new CredentialDescriptionRegistry();
-            sCredentialDescriptionSessionPerUser.put(userId, session);
+        private FilterResult(String packageName,
+                List<CredentialEntry> credentialEntries) {
+            mPackageName = packageName;
+            mCredentialEntries = credentialEntries;
         }
-        return session;
+    }
+
+    /** Get and/or create a {@link  CredentialDescription} for the given user id. */
+    @GuardedBy("sLock")
+    public static CredentialDescriptionRegistry forUser(int userId) {
+        sLock.lock();
+        try {
+            CredentialDescriptionRegistry session =
+                    sCredentialDescriptionSessionPerUser.get(userId, null);
+
+            if (session == null) {
+                session = new CredentialDescriptionRegistry();
+                sCredentialDescriptionSessionPerUser.put(userId, session);
+            }
+            return session;
+        } finally {
+            sLock.unlock();
+        }
+    }
+
+    /** Clears an existing session for a given user identifier. */
+    @GuardedBy("sLock")
+    public static void clearUserSession(int userId) {
+        sLock.lock();
+        try {
+            sCredentialDescriptionSessionPerUser.remove(userId);
+        } finally {
+            sLock.unlock();
+        }
     }
 
     private Map<String, Set<CredentialDescription>> mCredentialDescriptions;
@@ -74,7 +111,7 @@
             int size = mCredentialDescriptions.get(callingPackageName).size();
             mCredentialDescriptions.get(callingPackageName)
                     .addAll(descriptions);
-            mTotalDescriptionCount += size - mCredentialDescriptions.get(callingPackageName).size();
+            mTotalDescriptionCount += mCredentialDescriptions.get(callingPackageName).size() - size;
         }
 
     }
@@ -93,21 +130,33 @@
         }
     }
 
+    /** Returns package names and entries of a CredentialProviders that can satisfy a given
+     * {@link CredentialDescription}. */
+    public Set<FilterResult> getFilteredResultForProvider(String packageName,
+            List<String> flatRequestStrings) {
+        Set<FilterResult> result = new HashSet<>();
+        Set<CredentialDescription> currentSet = mCredentialDescriptions.get(packageName);
+        for (CredentialDescription containedDescription: currentSet) {
+            if (flatRequestStrings.contains(containedDescription.getFlattenedRequestString())) {
+                result.add(new FilterResult(packageName, containedDescription
+                        .getCredentialEntries()));
+            }
+        }
+        return result;
+    }
+
     /** Returns package names of CredentialProviders that can satisfy a given
      * {@link CredentialDescription}. */
-    public Set<String> filterCredentials(String flatRequestString) {
-
+    public Set<String> getMatchingProviders(Set<String> flatRequestString) {
         Set<String> result = new HashSet<>();
-
-        for (String componentName: mCredentialDescriptions.keySet()) {
-            Set<CredentialDescription> currentSet = mCredentialDescriptions.get(componentName);
-            for (CredentialDescription containedDescription: currentSet) {
-                if (flatRequestString.equals(containedDescription.getFlattenedRequestString())) {
-                    result.add(componentName);
+        for (String packageName: mCredentialDescriptions.keySet()) {
+            Set<CredentialDescription> currentSet = mCredentialDescriptions.get(packageName);
+            for (CredentialDescription containedDescription : currentSet) {
+                if (flatRequestString.contains(containedDescription.getFlattenedRequestString())) {
+                    result.add(packageName);
                 }
             }
         }
-
         return result;
     }
 
diff --git a/services/credentials/java/com/android/server/credentials/CredentialManagerService.java b/services/credentials/java/com/android/server/credentials/CredentialManagerService.java
index ff72ed7..a1e80d0 100644
--- a/services/credentials/java/com/android/server/credentials/CredentialManagerService.java
+++ b/services/credentials/java/com/android/server/credentials/CredentialManagerService.java
@@ -61,13 +61,11 @@
 import com.android.server.infra.SecureSettingsServiceNameResolver;
 
 import java.util.ArrayList;
-import java.util.Collection;
+import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Set;
 import java.util.function.Consumer;
-import java.util.function.Function;
 import java.util.stream.Collectors;
-import java.util.stream.Stream;
 
 /**
  * Entry point service for credential management.
@@ -236,6 +234,7 @@
         concatenatedServices.addAll(getOrConstructSystemServiceListLock(userId));
         return concatenatedServices;
     }
+
     public static boolean isCredentialDescriptionApiEnabled() {
         return DeviceConfig.getBoolean(
                 DeviceConfig.NAMESPACE_CREDENTIAL, DEVICE_CONFIG_ENABLE_CREDENTIAL_DESC_API, false);
@@ -244,44 +243,38 @@
     @SuppressWarnings("GuardedBy") // ErrorProne requires initiateProviderSessionForRequestLocked
     // to be guarded by 'service.mLock', which is the same as mLock.
     private List<ProviderSession> initiateProviderSessionsWithActiveContainers(
-            RequestSession session,
-            List<String> requestOptions, Set<ComponentName> activeCredentialContainers) {
+            GetRequestSession session,
+            List<String> requestOptions, Set<String> activeCredentialContainers) {
         List<ProviderSession> providerSessions = new ArrayList<>();
         // Invoke all services of a user to initiate a provider session
-        runForUser((service) -> {
-            if (activeCredentialContainers.contains(service.getComponentName())) {
-                ProviderSession providerSession = service
-                        .initiateProviderSessionForRequestLocked(session, requestOptions);
-                if (providerSession != null) {
-                    providerSessions.add(providerSession);
-                }
-            }
-        });
+        for (String packageName: activeCredentialContainers) {
+            providerSessions.add(ProviderRegistryGetSession.createNewSession(
+                    mContext,
+                    UserHandle.getCallingUserId(),
+                    session,
+                    packageName,
+                    requestOptions));
+        }
         return providerSessions;
     }
 
     @NonNull
-    private Set<String> getMatchingProviders(GetCredentialRequest request) {
+    private Set<String> getFilteredResultFromRegistry(List<CredentialOption> options) {
         // Session for active/provisioned credential descriptions;
         CredentialDescriptionRegistry registry = CredentialDescriptionRegistry
                 .forUser(UserHandle.getCallingUserId());
 
         // All requested credential descriptions based on the given request.
         Set<String> requestedCredentialDescriptions =
-                request.getCredentialOptions().stream().map(
-                        credentialOption -> credentialOption
+                options.stream().map(
+                        getCredentialOption -> getCredentialOption
                                         .getCredentialRetrievalData()
                                         .getString(CredentialOption
                                                 .FLATTENED_REQUEST))
                         .collect(Collectors.toSet());
 
         // All requested credential descriptions based on the given request.
-        return requestedCredentialDescriptions.stream()
-                .map(registry::filterCredentials)
-                .flatMap(
-                        (Function<Set<String>, Stream<String>>)
-                                Collection::stream)
-                .collect(Collectors.toSet());
+        return registry.getMatchingProviders(requestedCredentialDescriptions);
     }
 
     @SuppressWarnings("GuardedBy") // ErrorProne requires initiateProviderSessionForRequestLocked
@@ -304,6 +297,13 @@
         return providerSessions;
     }
 
+    @Override
+    @GuardedBy("CredentialDescriptionRegistry.sLock")
+    public void onUserStopped(@NonNull TargetUser user) {
+        super.onUserStopped(user);
+        CredentialDescriptionRegistry.clearUserSession(user.getUserIdentifier());
+    }
+
     private CallingAppInfo constructCallingAppInfo(String packageName, int userId) {
         final PackageInfo packageInfo;
         try {
@@ -340,13 +340,57 @@
                             request,
                             constructCallingAppInfo(callingPackage, userId));
 
-            // Initiate all provider sessions
-            List<ProviderSession> providerSessions =
-                    initiateProviderSessions(
-                            session,
-                            request.getCredentialOptions().stream()
-                                    .map(CredentialOption::getType)
-                                    .collect(Collectors.toList()));
+            List<ProviderSession> providerSessions;
+
+            if (isCredentialDescriptionApiEnabled()) {
+                List<CredentialOption> optionsThatRequireActiveCredentials =
+                        request.getCredentialOptions().stream()
+                                .filter(getCredentialOption ->
+                                        !TextUtils.isEmpty(getCredentialOption
+                                                .getCredentialRetrievalData().getString(
+                                                CredentialOption
+                                                        .FLATTENED_REQUEST, null)))
+                                .toList();
+
+                List<CredentialOption> optionsThatDoNotRequireActiveCredentials =
+                        request.getCredentialOptions().stream()
+                                .filter(getCredentialOption ->
+                                        TextUtils.isEmpty(getCredentialOption
+                                                .getCredentialRetrievalData().getString(
+                                                        CredentialOption
+                                                                .FLATTENED_REQUEST, null)))
+                                .toList();
+
+                List<ProviderSession> sessionsWithoutRemoteService =
+                        initiateProviderSessionsWithActiveContainers(session,
+                                optionsThatRequireActiveCredentials
+                                        .stream().map(getCredentialOption ->
+                                                getCredentialOption.getCredentialRetrievalData()
+                                                        .getString(CredentialOption
+                                                .FLATTENED_REQUEST))
+                                        .collect(Collectors.toList()),
+                                getFilteredResultFromRegistry(optionsThatRequireActiveCredentials));
+
+                List<ProviderSession> sessionsWithRemoteService = initiateProviderSessions(
+                        session,
+                        optionsThatDoNotRequireActiveCredentials.stream()
+                                .map(CredentialOption::getType)
+                                .collect(Collectors.toList()));
+
+                Set<ProviderSession> all = new LinkedHashSet<>();
+                all.addAll(sessionsWithRemoteService);
+                all.addAll(sessionsWithoutRemoteService);
+
+                providerSessions = new ArrayList<>(all);
+            } else {
+                // Initiate all provider sessions
+                providerSessions =
+                        initiateProviderSessions(
+                                session,
+                                request.getCredentialOptions().stream()
+                                        .map(CredentialOption::getType)
+                                        .collect(Collectors.toList()));
+            }
 
             if (providerSessions.isEmpty()) {
                 try {
@@ -363,6 +407,7 @@
 
             // Iterate over all provider sessions and invoke the request
             providerSessions.forEach(ProviderSession::invokeSession);
+
             return cancelTransport;
         }
 
diff --git a/services/credentials/java/com/android/server/credentials/ProviderClearSession.java b/services/credentials/java/com/android/server/credentials/ProviderClearSession.java
index b112649..b20f0cd 100644
--- a/services/credentials/java/com/android/server/credentials/ProviderClearSession.java
+++ b/services/credentials/java/com/android/server/credentials/ProviderClearSession.java
@@ -118,8 +118,8 @@
 
     @Override
     protected void invokeSession() {
-        this.mRemoteCredentialService.onClearCredentialState(
-                this.getProviderRequest(),
-                /*callback=*/this);
+        if (mRemoteCredentialService != null) {
+            mRemoteCredentialService.onClearCredentialState(mProviderRequest, this);
+        }
     }
 }
diff --git a/services/credentials/java/com/android/server/credentials/ProviderCreateSession.java b/services/credentials/java/com/android/server/credentials/ProviderCreateSession.java
index cc5a8ab..ade40ad 100644
--- a/services/credentials/java/com/android/server/credentials/ProviderCreateSession.java
+++ b/services/credentials/java/com/android/server/credentials/ProviderCreateSession.java
@@ -51,6 +51,8 @@
 
     // Key to be used as an entry key for a save entry
     private static final String SAVE_ENTRY_KEY = "save_entry_key";
+    // Key to be used as an entry key for a remote entry
+    private static final String REMOTE_ENTRY_KEY = "remote_entry_key";
 
     @NonNull
     private final Map<String, CreateEntry> mUiSaveEntries = new HashMap<>();
@@ -199,9 +201,9 @@
 
     @Override
     protected void invokeSession() {
-        this.mRemoteCredentialService.onCreateCredential(
-                this.getProviderRequest(),
-                /*callback=*/this);
+        if (mRemoteCredentialService != null) {
+            mRemoteCredentialService.onCreateCredential(mProviderRequest, this);
+        }
     }
 
     private List<Entry> prepareUiSaveEntries(@NonNull List<CreateEntry> saveEntries) {
diff --git a/services/credentials/java/com/android/server/credentials/ProviderGetSession.java b/services/credentials/java/com/android/server/credentials/ProviderGetSession.java
index dec3432..3ccead1 100644
--- a/services/credentials/java/com/android/server/credentials/ProviderGetSession.java
+++ b/services/credentials/java/com/android/server/credentials/ProviderGetSession.java
@@ -59,14 +59,14 @@
         implements
         RemoteCredentialService.ProviderCallbacks<BeginGetCredentialResponse> {
     private static final String TAG = "ProviderGetSession";
-
-    // Key to be used as an entry key for a credential entry
-    private static final String CREDENTIAL_ENTRY_KEY = "credential_key";
-
     // Key to be used as the entry key for an action entry
     private static final String ACTION_ENTRY_KEY = "action_key";
     // Key to be used as the entry key for the authentication entry
     private static final String AUTHENTICATION_ACTION_ENTRY_KEY = "authentication_action_key";
+    // Key to be used as an entry key for a remote entry
+    private static final String REMOTE_ENTRY_KEY = "remote_entry_key";
+    // Key to be used as an entry key for a credential entry
+    private static final String CREDENTIAL_ENTRY_KEY = "credential_key";
 
     @NonNull
     private final Map<String, CredentialEntry> mUiCredentialEntries = new HashMap<>();
@@ -101,23 +101,8 @@
         return null;
     }
 
-    private static BeginGetCredentialRequest constructQueryPhaseRequest(
-            android.credentials.GetCredentialRequest filteredRequest,
-            CallingAppInfo callingAppInfo
-    ) {
-        return new BeginGetCredentialRequest.Builder(callingAppInfo)
-                .setBeginGetCredentialOptions(
-                        filteredRequest.getCredentialOptions().stream().map(
-                                option -> {
-                                    return new BeginGetCredentialOption(
-                                            option.getType(),
-                                            option.getCandidateQueryData());
-                                }).collect(Collectors.toList()))
-                .build();
-    }
-
     @Nullable
-    private static android.credentials.GetCredentialRequest filterOptions(
+    protected static android.credentials.GetCredentialRequest filterOptions(
             List<String> providerCapabilities,
             android.credentials.GetCredentialRequest clientRequest
     ) {
@@ -142,6 +127,21 @@
         return null;
     }
 
+    private static BeginGetCredentialRequest constructQueryPhaseRequest(
+            android.credentials.GetCredentialRequest filteredRequest,
+            CallingAppInfo callingAppInfo
+    ) {
+        return new BeginGetCredentialRequest.Builder(callingAppInfo)
+                .setBeginGetCredentialOptions(
+                        filteredRequest.getCredentialOptions().stream().map(
+                                option -> {
+                                    return new BeginGetCredentialOption(
+                                            option.getType(),
+                                            option.getCandidateQueryData());
+                                }).collect(Collectors.toList()))
+                .build();
+    }
+
     public ProviderGetSession(Context context,
             CredentialProviderInfo info,
             ProviderInternalCallback<GetCredentialResponse> callbacks,
@@ -232,9 +232,9 @@
 
     @Override
     protected void invokeSession() {
-        this.mRemoteCredentialService.onBeginGetCredential(
-                        this.getProviderRequest(),
-                        /*callback=*/this);
+        if (mRemoteCredentialService != null) {
+            mRemoteCredentialService.onBeginGetCredential(mProviderRequest, this);
+        }
     }
 
     @Override // Call from request session to data to be shown on the UI
@@ -379,6 +379,28 @@
         invokeCallbackOnInternalInvalidState();
     }
 
+    @Nullable
+    protected GetCredentialException maybeGetPendingIntentException(
+            ProviderPendingIntentResponse pendingIntentResponse) {
+        if (pendingIntentResponse == null) {
+            Log.i(TAG, "pendingIntentResponse is null");
+            return null;
+        }
+        if (PendingIntentResultHandler.isValidResponse(pendingIntentResponse)) {
+            GetCredentialException exception = PendingIntentResultHandler
+                    .extractGetCredentialException(pendingIntentResponse.getResultData());
+            if (exception != null) {
+                Log.i(TAG, "Pending intent contains provider exception");
+                return exception;
+            }
+        } else if (PendingIntentResultHandler.isCancelledResponse(pendingIntentResponse)) {
+            return new GetCredentialException(GetCredentialException.TYPE_USER_CANCELED);
+        } else {
+            return new GetCredentialException(GetCredentialException.TYPE_NO_CREDENTIAL);
+        }
+        return null;
+    }
+
     private void onAuthenticationEntrySelected(
             @Nullable ProviderPendingIntentResponse providerPendingIntentResponse) {
         //TODO: Other provider intent statuses
@@ -431,28 +453,6 @@
         updateStatusAndInvokeCallback(Status.NO_CREDENTIALS);
     }
 
-    @Nullable
-    private GetCredentialException maybeGetPendingIntentException(
-            ProviderPendingIntentResponse pendingIntentResponse) {
-        if (pendingIntentResponse == null) {
-            Log.i(TAG, "pendingIntentResponse is null");
-            return null;
-        }
-        if (PendingIntentResultHandler.isValidResponse(pendingIntentResponse)) {
-            GetCredentialException exception = PendingIntentResultHandler
-                    .extractGetCredentialException(pendingIntentResponse.getResultData());
-            if (exception != null) {
-                Log.i(TAG, "Pending intent contains provider exception");
-                return exception;
-            }
-        } else if (PendingIntentResultHandler.isCancelledResponse(pendingIntentResponse)) {
-            return new GetCredentialException(GetCredentialException.TYPE_USER_CANCELED);
-        } else {
-            return new GetCredentialException(GetCredentialException.TYPE_NO_CREDENTIAL);
-        }
-        return null;
-    }
-
     /**
      * When an invalid state occurs, e.g. entry mismatch or no response from provider,
      * we send back a TYPE_UNKNOWN error as to the developer.
diff --git a/services/credentials/java/com/android/server/credentials/ProviderRegistryGetSession.java b/services/credentials/java/com/android/server/credentials/ProviderRegistryGetSession.java
new file mode 100644
index 0000000..461f447
--- /dev/null
+++ b/services/credentials/java/com/android/server/credentials/ProviderRegistryGetSession.java
@@ -0,0 +1,261 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.server.credentials;
+
+import android.annotation.NonNull;
+import android.annotation.Nullable;
+import android.annotation.UserIdInt;
+import android.content.Context;
+import android.content.Intent;
+import android.credentials.CredentialOption;
+import android.credentials.GetCredentialException;
+import android.credentials.GetCredentialRequest;
+import android.credentials.GetCredentialResponse;
+import android.credentials.ui.Entry;
+import android.credentials.ui.GetCredentialProviderData;
+import android.credentials.ui.ProviderData;
+import android.credentials.ui.ProviderPendingIntentResponse;
+import android.service.credentials.CallingAppInfo;
+import android.service.credentials.CredentialEntry;
+import android.service.credentials.CredentialProviderService;
+import android.telecom.Log;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+/**
+ * Central provider session that utilizes {@link CredentialDescriptionRegistry} and therefor is able
+ * to bypass having to use a {@link RemoteCredentialService}.
+ *
+ * @hide
+ */
+public class ProviderRegistryGetSession extends ProviderSession<GetCredentialRequest,
+        Set<CredentialDescriptionRegistry.FilterResult>> {
+
+    private static final String TAG = "ProviderRegistryGetSession";
+    private static final String CREDENTIAL_ENTRY_KEY = "credential_key";
+
+    /** Creates a new provider session to be used by the request session. */
+    @Nullable
+    public static ProviderRegistryGetSession createNewSession(
+            @NonNull Context context,
+            @UserIdInt int userId,
+            @NonNull GetRequestSession getRequestSession,
+            @NonNull String credentialProviderPackageName,
+            @NonNull List<String> requestOptions) {
+        return new ProviderRegistryGetSession(
+                context,
+                userId,
+                getRequestSession,
+                getRequestSession.mClientRequest,
+                getRequestSession.mClientAppInfo,
+                credentialProviderPackageName,
+                requestOptions);
+    }
+
+    @NonNull
+    private final Map<String, CredentialEntry> mUiCredentialEntries = new HashMap<>();
+    @NonNull
+    private final CredentialDescriptionRegistry mCredentialDescriptionRegistry;
+    @NonNull
+    private final CallingAppInfo mCallingAppInfo;
+    @NonNull
+    private final String mCredentialProviderPackageName;
+    @NonNull
+    private final GetRequestSession mGetRequestSession;
+    @NonNull
+    private final List<String> mRequestOptions;
+    private List<CredentialEntry> mCredentialEntries;
+
+    protected ProviderRegistryGetSession(@NonNull Context context,
+            @NonNull int userId,
+            @NonNull GetRequestSession session,
+            @NonNull GetCredentialRequest request,
+            @NonNull CallingAppInfo callingAppInfo,
+            @NonNull String servicePackageName,
+            @NonNull List<String> requestOptions) {
+        super(context, null, request, session, userId, null);
+        mGetRequestSession = session;
+        mCredentialDescriptionRegistry = CredentialDescriptionRegistry.forUser(userId);
+        mCallingAppInfo = callingAppInfo;
+        mCredentialProviderPackageName = servicePackageName;
+        mRequestOptions = requestOptions;
+    }
+
+    private List<Entry> prepareUiCredentialEntries(
+            @NonNull List<CredentialEntry> credentialEntries) {
+        Log.i(TAG, "in prepareUiProviderDataWithCredentials");
+        List<Entry> credentialUiEntries = new ArrayList<>();
+
+        // Populate the credential entries
+        for (CredentialEntry credentialEntry : credentialEntries) {
+            String entryId = generateEntryId();
+            mUiCredentialEntries.put(entryId, credentialEntry);
+            Log.i(TAG, "in prepareUiProviderData creating ui entry with id " + entryId);
+            credentialUiEntries.add(new Entry(CREDENTIAL_ENTRY_KEY, entryId,
+                    credentialEntry.getSlice(),
+                    setUpFillInIntent(credentialEntry.getType())));
+        }
+        return credentialUiEntries;
+    }
+
+    private Intent setUpFillInIntent(String type) {
+        Intent intent = new Intent();
+        for (CredentialOption option : mProviderRequest.getCredentialOptions()) {
+            if (option.getType().equals(type)) {
+                intent.putExtra(
+                        CredentialProviderService
+                                .EXTRA_GET_CREDENTIAL_REQUEST,
+                        new android.service.credentials.GetCredentialRequest(
+                                mCallingAppInfo, option));
+                return intent;
+            }
+        }
+        return intent;
+    }
+
+    @Override
+    protected ProviderData prepareUiData() {
+        Log.i(TAG, "In prepareUiData");
+        if (!ProviderSession.isUiInvokingStatus(getStatus())) {
+            Log.i(TAG, "In prepareUiData - provider does not want to show UI: "
+                    + mComponentName.flattenToString());
+            return null;
+        }
+        if (mProviderResponse == null) {
+            Log.i(TAG, "In prepareUiData response null");
+            throw new IllegalStateException("Response must be in completion mode");
+        }
+        return new GetCredentialProviderData.Builder(
+                mComponentName.flattenToString()).setActionChips(null)
+                .setCredentialEntries(prepareUiCredentialEntries(
+                        mProviderResponse.stream().flatMap((Function<CredentialDescriptionRegistry
+                                        .FilterResult,
+                                        Stream<CredentialEntry>>) filterResult ->
+                                        filterResult.mCredentialEntries.stream())
+                                .collect(Collectors.toList())))
+                .build();
+    }
+
+    @Override // Selection call from the request provider
+    protected void onUiEntrySelected(String entryType, String entryKey,
+            ProviderPendingIntentResponse providerPendingIntentResponse) {
+        switch (entryType) {
+            case CREDENTIAL_ENTRY_KEY:
+                CredentialEntry credentialEntry = mUiCredentialEntries.get(entryKey);
+                if (credentialEntry == null) {
+                    Log.i(TAG, "Unexpected credential entry key");
+                    return;
+                }
+                onCredentialEntrySelected(credentialEntry, providerPendingIntentResponse);
+                break;
+            default:
+                Log.i(TAG, "Unsupported entry type selected");
+        }
+    }
+
+    private void onCredentialEntrySelected(CredentialEntry credentialEntry,
+            ProviderPendingIntentResponse providerPendingIntentResponse) {
+        if (!mCredentialEntries.contains(credentialEntry)) {
+            invokeCallbackWithError("",
+                    "");
+        }
+
+        if (providerPendingIntentResponse != null) {
+            // Check if pending intent has an error
+            GetCredentialException exception = maybeGetPendingIntentException(
+                    providerPendingIntentResponse);
+            if (exception != null) {
+                invokeCallbackWithError(exception.getType(),
+                        exception.getMessage());
+                return;
+            }
+
+            // Check if pending intent has a credential
+            GetCredentialResponse getCredentialResponse = PendingIntentResultHandler
+                    .extractGetCredentialResponse(
+                            providerPendingIntentResponse.getResultData());
+            if (getCredentialResponse != null) {
+                if (mCallbacks != null) {
+                    mCallbacks.onFinalResponseReceived(mComponentName,
+                            getCredentialResponse);
+                }
+                return;
+            }
+
+            Log.i(TAG, "Pending intent response contains no credential, or error");
+        }
+        Log.i(TAG, "CredentialEntry does not have a credential or a pending intent result");
+    }
+
+    @Override
+    public void onProviderResponseSuccess(
+            @Nullable Set<CredentialDescriptionRegistry.FilterResult> response) {
+        // No need to do anything since this class does not rely on a remote service.
+    }
+
+    @Override
+    public void onProviderResponseFailure(int internalErrorCode, @Nullable Exception e) {
+        // No need to do anything since this class does not rely on a remote service.
+    }
+
+    @Override
+    public void onProviderServiceDied(RemoteCredentialService service) {
+        // No need to do anything since this class does not rely on a remote service.
+    }
+
+    @Override
+    protected void invokeSession() {
+        mProviderResponse = mCredentialDescriptionRegistry
+                .getFilteredResultForProvider(mCredentialProviderPackageName,
+                        mRequestOptions);
+        mCredentialEntries = mProviderResponse.stream().flatMap(
+                        (Function<CredentialDescriptionRegistry.FilterResult,
+                                Stream<CredentialEntry>>) filterResult
+                        -> filterResult.mCredentialEntries.stream())
+                .collect(Collectors.toList());
+        setStatus(Status.CREDENTIALS_RECEIVED);
+    }
+
+    @Nullable
+    protected GetCredentialException maybeGetPendingIntentException(
+            ProviderPendingIntentResponse pendingIntentResponse) {
+        if (pendingIntentResponse == null) {
+            android.util.Log.i(TAG, "pendingIntentResponse is null");
+            return null;
+        }
+        if (PendingIntentResultHandler.isValidResponse(pendingIntentResponse)) {
+            GetCredentialException exception = PendingIntentResultHandler
+                    .extractGetCredentialException(pendingIntentResponse.getResultData());
+            if (exception != null) {
+                android.util.Log.i(TAG, "Pending intent contains provider exception");
+                return exception;
+            }
+        } else if (PendingIntentResultHandler.isCancelledResponse(pendingIntentResponse)) {
+            return new GetCredentialException(GetCredentialException.TYPE_USER_CANCELED);
+        } else {
+            return new GetCredentialException(GetCredentialException.TYPE_NO_CREDENTIAL);
+        }
+        return null;
+    }
+}
diff --git a/services/credentials/java/com/android/server/credentials/ProviderSession.java b/services/credentials/java/com/android/server/credentials/ProviderSession.java
index 8e0d6f8..c479c4e 100644
--- a/services/credentials/java/com/android/server/credentials/ProviderSession.java
+++ b/services/credentials/java/com/android/server/credentials/ProviderSession.java
@@ -38,16 +38,14 @@
         implements RemoteCredentialService.ProviderCallbacks<R> {
 
     private static final String TAG = "ProviderSession";
-    // Key to be used as an entry key for a remote entry
-    protected static final String REMOTE_ENTRY_KEY = "remote_entry_key";
 
     @NonNull protected final Context mContext;
     @NonNull protected final ComponentName mComponentName;
-    @NonNull protected final CredentialProviderInfo mProviderInfo;
-    @NonNull protected final RemoteCredentialService mRemoteCredentialService;
+    @Nullable protected final CredentialProviderInfo mProviderInfo;
+    @Nullable protected final RemoteCredentialService mRemoteCredentialService;
     @NonNull protected final int mUserId;
     @NonNull protected Status mStatus = Status.NOT_STARTED;
-    @NonNull protected final ProviderInternalCallback mCallbacks;
+    @Nullable protected final ProviderInternalCallback mCallbacks;
     @Nullable protected Credential mFinalCredentialResponse;
     @NonNull protected final T mProviderRequest;
     @Nullable protected R mProviderResponse;
@@ -109,9 +107,9 @@
 
     protected ProviderSession(@NonNull Context context, @NonNull CredentialProviderInfo info,
             @NonNull T providerRequest,
-            @NonNull ProviderInternalCallback callbacks,
+            @Nullable ProviderInternalCallback callbacks,
             @NonNull int userId,
-            @NonNull RemoteCredentialService remoteCredentialService) {
+            @Nullable RemoteCredentialService remoteCredentialService) {
         mContext = context;
         mProviderInfo = info;
         mProviderRequest = providerRequest;
@@ -165,7 +163,7 @@
         return mComponentName;
     }
 
-    @NonNull
+    @Nullable
     protected RemoteCredentialService getRemoteCredentialService() {
         return mRemoteCredentialService;
     }