Add implementation for listDownloadedModels.

firebase-ml-modeldownloader/firebase-ml-modeldownloader.gradle

@@ -55,5 +55,6 @@ dependencies {
     testImplementation 'androidx.test:core:1.3.0'
     testImplementation 'com.google.truth:truth:1.0.1'
     testImplementation 'junit:junit:4.13'
+    testImplementation 'org.mockito:mockito-core:3.3.3'
     testImplementation "org.robolectric:robolectric:$robolectricVersion"
 }

firebase-ml-modeldownloader/src/main/java/com/google/firebase/ml/modeldownloader/FirebaseModelDownloader.java

@@ -18,16 +18,34 @@
 import androidx.annotation.VisibleForTesting;
 import com.google.android.gms.common.internal.Preconditions;
 import com.google.android.gms.tasks.Task;
+import com.google.android.gms.tasks.TaskCompletionSource;
 import com.google.firebase.FirebaseApp;
 import com.google.firebase.FirebaseOptions;
+import com.google.firebase.ml.modeldownloader.internal.SharedPreferencesUtil;
 import java.util.Set;
+import java.util.concurrent.Executor;
+import java.util.concurrent.Executors;
 
 public class FirebaseModelDownloader {
 
   private final FirebaseOptions firebaseOptions;
+  private final SharedPreferencesUtil sharedPreferencesUtil;
+  private final Executor executor;
 
-  FirebaseModelDownloader(FirebaseOptions firebaseOptions) {
+  FirebaseModelDownloader(FirebaseApp firebaseApp) {
+    this.firebaseOptions = firebaseApp.getOptions();
+    this.sharedPreferencesUtil = new SharedPreferencesUtil(firebaseApp);
+    this.executor = Executors.newCachedThreadPool();
+  }
+
+  @VisibleForTesting
+  FirebaseModelDownloader(
+      FirebaseOptions firebaseOptions,
+      SharedPreferencesUtil sharedPreferencesUtil,
+      Executor executor) {
     this.firebaseOptions = firebaseOptions;
+    this.sharedPreferencesUtil = sharedPreferencesUtil;
+    this.executor = executor;
   }
 
   /**
@@ -84,7 +102,10 @@ public Task<CustomModel> getModel(
   /** @return The set of all models that are downloaded to this device. */
   @NonNull
   public Task<Set<CustomModel>> listDownloadedModels() {
-    throw new UnsupportedOperationException("Not yet implemented.");
+    TaskCompletionSource<Set<CustomModel>> taskCompletionSource = new TaskCompletionSource<>();
+    executor.execute(
+        () -> taskCompletionSource.setResult(sharedPreferencesUtil.listDownloadedModels()));
+    return taskCompletionSource.getTask();
   }
 
   /*

firebase-ml-modeldownloader/src/main/java/com/google/firebase/ml/modeldownloader/FirebaseModelDownloaderRegistrar.java

@@ -16,7 +16,6 @@
 
 import androidx.annotation.NonNull;
 import com.google.firebase.FirebaseApp;
-import com.google.firebase.FirebaseOptions;
 import com.google.firebase.components.Component;
 import com.google.firebase.components.ComponentRegistrar;
 import com.google.firebase.components.Dependency;
@@ -38,8 +37,7 @@ public List<Component<?>> getComponents() {
     return Arrays.asList(
         Component.builder(FirebaseModelDownloader.class)
             .add(Dependency.required(FirebaseApp.class))
-            .add(Dependency.required(FirebaseOptions.class))
-            .factory(c -> new FirebaseModelDownloader(c.get(FirebaseOptions.class)))
+            .factory(c -> new FirebaseModelDownloader(c.get(FirebaseApp.class)))
             .build(),
         LibraryVersionComponent.create("firebase-ml-modeldownloader", BuildConfig.VERSION_NAME));
   }

firebase-ml-modeldownloader/src/main/java/com/google/firebase/ml/modeldownloader/internal/SharedPreferencesUtil.java

@@ -23,6 +23,10 @@
 import androidx.annotation.VisibleForTesting;
 import com.google.firebase.FirebaseApp;
 import com.google.firebase.ml.modeldownloader.CustomModel;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 /** @hide */
 public class SharedPreferencesUtil {
@@ -33,6 +37,8 @@ public class SharedPreferencesUtil {
   // local model details
   private static final String LOCAL_MODEL_HASH_PATTERN = "current_model_hash_%s_%s";
   private static final String LOCAL_MODEL_FILE_PATH_PATTERN = "current_model_path_%s_%s";
+  private static final String LOCAL_MODEL_FILE_PATH_MATCHER = "current_model_path_(.*?)_([^/]+)/?";
+
   private static final String LOCAL_MODEL_FILE_SIZE_PATTERN = "current_model_size_%s_%s";
   // details about model during download.
   private static final String DOWNLOADING_MODEL_HASH_PATTERN = "downloading_model_hash_%s_%s";
@@ -190,6 +196,41 @@ public synchronized void clearModelDetails(@NonNull String modelName, boolean cl
         .commit();
   }
 
+  public synchronized Set<CustomModel> listDownloadedModels() {
+    Set<CustomModel> customModels = new HashSet<>();
+    Set<String> keySet = getSharedPreferences().getAll().keySet();
+
+    for (String key : keySet) {
+      // if a local file path is present - get model details.
+      Matcher matcher = Pattern.compile(LOCAL_MODEL_FILE_PATH_MATCHER).matcher(key);
+      if (matcher.find()) {
+        String modelName = matcher.group(matcher.groupCount());
+        CustomModel extractModel = getCustomModelDetails(modelName);
+        if (extractModel != null) {
+          customModels.add(extractModel);
+        }
+      } else {
+        matcher = Pattern.compile(DOWNLOADING_MODEL_ID_PATTERN).matcher(key);
+        if (matcher.find()) {
+          String modelName = matcher.group(matcher.groupCount());
+          CustomModel extractModel = maybeGetUpdatedModel(modelName);
+          if (extractModel != null) {
+            customModels.add(extractModel);
+          }
+        }
+      }
+    }
+    return customModels;
+  }
+
+  synchronized CustomModel maybeGetUpdatedModel(String modelName) {
+    CustomModel downloadModel = getCustomModelDetails(modelName);
+    // TODO(annz) check here if download currently in progress have completed.
+    // if yes, then complete file relocation and return the updated model, otherwise return null
+
+    return null;
+  }
+
   /**
    * Clears all stored data related to a custom model download.
    *

firebase-ml-modeldownloader/src/test/java/com/google/firebase/ml/modeldownloader/FirebaseModelDownloaderTest.java

@@ -14,34 +14,71 @@
 
 package com.google.firebase.ml.modeldownloader;
 
+import static com.google.common.truth.Truth.assertThat;
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertThrows;
+import static org.mockito.Mockito.when;
 
 import androidx.test.core.app.ApplicationProvider;
+import com.google.android.gms.tasks.Task;
 import com.google.firebase.FirebaseApp;
 import com.google.firebase.FirebaseOptions;
+import com.google.firebase.FirebaseOptions.Builder;
+import com.google.firebase.ml.modeldownloader.internal.SharedPreferencesUtil;
+import java.util.Collections;
+import java.util.Set;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
 import org.robolectric.RobolectricTestRunner;
 
 @RunWith(RobolectricTestRunner.class)
 public class FirebaseModelDownloaderTest {
 
   public static final String TEST_PROJECT_ID = "777777777777";
+  public static final FirebaseOptions FIREBASE_OPTIONS =
+      new Builder()
+          .setApplicationId("1:123456789:android:abcdef")
+          .setProjectId(TEST_PROJECT_ID)
+          .build();
   public static final String MODEL_NAME = "MODEL_NAME_1";
   public static final CustomModelDownloadConditions DEFAULT_DOWNLOAD_CONDITIONS =
       new CustomModelDownloadConditions.Builder().build();
 
+  public static final String MODEL_HASH = "dsf324";
+  // TODO replace with uploaded model.
+  CustomModel CUSTOM_MODEL = new CustomModel(MODEL_NAME, 0, 100, MODEL_HASH);
+
+  FirebaseModelDownloader firebaseModelDownloader;
+  @Mock SharedPreferencesUtil mockPrefs;
+
+  ExecutorService executor;
+
   @Before
   public void setUp() {
+    MockitoAnnotations.initMocks(this);
     FirebaseApp.clearInstancesForTest();
     // default app
-    FirebaseApp.initializeApp(
-        ApplicationProvider.getApplicationContext(),
-        new FirebaseOptions.Builder()
-            .setApplicationId("1:123456789:android:abcdef")
-            .setProjectId(TEST_PROJECT_ID)
-            .build());
+    FirebaseApp.initializeApp(ApplicationProvider.getApplicationContext(), FIREBASE_OPTIONS);
+
+    executor = Executors.newSingleThreadExecutor();
+    firebaseModelDownloader = new FirebaseModelDownloader(FIREBASE_OPTIONS, mockPrefs, executor);
+  }
+
+  @After
+  public void cleanUp() {
+    try {
+      executor.awaitTermination(250, TimeUnit.MILLISECONDS);
+    } catch (InterruptedException e) {
+      // do nothing.
+    }
   }
 
   @Test
@@ -54,10 +91,32 @@ public void getModel_unimplemented() {
   }
 
   @Test
-  public void listDownloadedModels_unimplemented() {
-    assertThrows(
-        UnsupportedOperationException.class,
-        () -> FirebaseModelDownloader.getInstance().listDownloadedModels());
+  public void listDownloadedModels_returnsEmptyModelList()
+      throws ExecutionException, InterruptedException {
+    when(mockPrefs.listDownloadedModels()).thenReturn(Collections.emptySet());
+    TestOnCompleteListener<Set<CustomModel>> onCompleteListener = new TestOnCompleteListener<>();
+    Task<Set<CustomModel>> task = firebaseModelDownloader.listDownloadedModels();
+    task.addOnCompleteListener(executor, onCompleteListener);
+    Set<CustomModel> customModelSet = onCompleteListener.await();
+
+    assertThat(task.isComplete()).isTrue();
+    assertEquals(customModelSet, Collections.EMPTY_SET);
+  }
+
+  @Test
+  public void listDownloadedModels_returnsModelList()
+      throws ExecutionException, InterruptedException {
+    when(mockPrefs.listDownloadedModels()).thenReturn(Collections.singleton(CUSTOM_MODEL));
+
+    TestOnCompleteListener<Set<CustomModel>> onCompleteListener = new TestOnCompleteListener<>();
+    Task<Set<CustomModel>> task = firebaseModelDownloader.listDownloadedModels();
+    task.addOnCompleteListener(executor, onCompleteListener);
+    Set<CustomModel> customModelSet = onCompleteListener.await();
+
+    assertThat(task.isComplete()).isTrue();
+    assertEquals(customModelSet, Collections.singleton(CUSTOM_MODEL));
+
+    executor.awaitTermination(500, TimeUnit.MILLISECONDS);
   }
 
   @Test

firebase-ml-modeldownloader/src/test/java/com/google/firebase/ml/modeldownloader/TestOnCompleteListener.java

@@ -0,0 +1,68 @@
+// Copyright 2020 Google LLC
+//
+// 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.google.firebase.ml.modeldownloader;
+
+import androidx.annotation.NonNull;
+import com.google.android.gms.tasks.OnCompleteListener;
+import com.google.android.gms.tasks.Task;
+import java.io.IOException;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * Helper listener that works around a limitation of the Tasks API where await() cannot be called on
+ * the main thread. This listener works around it by running itself on a different thread, thus
+ * allowing the main thread to be woken up when the Tasks complete.
+ */
+public class TestOnCompleteListener<TResult> implements OnCompleteListener<TResult> {
+  private static final long TIMEOUT_MS = 5000;
+  private final CountDownLatch latch = new CountDownLatch(1);
+  private Task<TResult> task;
+  private volatile TResult result;
+  private volatile Exception exception;
+  private volatile boolean successful;
+
+  @Override
+  public void onComplete(@NonNull Task<TResult> task) {
+    this.task = task;
+    successful = task.isSuccessful();
+    if (successful) {
+      result = task.getResult();
+    } else {
+      exception = task.getException();
+    }
+    latch.countDown();
+  }
+
+  /** Blocks until the {@link #onComplete} is called. */
+  public TResult await() throws InterruptedException, ExecutionException {
+    if (!latch.await(TIMEOUT_MS, TimeUnit.MILLISECONDS)) {
+      throw new InterruptedException("timed out waiting for result");
+    }
+    if (successful) {
+      return result;
+    } else {
+      if (exception instanceof InterruptedException) {
+        throw (InterruptedException) exception;
+      }
+      // todo(annz) add firebase ml exception handling here.
+      if (exception instanceof IOException) {
+        throw new ExecutionException(exception);
+      }
+      throw new IllegalStateException("got an unexpected exception type", exception);
+    }
+  }
+}

firebase-ml-modeldownloader/src/test/java/com/google/firebase/ml/modeldownloader/internal/SharedPreferencesUtilTest.java

@@ -17,11 +17,13 @@
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
 
 import androidx.test.core.app.ApplicationProvider;
 import com.google.firebase.FirebaseApp;
 import com.google.firebase.FirebaseOptions;
 import com.google.firebase.ml.modeldownloader.CustomModel;
+import java.util.Set;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -118,4 +120,43 @@ public void clearDownloadingModelDetails_keepsLocalModel() throws IllegalArgumen
     retrievedModel = sharedPreferencesUtil.getCustomModelDetails(MODEL_NAME);
     assertEquals(retrievedModel, CUSTOM_MODEL_DOWNLOAD_COMPLETE);
   }
+
+  @Test
+  public void listDownloadedModels_localModelFound() throws IllegalArgumentException {
+    sharedPreferencesUtil.setUploadedCustomModelDetails(CUSTOM_MODEL_DOWNLOAD_COMPLETE);
+    Set<CustomModel> retrievedModel = sharedPreferencesUtil.listDownloadedModels();
+    assertEquals(retrievedModel.size(), 1);
+    assertEquals(retrievedModel.iterator().next(), CUSTOM_MODEL_DOWNLOAD_COMPLETE);
+  }
+
+  @Test
+  public void listDownloadedModels_downloadingModelNotFound() throws IllegalArgumentException {
+    sharedPreferencesUtil.setDownloadingCustomModelDetails(CUSTOM_MODEL_DOWNLOADING);
+    assertEquals(sharedPreferencesUtil.listDownloadedModels().size(), 0);
+  }
+
+  @Test
+  public void listDownloadedModels_noModels() throws IllegalArgumentException {
+    assertEquals(sharedPreferencesUtil.listDownloadedModels().size(), 0);
+  }
+
+  @Test
+  public void listDownloadedModels_multipleModels() throws IllegalArgumentException {
+    sharedPreferencesUtil.setUploadedCustomModelDetails(CUSTOM_MODEL_DOWNLOAD_COMPLETE);
+
+    CustomModel model2 =
+        new CustomModel(MODEL_NAME + "2", 0, 102, MODEL_HASH + "2", "file/path/store/ModelName2/1");
+    sharedPreferencesUtil.setUploadedCustomModelDetails(model2);
+
+    CustomModel model3 =
+        new CustomModel(MODEL_NAME + "3", 0, 103, MODEL_HASH + "3", "file/path/store/ModelName3/1");
+
+    sharedPreferencesUtil.setUploadedCustomModelDetails(model3);
+
+    Set<CustomModel> retrievedModel = sharedPreferencesUtil.listDownloadedModels();
+    assertEquals(retrievedModel.size(), 3);
+    assertTrue(retrievedModel.contains(CUSTOM_MODEL_DOWNLOAD_COMPLETE));
+    assertTrue(retrievedModel.contains(model2));
+    assertTrue(retrievedModel.contains(model3));
+  }
 }