Adding get Model for local downloads

firebase-ml-modeldownloader/api.txt

@@ -3,7 +3,7 @@ package com.google.firebase.ml.modeldownloader {
 
   public class CustomModel {
     method public long getDownloadId();
-    method @Nullable public java.io.File getFile();
+    method @Nullable public java.io.File getFile() throws java.lang.Exception;
     method @NonNull public String getModelHash();
     method @NonNull public String getName();
     method public long getSize();
@@ -33,9 +33,19 @@ package com.google.firebase.ml.modeldownloader {
     method @NonNull public com.google.android.gms.tasks.Task<java.lang.Void> deleteDownloadedModel(@NonNull String);
     method @NonNull public static com.google.firebase.ml.modeldownloader.FirebaseModelDownloader getInstance();
     method @NonNull public static com.google.firebase.ml.modeldownloader.FirebaseModelDownloader getInstance(@NonNull com.google.firebase.FirebaseApp);
-    method @NonNull public com.google.android.gms.tasks.Task<com.google.firebase.ml.modeldownloader.CustomModel> getModel(@NonNull String, @NonNull com.google.firebase.ml.modeldownloader.DownloadType, @Nullable com.google.firebase.ml.modeldownloader.CustomModelDownloadConditions);
+    method @NonNull public com.google.android.gms.tasks.Task<com.google.firebase.ml.modeldownloader.CustomModel> getModel(@NonNull String, @NonNull com.google.firebase.ml.modeldownloader.DownloadType, @Nullable com.google.firebase.ml.modeldownloader.CustomModelDownloadConditions) throws java.lang.Exception;
     method @NonNull public com.google.android.gms.tasks.Task<java.util.Set<com.google.firebase.ml.modeldownloader.CustomModel>> listDownloadedModels();
   }
 
 }
 
+package com.google.firebase.ml.modeldownloader.internal {
+
+  public class ModelFileManager {
+    ctor public ModelFileManager(@NonNull com.google.firebase.FirebaseApp);
+    method @NonNull public static com.google.firebase.ml.modeldownloader.internal.ModelFileManager getInstance();
+    method @Nullable @WorkerThread public java.io.File moveModelToDestinationFolder(@NonNull com.google.firebase.ml.modeldownloader.CustomModel, @NonNull android.os.ParcelFileDescriptor) throws java.lang.Exception;
+  }
+
+}
+

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

@@ -25,7 +25,7 @@ android {
     compileSdkVersion project.targetSdkVersion
 
     defaultConfig {
-        minSdkVersion project.minSdkVersion
+        minSdkVersion 16
         targetSdkVersion project.targetSdkVersion
         multiDexEnabled true
         versionName version

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

@@ -16,7 +16,9 @@
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
+import androidx.annotation.VisibleForTesting;
 import com.google.android.gms.common.internal.Objects;
+import com.google.firebase.ml.modeldownloader.internal.ModelFileDownloadService;
 import java.io.File;
 
 /**
@@ -127,11 +129,30 @@ public String getName() {
    *     progress, returns null, if file update is in progress returns last fully uploaded model.
    */
   @Nullable
-  public File getFile() {
+  public File getFile() throws Exception {
+    return getFile(ModelFileDownloadService.getInstance());
+  }
+
+  /**
+   * The local model file. If null is returned, use the download Id to check the download status.
+   *
+   * @return the local file associated with the model. If the original file download is still in
+   *     progress, returns null. If file update is in progress, returns the last fully uploaded
+   *     model.
+   */
+  @Nullable
+  @VisibleForTesting
+  File getFile(ModelFileDownloadService fileDownloadService) throws Exception {
+    // check for completed download
+    File newDownloadFile = fileDownloadService.loadNewlyDownloadedModelFile(this);
+    if (newDownloadFile != null) {
+      return newDownloadFile;
+    }
+    // return local file, if present
     if (localFilePath == null || localFilePath.isEmpty()) {
       return null;
     }
-    throw new UnsupportedOperationException("Not implemented, file retrieval coming soon.");
+    return new File(localFilePath);
   }
 
   /**
@@ -144,7 +165,11 @@ public long getSize() {
     return fileSize;
   }
 
-  /** @return the model hash */
+  /**
+   * Retrieves the model Hash.
+   *
+   * @return the model hash
+   */
   @NonNull
   public String getModelHash() {
     return modelHash;
@@ -161,6 +186,31 @@ public long getDownloadId() {
     return downloadId;
   }
 
+  @NonNull
+  @Override
+  public String toString() {
+    Objects.ToStringHelper stringHelper =
+        Objects.toStringHelper(this)
+            .add("name", name)
+            .add("modelHash", modelHash)
+            .add("fileSize", fileSize);
+
+    if (localFilePath != null && !localFilePath.isEmpty()) {
+      stringHelper.add("localFilePath", localFilePath);
+    }
+    if (downloadId != 0L) {
+      stringHelper.add("downloadId", downloadId);
+    }
+    if (downloadUrl != null && !downloadUrl.isEmpty()) {
+      stringHelper.add("downloadUrl", downloadUrl);
+    }
+    if (downloadUrlExpiry != 0L && !localFilePath.isEmpty()) {
+      stringHelper.add("downloadUrlExpiry", downloadUrlExpiry);
+    }
+
+    return stringHelper.toString();
+  }
+
   @Override
   public boolean equals(Object o) {
     if (o == this) {
@@ -200,6 +250,8 @@ public long getDownloadUrlExpiry() {
   }
 
   /**
+   * Returns the model download url, usually only present when download is about to occur.
+   *
    * @return the model download url
    *     <p>Internal use only
    * @hide

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

@@ -13,14 +13,20 @@
 // limitations under the License.
 package com.google.firebase.ml.modeldownloader;
 
+import android.os.Build.VERSION_CODES;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
+import androidx.annotation.RequiresApi;
 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.android.gms.tasks.Tasks;
 import com.google.firebase.FirebaseApp;
 import com.google.firebase.FirebaseOptions;
+import com.google.firebase.installations.FirebaseInstallationsApi;
+import com.google.firebase.ml.modeldownloader.internal.CustomModelDownloadService;
+import com.google.firebase.ml.modeldownloader.internal.ModelFileDownloadService;
 import com.google.firebase.ml.modeldownloader.internal.SharedPreferencesUtil;
 import java.util.Set;
 import java.util.concurrent.Executor;
@@ -30,21 +36,32 @@ public class FirebaseModelDownloader {
 
   private final FirebaseOptions firebaseOptions;
   private final SharedPreferencesUtil sharedPreferencesUtil;
+  private final ModelFileDownloadService fileDownloadService;
+  private final CustomModelDownloadService modelDownloadService;
   private final Executor executor;
 
-  FirebaseModelDownloader(FirebaseApp firebaseApp) {
+  @RequiresApi(api = VERSION_CODES.KITKAT)
+  FirebaseModelDownloader(
+      FirebaseApp firebaseApp, FirebaseInstallationsApi firebaseInstallationsApi) {
     this.firebaseOptions = firebaseApp.getOptions();
+    this.fileDownloadService = new ModelFileDownloadService(firebaseApp);
     this.sharedPreferencesUtil = new SharedPreferencesUtil(firebaseApp);
+    this.modelDownloadService =
+        new CustomModelDownloadService(firebaseOptions, firebaseInstallationsApi);
     this.executor = Executors.newCachedThreadPool();
   }
 
   @VisibleForTesting
   FirebaseModelDownloader(
       FirebaseOptions firebaseOptions,
       SharedPreferencesUtil sharedPreferencesUtil,
+      ModelFileDownloadService fileDownloadService,
+      CustomModelDownloadService modelDownloadService,
       Executor executor) {
     this.firebaseOptions = firebaseOptions;
     this.sharedPreferencesUtil = sharedPreferencesUtil;
+    this.fileDownloadService = fileDownloadService;
+    this.modelDownloadService = modelDownloadService;
     this.executor = executor;
   }
 
@@ -95,21 +112,77 @@ public static FirebaseModelDownloader getInstance(@NonNull FirebaseApp app) {
   public Task<CustomModel> getModel(
       @NonNull String modelName,
       @NonNull DownloadType downloadType,
-      @Nullable CustomModelDownloadConditions conditions) {
+      @Nullable CustomModelDownloadConditions conditions)
+      throws Exception {
+    CustomModel localModel = sharedPreferencesUtil.getCustomModelDetails(modelName);
+    switch (downloadType) {
+      case LOCAL_MODEL:
+        if (localModel != null) {
+          return Tasks.forResult(localModel);
+        }
+        Task<CustomModel> modelDetails =
+            modelDownloadService.getCustomModelDetails(
+                firebaseOptions.getProjectId(), modelName, null);
+
+        // no local model - start download.
+        return modelDetails.continueWithTask(
+            executor,
+            modelDetailTask -> {
+              if (modelDetailTask.isSuccessful()) {
+                // start download
+                return fileDownloadService
+                    .download(modelDetailTask.getResult(), conditions)
+                    .continueWithTask(
+                        executor,
+                        downloadTask -> {
+                          if (downloadTask.isSuccessful()) {
+                            // read the updated model
+                            CustomModel downloadedModel =
+                                sharedPreferencesUtil.getCustomModelDetails(modelName);
+                            // TODO(annz) trigger file move here as well... right now it's temp
+                            // call loadNewlyDownloadedModelFile
+                            return Tasks.forResult(downloadedModel);
+                          }
+                          return Tasks.forException(new Exception("File download failed."));
+                        });
+              }
+              return Tasks.forException(modelDetailTask.getException());
+            });
+      case LATEST_MODEL:
+        // check for latest model and download newest
+        break;
+      case LOCAL_MODEL_UPDATE_IN_BACKGROUND:
+        // start download in back ground return current model if not null.
+        break;
+    }
     throw new UnsupportedOperationException("Not yet implemented.");
   }
 
-  /** @return The set of all models that are downloaded to this device. */
+  /**
+   * Triggers the move to permanent storage of successful model downloads and lists all models
+   * downloaded to device.
+   *
+   * @return The set of all models that are downloaded to this device, triggers completion of file
+   *     moves for completed model downloads.
+   */
   @NonNull
   public Task<Set<CustomModel>> listDownloadedModels() {
+    // trigger completion of file moves for download files.
+    try {
+      fileDownloadService.maybeCheckDownloadingComplete();
+    } catch (Exception ex) {
+      System.out.println("Error checking for in progress downloads: " + ex.getMessage());
+    }
+
     TaskCompletionSource<Set<CustomModel>> taskCompletionSource = new TaskCompletionSource<>();
     executor.execute(
         () -> taskCompletionSource.setResult(sharedPreferencesUtil.listDownloadedModels()));
     return taskCompletionSource.getTask();
   }
 
-  /*
+  /**
    * Delete old local models, when no longer in use.
+   *
    * @param modelName - name of the model
    */
   @NonNull

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

@@ -24,6 +24,8 @@
 import com.google.firebase.components.Dependency;
 import com.google.firebase.installations.FirebaseInstallationsApi;
 import com.google.firebase.ml.modeldownloader.internal.CustomModelDownloadService;
+import com.google.firebase.ml.modeldownloader.internal.ModelFileDownloadService;
+import com.google.firebase.ml.modeldownloader.internal.ModelFileManager;
 import com.google.firebase.ml.modeldownloader.internal.SharedPreferencesUtil;
 import com.google.firebase.platforminfo.LibraryVersionComponent;
 import java.util.Arrays;
@@ -44,12 +46,24 @@ public List<Component<?>> getComponents() {
     return Arrays.asList(
         Component.builder(FirebaseModelDownloader.class)
             .add(Dependency.required(FirebaseApp.class))
-            .factory(c -> new FirebaseModelDownloader(c.get(FirebaseApp.class)))
+            .add(Dependency.required(FirebaseInstallationsApi.class))
+            .factory(
+                c ->
+                    new FirebaseModelDownloader(
+                        c.get(FirebaseApp.class), c.get(FirebaseInstallationsApi.class)))
             .build(),
         Component.builder(SharedPreferencesUtil.class)
             .add(Dependency.required(FirebaseApp.class))
             .factory(c -> new SharedPreferencesUtil(c.get(FirebaseApp.class)))
             .build(),
+        Component.builder(ModelFileManager.class)
+            .add(Dependency.required(FirebaseApp.class))
+            .factory(c -> new ModelFileManager(c.get(FirebaseApp.class)))
+            .build(),
+        Component.builder(ModelFileDownloadService.class)
+            .add(Dependency.required(FirebaseApp.class))
+            .factory(c -> new ModelFileDownloadService(c.get(FirebaseApp.class)))
+            .build(),
         Component.builder(CustomModelDownloadService.class)
             .add(Dependency.required(FirebaseOptions.class))
             .add(Dependency.required(FirebaseInstallationsApi.class))

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

@@ -14,12 +14,10 @@
 
 package com.google.firebase.ml.modeldownloader.internal;
 
-import android.os.Build.VERSION_CODES;
 import android.util.JsonReader;
 import android.util.Log;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
-import androidx.annotation.RequiresApi;
 import com.google.android.gms.common.util.VisibleForTesting;
 import com.google.android.gms.tasks.Task;
 import com.google.android.gms.tasks.Tasks;
@@ -34,7 +32,6 @@
 import java.net.HttpURLConnection;
 import java.net.URL;
 import java.nio.charset.Charset;
-import java.nio.charset.StandardCharsets;
 import java.text.ParseException;
 import java.text.SimpleDateFormat;
 import java.util.Date;
@@ -51,12 +48,10 @@
  *
  * @hide
  */
-@RequiresApi(api = VERSION_CODES.KITKAT)
-public final class CustomModelDownloadService {
-
+public class CustomModelDownloadService {
   private static final String TAG = "CustomModelDownloadSer";
   private static final int CONNECTION_TIME_OUT_MS = 2000; // 2 seconds.
-  private static final Charset UTF_8 = StandardCharsets.UTF_8;
+  private static final Charset UTF_8 = Charset.forName("UTF-8");
   private static final String ISO_DATE_PATTERN = "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'";
   private static final String ACCEPT_ENCODING_HEADER_KEY = "Accept-Encoding";
   private static final String CONTENT_ENCODING_HEADER_KEY = "Content-Encoding";
@@ -76,8 +71,8 @@ public final class CustomModelDownloadService {
   static final String DOWNLOAD_MODEL_REGEX = "%s/v1beta2/projects/%s/models/%s:download";
 
   private final ExecutorService executorService;
-  private FirebaseInstallationsApi firebaseInstallations;
-  private String apiKey;
+  private final FirebaseInstallationsApi firebaseInstallations;
+  private final String apiKey;
   private String downloadHost = FIREBASE_DOWNLOAD_HOST;
 
   public CustomModelDownloadService(