To extend this class, you must declare the service in your manifest file with the + * {@link android.Manifest.permission#BIND_EXTERNAL_STORAGE_SERVICE} permission, + * and include an intent filter with the {@link #SERVICE_INTERFACE} action. + * For example:
+ *+ * <service android:name=".ExternalStorageServiceImpl" + * android:exported="true" + * android:priority="100" + * android:permission="android.permission.BIND_EXTERNAL_STORAGE_SERVICE"> + * <intent-filter> + * <action android:name="android.service.storage.ExternalStorageService" /> + * </intent-filter> + * </service> + *+ * @hide + */ +@SystemApi +public abstract class ExternalStorageService extends Service { + /** + * The Intent action that a service must respond to. Add it as an intent filter in the + * manifest declaration of the implementing service. + */ + @SdkConstant(SdkConstant.SdkConstantType.SERVICE_ACTION) + public static final String SERVICE_INTERFACE = "android.service.storage.ExternalStorageService"; + /** + * Whether the session associated with the device file descriptor when calling + * {@link #onStartSession} is a FUSE session. + */ + public static final int FLAG_SESSION_TYPE_FUSE = 1 << 0; + + /** + * Whether the upper file system path specified when calling {@link #onStartSession} + * should be indexed. + */ + public static final int FLAG_SESSION_ATTRIBUTE_INDEXABLE = 1 << 1; + + /** + * {@link Bundle} key for a {@link String} value. + * + * {@hide} + */ + public static final String EXTRA_SESSION_ID = + "android.service.storage.extra.session_id"; + /** + * {@link Bundle} key for a {@link ParcelableException} value. + * + * {@hide} + */ + public static final String EXTRA_ERROR = + "android.service.storage.extra.error"; + + /** @hide */ + @IntDef(flag = true, prefix = {"FLAG_SESSION_"}, + value = {FLAG_SESSION_TYPE_FUSE, FLAG_SESSION_ATTRIBUTE_INDEXABLE}) + @Retention(RetentionPolicy.SOURCE) + public @interface SessionFlag {} + + private final ExternalStorageServiceWrapper mWrapper = new ExternalStorageServiceWrapper(); + private final Handler mHandler = new Handler(Looper.getMainLooper(), null, true); + + /** + * Called when the system starts a session associated with {@code deviceFd} + * identified by {@code sessionId} to handle filesystem I/O for other apps. The type of + * session and other attributes are passed in {@code flag}. + * + *
I/O is received as requests originating from {@code upperFileSystemPath} on + * {@code deviceFd}. Implementors should handle the I/O by responding to these requests + * using the data on the {@code lowerFileSystemPath}. + * + *
Additional calls to start a session for the same {@code sessionId} while the session + * is still starting or already started should have no effect. + */ + public abstract void onStartSession(@NonNull String sessionId, @SessionFlag int flag, + @NonNull ParcelFileDescriptor deviceFd, @NonNull String upperFileSystemPath, + @NonNull String lowerFileSystemPath) throws IOException; + + /** + * Called when the system ends the session identified by {@code sessionId}. Implementors should + * stop handling filesystem I/O and clean up resources from the ended session. + * + *
Additional calls to end a session for the same {@code sessionId} while the session
+ * is still ending or has not started should have no effect.
+ */
+ public abstract void onEndSession(@NonNull String sessionId) throws IOException;
+
+ @Override
+ @NonNull
+ public final IBinder onBind(@NonNull Intent intent) {
+ return mWrapper;
+ }
+
+ private class ExternalStorageServiceWrapper extends IExternalStorageService.Stub {
+ @Override
+ public void startSession(String sessionId, @SessionFlag int flag,
+ ParcelFileDescriptor deviceFd, String upperPath, String lowerPath,
+ RemoteCallback callback) throws RemoteException {
+ mHandler.post(() -> {
+ try {
+ onStartSession(sessionId, flag, deviceFd, upperPath, lowerPath);
+ sendResult(sessionId, null /* throwable */, callback);
+ } catch (Throwable t) {
+ sendResult(sessionId, t, callback);
+ }
+ });
+ }
+
+ @Override
+ public void endSession(String sessionId, RemoteCallback callback) throws RemoteException {
+ mHandler.post(() -> {
+ try {
+ onEndSession(sessionId);
+ sendResult(sessionId, null /* throwable */, callback);
+ } catch (Throwable t) {
+ sendResult(sessionId, t, callback);
+ }
+ });
+ }
+
+ private void sendResult(String sessionId, Throwable throwable, RemoteCallback callback) {
+ Bundle bundle = new Bundle();
+ bundle.putString(EXTRA_SESSION_ID, sessionId);
+ if (throwable != null) {
+ bundle.putParcelable(EXTRA_ERROR, new ParcelableException(throwable));
+ }
+ callback.sendResult(bundle);
+ }
+ }
+}
diff --git a/core/java/android/service/storage/IExternalStorageService.aidl b/core/java/android/service/storage/IExternalStorageService.aidl
new file mode 100644
index 0000000000000..ae46f1fc2fd26
--- /dev/null
+++ b/core/java/android/service/storage/IExternalStorageService.aidl
@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2019 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 android.service.storage;
+
+import android.os.ParcelFileDescriptor;
+import android.os.RemoteCallback;
+
+/**
+ * @hide
+ */
+oneway interface IExternalStorageService
+{
+ void startSession(@utf8InCpp String sessionId, int type, in ParcelFileDescriptor deviceFd,
+ @utf8InCpp String upperPath, @utf8InCpp String lowerPath, in RemoteCallback callback);
+ void endSession(@utf8InCpp String sessionId, in RemoteCallback callback);
+}
\ No newline at end of file
diff --git a/core/res/AndroidManifest.xml b/core/res/AndroidManifest.xml
index cff9275477ca6..c0a8650a179ab 100644
--- a/core/res/AndroidManifest.xml
+++ b/core/res/AndroidManifest.xml
@@ -4524,6 +4524,13 @@