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      1 /*
      2  * Copyright (C) 2017 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 package com.android.bluetooth.opp;
     17 
     18 import android.content.BroadcastReceiver;
     19 import android.content.Context;
     20 import android.content.Intent;
     21 import android.content.IntentFilter;
     22 import android.content.pm.ProviderInfo;
     23 import android.net.Uri;
     24 import android.os.UserHandle;
     25 import android.os.UserManager;
     26 import android.support.v4.content.FileProvider;
     27 import android.util.Log;
     28 import java.io.File;
     29 
     30 /**
     31  * A FileProvider for files received by Bluetooth share
     32  */
     33 public class BluetoothOppFileProvider extends FileProvider {
     34     private static final String TAG = "BluetoothOppFileProvider";
     35 
     36     private Context mContext = null;
     37     private ProviderInfo mProviderInfo = null;
     38     private boolean mRegisteredReceiver = false;
     39     private boolean mInitialized = false;
     40 
     41     /** Broadcast receiver that attach FileProvider info when user unlocks the phone for the
     42      *  first time after reboot and the credential-encrypted storage is available.
     43      */
     44     private final BroadcastReceiver mBroadcastReceiver = new BroadcastReceiver() {
     45         @Override
     46         public void onReceive(final Context context, Intent intent) {
     47             if (Intent.ACTION_USER_UNLOCKED.equals(intent.getAction())) {
     48                 attachInfo(mContext, mProviderInfo);
     49             }
     50         }
     51     };
     52 
     53     /**
     54      * After the FileProvider is instantiated, this method is called to provide the system with
     55      * information about the provider. The actual initialization is delayed until user unlock the
     56      * device
     57      *
     58      * @param context A {@link Context} for the current component.
     59      * @param info A {@link ProviderInfo} for the new provider.
     60      */
     61     @Override
     62     public void attachInfo(Context context, ProviderInfo info) {
     63         synchronized (this) {
     64             mContext = context;
     65             mProviderInfo = info;
     66             if (!mRegisteredReceiver) {
     67                 IntentFilter userFilter = new IntentFilter();
     68                 userFilter.addAction(Intent.ACTION_USER_UNLOCKED);
     69                 mContext.registerReceiverAsUser(
     70                         mBroadcastReceiver, UserHandle.CURRENT, userFilter, null, null);
     71                 mRegisteredReceiver = true;
     72             }
     73             UserManager userManager = (UserManager) mContext.getSystemService(Context.USER_SERVICE);
     74             if (userManager.isUserUnlocked()) {
     75                 if (!mInitialized) {
     76                     if (Constants.DEBUG) Log.d(TAG, "Initialized");
     77                     super.attachInfo(mContext, mProviderInfo);
     78                     mInitialized = true;
     79                 }
     80                 if (mRegisteredReceiver) {
     81                     mContext.unregisterReceiver(mBroadcastReceiver);
     82                     mRegisteredReceiver = false;
     83                 }
     84             }
     85         }
     86     }
     87 
     88     /**
     89      * Return a content URI for a given {@link File}. Specific temporary
     90      * permissions for the content URI can be set with
     91      * {@link Context#grantUriPermission(String, Uri, int)}, or added
     92      * to an {@link Intent} by calling {@link Intent#setData(Uri) setData()} and then
     93      * {@link Intent#setFlags(int) setFlags()}; in both cases, the applicable flags are
     94      * {@link Intent#FLAG_GRANT_READ_URI_PERMISSION} and
     95      * {@link Intent#FLAG_GRANT_WRITE_URI_PERMISSION}. A FileProvider can only return a
     96      * <code>content</code> {@link Uri} for file paths defined in their <code>&lt;paths&gt;</code>
     97      * meta-data element. See the Class Overview for more information.
     98      *
     99      * @param context A {@link Context} for the current component.
    100      * @param authority The authority of a {@link FileProvider} defined in a
    101      *            {@code <provider>} element in your app's manifest.
    102      * @param file A {@link File} pointing to the filename for which you want a
    103      * <code>content</code> {@link Uri}.
    104      * @return A content URI for the file. Null if the user hasn't unlock the phone
    105      * @throws IllegalArgumentException When the given {@link File} is outside
    106      * the paths supported by the provider.
    107      */
    108     public static Uri getUriForFile(Context context, String authority, File file) {
    109         UserManager userManager = (UserManager) context.getSystemService(Context.USER_SERVICE);
    110         if (!userManager.isUserUnlocked()) {
    111             return null;
    112         }
    113         context = context.createCredentialProtectedStorageContext();
    114         return FileProvider.getUriForFile(context, authority, file);
    115     }
    116 }
    117