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      1 /*
      2  * Copyright (C) 2016 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 
     17 package com.android.documentsui;
     18 
     19 import android.app.Activity;
     20 import android.content.BroadcastReceiver;
     21 import android.content.Context;
     22 import android.content.Intent;
     23 import android.content.IntentFilter;
     24 import android.net.Uri;
     25 import android.support.v4.content.LocalBroadcastManager;
     26 
     27 import com.android.documentsui.AbstractActionHandler.CommonAddons;
     28 import com.android.documentsui.base.DocumentInfo;
     29 import com.android.documentsui.base.PairedTask;
     30 import com.android.documentsui.base.RootInfo;
     31 import com.android.documentsui.base.State;
     32 import com.android.documentsui.dirlist.AnimationView;
     33 import com.android.documentsui.queries.SearchViewManager;
     34 import com.android.documentsui.roots.ProvidersAccess;
     35 
     36 import java.util.Collection;
     37 
     38 /**
     39  * Monitors roots change and refresh the page when necessary.
     40  */
     41 final class RootsMonitor<T extends Activity & CommonAddons> {
     42 
     43     private final LocalBroadcastManager mManager;
     44     private final BroadcastReceiver mReceiver;
     45 
     46     RootsMonitor(
     47             final T activity,
     48             final ActionHandler actions,
     49             final ProvidersAccess providers,
     50             final DocumentsAccess docs,
     51             final State state,
     52             final SearchViewManager searchMgr,
     53             final Runnable actionModeFinisher) {
     54         mManager = LocalBroadcastManager.getInstance(activity);
     55 
     56         mReceiver = new BroadcastReceiver() {
     57             @Override
     58             public void onReceive(Context context, Intent intent) {
     59                 new HandleRootsChangedTask<>(
     60                         activity,
     61                         actions,
     62                         providers,
     63                         docs,
     64                         state,
     65                         searchMgr,
     66                         actionModeFinisher).execute(activity.getCurrentRoot());
     67             }
     68         };
     69     }
     70 
     71     void start() {
     72         mManager.registerReceiver(mReceiver, new IntentFilter(ProvidersAccess.BROADCAST_ACTION));
     73     }
     74 
     75     void stop() {
     76         mManager.unregisterReceiver(mReceiver);
     77     }
     78 
     79     private static class HandleRootsChangedTask<T extends Activity & CommonAddons>
     80             extends PairedTask<T, RootInfo, RootInfo> {
     81         private final ActionHandler mActions;
     82         private final ProvidersAccess mProviders;
     83         private final DocumentsAccess mDocs;
     84         private final State mState;
     85         private final SearchViewManager mSearchMgr;
     86         private final Runnable mActionModeFinisher;
     87 
     88         private RootInfo mCurrentRoot;
     89         private DocumentInfo mDefaultRootDocument;
     90 
     91         private HandleRootsChangedTask(
     92                 T activity,
     93                 ActionHandler actions,
     94                 ProvidersAccess providers,
     95                 DocumentsAccess docs,
     96                 State state,
     97                 SearchViewManager searchMgr,
     98                 Runnable actionModeFinisher) {
     99             super(activity);
    100             mActions = actions;
    101             mProviders = providers;
    102             mDocs = docs;
    103             mState = state;
    104             mSearchMgr = searchMgr;
    105             mActionModeFinisher = actionModeFinisher;
    106         }
    107 
    108         @Override
    109         protected RootInfo run(RootInfo... roots) {
    110             assert (roots.length == 1);
    111             mCurrentRoot = roots[0];
    112             final Collection<RootInfo> cachedRoots = mProviders.getRootsBlocking();
    113             for (final RootInfo root : cachedRoots) {
    114                 if (root.getUri().equals(mCurrentRoot.getUri())) {
    115                     // We don't need to change the current root as the current root was not removed.
    116                     return null;
    117                 }
    118             }
    119 
    120             // Choose the default root.
    121             final RootInfo defaultRoot = mProviders.getDefaultRootBlocking(mState);
    122             assert (defaultRoot != null);
    123             if (!defaultRoot.isRecents()) {
    124                 mDefaultRootDocument = mDocs.getRootDocument(defaultRoot);
    125             }
    126             return defaultRoot;
    127         }
    128 
    129         @Override
    130         protected void finish(RootInfo defaultRoot) {
    131             if (defaultRoot == null) {
    132                 return;
    133             }
    134 
    135             // If the activity has been launched for the specific root and it is removed, finish the
    136             // activity.
    137             final Uri uri = mOwner.getIntent().getData();
    138             if (uri != null && uri.equals(mCurrentRoot.getUri())) {
    139                 mOwner.finish();
    140                 return;
    141             }
    142 
    143             // Clean action mode before changing root.
    144             mActionModeFinisher.run();
    145 
    146             // Clear entire backstack and start in new root.
    147             mState.stack.changeRoot(defaultRoot);
    148             mSearchMgr.update(mState.stack);
    149 
    150             if (defaultRoot.isRecents()) {
    151                 mOwner.refreshCurrentRootAndDirectory(AnimationView.ANIM_NONE);
    152             } else {
    153                 mActions.openContainerDocument(mDefaultRootDocument);
    154             }
    155         }
    156     }
    157 }
    158