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      1 /*
      2  * Copyright (C) 2013 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.model;
     18 
     19 import android.content.ContentResolver;
     20 import android.os.Parcel;
     21 import android.os.Parcelable;
     22 import android.provider.DocumentsProvider;
     23 
     24 import java.io.DataInputStream;
     25 import java.io.DataOutputStream;
     26 import java.io.FileNotFoundException;
     27 import java.io.IOException;
     28 import java.net.ProtocolException;
     29 import java.util.Collection;
     30 import java.util.LinkedList;
     31 
     32 /**
     33  * Representation of a stack of {@link DocumentInfo}, usually the result of a
     34  * user-driven traversal.
     35  */
     36 public class DocumentStack extends LinkedList<DocumentInfo> implements Durable, Parcelable {
     37     private static final int VERSION_INIT = 1;
     38     private static final int VERSION_ADD_ROOT = 2;
     39 
     40     public RootInfo root;
     41 
     42     public String getTitle() {
     43         if (size() == 1 && root != null) {
     44             return root.title;
     45         } else if (size() > 1) {
     46             return peek().displayName;
     47         } else {
     48             return null;
     49         }
     50     }
     51 
     52     public boolean isRecents() {
     53         return size() == 0;
     54     }
     55 
     56     public void updateRoot(Collection<RootInfo> matchingRoots) throws FileNotFoundException {
     57         for (RootInfo root : matchingRoots) {
     58             if (root.equals(this.root)) {
     59                 this.root = root;
     60                 return;
     61             }
     62         }
     63         throw new FileNotFoundException("Failed to find matching root for " + root);
     64     }
     65 
     66     /**
     67      * Update a possibly stale restored stack against a live
     68      * {@link DocumentsProvider}.
     69      */
     70     public void updateDocuments(ContentResolver resolver) throws FileNotFoundException {
     71         for (DocumentInfo info : this) {
     72             info.updateSelf(resolver);
     73         }
     74     }
     75 
     76     /**
     77      * Build key that uniquely identifies this stack. It omits most of the raw
     78      * details included in {@link #write(DataOutputStream)}, since they change
     79      * too regularly to be used as a key.
     80      */
     81     public String buildKey() {
     82         final StringBuilder builder = new StringBuilder();
     83         if (root != null) {
     84             builder.append(root.authority).append('#');
     85             builder.append(root.rootId).append('#');
     86         } else {
     87             builder.append("[null]").append('#');
     88         }
     89         for (DocumentInfo doc : this) {
     90             builder.append(doc.documentId).append('#');
     91         }
     92         return builder.toString();
     93     }
     94 
     95     @Override
     96     public void reset() {
     97         clear();
     98         root = null;
     99     }
    100 
    101     @Override
    102     public void read(DataInputStream in) throws IOException {
    103         final int version = in.readInt();
    104         switch (version) {
    105             case VERSION_INIT:
    106                 throw new ProtocolException("Ignored upgrade");
    107             case VERSION_ADD_ROOT:
    108                 if (in.readBoolean()) {
    109                     root = new RootInfo();
    110                     root.read(in);
    111                 }
    112                 final int size = in.readInt();
    113                 for (int i = 0; i < size; i++) {
    114                     final DocumentInfo doc = new DocumentInfo();
    115                     doc.read(in);
    116                     add(doc);
    117                 }
    118                 break;
    119             default:
    120                 throw new ProtocolException("Unknown version " + version);
    121         }
    122     }
    123 
    124     @Override
    125     public void write(DataOutputStream out) throws IOException {
    126         out.writeInt(VERSION_ADD_ROOT);
    127         if (root != null) {
    128             out.writeBoolean(true);
    129             root.write(out);
    130         } else {
    131             out.writeBoolean(false);
    132         }
    133         final int size = size();
    134         out.writeInt(size);
    135         for (int i = 0; i < size; i++) {
    136             final DocumentInfo doc = get(i);
    137             doc.write(out);
    138         }
    139     }
    140 
    141     @Override
    142     public int describeContents() {
    143         return 0;
    144     }
    145 
    146     @Override
    147     public void writeToParcel(Parcel dest, int flags) {
    148         DurableUtils.writeToParcel(dest, this);
    149     }
    150 
    151     public static final Creator<DocumentStack> CREATOR = new Creator<DocumentStack>() {
    152         @Override
    153         public DocumentStack createFromParcel(Parcel in) {
    154             final DocumentStack stack = new DocumentStack();
    155             DurableUtils.readFromParcel(in, stack);
    156             return stack;
    157         }
    158 
    159         @Override
    160         public DocumentStack[] newArray(int size) {
    161             return new DocumentStack[size];
    162         }
    163     };
    164 }
    165