Home | History | Annotate | Download | only in model
      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 static com.android.documentsui.Shared.TAG;
     20 
     21 import android.os.BadParcelableException;
     22 import android.os.Parcel;
     23 import android.util.Log;
     24 
     25 import java.io.ByteArrayInputStream;
     26 import java.io.ByteArrayOutputStream;
     27 import java.io.DataInputStream;
     28 import java.io.DataOutputStream;
     29 import java.io.IOException;
     30 
     31 public class DurableUtils {
     32     public static <D extends Durable> byte[] writeToArray(D d) throws IOException {
     33         final ByteArrayOutputStream out = new ByteArrayOutputStream();
     34         d.write(new DataOutputStream(out));
     35         return out.toByteArray();
     36     }
     37 
     38     public static <D extends Durable> D readFromArray(byte[] data, D d) throws IOException {
     39         if (data == null) throw new IOException("Missing data");
     40         final ByteArrayInputStream in = new ByteArrayInputStream(data);
     41         d.reset();
     42         try {
     43             d.read(new DataInputStream(in));
     44         } catch (IOException e) {
     45             d.reset();
     46             throw e;
     47         }
     48         return d;
     49     }
     50 
     51     public static <D extends Durable> byte[] writeToArrayOrNull(D d) {
     52         try {
     53             return writeToArray(d);
     54         } catch (IOException e) {
     55             Log.w(TAG, "Failed to write", e);
     56             return null;
     57         }
     58     }
     59 
     60     public static <D extends Durable> D readFromArrayOrNull(byte[] data, D d) {
     61         try {
     62             return readFromArray(data, d);
     63         } catch (IOException e) {
     64             Log.w(TAG, "Failed to read", e);
     65             return null;
     66         }
     67     }
     68 
     69     public static <D extends Durable> void writeToParcel(Parcel parcel, D d) {
     70         try {
     71             parcel.writeByteArray(writeToArray(d));
     72         } catch (IOException e) {
     73             throw new BadParcelableException(e);
     74         }
     75     }
     76 
     77     public static <D extends Durable> D readFromParcel(Parcel parcel, D d) {
     78         try {
     79             return readFromArray(parcel.createByteArray(), d);
     80         } catch (IOException e) {
     81             throw new BadParcelableException(e);
     82         }
     83     }
     84 
     85     public static void writeNullableString(DataOutputStream out, String value) throws IOException {
     86         if (value != null) {
     87             out.write(1);
     88             out.writeUTF(value);
     89         } else {
     90             out.write(0);
     91         }
     92     }
     93 
     94     public static String readNullableString(DataInputStream in) throws IOException {
     95         if (in.read() != 0) {
     96             return in.readUTF();
     97         } else {
     98             return null;
     99         }
    100     }
    101 }
    102