1 /* 2 * Copyright (C) 2014 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 android.service.persistentdata; 18 19 import android.annotation.SystemApi; 20 import android.os.RemoteException; 21 import android.util.Slog; 22 23 /** 24 * Interface for reading and writing data blocks to a persistent partition. 25 * 26 * Allows writing one block at a time. Namely, each time 27 * {@link PersistentDataBlockManager#write(byte[])} 28 * is called, it will overwite the data that was previously written on the block. 29 * 30 * Clients can query the size of the currently written block via 31 * {@link PersistentDataBlockManager#getDataBlockSize()}. 32 * 33 * Clients can query the maximum size for a block via 34 * {@link PersistentDataBlockManager#getMaximumDataBlockSize()} 35 * 36 * Clients can read the currently written block by invoking 37 * {@link PersistentDataBlockManager#read()}. 38 * 39 * @hide 40 */ 41 @SystemApi 42 public class PersistentDataBlockManager { 43 private static final String TAG = PersistentDataBlockManager.class.getSimpleName(); 44 private IPersistentDataBlockService sService; 45 46 public PersistentDataBlockManager(IPersistentDataBlockService service) { 47 sService = service; 48 } 49 50 /** 51 * Writes {@code data} to the persistent partition. Previously written data 52 * will be overwritten. This data will persist across factory resets. 53 * 54 * Returns the number of bytes written or -1 on error. If the block is too big 55 * to fit on the partition, returns -MAX_BLOCK_SIZE. 56 * 57 * @param data the data to write 58 */ 59 public int write(byte[] data) { 60 try { 61 return sService.write(data); 62 } catch (RemoteException e) { 63 onError("writing data"); 64 return -1; 65 } 66 } 67 68 /** 69 * Returns the data block stored on the persistent partition. 70 */ 71 public byte[] read() { 72 try { 73 return sService.read(); 74 } catch (RemoteException e) { 75 onError("reading data"); 76 return null; 77 } 78 } 79 80 /** 81 * Retrieves the size of the block currently written to the persistent partition. 82 * 83 * Return -1 on error. 84 */ 85 public int getDataBlockSize() { 86 try { 87 return sService.getDataBlockSize(); 88 } catch (RemoteException e) { 89 onError("getting data block size"); 90 return -1; 91 } 92 } 93 94 /** 95 * Retrieves the maximum size allowed for a data block. 96 * 97 * Returns -1 on error. 98 */ 99 public long getMaximumDataBlockSize() { 100 try { 101 return sService.getMaximumDataBlockSize(); 102 } catch (RemoteException e) { 103 onError("getting maximum data block size"); 104 return -1; 105 } 106 } 107 108 /** 109 * Zeroes the previously written block in its entirety. Calling this method 110 * will erase all data written to the persistent data partition. 111 */ 112 public void wipe() { 113 try { 114 sService.wipe(); 115 } catch (RemoteException e) { 116 onError("wiping persistent partition"); 117 } 118 } 119 120 /** 121 * Writes a byte enabling or disabling the ability to "OEM unlock" the device. 122 */ 123 public void setOemUnlockEnabled(boolean enabled) { 124 try { 125 sService.setOemUnlockEnabled(enabled); 126 } catch (RemoteException e) { 127 onError("setting OEM unlock enabled to " + enabled); 128 } 129 } 130 131 /** 132 * Returns whether or not "OEM unlock" is enabled or disabled on this device. 133 */ 134 public boolean getOemUnlockEnabled() { 135 try { 136 return sService.getOemUnlockEnabled(); 137 } catch (RemoteException e) { 138 onError("getting OEM unlock enabled bit"); 139 return false; 140 } 141 } 142 143 private void onError(String msg) { 144 Slog.v(TAG, "Remote exception while " + msg); 145 } 146 } 147