DropBoxManager.java revision 3685db7f5dd8a830a4e096404d4924e12697fb78
1/* 2 * Copyright (C) 2009 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 17package android.os; 18 19import android.util.Log; 20 21import com.android.internal.os.IDropBoxManagerService; 22 23import java.io.ByteArrayInputStream; 24import java.io.File; 25import java.io.FileInputStream; 26import java.io.IOException; 27import java.io.InputStream; 28import java.util.zip.GZIPInputStream; 29 30/** 31 * Enqueues chunks of data (from various sources -- application crashes, kernel 32 * log records, etc.). The queue is size bounded and will drop old data if the 33 * enqueued data exceeds the maximum size. You can think of this as a 34 * persistent, system-wide, blob-oriented "logcat". 35 * 36 * <p>You can obtain an instance of this class by calling 37 * {@link android.content.Context#getSystemService} 38 * with {@link android.content.Context#DROPBOX_SERVICE}. 39 * 40 * <p>DropBoxManager entries are not sent anywhere directly, but other system 41 * services and debugging tools may scan and upload entries for processing. 42 */ 43public class DropBoxManager { 44 private static final String TAG = "DropBoxManager"; 45 private final IDropBoxManagerService mService; 46 47 /** Flag value: Entry's content was deleted to save space. */ 48 public static final int IS_EMPTY = 1; 49 50 /** Flag value: Content is human-readable UTF-8 text (can be combined with IS_GZIPPED). */ 51 public static final int IS_TEXT = 2; 52 53 /** Flag value: Content can be decompressed with {@link java.util.zip.GZIPOutputStream}. */ 54 public static final int IS_GZIPPED = 4; 55 56 /** Flag value for serialization only: Value is a byte array, not a file descriptor */ 57 private static final int HAS_BYTE_ARRAY = 8; 58 59 /** 60 * A single entry retrieved from the drop box. 61 * This may include a reference to a stream, so you must call 62 * {@link #close()} when you are done using it. 63 */ 64 public static class Entry implements Parcelable { 65 private final String mTag; 66 private final long mTimeMillis; 67 68 private final byte[] mData; 69 private final ParcelFileDescriptor mFileDescriptor; 70 private final int mFlags; 71 72 /** Create a new empty Entry with no contents. */ 73 public Entry(String tag, long millis) { 74 if (tag == null) throw new NullPointerException("tag == null"); 75 76 mTag = tag; 77 mTimeMillis = millis; 78 mData = null; 79 mFileDescriptor = null; 80 mFlags = IS_EMPTY; 81 } 82 83 /** Create a new Entry with plain text contents. */ 84 public Entry(String tag, long millis, String text) { 85 if (tag == null) throw new NullPointerException("tag == null"); 86 if (text == null) throw new NullPointerException("text == null"); 87 88 mTag = tag; 89 mTimeMillis = millis; 90 mData = text.getBytes(); 91 mFileDescriptor = null; 92 mFlags = IS_TEXT; 93 } 94 95 /** 96 * Create a new Entry with byte array contents. 97 * The data array must not be modified after creating this entry. 98 */ 99 public Entry(String tag, long millis, byte[] data, int flags) { 100 if (tag == null) throw new NullPointerException("tag == null"); 101 if (((flags & IS_EMPTY) != 0) != (data == null)) { 102 throw new IllegalArgumentException("Bad flags: " + flags); 103 } 104 105 mTag = tag; 106 mTimeMillis = millis; 107 mData = data; 108 mFileDescriptor = null; 109 mFlags = flags; 110 } 111 112 /** 113 * Create a new Entry with streaming data contents. 114 * Takes ownership of the ParcelFileDescriptor. 115 */ 116 public Entry(String tag, long millis, ParcelFileDescriptor data, int flags) { 117 if (tag == null) throw new NullPointerException("tag == null"); 118 if (((flags & IS_EMPTY) != 0) != (data == null)) { 119 throw new IllegalArgumentException("Bad flags: " + flags); 120 } 121 122 mTag = tag; 123 mTimeMillis = millis; 124 mData = null; 125 mFileDescriptor = data; 126 mFlags = flags; 127 } 128 129 /** 130 * Create a new Entry with the contents read from a file. 131 * The file will be read when the entry's contents are requested. 132 */ 133 public Entry(String tag, long millis, File data, int flags) throws IOException { 134 if (tag == null) throw new NullPointerException("tag == null"); 135 if ((flags & IS_EMPTY) != 0) throw new IllegalArgumentException("Bad flags: " + flags); 136 137 mTag = tag; 138 mTimeMillis = millis; 139 mData = null; 140 mFileDescriptor = ParcelFileDescriptor.open(data, ParcelFileDescriptor.MODE_READ_ONLY); 141 mFlags = flags; 142 } 143 144 /** Close the input stream associated with this entry. */ 145 public void close() { 146 try { if (mFileDescriptor != null) mFileDescriptor.close(); } catch (IOException e) { } 147 } 148 149 /** @return the tag originally attached to the entry. */ 150 public String getTag() { return mTag; } 151 152 /** @return time when the entry was originally created. */ 153 public long getTimeMillis() { return mTimeMillis; } 154 155 /** @return flags describing the content returned by @{link #getInputStream()}. */ 156 public int getFlags() { return mFlags & ~IS_GZIPPED; } // getInputStream() decompresses. 157 158 /** 159 * @param maxBytes of string to return (will truncate at this length). 160 * @return the uncompressed text contents of the entry, null if the entry is not text. 161 */ 162 public String getText(int maxBytes) { 163 if ((mFlags & IS_TEXT) == 0) return null; 164 if (mData != null) return new String(mData, 0, Math.min(maxBytes, mData.length)); 165 166 InputStream is = null; 167 try { 168 is = getInputStream(); 169 if (is == null) return null; 170 byte[] buf = new byte[maxBytes]; 171 return new String(buf, 0, Math.max(0, is.read(buf))); 172 } catch (IOException e) { 173 return null; 174 } finally { 175 try { if (is != null) is.close(); } catch (IOException e) {} 176 } 177 } 178 179 /** @return the uncompressed contents of the entry, or null if the contents were lost */ 180 public InputStream getInputStream() throws IOException { 181 InputStream is; 182 if (mData != null) { 183 is = new ByteArrayInputStream(mData); 184 } else if (mFileDescriptor != null) { 185 is = new ParcelFileDescriptor.AutoCloseInputStream(mFileDescriptor); 186 } else { 187 return null; 188 } 189 return (mFlags & IS_GZIPPED) != 0 ? new GZIPInputStream(is) : is; 190 } 191 192 public static final Parcelable.Creator<Entry> CREATOR = new Parcelable.Creator() { 193 public Entry[] newArray(int size) { return new Entry[size]; } 194 public Entry createFromParcel(Parcel in) { 195 String tag = in.readString(); 196 long millis = in.readLong(); 197 int flags = in.readInt(); 198 if ((flags & HAS_BYTE_ARRAY) != 0) { 199 return new Entry(tag, millis, in.createByteArray(), flags & ~HAS_BYTE_ARRAY); 200 } else { 201 return new Entry(tag, millis, in.readFileDescriptor(), flags); 202 } 203 } 204 }; 205 206 public int describeContents() { 207 return mFileDescriptor != null ? Parcelable.CONTENTS_FILE_DESCRIPTOR : 0; 208 } 209 210 public void writeToParcel(Parcel out, int flags) { 211 out.writeString(mTag); 212 out.writeLong(mTimeMillis); 213 if (mFileDescriptor != null) { 214 out.writeInt(mFlags & ~HAS_BYTE_ARRAY); // Clear bit just to be safe 215 mFileDescriptor.writeToParcel(out, flags); 216 } else { 217 out.writeInt(mFlags | HAS_BYTE_ARRAY); 218 out.writeByteArray(mData); 219 } 220 } 221 } 222 223 /** {@hide} */ 224 public DropBoxManager(IDropBoxManagerService service) { mService = service; } 225 226 /** 227 * Create a dummy instance for testing. All methods will fail unless 228 * overridden with an appropriate mock implementation. To obtain a 229 * functional instance, use {@link android.content.Context#getSystemService}. 230 */ 231 protected DropBoxManager() { mService = null; } 232 233 /** 234 * Stores human-readable text. The data may be discarded eventually (or even 235 * immediately) if space is limited, or ignored entirely if the tag has been 236 * blocked (see {@link #isTagEnabled}). 237 * 238 * @param tag describing the type of entry being stored 239 * @param data value to store 240 */ 241 public void addText(String tag, String data) { 242 try { mService.add(new Entry(tag, 0, data)); } catch (RemoteException e) {} 243 } 244 245 /** 246 * Stores binary data, which may be ignored or discarded as with {@link #addText}. 247 * 248 * @param tag describing the type of entry being stored 249 * @param data value to store 250 * @param flags describing the data 251 */ 252 public void addData(String tag, byte[] data, int flags) { 253 if (data == null) throw new NullPointerException("data == null"); 254 try { mService.add(new Entry(tag, 0, data, flags)); } catch (RemoteException e) {} 255 } 256 257 /** 258 * Stores the contents of a file, which may be ignored or discarded as with 259 * {@link #addText}. 260 * 261 * @param tag describing the type of entry being stored 262 * @param file to read from 263 * @param flags describing the data 264 * @throws IOException if the file can't be opened 265 */ 266 public void addFile(String tag, File file, int flags) throws IOException { 267 if (file == null) throw new NullPointerException("file == null"); 268 Entry entry = new Entry(tag, 0, file, flags); 269 try { 270 mService.add(entry); 271 } catch (RemoteException e) { 272 // ignore 273 } finally { 274 entry.close(); 275 } 276 } 277 278 /** 279 * Checks any blacklists (set in system settings) to see whether a certain 280 * tag is allowed. Entries with disabled tags will be dropped immediately, 281 * so you can save the work of actually constructing and sending the data. 282 * 283 * @param tag that would be used in {@link #addText} or {@link #addFile} 284 * @return whether events with that tag would be accepted 285 */ 286 public boolean isTagEnabled(String tag) { 287 try { return mService.isTagEnabled(tag); } catch (RemoteException e) { return false; } 288 } 289 290 /** 291 * Gets the next entry from the drop box *after* the specified time. 292 * Requires android.permission.READ_LOGS. You must always call 293 * {@link Entry#close()} on the return value! 294 * 295 * @param tag of entry to look for, null for all tags 296 * @param msec time of the last entry seen 297 * @return the next entry, or null if there are no more entries 298 */ 299 public Entry getNextEntry(String tag, long msec) { 300 try { return mService.getNextEntry(tag, msec); } catch (RemoteException e) { return null; } 301 } 302 303 // TODO: It may be useful to have some sort of notification mechanism 304 // when data is added to the dropbox, for demand-driven readers -- 305 // for now readers need to poll the dropbox to find new data. 306} 307