DropBoxManager.java revision 14418945bdc7a9c2e1cba8deaac5cb6dddfd6412
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 /** 57 * A single entry retrieved from the drop box. 58 * This may include a reference to a stream, so you must call 59 * {@link #close()} when you are done using it. 60 */ 61 public static class Entry implements Parcelable { 62 private final String mTag; 63 private final long mTimeMillis; 64 65 private final byte[] mData; 66 private final ParcelFileDescriptor mFileDescriptor; 67 private final int mFlags; 68 69 /** Create a new empty Entry with no contents. */ 70 public Entry(String tag, long millis) { 71 this(tag, millis, (Object) null, IS_EMPTY); 72 } 73 74 /** Create a new Entry with plain text contents. */ 75 public Entry(String tag, long millis, String text) { 76 this(tag, millis, (Object) text.getBytes(), IS_TEXT); 77 } 78 79 /** 80 * Create a new Entry with byte array contents. 81 * The data array must not be modified after creating this entry. 82 */ 83 public Entry(String tag, long millis, byte[] data, int flags) { 84 this(tag, millis, (Object) data, flags); 85 } 86 87 /** 88 * Create a new Entry with streaming data contents. 89 * Takes ownership of the ParcelFileDescriptor. 90 */ 91 public Entry(String tag, long millis, ParcelFileDescriptor data, int flags) { 92 this(tag, millis, (Object) data, flags); 93 } 94 95 /** 96 * Create a new Entry with the contents read from a file. 97 * The file will be read when the entry's contents are requested. 98 */ 99 public Entry(String tag, long millis, File data, int flags) throws IOException { 100 this(tag, millis, (Object) ParcelFileDescriptor.open( 101 data, ParcelFileDescriptor.MODE_READ_ONLY), flags); 102 } 103 104 /** Internal constructor for CREATOR.createFromParcel(). */ 105 private Entry(String tag, long millis, Object value, int flags) { 106 if (tag == null) throw new NullPointerException(); 107 if (((flags & IS_EMPTY) != 0) != (value == null)) throw new IllegalArgumentException(); 108 109 mTag = tag; 110 mTimeMillis = millis; 111 mFlags = flags; 112 113 if (value == null) { 114 mData = null; 115 mFileDescriptor = null; 116 } else if (value instanceof byte[]) { 117 mData = (byte[]) value; 118 mFileDescriptor = null; 119 } else if (value instanceof ParcelFileDescriptor) { 120 mData = null; 121 mFileDescriptor = (ParcelFileDescriptor) value; 122 } else { 123 throw new IllegalArgumentException(); 124 } 125 } 126 127 /** Close the input stream associated with this entry. */ 128 public void close() { 129 try { if (mFileDescriptor != null) mFileDescriptor.close(); } catch (IOException e) { } 130 } 131 132 /** @return the tag originally attached to the entry. */ 133 public String getTag() { return mTag; } 134 135 /** @return time when the entry was originally created. */ 136 public long getTimeMillis() { return mTimeMillis; } 137 138 /** @return flags describing the content returned by @{link #getInputStream()}. */ 139 public int getFlags() { return mFlags & ~IS_GZIPPED; } // getInputStream() decompresses. 140 141 /** 142 * @param maxBytes of string to return (will truncate at this length). 143 * @return the uncompressed text contents of the entry, null if the entry is not text. 144 */ 145 public String getText(int maxBytes) { 146 if ((mFlags & IS_TEXT) == 0) return null; 147 if (mData != null) return new String(mData, 0, Math.min(maxBytes, mData.length)); 148 149 InputStream is = null; 150 try { 151 is = getInputStream(); 152 byte[] buf = new byte[maxBytes]; 153 return new String(buf, 0, Math.max(0, is.read(buf))); 154 } catch (IOException e) { 155 return null; 156 } finally { 157 try { if (is != null) is.close(); } catch (IOException e) {} 158 } 159 } 160 161 /** @return the uncompressed contents of the entry, or null if the contents were lost */ 162 public InputStream getInputStream() throws IOException { 163 InputStream is; 164 if (mData != null) { 165 is = new ByteArrayInputStream(mData); 166 } else if (mFileDescriptor != null) { 167 is = new ParcelFileDescriptor.AutoCloseInputStream(mFileDescriptor); 168 } else { 169 return null; 170 } 171 return (mFlags & IS_GZIPPED) != 0 ? new GZIPInputStream(is) : is; 172 } 173 174 public static final Parcelable.Creator<Entry> CREATOR = new Parcelable.Creator() { 175 public Entry[] newArray(int size) { return new Entry[size]; } 176 public Entry createFromParcel(Parcel in) { 177 return new Entry( 178 in.readString(), in.readLong(), in.readValue(null), in.readInt()); 179 } 180 }; 181 182 public int describeContents() { 183 return mFileDescriptor != null ? Parcelable.CONTENTS_FILE_DESCRIPTOR : 0; 184 } 185 186 public void writeToParcel(Parcel out, int flags) { 187 out.writeString(mTag); 188 out.writeLong(mTimeMillis); 189 if (mFileDescriptor != null) { 190 out.writeValue(mFileDescriptor); 191 } else { 192 out.writeValue(mData); 193 } 194 out.writeInt(mFlags); 195 } 196 } 197 198 /** {@hide} */ 199 public DropBoxManager(IDropBoxManagerService service) { mService = service; } 200 201 /** 202 * Create a dummy instance for testing. All methods will fail unless 203 * overridden with an appropriate mock implementation. To obtain a 204 * functional instance, use {@link android.content.Context#getSystemService}. 205 */ 206 protected DropBoxManager() { mService = null; } 207 208 /** 209 * Stores human-readable text. The data may be discarded eventually (or even 210 * immediately) if space is limited, or ignored entirely if the tag has been 211 * blocked (see {@link #isTagEnabled}). 212 * 213 * @param tag describing the type of entry being stored 214 * @param data value to store 215 */ 216 public void addText(String tag, String data) { 217 try { mService.add(new Entry(tag, 0, data)); } catch (RemoteException e) {} 218 } 219 220 /** 221 * Stores binary data, which may be ignored or discarded as with {@link #addText}. 222 * 223 * @param tag describing the type of entry being stored 224 * @param data value to store 225 * @param flags describing the data 226 */ 227 public void addData(String tag, byte[] data, int flags) { 228 if (data == null) throw new NullPointerException(); 229 try { mService.add(new Entry(tag, 0, data, flags)); } catch (RemoteException e) {} 230 } 231 232 /** 233 * Stores the contents of a file, which may be ignored or discarded as with 234 * {@link #addText}. 235 * 236 * @param tag describing the type of entry being stored 237 * @param file to read from 238 * @param flags describing the data 239 * @throws IOException if the file can't be opened 240 */ 241 public void addFile(String tag, File file, int flags) throws IOException { 242 if (file == null) throw new NullPointerException(); 243 Entry entry = new Entry(tag, 0, file, flags); 244 try { 245 mService.add(entry); 246 } catch (RemoteException e) { 247 // ignore 248 } finally { 249 entry.close(); 250 } 251 } 252 253 /** 254 * Checks any blacklists (set in system settings) to see whether a certain 255 * tag is allowed. Entries with disabled tags will be dropped immediately, 256 * so you can save the work of actually constructing and sending the data. 257 * 258 * @param tag that would be used in {@link #addText} or {@link #addFile} 259 * @return whether events with that tag would be accepted 260 */ 261 public boolean isTagEnabled(String tag) { 262 try { return mService.isTagEnabled(tag); } catch (RemoteException e) { return false; } 263 } 264 265 /** 266 * Gets the next entry from the drop box *after* the specified time. 267 * Requires android.permission.READ_LOGS. You must always call 268 * {@link Entry#close()} on the return value! 269 * 270 * @param tag of entry to look for, null for all tags 271 * @param msec time of the last entry seen 272 * @return the next entry, or null if there are no more entries 273 */ 274 public Entry getNextEntry(String tag, long msec) { 275 try { return mService.getNextEntry(tag, msec); } catch (RemoteException e) { return null; } 276 } 277 278 // TODO: It may be useful to have some sort of notification mechanism 279 // when data is added to the dropbox, for demand-driven readers -- 280 // for now readers need to poll the dropbox to find new data. 281} 282