AttachmentProvider.java revision 86753bc41c3957b3bba49846f6603ed29f13c84e
1/* 2 * Copyright (C) 2008 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 com.android.email.provider; 18 19import com.android.email.Email; 20import com.android.email.mail.internet.MimeUtility; 21import com.android.email.provider.EmailContent.Attachment; 22import com.android.email.provider.EmailContent.AttachmentColumns; 23import com.android.email.provider.EmailContent.Message; 24import com.android.email.provider.EmailContent.MessageColumns; 25 26import android.content.ContentProvider; 27import android.content.ContentResolver; 28import android.content.ContentUris; 29import android.content.ContentValues; 30import android.content.Context; 31import android.database.Cursor; 32import android.database.MatrixCursor; 33import android.graphics.Bitmap; 34import android.graphics.BitmapFactory; 35import android.net.Uri; 36import android.os.Binder; 37import android.os.ParcelFileDescriptor; 38import android.text.TextUtils; 39import android.util.Log; 40import android.webkit.MimeTypeMap; 41 42import java.io.File; 43import java.io.FileNotFoundException; 44import java.io.FileOutputStream; 45import java.io.IOException; 46import java.io.InputStream; 47import java.util.List; 48 49/* 50 * A simple ContentProvider that allows file access to Email's attachments. 51 * 52 * The URI scheme is as follows. For raw file access: 53 * content://com.android.email.attachmentprovider/acct#/attach#/RAW 54 * 55 * And for access to thumbnails: 56 * content://com.android.email.attachmentprovider/acct#/attach#/THUMBNAIL/width#/height# 57 * 58 * The on-disk (storage) schema is as follows. 59 * 60 * Attachments are stored at: <database-path>/account#.db_att/item# 61 * Thumbnails are stored at: <cache-path>/thmb_account#_item# 62 * 63 * Using the standard application context, account #10 and attachment # 20, this would be: 64 * /data/data/com.android.email/databases/10.db_att/20 65 * /data/data/com.android.email/cache/thmb_10_20 66 */ 67public class AttachmentProvider extends ContentProvider { 68 69 public static final String AUTHORITY = "com.android.email.attachmentprovider"; 70 public static final Uri CONTENT_URI = Uri.parse( "content://" + AUTHORITY); 71 72 private static final String FORMAT_RAW = "RAW"; 73 private static final String FORMAT_THUMBNAIL = "THUMBNAIL"; 74 75 public static class AttachmentProviderColumns { 76 public static final String _ID = "_id"; 77 public static final String DATA = "_data"; 78 public static final String DISPLAY_NAME = "_display_name"; 79 public static final String SIZE = "_size"; 80 } 81 82 private static final String[] MIME_TYPE_PROJECTION = new String[] { 83 AttachmentColumns.MIME_TYPE, AttachmentColumns.FILENAME }; 84 private static final int MIME_TYPE_COLUMN_MIME_TYPE = 0; 85 private static final int MIME_TYPE_COLUMN_FILENAME = 1; 86 87 private static final String[] PROJECTION_QUERY = new String[] { AttachmentColumns.FILENAME, 88 AttachmentColumns.SIZE, AttachmentColumns.CONTENT_URI }; 89 90 public static Uri getAttachmentUri(long accountId, long id) { 91 return CONTENT_URI.buildUpon() 92 .appendPath(Long.toString(accountId)) 93 .appendPath(Long.toString(id)) 94 .appendPath(FORMAT_RAW) 95 .build(); 96 } 97 98 public static Uri getAttachmentThumbnailUri(long accountId, long id, 99 int width, int height) { 100 return CONTENT_URI.buildUpon() 101 .appendPath(Long.toString(accountId)) 102 .appendPath(Long.toString(id)) 103 .appendPath(FORMAT_THUMBNAIL) 104 .appendPath(Integer.toString(width)) 105 .appendPath(Integer.toString(height)) 106 .build(); 107 } 108 109 /** 110 * Return the filename for a given attachment. This should be used by any code that is 111 * going to *write* attachments. 112 * 113 * This does not create or write the file, or even the directories. It simply builds 114 * the filename that should be used. 115 */ 116 public static File getAttachmentFilename(Context context, long accountId, long attachmentId) { 117 return new File(getAttachmentDirectory(context, accountId), Long.toString(attachmentId)); 118 } 119 120 /** 121 * Return the directory for a given attachment. This should be used by any code that is 122 * going to *write* attachments. 123 * 124 * This does not create or write the directory. It simply builds the pathname that should be 125 * used. 126 */ 127 public static File getAttachmentDirectory(Context context, long accountId) { 128 return context.getDatabasePath(accountId + ".db_att"); 129 } 130 131 @Override 132 public boolean onCreate() { 133 /* 134 * We use the cache dir as a temporary directory (since Android doesn't give us one) so 135 * on startup we'll clean up any .tmp files from the last run. 136 */ 137 File[] files = getContext().getCacheDir().listFiles(); 138 for (File file : files) { 139 String filename = file.getName(); 140 if (filename.endsWith(".tmp") || filename.startsWith("thmb_")) { 141 file.delete(); 142 } 143 } 144 return true; 145 } 146 147 /** 148 * Returns the mime type for a given attachment. There are three possible results: 149 * - If thumbnail Uri, always returns "image/png" (even if there's no attachment) 150 * - If the attachment does not exist, returns null 151 * - Returns the mime type of the attachment 152 */ 153 @Override 154 public String getType(Uri uri) { 155 long callingId = Binder.clearCallingIdentity(); 156 try { 157 List<String> segments = uri.getPathSegments(); 158 String id = segments.get(1); 159 String format = segments.get(2); 160 if (FORMAT_THUMBNAIL.equals(format)) { 161 return "image/png"; 162 } else { 163 uri = ContentUris.withAppendedId(Attachment.CONTENT_URI, Long.parseLong(id)); 164 Cursor c = getContext().getContentResolver().query(uri, MIME_TYPE_PROJECTION, 165 null, null, null); 166 try { 167 if (c.moveToFirst()) { 168 String mimeType = c.getString(MIME_TYPE_COLUMN_MIME_TYPE); 169 String fileName = c.getString(MIME_TYPE_COLUMN_FILENAME); 170 mimeType = inferMimeType(fileName, mimeType); 171 return mimeType; 172 } 173 } finally { 174 c.close(); 175 } 176 return null; 177 } 178 } finally { 179 Binder.restoreCallingIdentity(callingId); 180 } 181 } 182 183 /** 184 * Helper to convert unknown or unmapped attachments to something useful based on filename 185 * extensions. Imperfect, but helps. 186 * 187 * If the file extension is ".eml", return "message/rfc822", which is necessary for the email 188 * app to open it. 189 * If the given mime type is non-empty and anything other than "application/octet-stream", 190 * just return it. (This is the most common case.) 191 * If the filename has a recognizable extension and it converts to a mime type, return that. 192 * If the filename has an unrecognized extension, return "application/extension" 193 * Otherwise return "application/octet-stream". 194 * 195 * @param fileName The given filename 196 * @param mimeType The given mime type 197 * @return A likely mime type for the attachment 198 */ 199 public static String inferMimeType(String fileName, String mimeType) { 200 if (fileName != null && fileName.toLowerCase().endsWith(".eml")) { 201 return "message/rfc822"; 202 } 203 // If the given mime type appears to be non-empty and non-generic - return it 204 if (!TextUtils.isEmpty(mimeType) && 205 !"application/octet-stream".equalsIgnoreCase(mimeType)) { 206 return mimeType; 207 } 208 209 // Try to find an extension in the filename 210 if (!TextUtils.isEmpty(fileName)) { 211 String extension = getFilenameExtension(fileName); 212 if (!TextUtils.isEmpty(extension)) { 213 // Extension found. Look up mime type, or synthesize if none found. 214 mimeType = MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension); 215 if (mimeType == null) { 216 mimeType = "application/" + extension; 217 } 218 return mimeType; 219 } 220 } 221 222 // Fallback case - no good guess could be made. 223 return "application/octet-stream"; 224 } 225 226 /** 227 * Extract and return filename's extension, converted to lower case, and not including the "." 228 * 229 * @return extension, or null if not found (or null/empty filename) 230 */ 231 public static String getFilenameExtension(String fileName) { 232 String extension = null; 233 if (!TextUtils.isEmpty(fileName)) { 234 int lastDot = fileName.lastIndexOf('.'); 235 if ((lastDot > 0) && (lastDot < fileName.length() - 1)) { 236 extension = fileName.substring(lastDot + 1).toLowerCase(); 237 } 238 } 239 return extension; 240 } 241 242 /** 243 * Open an attachment file. There are two "modes" - "raw", which returns an actual file, 244 * and "thumbnail", which attempts to generate a thumbnail image. 245 * 246 * Thumbnails are cached for easy space recovery and cleanup. 247 * 248 * TODO: The thumbnail mode returns null for its failure cases, instead of throwing 249 * FileNotFoundException, and should be fixed for consistency. 250 * 251 * @throws FileNotFoundException 252 */ 253 @Override 254 public ParcelFileDescriptor openFile(Uri uri, String mode) throws FileNotFoundException { 255 long callingId = Binder.clearCallingIdentity(); 256 try { 257 List<String> segments = uri.getPathSegments(); 258 String accountId = segments.get(0); 259 String id = segments.get(1); 260 String format = segments.get(2); 261 if (FORMAT_THUMBNAIL.equals(format)) { 262 int width = Integer.parseInt(segments.get(3)); 263 int height = Integer.parseInt(segments.get(4)); 264 String filename = "thmb_" + accountId + "_" + id; 265 File dir = getContext().getCacheDir(); 266 File file = new File(dir, filename); 267 if (!file.exists()) { 268 Uri attachmentUri = 269 getAttachmentUri(Long.parseLong(accountId), Long.parseLong(id)); 270 Cursor c = query(attachmentUri, 271 new String[] { AttachmentProviderColumns.DATA }, null, null, null); 272 if (c != null) { 273 try { 274 if (c.moveToFirst()) { 275 attachmentUri = Uri.parse(c.getString(0)); 276 } else { 277 return null; 278 } 279 } finally { 280 c.close(); 281 } 282 } 283 String type = getContext().getContentResolver().getType(attachmentUri); 284 try { 285 InputStream in = 286 getContext().getContentResolver().openInputStream(attachmentUri); 287 Bitmap thumbnail = createThumbnail(type, in); 288 if (thumbnail == null) { 289 return null; 290 } 291 thumbnail = Bitmap.createScaledBitmap(thumbnail, width, height, true); 292 FileOutputStream out = new FileOutputStream(file); 293 thumbnail.compress(Bitmap.CompressFormat.PNG, 100, out); 294 out.close(); 295 in.close(); 296 } catch (IOException ioe) { 297 Log.d(Email.LOG_TAG, "openFile/thumbnail failed with " + ioe.getMessage()); 298 return null; 299 } catch (OutOfMemoryError oome) { 300 Log.d(Email.LOG_TAG, "openFile/thumbnail failed with " + oome.getMessage()); 301 return null; 302 } 303 } 304 return ParcelFileDescriptor.open(file, ParcelFileDescriptor.MODE_READ_ONLY); 305 } 306 else { 307 return ParcelFileDescriptor.open( 308 new File(getContext().getDatabasePath(accountId + ".db_att"), id), 309 ParcelFileDescriptor.MODE_READ_ONLY); 310 } 311 } finally { 312 Binder.restoreCallingIdentity(callingId); 313 } 314 } 315 316 @Override 317 public int delete(Uri uri, String arg1, String[] arg2) { 318 return 0; 319 } 320 321 @Override 322 public Uri insert(Uri uri, ContentValues values) { 323 return null; 324 } 325 326 /** 327 * Returns a cursor based on the data in the attachments table, or null if the attachment 328 * is not recorded in the table. 329 * 330 * Supports REST Uri only, for a single row - selection, selection args, and sortOrder are 331 * ignored (non-null values should probably throw an exception....) 332 */ 333 @Override 334 public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, 335 String sortOrder) { 336 long callingId = Binder.clearCallingIdentity(); 337 try { 338 if (projection == null) { 339 projection = 340 new String[] { 341 AttachmentProviderColumns._ID, 342 AttachmentProviderColumns.DATA, 343 }; 344 } 345 346 List<String> segments = uri.getPathSegments(); 347 String accountId = segments.get(0); 348 String id = segments.get(1); 349 String format = segments.get(2); 350 String name = null; 351 int size = -1; 352 String contentUri = null; 353 354 uri = ContentUris.withAppendedId(Attachment.CONTENT_URI, Long.parseLong(id)); 355 Cursor c = getContext().getContentResolver().query(uri, PROJECTION_QUERY, 356 null, null, null); 357 try { 358 if (c.moveToFirst()) { 359 name = c.getString(0); 360 size = c.getInt(1); 361 contentUri = c.getString(2); 362 } else { 363 return null; 364 } 365 } finally { 366 c.close(); 367 } 368 369 MatrixCursor ret = new MatrixCursor(projection); 370 Object[] values = new Object[projection.length]; 371 for (int i = 0, count = projection.length; i < count; i++) { 372 String column = projection[i]; 373 if (AttachmentProviderColumns._ID.equals(column)) { 374 values[i] = id; 375 } 376 else if (AttachmentProviderColumns.DATA.equals(column)) { 377 values[i] = contentUri; 378 } 379 else if (AttachmentProviderColumns.DISPLAY_NAME.equals(column)) { 380 values[i] = name; 381 } 382 else if (AttachmentProviderColumns.SIZE.equals(column)) { 383 values[i] = size; 384 } 385 } 386 ret.addRow(values); 387 return ret; 388 } finally { 389 Binder.restoreCallingIdentity(callingId); 390 } 391 } 392 393 @Override 394 public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) { 395 return 0; 396 } 397 398 private Bitmap createThumbnail(String type, InputStream data) { 399 if(MimeUtility.mimeTypeMatches(type, "image/*")) { 400 return createImageThumbnail(data); 401 } 402 return null; 403 } 404 405 private Bitmap createImageThumbnail(InputStream data) { 406 try { 407 Bitmap bitmap = BitmapFactory.decodeStream(data); 408 return bitmap; 409 } catch (OutOfMemoryError oome) { 410 Log.d(Email.LOG_TAG, "createImageThumbnail failed with " + oome.getMessage()); 411 return null; 412 } catch (Exception e) { 413 Log.d(Email.LOG_TAG, "createImageThumbnail failed with " + e.getMessage()); 414 return null; 415 } 416 } 417 418 /** 419 * Resolve attachment id to content URI. Returns the resolved content URI (from the attachment 420 * DB) or, if not found, simply returns the incoming value. 421 * 422 * @param attachmentUri 423 * @return resolved content URI 424 * 425 * TODO: Throws an SQLite exception on a missing DB file (e.g. unknown URI) instead of just 426 * returning the incoming uri, as it should. 427 */ 428 public static Uri resolveAttachmentIdToContentUri(ContentResolver resolver, Uri attachmentUri) { 429 Cursor c = resolver.query(attachmentUri, 430 new String[] { AttachmentProvider.AttachmentProviderColumns.DATA }, 431 null, null, null); 432 if (c != null) { 433 try { 434 if (c.moveToFirst()) { 435 final String strUri = c.getString(0); 436 if (strUri != null) { 437 return Uri.parse(strUri); 438 } else { 439 Email.log("AttachmentProvider: attachment with null contentUri"); 440 } 441 } 442 } finally { 443 c.close(); 444 } 445 } 446 return attachmentUri; 447 } 448 449 /** 450 * In support of deleting a message, find all attachments and delete associated attachment 451 * files. 452 * @param context 453 * @param accountId the account for the message 454 * @param messageId the message 455 */ 456 public static void deleteAllAttachmentFiles(Context context, long accountId, long messageId) { 457 Uri uri = ContentUris.withAppendedId(Attachment.MESSAGE_ID_URI, messageId); 458 Cursor c = context.getContentResolver().query(uri, Attachment.ID_PROJECTION, 459 null, null, null); 460 try { 461 while (c.moveToNext()) { 462 long attachmentId = c.getLong(Attachment.ID_PROJECTION_COLUMN); 463 File attachmentFile = getAttachmentFilename(context, accountId, attachmentId); 464 // Note, delete() throws no exceptions for basic FS errors (e.g. file not found) 465 // it just returns false, which we ignore, and proceed to the next file. 466 // This entire loop is best-effort only. 467 attachmentFile.delete(); 468 } 469 } finally { 470 c.close(); 471 } 472 } 473 474 /** 475 * In support of deleting a mailbox, find all messages and delete their attachments. 476 * 477 * @param context 478 * @param accountId the account for the mailbox 479 * @param mailboxId the mailbox for the messages 480 */ 481 public static void deleteAllMailboxAttachmentFiles(Context context, long accountId, 482 long mailboxId) { 483 Cursor c = context.getContentResolver().query(Message.CONTENT_URI, 484 Message.ID_COLUMN_PROJECTION, MessageColumns.MAILBOX_KEY + "=?", 485 new String[] { Long.toString(mailboxId) }, null); 486 try { 487 while (c.moveToNext()) { 488 long messageId = c.getLong(Message.ID_PROJECTION_COLUMN); 489 deleteAllAttachmentFiles(context, accountId, messageId); 490 } 491 } finally { 492 c.close(); 493 } 494 } 495 496 /** 497 * In support of deleting or wiping an account, delete all related attachments. 498 * 499 * @param context 500 * @param accountId the account to scrub 501 */ 502 public static void deleteAllAccountAttachmentFiles(Context context, long accountId) { 503 File[] files = getAttachmentDirectory(context, accountId).listFiles(); 504 if (files == null) return; 505 for (File file : files) { 506 boolean result = file.delete(); 507 if (!result) { 508 Log.e(Email.LOG_TAG, "Failed to delete attachment file " + file.getName()); 509 } 510 } 511 } 512 513 /** 514 * Need this to suppress warning in unit tests. 515 */ 516 @Override 517 public void shutdown() { 518 // Don't call super.shutdown(), which emits a warning... 519 } 520} 521