1 /** 2 * Copyright (C) 2010 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.internal.util; 18 19 import android.content.ComponentName; 20 import android.content.Context; 21 import android.content.Intent; 22 import android.content.ServiceConnection; 23 import android.os.Handler; 24 import android.os.HandlerThread; 25 import android.os.IBinder; 26 import android.os.Looper; 27 import android.os.Message; 28 import android.os.Messenger; 29 import android.os.RemoteException; 30 import android.util.Slog; 31 32 import java.util.Stack; 33 34 /** 35 * <p>An asynchronous channel between two handlers.</p> 36 * 37 * <p>The handlers maybe in the same process or in another process. There 38 * are two protocol styles that can be used with an AysncChannel. The 39 * first is a simple request/reply protocol where the server does 40 * not need to know which client is issuing the request.</p> 41 * 42 * <p>In a simple request/reply protocol the client/source sends requests to the 43 * server/destination. And the server uses the replyToMessage methods. 44 * In this usage model there is no need for the destination to 45 * use the connect methods. The typical sequence of operations is:</p> 46 *<ol> 47 * <li>Client calls AsyncChannel#connectSync or Asynchronously:</li> 48 * <ol>For an asynchronous half connection client calls AsyncChannel#connect.</ol> 49 * <li>Client receives CMD_CHANNEL_HALF_CONNECTED from AsyncChannel</li> 50 * </ol> 51 * <li><code>comm-loop:</code></li> 52 * <li>Client calls AsyncChannel#sendMessage</li> 53 * <li>Server processes messages and optionally replies using AsyncChannel#replyToMessage 54 * <li>Loop to <code>comm-loop</code> until done</li> 55 * <li>When done Client calls {@link AsyncChannel#disconnect}</li> 56 * <li>Client/Server receives CMD_CHANNEL_DISCONNECTED from AsyncChannel</li> 57 *</ol> 58 *<br/> 59 * <p>A second usage model is where the server/destination needs to know 60 * which client it's connected too. For example the server needs to 61 * send unsolicited messages back to the client. Or the server keeps 62 * different state for each client. In this model the server will also 63 * use the connect methods. The typical sequence of operation is:</p> 64 *<ol> 65 * <li>Client calls AsyncChannel#fullyConnectSync or Asynchronously:<li> 66 * <ol>For an asynchronous full connection it calls AsyncChannel#connect</li> 67 * <li>Client receives CMD_CHANNEL_HALF_CONNECTED from AsyncChannel</li> 68 * <li>Client calls AsyncChannel#sendMessage(CMD_CHANNEL_FULL_CONNECTION)</li> 69 * </ol> 70 * <li>Server receives CMD_CHANNEL_FULL_CONNECTION</li> 71 * <li>Server calls AsyncChannel#connected</li> 72 * <li>Server sends AsyncChannel#sendMessage(CMD_CHANNEL_FULLY_CONNECTED)</li> 73 * <li>Client receives CMD_CHANNEL_FULLY_CONNECTED</li> 74 * <li><code>comm-loop:</code></li> 75 * <li>Client/Server uses AsyncChannel#sendMessage/replyToMessage 76 * to communicate and perform work</li> 77 * <li>Loop to <code>comm-loop</code> until done</li> 78 * <li>When done Client/Server calls {@link AsyncChannel#disconnect}</li> 79 * <li>Client/Server receives CMD_CHANNEL_DISCONNECTED from AsyncChannel</li> 80 *</ol> 81 * 82 * TODO: Consider simplifying where we have connect and fullyConnect with only one response 83 * message RSP_CHANNEL_CONNECT instead of two, CMD_CHANNEL_HALF_CONNECTED and 84 * CMD_CHANNEL_FULLY_CONNECTED. We'd also change CMD_CHANNEL_FULL_CONNECTION to REQ_CHANNEL_CONNECT. 85 */ 86 public class AsyncChannel { 87 /** Log tag */ 88 private static final String TAG = "AsyncChannel"; 89 90 /** Enable to turn on debugging */ 91 private static final boolean DBG = false; 92 93 private static final int BASE = Protocol.BASE_SYSTEM_ASYNC_CHANNEL; 94 95 /** 96 * Command sent when the channel is half connected. Half connected 97 * means that the channel can be used to send commends to the destination 98 * but the destination is unaware that the channel exists. The first 99 * command sent to the destination is typically CMD_CHANNEL_FULL_CONNECTION if 100 * it is desired to establish a long term connection, but any command maybe 101 * sent. 102 * 103 * msg.arg1 == 0 : STATUS_SUCCESSFUL 104 * 1 : STATUS_BINDING_UNSUCCESSFUL 105 * msg.obj == the AsyncChannel 106 * msg.replyTo == dstMessenger if successful 107 */ 108 public static final int CMD_CHANNEL_HALF_CONNECTED = BASE + 0; 109 110 /** 111 * Command typically sent when after receiving the CMD_CHANNEL_HALF_CONNECTED. 112 * This is used to initiate a long term connection with the destination and 113 * typically the destination will reply with CMD_CHANNEL_FULLY_CONNECTED. 114 * 115 * msg.replyTo = srcMessenger. 116 */ 117 public static final int CMD_CHANNEL_FULL_CONNECTION = BASE + 1; 118 119 /** 120 * Command typically sent after the destination receives a CMD_CHANNEL_FULL_CONNECTION. 121 * This signifies the acceptance or rejection of the channel by the sender. 122 * 123 * msg.arg1 == 0 : Accept connection 124 * : All other values signify the destination rejected the connection 125 * and {@link AsyncChannel#disconnect} would typically be called. 126 */ 127 public static final int CMD_CHANNEL_FULLY_CONNECTED = BASE + 2; 128 129 /** 130 * Command sent when one side or the other wishes to disconnect. The sender 131 * may or may not be able to receive a reply depending upon the protocol and 132 * the state of the connection. The receiver should call {@link AsyncChannel#disconnect} 133 * to close its side of the channel and it will receive a CMD_CHANNEL_DISCONNECTED 134 * when the channel is closed. 135 * 136 * msg.replyTo = messenger that is disconnecting 137 */ 138 public static final int CMD_CHANNEL_DISCONNECT = BASE + 3; 139 140 /** 141 * Command sent when the channel becomes disconnected. This is sent when the 142 * channel is forcibly disconnected by the system or as a reply to CMD_CHANNEL_DISCONNECT. 143 * 144 * msg.arg1 == 0 : STATUS_SUCCESSFUL 145 * 1 : STATUS_BINDING_UNSUCCESSFUL 146 * 2 : STATUS_SEND_UNSUCCESSFUL 147 * : All other values signify failure and the channel state is indeterminate 148 * msg.obj == the AsyncChannel 149 * msg.replyTo = messenger disconnecting or null if it was never connected. 150 */ 151 public static final int CMD_CHANNEL_DISCONNECTED = BASE + 4; 152 153 private static final int CMD_TO_STRING_COUNT = CMD_CHANNEL_DISCONNECTED - BASE + 1; 154 private static String[] sCmdToString = new String[CMD_TO_STRING_COUNT]; 155 static { 156 sCmdToString[CMD_CHANNEL_HALF_CONNECTED - BASE] = "CMD_CHANNEL_HALF_CONNECTED"; 157 sCmdToString[CMD_CHANNEL_FULL_CONNECTION - BASE] = "CMD_CHANNEL_FULL_CONNECTION"; 158 sCmdToString[CMD_CHANNEL_FULLY_CONNECTED - BASE] = "CMD_CHANNEL_FULLY_CONNECTED"; 159 sCmdToString[CMD_CHANNEL_DISCONNECT - BASE] = "CMD_CHANNEL_DISCONNECT"; 160 sCmdToString[CMD_CHANNEL_DISCONNECTED - BASE] = "CMD_CHANNEL_DISCONNECTED"; 161 } cmdToString(int cmd)162 protected static String cmdToString(int cmd) { 163 cmd -= BASE; 164 if ((cmd >= 0) && (cmd < sCmdToString.length)) { 165 return sCmdToString[cmd]; 166 } else { 167 return null; 168 } 169 } 170 171 /** Successful status always 0, !0 is an unsuccessful status */ 172 public static final int STATUS_SUCCESSFUL = 0; 173 174 /** Error attempting to bind on a connect */ 175 public static final int STATUS_BINDING_UNSUCCESSFUL = 1; 176 177 /** Error attempting to send a message */ 178 public static final int STATUS_SEND_UNSUCCESSFUL = 2; 179 180 /** CMD_FULLY_CONNECTED refused because a connection already exists*/ 181 public static final int STATUS_FULL_CONNECTION_REFUSED_ALREADY_CONNECTED = 3; 182 183 /** Error indicating abnormal termination of destination messenger */ 184 public static final int STATUS_REMOTE_DISCONNECTION = 4; 185 186 /** Service connection */ 187 private AsyncChannelConnection mConnection; 188 189 /** Context for source */ 190 private Context mSrcContext; 191 192 /** Handler for source */ 193 private Handler mSrcHandler; 194 195 /** Messenger for source */ 196 private Messenger mSrcMessenger; 197 198 /** Messenger for destination */ 199 private Messenger mDstMessenger; 200 201 /** Death Monitor for destination messenger */ 202 private DeathMonitor mDeathMonitor; 203 204 /** 205 * AsyncChannel constructor 206 */ AsyncChannel()207 public AsyncChannel() { 208 } 209 210 /** 211 * Connect handler to named package/class synchronously. 212 * 213 * @param srcContext is the context of the source 214 * @param srcHandler is the hander to receive CONNECTED & DISCONNECTED 215 * messages 216 * @param dstPackageName is the destination package name 217 * @param dstClassName is the fully qualified class name (i.e. contains 218 * package name) 219 * 220 * @return STATUS_SUCCESSFUL on success any other value is an error. 221 */ connectSrcHandlerToPackageSync( Context srcContext, Handler srcHandler, String dstPackageName, String dstClassName)222 public int connectSrcHandlerToPackageSync( 223 Context srcContext, Handler srcHandler, String dstPackageName, String dstClassName) { 224 if (DBG) log("connect srcHandler to dst Package & class E"); 225 226 mConnection = new AsyncChannelConnection(); 227 228 /* Initialize the source information */ 229 mSrcContext = srcContext; 230 mSrcHandler = srcHandler; 231 mSrcMessenger = new Messenger(srcHandler); 232 233 /* 234 * Initialize destination information to null they will 235 * be initialized when the AsyncChannelConnection#onServiceConnected 236 * is called 237 */ 238 mDstMessenger = null; 239 240 /* Send intent to create the connection */ 241 Intent intent = new Intent(Intent.ACTION_MAIN); 242 intent.setClassName(dstPackageName, dstClassName); 243 boolean result = srcContext.bindService(intent, mConnection, Context.BIND_AUTO_CREATE); 244 if (DBG) log("connect srcHandler to dst Package & class X result=" + result); 245 return result ? STATUS_SUCCESSFUL : STATUS_BINDING_UNSUCCESSFUL; 246 } 247 248 /** 249 * Connect a handler to Messenger synchronously. 250 * 251 * @param srcContext is the context of the source 252 * @param srcHandler is the hander to receive CONNECTED & DISCONNECTED 253 * messages 254 * @param dstMessenger is the hander to send messages to. 255 * 256 * @return STATUS_SUCCESSFUL on success any other value is an error. 257 */ connectSync(Context srcContext, Handler srcHandler, Messenger dstMessenger)258 public int connectSync(Context srcContext, Handler srcHandler, Messenger dstMessenger) { 259 if (DBG) log("halfConnectSync srcHandler to the dstMessenger E"); 260 261 // We are connected 262 connected(srcContext, srcHandler, dstMessenger); 263 264 if (DBG) log("halfConnectSync srcHandler to the dstMessenger X"); 265 return STATUS_SUCCESSFUL; 266 } 267 268 /** 269 * connect two local Handlers synchronously. 270 * 271 * @param srcContext is the context of the source 272 * @param srcHandler is the hander to receive CONNECTED & DISCONNECTED 273 * messages 274 * @param dstHandler is the hander to send messages to. 275 * 276 * @return STATUS_SUCCESSFUL on success any other value is an error. 277 */ connectSync(Context srcContext, Handler srcHandler, Handler dstHandler)278 public int connectSync(Context srcContext, Handler srcHandler, Handler dstHandler) { 279 return connectSync(srcContext, srcHandler, new Messenger(dstHandler)); 280 } 281 282 /** 283 * Fully connect two local Handlers synchronously. 284 * 285 * @param srcContext is the context of the source 286 * @param srcHandler is the hander to receive CONNECTED & DISCONNECTED 287 * messages 288 * @param dstHandler is the hander to send messages to. 289 * 290 * @return STATUS_SUCCESSFUL on success any other value is an error. 291 */ fullyConnectSync(Context srcContext, Handler srcHandler, Handler dstHandler)292 public int fullyConnectSync(Context srcContext, Handler srcHandler, Handler dstHandler) { 293 int status = connectSync(srcContext, srcHandler, dstHandler); 294 if (status == STATUS_SUCCESSFUL) { 295 Message response = sendMessageSynchronously(CMD_CHANNEL_FULL_CONNECTION); 296 status = response.arg1; 297 } 298 return status; 299 } 300 301 /** 302 * Connect handler to named package/class. 303 * 304 * Sends a CMD_CHANNEL_HALF_CONNECTED message to srcHandler when complete. 305 * msg.arg1 = status 306 * msg.obj = the AsyncChannel 307 * 308 * @param srcContext is the context of the source 309 * @param srcHandler is the hander to receive CONNECTED & DISCONNECTED 310 * messages 311 * @param dstPackageName is the destination package name 312 * @param dstClassName is the fully qualified class name (i.e. contains 313 * package name) 314 */ connect(Context srcContext, Handler srcHandler, String dstPackageName, String dstClassName)315 public void connect(Context srcContext, Handler srcHandler, String dstPackageName, 316 String dstClassName) { 317 if (DBG) log("connect srcHandler to dst Package & class E"); 318 319 final class ConnectAsync implements Runnable { 320 Context mSrcCtx; 321 Handler mSrcHdlr; 322 String mDstPackageName; 323 String mDstClassName; 324 325 ConnectAsync(Context srcContext, Handler srcHandler, String dstPackageName, 326 String dstClassName) { 327 mSrcCtx = srcContext; 328 mSrcHdlr = srcHandler; 329 mDstPackageName = dstPackageName; 330 mDstClassName = dstClassName; 331 } 332 333 @Override 334 public void run() { 335 int result = connectSrcHandlerToPackageSync(mSrcCtx, mSrcHdlr, mDstPackageName, 336 mDstClassName); 337 replyHalfConnected(result); 338 } 339 } 340 341 ConnectAsync ca = new ConnectAsync(srcContext, srcHandler, dstPackageName, dstClassName); 342 new Thread(ca).start(); 343 344 if (DBG) log("connect srcHandler to dst Package & class X"); 345 } 346 347 /** 348 * Connect handler to a class 349 * 350 * Sends a CMD_CHANNEL_HALF_CONNECTED message to srcHandler when complete. 351 * msg.arg1 = status 352 * msg.obj = the AsyncChannel 353 * 354 * @param srcContext 355 * @param srcHandler 356 * @param klass is the class to send messages to. 357 */ connect(Context srcContext, Handler srcHandler, Class<?> klass)358 public void connect(Context srcContext, Handler srcHandler, Class<?> klass) { 359 connect(srcContext, srcHandler, klass.getPackage().getName(), klass.getName()); 360 } 361 362 /** 363 * Connect handler and messenger. 364 * 365 * Sends a CMD_CHANNEL_HALF_CONNECTED message to srcHandler when complete. 366 * msg.arg1 = status 367 * msg.obj = the AsyncChannel 368 * 369 * @param srcContext 370 * @param srcHandler 371 * @param dstMessenger 372 */ connect(Context srcContext, Handler srcHandler, Messenger dstMessenger)373 public void connect(Context srcContext, Handler srcHandler, Messenger dstMessenger) { 374 if (DBG) log("connect srcHandler to the dstMessenger E"); 375 376 // We are connected 377 connected(srcContext, srcHandler, dstMessenger); 378 379 // Tell source we are half connected 380 replyHalfConnected(STATUS_SUCCESSFUL); 381 382 if (DBG) log("connect srcHandler to the dstMessenger X"); 383 } 384 385 /** 386 * Connect handler to messenger. This method is typically called 387 * when a server receives a CMD_CHANNEL_FULL_CONNECTION request 388 * and initializes the internal instance variables to allow communication 389 * with the dstMessenger. 390 * 391 * @param srcContext 392 * @param srcHandler 393 * @param dstMessenger 394 */ connected(Context srcContext, Handler srcHandler, Messenger dstMessenger)395 public void connected(Context srcContext, Handler srcHandler, Messenger dstMessenger) { 396 if (DBG) log("connected srcHandler to the dstMessenger E"); 397 398 // Initialize source fields 399 mSrcContext = srcContext; 400 mSrcHandler = srcHandler; 401 mSrcMessenger = new Messenger(mSrcHandler); 402 403 // Initialize destination fields 404 mDstMessenger = dstMessenger; 405 406 if (DBG) log("connected srcHandler to the dstMessenger X"); 407 } 408 409 /** 410 * Connect two local Handlers. 411 * 412 * @param srcContext is the context of the source 413 * @param srcHandler is the hander to receive CONNECTED & DISCONNECTED 414 * messages 415 * @param dstHandler is the hander to send messages to. 416 */ connect(Context srcContext, Handler srcHandler, Handler dstHandler)417 public void connect(Context srcContext, Handler srcHandler, Handler dstHandler) { 418 connect(srcContext, srcHandler, new Messenger(dstHandler)); 419 } 420 421 /** 422 * Connect service and messenger. 423 * 424 * Sends a CMD_CHANNEL_HALF_CONNECTED message to srcAsyncService when complete. 425 * msg.arg1 = status 426 * msg.obj = the AsyncChannel 427 * 428 * @param srcAsyncService 429 * @param dstMessenger 430 */ connect(AsyncService srcAsyncService, Messenger dstMessenger)431 public void connect(AsyncService srcAsyncService, Messenger dstMessenger) { 432 connect(srcAsyncService, srcAsyncService.getHandler(), dstMessenger); 433 } 434 435 /** 436 * To close the connection call when handler receives CMD_CHANNEL_DISCONNECTED 437 */ disconnected()438 public void disconnected() { 439 mSrcContext = null; 440 mSrcHandler = null; 441 mSrcMessenger = null; 442 mDstMessenger = null; 443 mDeathMonitor = null; 444 mConnection = null; 445 } 446 447 /** 448 * Disconnect 449 */ disconnect()450 public void disconnect() { 451 if ((mConnection != null) && (mSrcContext != null)) { 452 mSrcContext.unbindService(mConnection); 453 mConnection = null; 454 } 455 try { 456 // Send the DISCONNECTED, although it may not be received 457 // but its the best we can do. 458 Message msg = Message.obtain(); 459 msg.what = CMD_CHANNEL_DISCONNECTED; 460 msg.replyTo = mSrcMessenger; 461 mDstMessenger.send(msg); 462 } catch(Exception e) { 463 } 464 // Tell source we're disconnected. 465 if (mSrcHandler != null) { 466 replyDisconnected(STATUS_SUCCESSFUL); 467 mSrcHandler = null; 468 } 469 // Unlink only when bindService isn't used 470 if (mConnection == null && mDstMessenger != null && mDeathMonitor!= null) { 471 mDstMessenger.getBinder().unlinkToDeath(mDeathMonitor, 0); 472 mDeathMonitor = null; 473 } 474 } 475 476 /** 477 * Send a message to the destination handler. 478 * 479 * @param msg 480 */ sendMessage(Message msg)481 public void sendMessage(Message msg) { 482 msg.replyTo = mSrcMessenger; 483 try { 484 mDstMessenger.send(msg); 485 } catch (RemoteException e) { 486 replyDisconnected(STATUS_SEND_UNSUCCESSFUL); 487 } 488 } 489 490 /** 491 * Send a message to the destination handler 492 * 493 * @param what 494 */ sendMessage(int what)495 public void sendMessage(int what) { 496 Message msg = Message.obtain(); 497 msg.what = what; 498 sendMessage(msg); 499 } 500 501 /** 502 * Send a message to the destination handler 503 * 504 * @param what 505 * @param arg1 506 */ sendMessage(int what, int arg1)507 public void sendMessage(int what, int arg1) { 508 Message msg = Message.obtain(); 509 msg.what = what; 510 msg.arg1 = arg1; 511 sendMessage(msg); 512 } 513 514 /** 515 * Send a message to the destination handler 516 * 517 * @param what 518 * @param arg1 519 * @param arg2 520 */ sendMessage(int what, int arg1, int arg2)521 public void sendMessage(int what, int arg1, int arg2) { 522 Message msg = Message.obtain(); 523 msg.what = what; 524 msg.arg1 = arg1; 525 msg.arg2 = arg2; 526 sendMessage(msg); 527 } 528 529 /** 530 * Send a message to the destination handler 531 * 532 * @param what 533 * @param arg1 534 * @param arg2 535 * @param obj 536 */ sendMessage(int what, int arg1, int arg2, Object obj)537 public void sendMessage(int what, int arg1, int arg2, Object obj) { 538 Message msg = Message.obtain(); 539 msg.what = what; 540 msg.arg1 = arg1; 541 msg.arg2 = arg2; 542 msg.obj = obj; 543 sendMessage(msg); 544 } 545 546 /** 547 * Send a message to the destination handler 548 * 549 * @param what 550 * @param obj 551 */ sendMessage(int what, Object obj)552 public void sendMessage(int what, Object obj) { 553 Message msg = Message.obtain(); 554 msg.what = what; 555 msg.obj = obj; 556 sendMessage(msg); 557 } 558 559 /** 560 * Reply to srcMsg sending dstMsg 561 * 562 * @param srcMsg 563 * @param dstMsg 564 */ replyToMessage(Message srcMsg, Message dstMsg)565 public void replyToMessage(Message srcMsg, Message dstMsg) { 566 try { 567 dstMsg.replyTo = mSrcMessenger; 568 srcMsg.replyTo.send(dstMsg); 569 } catch (RemoteException e) { 570 log("TODO: handle replyToMessage RemoteException" + e); 571 e.printStackTrace(); 572 } 573 } 574 575 /** 576 * Reply to srcMsg 577 * 578 * @param srcMsg 579 * @param what 580 */ replyToMessage(Message srcMsg, int what)581 public void replyToMessage(Message srcMsg, int what) { 582 Message msg = Message.obtain(); 583 msg.what = what; 584 replyToMessage(srcMsg, msg); 585 } 586 587 /** 588 * Reply to srcMsg 589 * 590 * @param srcMsg 591 * @param what 592 * @param arg1 593 */ replyToMessage(Message srcMsg, int what, int arg1)594 public void replyToMessage(Message srcMsg, int what, int arg1) { 595 Message msg = Message.obtain(); 596 msg.what = what; 597 msg.arg1 = arg1; 598 replyToMessage(srcMsg, msg); 599 } 600 601 /** 602 * Reply to srcMsg 603 * 604 * @param srcMsg 605 * @param what 606 * @param arg1 607 * @param arg2 608 */ replyToMessage(Message srcMsg, int what, int arg1, int arg2)609 public void replyToMessage(Message srcMsg, int what, int arg1, int arg2) { 610 Message msg = Message.obtain(); 611 msg.what = what; 612 msg.arg1 = arg1; 613 msg.arg2 = arg2; 614 replyToMessage(srcMsg, msg); 615 } 616 617 /** 618 * Reply to srcMsg 619 * 620 * @param srcMsg 621 * @param what 622 * @param arg1 623 * @param arg2 624 * @param obj 625 */ replyToMessage(Message srcMsg, int what, int arg1, int arg2, Object obj)626 public void replyToMessage(Message srcMsg, int what, int arg1, int arg2, Object obj) { 627 Message msg = Message.obtain(); 628 msg.what = what; 629 msg.arg1 = arg1; 630 msg.arg2 = arg2; 631 msg.obj = obj; 632 replyToMessage(srcMsg, msg); 633 } 634 635 /** 636 * Reply to srcMsg 637 * 638 * @param srcMsg 639 * @param what 640 * @param obj 641 */ replyToMessage(Message srcMsg, int what, Object obj)642 public void replyToMessage(Message srcMsg, int what, Object obj) { 643 Message msg = Message.obtain(); 644 msg.what = what; 645 msg.obj = obj; 646 replyToMessage(srcMsg, msg); 647 } 648 649 /** 650 * Send the Message synchronously. 651 * 652 * @param msg to send 653 * @return reply message or null if an error. 654 */ sendMessageSynchronously(Message msg)655 public Message sendMessageSynchronously(Message msg) { 656 Message resultMsg = SyncMessenger.sendMessageSynchronously(mDstMessenger, msg); 657 return resultMsg; 658 } 659 660 /** 661 * Send the Message synchronously. 662 * 663 * @param what 664 * @return reply message or null if an error. 665 */ sendMessageSynchronously(int what)666 public Message sendMessageSynchronously(int what) { 667 Message msg = Message.obtain(); 668 msg.what = what; 669 Message resultMsg = sendMessageSynchronously(msg); 670 return resultMsg; 671 } 672 673 /** 674 * Send the Message synchronously. 675 * 676 * @param what 677 * @param arg1 678 * @return reply message or null if an error. 679 */ sendMessageSynchronously(int what, int arg1)680 public Message sendMessageSynchronously(int what, int arg1) { 681 Message msg = Message.obtain(); 682 msg.what = what; 683 msg.arg1 = arg1; 684 Message resultMsg = sendMessageSynchronously(msg); 685 return resultMsg; 686 } 687 688 /** 689 * Send the Message synchronously. 690 * 691 * @param what 692 * @param arg1 693 * @param arg2 694 * @return reply message or null if an error. 695 */ sendMessageSynchronously(int what, int arg1, int arg2)696 public Message sendMessageSynchronously(int what, int arg1, int arg2) { 697 Message msg = Message.obtain(); 698 msg.what = what; 699 msg.arg1 = arg1; 700 msg.arg2 = arg2; 701 Message resultMsg = sendMessageSynchronously(msg); 702 return resultMsg; 703 } 704 705 /** 706 * Send the Message synchronously. 707 * 708 * @param what 709 * @param arg1 710 * @param arg2 711 * @param obj 712 * @return reply message or null if an error. 713 */ sendMessageSynchronously(int what, int arg1, int arg2, Object obj)714 public Message sendMessageSynchronously(int what, int arg1, int arg2, Object obj) { 715 Message msg = Message.obtain(); 716 msg.what = what; 717 msg.arg1 = arg1; 718 msg.arg2 = arg2; 719 msg.obj = obj; 720 Message resultMsg = sendMessageSynchronously(msg); 721 return resultMsg; 722 } 723 724 /** 725 * Send the Message synchronously. 726 * 727 * @param what 728 * @param obj 729 * @return reply message or null if an error. 730 */ sendMessageSynchronously(int what, Object obj)731 public Message sendMessageSynchronously(int what, Object obj) { 732 Message msg = Message.obtain(); 733 msg.what = what; 734 msg.obj = obj; 735 Message resultMsg = sendMessageSynchronously(msg); 736 return resultMsg; 737 } 738 739 /** 740 * Helper class to send messages synchronously 741 */ 742 private static class SyncMessenger { 743 /** A stack of SyncMessengers */ 744 private static Stack<SyncMessenger> sStack = new Stack<SyncMessenger>(); 745 /** A number of SyncMessengers created */ 746 private static int sCount = 0; 747 /** The handler thread */ 748 private HandlerThread mHandlerThread; 749 /** The handler that will receive the result */ 750 private SyncHandler mHandler; 751 /** The messenger used to send the message */ 752 private Messenger mMessenger; 753 754 /** private constructor */ SyncMessenger()755 private SyncMessenger() { 756 } 757 758 /** Synchronous Handler class */ 759 private class SyncHandler extends Handler { 760 /** The object used to wait/notify */ 761 private Object mLockObject = new Object(); 762 /** The resulting message */ 763 private Message mResultMsg; 764 765 /** Constructor */ SyncHandler(Looper looper)766 private SyncHandler(Looper looper) { 767 super(looper); 768 } 769 770 /** Handle of the reply message */ 771 @Override handleMessage(Message msg)772 public void handleMessage(Message msg) { 773 mResultMsg = Message.obtain(); 774 mResultMsg.copyFrom(msg); 775 synchronized(mLockObject) { 776 mLockObject.notify(); 777 } 778 } 779 } 780 781 /** 782 * @return the SyncMessenger 783 */ obtain()784 private static SyncMessenger obtain() { 785 SyncMessenger sm; 786 synchronized (sStack) { 787 if (sStack.isEmpty()) { 788 sm = new SyncMessenger(); 789 sm.mHandlerThread = new HandlerThread("SyncHandler-" + sCount++); 790 sm.mHandlerThread.start(); 791 sm.mHandler = sm.new SyncHandler(sm.mHandlerThread.getLooper()); 792 sm.mMessenger = new Messenger(sm.mHandler); 793 } else { 794 sm = sStack.pop(); 795 } 796 } 797 return sm; 798 } 799 800 /** 801 * Recycle this object 802 */ recycle()803 private void recycle() { 804 synchronized (sStack) { 805 sStack.push(this); 806 } 807 } 808 809 /** 810 * Send a message synchronously. 811 * 812 * @param msg to send 813 * @return result message or null if an error occurs 814 */ sendMessageSynchronously(Messenger dstMessenger, Message msg)815 private static Message sendMessageSynchronously(Messenger dstMessenger, Message msg) { 816 SyncMessenger sm = SyncMessenger.obtain(); 817 try { 818 if (dstMessenger != null && msg != null) { 819 msg.replyTo = sm.mMessenger; 820 synchronized (sm.mHandler.mLockObject) { 821 dstMessenger.send(msg); 822 sm.mHandler.mLockObject.wait(); 823 } 824 } else { 825 sm.mHandler.mResultMsg = null; 826 } 827 } catch (InterruptedException e) { 828 sm.mHandler.mResultMsg = null; 829 } catch (RemoteException e) { 830 sm.mHandler.mResultMsg = null; 831 } 832 Message resultMsg = sm.mHandler.mResultMsg; 833 sm.recycle(); 834 return resultMsg; 835 } 836 } 837 838 /** 839 * Reply to the src handler that we're half connected. 840 * see: CMD_CHANNEL_HALF_CONNECTED for message contents 841 * 842 * @param status to be stored in msg.arg1 843 */ replyHalfConnected(int status)844 private void replyHalfConnected(int status) { 845 Message msg = mSrcHandler.obtainMessage(CMD_CHANNEL_HALF_CONNECTED); 846 msg.arg1 = status; 847 msg.obj = this; 848 msg.replyTo = mDstMessenger; 849 850 /* 851 * Link to death only when bindService isn't used. 852 */ 853 if (mConnection == null) { 854 mDeathMonitor = new DeathMonitor(); 855 try { 856 mDstMessenger.getBinder().linkToDeath(mDeathMonitor, 0); 857 } catch (RemoteException e) { 858 mDeathMonitor = null; 859 // Override status to indicate failure 860 msg.arg1 = STATUS_BINDING_UNSUCCESSFUL; 861 } 862 } 863 864 mSrcHandler.sendMessage(msg); 865 } 866 867 /** 868 * Reply to the src handler that we are disconnected 869 * see: CMD_CHANNEL_DISCONNECTED for message contents 870 * 871 * @param status to be stored in msg.arg1 872 */ replyDisconnected(int status)873 private void replyDisconnected(int status) { 874 Message msg = mSrcHandler.obtainMessage(CMD_CHANNEL_DISCONNECTED); 875 msg.arg1 = status; 876 msg.obj = this; 877 msg.replyTo = mDstMessenger; 878 mSrcHandler.sendMessage(msg); 879 } 880 881 882 /** 883 * ServiceConnection to receive call backs. 884 */ 885 class AsyncChannelConnection implements ServiceConnection { AsyncChannelConnection()886 AsyncChannelConnection() { 887 } 888 889 @Override onServiceConnected(ComponentName className, IBinder service)890 public void onServiceConnected(ComponentName className, IBinder service) { 891 mDstMessenger = new Messenger(service); 892 replyHalfConnected(STATUS_SUCCESSFUL); 893 } 894 895 @Override onServiceDisconnected(ComponentName className)896 public void onServiceDisconnected(ComponentName className) { 897 replyDisconnected(STATUS_SUCCESSFUL); 898 } 899 } 900 901 /** 902 * Log the string. 903 * 904 * @param s 905 */ log(String s)906 private static void log(String s) { 907 Slog.d(TAG, s); 908 } 909 910 private final class DeathMonitor implements IBinder.DeathRecipient { 911 DeathMonitor()912 DeathMonitor() { 913 } 914 binderDied()915 public void binderDied() { 916 replyDisconnected(STATUS_REMOTE_DISCONNECTION); 917 } 918 919 } 920 } 921