1.Broadcast种类
Android广播大体可以分为几类：
-
App应用内广播（LocalBroadcast）
这个应用自己发给自己的，通过LocalBroadcastManager管理。这里不做介绍。 -
系统广播
这种不是普通应用发出来的，比如包的安装移除，（userId）用户的添加删除。当然，这些广播一般的普通应用也能接收得到。否则我们很多应用行为就异常了。这里列出一些应用，可以看到在Android Q上，这些系统广播发出后，先触发了system_server的一些行为，才进入广播发送流程。
case Intent.ACTION_UID_REMOVED:
case Intent.ACTION_PACKAGE_REMOVED:
case Intent.ACTION_PACKAGE_CHANGED:
case Intent.ACTION_EXTERNAL_APPLICATIONS_UNAVAILABLE:
case Intent.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE:
case Intent.ACTION_PACKAGES_SUSPENDED:
case Intent.ACTION_PACKAGES_UNSUSPENDED:
粘性广播
android 5.0/api 21中deprecated,不再推荐使用。当然，源码里当前还支持粘性广播。无序广播
完全异步的广播，广播的接收者们不会互相干扰广播的接收。有序广播
同步的广播，广播的接收者门会按照优先级，依次接收到广播。
按最新的android Q设计来看的话，当前应该只需要关注两种广播，有序广播和无序广播 就好了。其他的倒不是有很大助益。
2.BroadCast时序图
老规矩，看代码前先放图。这里放得简单些，描述大体流程，把一些类似Activity的交互给省去。具体的细分业务逻辑，从代码里来看。
registerReciver和sendBroadcast
3.广播动态注册
对应还有静态注册，主要是PMS相关逻辑，后续介绍。
我们调用registerRecevier还是一路调用到ContextImpl的registerReceiverInternal方法。从这里可以可以看到，它将一个BroadcastReceiver对象封装成了一个LoadedApk.ReceiverDispatcher对象，然后返回了一个IIntentReceiver（在这里是InnerReceiver）进行注册。
在前面我们已经说到过，android跨进程调用，是通过aidl的方式。BroadcastReceiver作为一个普通的类对象，肯定是不能直接跨进程调用的。所以这里的应用链关系为InnerReceiver->ReceiverDispatcher->BroadcastReceiver，保证了BroadcastReceiver的调用准确。
ContextImpl
@Override
public Intent registerReceiver(BroadcastReceiver receiver, IntentFilter filter,
String broadcastPermission, Handler scheduler) {
return registerReceiverInternal(receiver, getUserId(),
filter, broadcastPermission, scheduler, getOuterContext(), 0);
}
private Intent registerReceiverInternal(BroadcastReceiver receiver, int userId,
IntentFilter filter, String broadcastPermission,
Handler scheduler, Context context, int flags) {
IIntentReceiver rd = null;
if (receiver != null) {
if (mPackageInfo != null && context != null) {
if (scheduler == null) {
scheduler = mMainThread.getHandler();
}
//往getReceiverDispatcher这个里面看，
//getOuterContext()获取到的外层的Context被作为Key存贮到了LoadedApk的mReceivers里。
//这也就是常见得广播不解注册会导致内存泄漏
rd = mPackageInfo.getReceiverDispatcher(
receiver, context, scheduler,
mMainThread.getInstrumentation(), true);
} else {
if (scheduler == null) {
scheduler = mMainThread.getHandler();
}
rd = new LoadedApk.ReceiverDispatcher(
receiver, context, scheduler, null, true).getIIntentReceiver();
}
}
try {
final Intent intent = ActivityManager.getService().registerReceiver(
mMainThread.getApplicationThread(), mBasePackageName, rd, filter,
broadcastPermission, userId, flags);
if (intent != null) {
intent.setExtrasClassLoader(getClassLoader());
intent.prepareToEnterProcess();
}
return intent;
} catch (RemoteException e) {
throw e.rethrowFromSystemServer();
}
}
从Server端来看，ActivityManagerService调用registerReceiver方法，就是将Recevier和Filter封装成一个BroadcastFilter，添加到了mReceiverResolver里。
ActivityManagerService
public Intent registerReceiver(IApplicationThread caller, String callerPackage,
IIntentReceiver receiver, IntentFilter filter, String permission, int userId,
int flags) {
enforceNotIsolatedCaller("registerReceiver");
ArrayList<Intent> stickyIntents = null;
ProcessRecord callerApp = null;
//谷歌的Instant Apps
final boolean visibleToInstantApps
= (flags & Context.RECEIVER_VISIBLE_TO_INSTANT_APPS) != 0;
int callingUid;
int callingPid;
boolean instantApp;
synchronized(this) {
if (caller != null) {
callerApp = getRecordForAppLocked(caller);
if (callerApp == null) {
throw new SecurityException(
"Unable to find app for caller " + caller
+ " (pid=" + Binder.getCallingPid()
+ ") when registering receiver " + receiver);
}
if (callerApp.info.uid != SYSTEM_UID &&
!callerApp.pkgList.containsKey(callerPackage) &&
!"android".equals(callerPackage)) {
throw new SecurityException("Given caller package " + callerPackage
+ " is not running in process " + callerApp);
}
callingUid = callerApp.info.uid;
callingPid = callerApp.pid;
} else {
callerPackage = null;
callingUid = Binder.getCallingUid();
callingPid = Binder.getCallingPid();
}
instantApp = isInstantApp(callerApp, callerPackage, callingUid);
userId = mUserController.handleIncomingUser(callingPid, callingUid, userId, true,
ALLOW_FULL_ONLY, "registerReceiver", callerPackage);
Iterator<String> actions = filter.actionsIterator();
if (actions == null) {
ArrayList<String> noAction = new ArrayList<String>(1);
noAction.add(null);
actions = noAction.iterator();
}
//先查出是不是有符合Action的粘性广播
// Collect stickies of users
int[] userIds = { UserHandle.USER_ALL, UserHandle.getUserId(callingUid) };
while (actions.hasNext()) {
String action = actions.next();
for (int id : userIds) {
ArrayMap<String, ArrayList<Intent>> stickies = mStickyBroadcasts.get(id);
if (stickies != null) {
ArrayList<Intent> intents = stickies.get(action);
if (intents != null) {
if (stickyIntents == null) {
stickyIntents = new ArrayList<Intent>();
}
stickyIntents.addAll(intents);
}
}
}
}
}
ArrayList<Intent> allSticky = null;
if (stickyIntents != null) {
final ContentResolver resolver = mContext.getContentResolver();
// Look for any matching sticky broadcasts...
for (int i = 0, N = stickyIntents.size(); i < N; i++) {
Intent intent = stickyIntents.get(i);
// Don't provided intents that aren't available to instant apps.
if (instantApp &&
(intent.getFlags() & Intent.FLAG_RECEIVER_VISIBLE_TO_INSTANT_APPS) == 0) {
continue;
}
// If intent has scheme "content", it will need to acccess
// provider that needs to lock mProviderMap in ActivityThread
// and also it may need to wait application response, so we
// cannot lock ActivityManagerService here.
if (filter.match(resolver, intent, true, TAG) >= 0) {
if (allSticky == null) {
allSticky = new ArrayList<Intent>();
}
allSticky.add(intent);
}
}
}
// The first sticky in the list is returned directly back to the client.
Intent sticky = allSticky != null ? allSticky.get(0) : null;
if (DEBUG_BROADCAST) Slog.v(TAG_BROADCAST, "Register receiver " + filter + ": " + sticky);
if (receiver == null) {
return sticky;
}
synchronized (this) {
if (callerApp != null && (callerApp.thread == null
|| callerApp.thread.asBinder() != caller.asBinder())) {
// Original caller already died
return null;
}
//这里还蛮奇怪的，看着应该不需要是一个列表才对
ReceiverList rl = mRegisteredReceivers.get(receiver.asBinder());
if (rl == null) {
rl = new ReceiverList(this, callerApp, callingPid, callingUid,
userId, receiver);
if (rl.app != null) {
final int totalReceiversForApp = rl.app.receivers.size();
if (totalReceiversForApp >= MAX_RECEIVERS_ALLOWED_PER_APP) {
throw new IllegalStateException("Too many receivers, total of "
+ totalReceiversForApp + ", registered for pid: "
+ rl.pid + ", callerPackage: " + callerPackage);
}
rl.app.receivers.add(rl);
} else {
try {
receiver.asBinder().linkToDeath(rl, 0);
} catch (RemoteException e) {
return sticky;
}
rl.linkedToDeath = true;
}
mRegisteredReceivers.put(receiver.asBinder(), rl);
} else if (rl.uid != callingUid) {
throw new IllegalArgumentException(
"Receiver requested to register for uid " + callingUid
+ " was previously registered for uid " + rl.uid
+ " callerPackage is " + callerPackage);
} else if (rl.pid != callingPid) {
throw new IllegalArgumentException(
"Receiver requested to register for pid " + callingPid
+ " was previously registered for pid " + rl.pid
+ " callerPackage is " + callerPackage);
} else if (rl.userId != userId) {
throw new IllegalArgumentException(
"Receiver requested to register for user " + userId
+ " was previously registered for user " + rl.userId
+ " callerPackage is " + callerPackage);
}
//这里将cast和filter封装成了一个BroadcastFilter
//静态注册不是BroadcastFilter对象
BroadcastFilter bf = new BroadcastFilter(filter, rl, callerPackage,
permission, callingUid, userId, instantApp, visibleToInstantApps);
if (rl.containsFilter(filter)) {
Slog.w(TAG, "Receiver with filter " + filter
+ " already registered for pid " + rl.pid
+ ", callerPackage is " + callerPackage);
} else {
rl.add(bf);
if (!bf.debugCheck()) {
Slog.w(TAG, "==> For Dynamic broadcast");
}
mReceiverResolver.addFilter(bf);
}
//有粘性广播需要被执行，这里就会执行粘性广播
// Enqueue broadcasts for all existing stickies that match
// this filter.
if (allSticky != null) {
ArrayList receivers = new ArrayList();
receivers.add(bf);
final int stickyCount = allSticky.size();
for (int i = 0; i < stickyCount; i++) {
Intent intent = allSticky.get(i);
BroadcastQueue queue = broadcastQueueForIntent(intent);
BroadcastRecord r = new BroadcastRecord(queue, intent, null,
null, -1, -1, false, null, null, OP_NONE, null, receivers,
null, 0, null, null, false, true, true, -1, false,
false /* only PRE_BOOT_COMPLETED should be exempt, no stickies */);
queue.enqueueParallelBroadcastLocked(r);
queue.scheduleBroadcastsLocked();
}
}
return sticky;
}
4.发送广播
ContextImpl
@Override
public void sendBroadcast(Intent intent) {
warnIfCallingFromSystemProcess();
String resolvedType = intent.resolveTypeIfNeeded(getContentResolver());
try {
intent.prepareToLeaveProcess(this);
//注意一下，这里倒数第三个参数false声明了是无序广播
ActivityManager.getService().broadcastIntent(
mMainThread.getApplicationThread(), intent, resolvedType, null,
Activity.RESULT_OK, null, null, null, AppOpsManager.OP_NONE, null, false, false,
getUserId());
} catch (RemoteException e) {
throw e.rethrowFromSystemServer();
}
}
在ActivityManagerService的逻辑里，发送广播的逻辑分成了两种情形：
- 粘性广播条件到粘性广播列表
ActivityManagerService#mStickyBroadcasts里 -
无序广播：把动态注册的广播直接就添加到无序广播列表BroadcastQueue#mParallelBroadcasts，然后静态注册的Receiver添加到有序广播列表BroadcastDispatcher#mOrderedBroadcasts -
有序广播：把动态和静态注册的广播合成一个列表，然后添加到receivers里。
然后触发了queue.scheduleBroadcastsLocked()逻辑。那我们再看它到底做了什么动作。
ActivityManagerService
public final int broadcastIntent(IApplicationThread caller,
Intent intent, String resolvedType, IIntentReceiver resultTo,
int resultCode, String resultData, Bundle resultExtras,
String[] requiredPermissions, int appOp, Bundle bOptions,
boolean serialized, boolean sticky, int userId) {
enforceNotIsolatedCaller("broadcastIntent");
synchronized(this) {
intent = verifyBroadcastLocked(intent);
final ProcessRecord callerApp = getRecordForAppLocked(caller);
final int callingPid = Binder.getCallingPid();
final int callingUid = Binder.getCallingUid();
final long origId = Binder.clearCallingIdentity();
try {
return broadcastIntentLocked(callerApp,
callerApp != null ? callerApp.info.packageName : null,
intent, resolvedType, resultTo, resultCode, resultData, resultExtras,
requiredPermissions, appOp, bOptions, serialized, sticky,
callingPid, callingUid, callingUid, callingPid, userId);
} finally {
Binder.restoreCallingIdentity(origId);
}
}
}
//处理的过程就要慢慢看了
final int broadcastIntentLocked(ProcessRecord callerApp,
String callerPackage, Intent intent, String resolvedType,
IIntentReceiver resultTo, int resultCode, String resultData,
Bundle resultExtras, String[] requiredPermissions, int appOp, Bundle bOptions,
boolean ordered, boolean sticky, int callingPid, int callingUid, int realCallingUid,
int realCallingPid, int userId, boolean allowBackgroundActivityStarts) {
intent = new Intent(intent);
final boolean callerInstantApp = isInstantApp(callerApp, callerPackage, callingUid);
// Instant Apps cannot use FLAG_RECEIVER_VISIBLE_TO_INSTANT_APPS
if (callerInstantApp) {
intent.setFlags(intent.getFlags() & ~Intent.FLAG_RECEIVER_VISIBLE_TO_INSTANT_APPS);
}
//默认不会拉活停用的App
//所以如果要拉活应用，发广播的时候要添加标志FLAG_INCLUDE_STOPED_PACKAGES
// By default broadcasts do not go to stopped apps.
intent.addFlags(Intent.FLAG_EXCLUDE_STOPPED_PACKAGES);
// If we have not finished booting, don't allow this to launch new processes.
if (!mProcessesReady && (intent.getFlags()&Intent.FLAG_RECEIVER_BOOT_UPGRADE) == 0) {
intent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY);
}
if (DEBUG_BROADCAST_LIGHT) Slog.v(TAG_BROADCAST,
(sticky ? "Broadcast sticky: ": "Broadcast: ") + intent
+ " ordered=" + ordered + " userid=" + userId);
if ((resultTo != null) && !ordered) {
Slog.w(TAG, "Broadcast " + intent + " not ordered but result callback requested!");
}
userId = mUserController.handleIncomingUser(callingPid, callingUid, userId, true,
ALLOW_NON_FULL, "broadcast", callerPackage);
// Make sure that the user who is receiving this broadcast or its parent is running.
// If not, we will just skip it. Make an exception for shutdown broadcasts, upgrade steps.
if (userId != UserHandle.USER_ALL && !mUserController.isUserOrItsParentRunning(userId)) {
if ((callingUid != SYSTEM_UID
|| (intent.getFlags() & Intent.FLAG_RECEIVER_BOOT_UPGRADE) == 0)
&& !Intent.ACTION_SHUTDOWN.equals(intent.getAction())) {
Slog.w(TAG, "Skipping broadcast of " + intent
+ ": user " + userId + " and its parent (if any) are stopped");
return ActivityManager.BROADCAST_FAILED_USER_STOPPED;
}
}
//权限校验
final String action = intent.getAction();
BroadcastOptions brOptions = null;
if (bOptions != null) {
brOptions = new BroadcastOptions(bOptions);
if (brOptions.getTemporaryAppWhitelistDuration() > 0) {
// See if the caller is allowed to do this. Note we are checking against
// the actual real caller (not whoever provided the operation as say a
// PendingIntent), because that who is actually supplied the arguments.
if (checkComponentPermission(
android.Manifest.permission.CHANGE_DEVICE_IDLE_TEMP_WHITELIST,
realCallingPid, realCallingUid, -1, true)
!= PackageManager.PERMISSION_GRANTED) {
String msg = "Permission Denial: " + intent.getAction()
+ " broadcast from " + callerPackage + " (pid=" + callingPid
+ ", uid=" + callingUid + ")"
+ " requires "
+ android.Manifest.permission.CHANGE_DEVICE_IDLE_TEMP_WHITELIST;
Slog.w(TAG, msg);
throw new SecurityException(msg);
}
}
if (brOptions.isDontSendToRestrictedApps()
&& !isUidActiveLocked(callingUid)
&& isBackgroundRestrictedNoCheck(callingUid, callerPackage)) {
Slog.i(TAG, "Not sending broadcast " + action + " - app " + callerPackage
+ " has background restrictions");
return ActivityManager.START_CANCELED;
}
if (brOptions.allowsBackgroundActivityStarts()) {
// See if the caller is allowed to do this. Note we are checking against
// the actual real caller (not whoever provided the operation as say a
// PendingIntent), because that who is actually supplied the arguments.
if (checkComponentPermission(
android.Manifest.permission.START_ACTIVITIES_FROM_BACKGROUND,
realCallingPid, realCallingUid, -1, true)
!= PackageManager.PERMISSION_GRANTED) {
String msg = "Permission Denial: " + intent.getAction()
+ " broadcast from " + callerPackage + " (pid=" + callingPid
+ ", uid=" + callingUid + ")"
+ " requires "
+ android.Manifest.permission.START_ACTIVITIES_FROM_BACKGROUND;
Slog.w(TAG, msg);
throw new SecurityException(msg);
} else {
allowBackgroundActivityStarts = true;
}
}
}
//一大段校验系统广播和处理系统广播的逻辑
// Verify that protected broadcasts are only being sent by system code,
// and that system code is only sending protected broadcasts.
final boolean isProtectedBroadcast;
try {
isProtectedBroadcast = AppGlobals.getPackageManager().isProtectedBroadcast(action);
} catch (RemoteException e) {
Slog.w(TAG, "Remote exception", e);
return ActivityManager.BROADCAST_SUCCESS;
}
final boolean isCallerSystem;
switch (UserHandle.getAppId(callingUid)) {
case ROOT_UID:
case SYSTEM_UID:
case PHONE_UID:
case BLUETOOTH_UID:
case NFC_UID:
case SE_UID:
case NETWORK_STACK_UID:
isCallerSystem = true;
break;
default:
isCallerSystem = (callerApp != null) && callerApp.isPersistent();
break;
}
// First line security check before anything else: stop non-system apps from
// sending protected broadcasts.
if (!isCallerSystem) {
if (isProtectedBroadcast) {
String msg = "Permission Denial: not allowed to send broadcast "
+ action + " from pid="
+ callingPid + ", uid=" + callingUid;
Slog.w(TAG, msg);
throw new SecurityException(msg);
} else if (AppWidgetManager.ACTION_APPWIDGET_CONFIGURE.equals(action)
|| AppWidgetManager.ACTION_APPWIDGET_UPDATE.equals(action)) {
// Special case for compatibility: we don't want apps to send this,
// but historically it has not been protected and apps may be using it
// to poke their own app widget. So, instead of making it protected,
// just limit it to the caller.
if (callerPackage == null) {
String msg = "Permission Denial: not allowed to send broadcast "
+ action + " from unknown caller.";
Slog.w(TAG, msg);
throw new SecurityException(msg);
} else if (intent.getComponent() != null) {
// They are good enough to send to an explicit component... verify
// it is being sent to the calling app.
if (!intent.getComponent().getPackageName().equals(
callerPackage)) {
String msg = "Permission Denial: not allowed to send broadcast "
+ action + " to "
+ intent.getComponent().getPackageName() + " from "
+ callerPackage;
Slog.w(TAG, msg);
throw new SecurityException(msg);
}
} else {
// Limit broadcast to their own package.
intent.setPackage(callerPackage);
}
}
}
boolean timeoutExempt = false;
if (action != null) {
if (getBackgroundLaunchBroadcasts().contains(action)) {
if (DEBUG_BACKGROUND_CHECK) {
Slog.i(TAG, "Broadcast action " + action + " forcing include-background");
}
intent.addFlags(Intent.FLAG_RECEIVER_INCLUDE_BACKGROUND);
}
switch (action) {
case Intent.ACTION_UID_REMOVED:
case Intent.ACTION_PACKAGE_REMOVED:
case Intent.ACTION_PACKAGE_CHANGED:
case Intent.ACTION_EXTERNAL_APPLICATIONS_UNAVAILABLE:
case Intent.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE:
case Intent.ACTION_PACKAGES_SUSPENDED:
case Intent.ACTION_PACKAGES_UNSUSPENDED:
// Handle special intents: if this broadcast is from the package
// manager about a package being removed, we need to remove all of
// its activities from the history stack.
if (checkComponentPermission(
android.Manifest.permission.BROADCAST_PACKAGE_REMOVED,
callingPid, callingUid, -1, true)
!= PackageManager.PERMISSION_GRANTED) {
String msg = "Permission Denial: " + intent.getAction()
+ " broadcast from " + callerPackage + " (pid=" + callingPid
+ ", uid=" + callingUid + ")"
+ " requires "
+ android.Manifest.permission.BROADCAST_PACKAGE_REMOVED;
Slog.w(TAG, msg);
throw new SecurityException(msg);
}
switch (action) {
case Intent.ACTION_UID_REMOVED:
final int uid = getUidFromIntent(intent);
if (uid >= 0) {
mBatteryStatsService.removeUid(uid);
mAppOpsService.uidRemoved(uid);
}
break;
case Intent.ACTION_EXTERNAL_APPLICATIONS_UNAVAILABLE:
// If resources are unavailable just force stop all those packages
// and flush the attribute cache as well.
String list[] =
intent.getStringArrayExtra(Intent.EXTRA_CHANGED_PACKAGE_LIST);
if (list != null && list.length > 0) {
for (int i = 0; i < list.length; i++) {
forceStopPackageLocked(list[i], -1, false, true, true,
false, false, userId, "storage unmount");
}
mAtmInternal.cleanupRecentTasksForUser(UserHandle.USER_ALL);
sendPackageBroadcastLocked(
ApplicationThreadConstants.EXTERNAL_STORAGE_UNAVAILABLE,
list, userId);
}
break;
case Intent.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE:
mAtmInternal.cleanupRecentTasksForUser(UserHandle.USER_ALL);
break;
case Intent.ACTION_PACKAGE_REMOVED:
case Intent.ACTION_PACKAGE_CHANGED:
Uri data = intent.getData();
String ssp;
if (data != null && (ssp=data.getSchemeSpecificPart()) != null) {
boolean removed = Intent.ACTION_PACKAGE_REMOVED.equals(action);
final boolean replacing =
intent.getBooleanExtra(Intent.EXTRA_REPLACING, false);
final boolean killProcess =
!intent.getBooleanExtra(Intent.EXTRA_DONT_KILL_APP, false);
final boolean fullUninstall = removed && !replacing;
if (removed) {
if (killProcess) {
forceStopPackageLocked(ssp, UserHandle.getAppId(
intent.getIntExtra(Intent.EXTRA_UID, -1)),
false, true, true, false, fullUninstall, userId,
removed ? "pkg removed" : "pkg changed");
}
final int cmd = killProcess
? ApplicationThreadConstants.PACKAGE_REMOVED
: ApplicationThreadConstants.PACKAGE_REMOVED_DONT_KILL;
sendPackageBroadcastLocked(cmd,
new String[] {ssp}, userId);
if (fullUninstall) {
mAppOpsService.packageRemoved(
intent.getIntExtra(Intent.EXTRA_UID, -1), ssp);
// Remove all permissions granted from/to this package
mUgmInternal.removeUriPermissionsForPackage(ssp, userId,
true, false);
mAtmInternal.removeRecentTasksByPackageName(ssp, userId);
mServices.forceStopPackageLocked(ssp, userId);
mAtmInternal.onPackageUninstalled(ssp);
mBatteryStatsService.notePackageUninstalled(ssp);
}
} else {
if (killProcess) {
final int extraUid = intent.getIntExtra(Intent.EXTRA_UID,
-1);
mProcessList.killPackageProcessesLocked(ssp,
UserHandle.getAppId(extraUid),
userId, ProcessList.INVALID_ADJ, "change " + ssp);
}
cleanupDisabledPackageComponentsLocked(ssp, userId,
intent.getStringArrayExtra(
Intent.EXTRA_CHANGED_COMPONENT_NAME_LIST));
}
}
break;
case Intent.ACTION_PACKAGES_SUSPENDED:
case Intent.ACTION_PACKAGES_UNSUSPENDED:
final boolean suspended = Intent.ACTION_PACKAGES_SUSPENDED.equals(
intent.getAction());
final String[] packageNames = intent.getStringArrayExtra(
Intent.EXTRA_CHANGED_PACKAGE_LIST);
final int userHandle = intent.getIntExtra(
Intent.EXTRA_USER_HANDLE, UserHandle.USER_NULL);
mAtmInternal.onPackagesSuspendedChanged(packageNames, suspended,
userHandle);
break;
}
break;
case Intent.ACTION_PACKAGE_REPLACED:
{
final Uri data = intent.getData();
final String ssp;
if (data != null && (ssp = data.getSchemeSpecificPart()) != null) {
ApplicationInfo aInfo = null;
try {
aInfo = AppGlobals.getPackageManager()
.getApplicationInfo(ssp, STOCK_PM_FLAGS, userId);
} catch (RemoteException ignore) {}
if (aInfo == null) {
Slog.w(TAG, "Dropping ACTION_PACKAGE_REPLACED for non-existent pkg:"
+ " ssp=" + ssp + " data=" + data);
return ActivityManager.BROADCAST_SUCCESS;
}
updateAssociationForApp(aInfo);
mAtmInternal.onPackageReplaced(aInfo);
mServices.updateServiceApplicationInfoLocked(aInfo);
sendPackageBroadcastLocked(ApplicationThreadConstants.PACKAGE_REPLACED,
new String[] {ssp}, userId);
}
break;
}
case Intent.ACTION_PACKAGE_ADDED:
{
// Special case for adding a package: by default turn on compatibility mode.
Uri data = intent.getData();
String ssp;
if (data != null && (ssp = data.getSchemeSpecificPart()) != null) {
final boolean replacing =
intent.getBooleanExtra(Intent.EXTRA_REPLACING, false);
mAtmInternal.onPackageAdded(ssp, replacing);
try {
ApplicationInfo ai = AppGlobals.getPackageManager().
getApplicationInfo(ssp, STOCK_PM_FLAGS, 0);
mBatteryStatsService.notePackageInstalled(ssp,
ai != null ? ai.longVersionCode : 0);
} catch (RemoteException e) {
}
}
break;
}
case Intent.ACTION_PACKAGE_DATA_CLEARED:
{
Uri data = intent.getData();
String ssp;
if (data != null && (ssp = data.getSchemeSpecificPart()) != null) {
mAtmInternal.onPackageDataCleared(ssp);
}
break;
}
case Intent.ACTION_TIMEZONE_CHANGED:
// If this is the time zone changed action, queue up a message that will reset
// the timezone of all currently running processes. This message will get
// queued up before the broadcast happens.
mHandler.sendEmptyMessage(UPDATE_TIME_ZONE);
break;
case Intent.ACTION_TIME_CHANGED:
// EXTRA_TIME_PREF_24_HOUR_FORMAT is optional so we must distinguish between
// the tri-state value it may contain and "unknown".
// For convenience we re-use the Intent extra values.
final int NO_EXTRA_VALUE_FOUND = -1;
final int timeFormatPreferenceMsgValue = intent.getIntExtra(
Intent.EXTRA_TIME_PREF_24_HOUR_FORMAT,
NO_EXTRA_VALUE_FOUND /* defaultValue */);
// Only send a message if the time preference is available.
if (timeFormatPreferenceMsgValue != NO_EXTRA_VALUE_FOUND) {
Message updateTimePreferenceMsg =
mHandler.obtainMessage(UPDATE_TIME_PREFERENCE_MSG,
timeFormatPreferenceMsgValue, 0);
mHandler.sendMessage(updateTimePreferenceMsg);
}
BatteryStatsImpl stats = mBatteryStatsService.getActiveStatistics();
synchronized (stats) {
stats.noteCurrentTimeChangedLocked();
}
break;
case Intent.ACTION_CLEAR_DNS_CACHE:
mHandler.sendEmptyMessage(CLEAR_DNS_CACHE_MSG);
break;
case Proxy.PROXY_CHANGE_ACTION:
mHandler.sendMessage(mHandler.obtainMessage(UPDATE_HTTP_PROXY_MSG));
break;
case android.hardware.Camera.ACTION_NEW_PICTURE:
case android.hardware.Camera.ACTION_NEW_VIDEO:
// In N we just turned these off; in O we are turing them back on partly,
// only for registered receivers. This will still address the main problem
// (a spam of apps waking up when a picture is taken putting significant
// memory pressure on the system at a bad point), while still allowing apps
// that are already actively running to know about this happening.
intent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY);
break;
case android.security.KeyChain.ACTION_TRUST_STORE_CHANGED:
mHandler.sendEmptyMessage(HANDLE_TRUST_STORAGE_UPDATE_MSG);
break;
case "com.android.launcher.action.INSTALL_SHORTCUT":
// As of O, we no longer support this broadcasts, even for pre-O apps.
// Apps should now be using ShortcutManager.pinRequestShortcut().
Log.w(TAG, "Broadcast " + action
+ " no longer supported. It will not be delivered.");
return ActivityManager.BROADCAST_SUCCESS;
case Intent.ACTION_PRE_BOOT_COMPLETED:
timeoutExempt = true;
break;
}
if (Intent.ACTION_PACKAGE_ADDED.equals(action) ||
Intent.ACTION_PACKAGE_REMOVED.equals(action) ||
Intent.ACTION_PACKAGE_REPLACED.equals(action)) {
final int uid = getUidFromIntent(intent);
if (uid != -1) {
final UidRecord uidRec = mProcessList.getUidRecordLocked(uid);
if (uidRec != null) {
uidRec.updateHasInternetPermission();
}
}
}
}
//终于跳过了系统广播处理！！！
//先处理粘性广播
// Add to the sticky list if requested.
if (sticky) {
if (checkPermission(android.Manifest.permission.BROADCAST_STICKY,
callingPid, callingUid)
!= PackageManager.PERMISSION_GRANTED) {
String msg = "Permission Denial: broadcastIntent() requesting a sticky broadcast from pid="
+ callingPid + ", uid=" + callingUid
+ " requires " + android.Manifest.permission.BROADCAST_STICKY;
Slog.w(TAG, msg);
throw new SecurityException(msg);
}
if (requiredPermissions != null && requiredPermissions.length > 0) {
Slog.w(TAG, "Can't broadcast sticky intent " + intent
+ " and enforce permissions " + Arrays.toString(requiredPermissions));
return ActivityManager.BROADCAST_STICKY_CANT_HAVE_PERMISSION;
}
if (intent.getComponent() != null) {
throw new SecurityException(
"Sticky broadcasts can't target a specific component");
}
// We use userId directly here, since the "all" target is maintained
// as a separate set of sticky broadcasts.
if (userId != UserHandle.USER_ALL) {
// But first, if this is not a broadcast to all users, then
// make sure it doesn't conflict with an existing broadcast to
// all users.
ArrayMap<String, ArrayList<Intent>> stickies = mStickyBroadcasts.get(
UserHandle.USER_ALL);
if (stickies != null) {
ArrayList<Intent> list = stickies.get(intent.getAction());
if (list != null) {
int N = list.size();
int i;
for (i=0; i<N; i++) {
if (intent.filterEquals(list.get(i))) {
throw new IllegalArgumentException(
"Sticky broadcast " + intent + " for user "
+ userId + " conflicts with existing global broadcast");
}
}
}
}
}
//将粘性广播保存在mStickyBroadcasts里了
ArrayMap<String, ArrayList<Intent>> stickies = mStickyBroadcasts.get(userId);
if (stickies == null) {
stickies = new ArrayMap<>();
mStickyBroadcasts.put(userId, stickies);
}
ArrayList<Intent> list = stickies.get(intent.getAction());
if (list == null) {
list = new ArrayList<>();
stickies.put(intent.getAction(), list);
}
final int stickiesCount = list.size();
int i;
for (i = 0; i < stickiesCount; i++) {
if (intent.filterEquals(list.get(i))) {
// This sticky already exists, replace it.
list.set(i, new Intent(intent));
break;
}
}
if (i >= stickiesCount) {
list.add(new Intent(intent));
}
}
int[] users;
if (userId == UserHandle.USER_ALL) {
// Caller wants broadcast to go to all started users.
users = mUserController.getStartedUserArray();
} else {
// Caller wants broadcast to go to one specific user.
users = new int[] {userId};
}
// Figure out who all will receive this broadcast.
List receivers = null;
List<BroadcastFilter> registeredReceivers = null;
// Need to resolve the intent to interested receivers...
if ((intent.getFlags()&Intent.FLAG_RECEIVER_REGISTERED_ONLY)
== 0) {
//这里通过PMS，查出对应接收的静态广播接收者
receivers = collectReceiverComponents(intent, resolvedType, callingUid, users);
}
if (intent.getComponent() == null) {
if (userId == UserHandle.USER_ALL && callingUid == SHELL_UID) {
// Query one target user at a time, excluding shell-restricted users
for (int i = 0; i < users.length; i++) {
if (mUserController.hasUserRestriction(
UserManager.DISALLOW_DEBUGGING_FEATURES, users[i])) {
continue;
}
List<BroadcastFilter> registeredReceiversForUser =
mReceiverResolver.queryIntent(intent,
resolvedType, false /*defaultOnly*/, users[i]);
if (registeredReceivers == null) {
registeredReceivers = registeredReceiversForUser;
} else if (registeredReceiversForUser != null) {
registeredReceivers.addAll(registeredReceiversForUser);
}
}
} else {
//这里就从我们上面动态注册的列表里
//查询可以消费Intent的Receiver
registeredReceivers = mReceiverResolver.queryIntent(intent,
resolvedType, false /*defaultOnly*/, userId);
}
}
final boolean replacePending =
(intent.getFlags()&Intent.FLAG_RECEIVER_REPLACE_PENDING) != 0;
if (DEBUG_BROADCAST) Slog.v(TAG_BROADCAST, "Enqueueing broadcast: " + intent.getAction()
+ " replacePending=" + replacePending);
int NR = registeredReceivers != null ? registeredReceivers.size() : 0;
//如果是无序广播，就直接发送给动态接收者
if (!ordered && NR > 0) {
// If we are not serializing this broadcast, then send the
// registered receivers separately so they don't wait for the
// components to be launched.
if (isCallerSystem) {
checkBroadcastFromSystem(intent, callerApp, callerPackage, callingUid,
isProtectedBroadcast, registeredReceivers);
}
final BroadcastQueue queue = broadcastQueueForIntent(intent);
BroadcastRecord r = new BroadcastRecord(queue, intent, callerApp,
callerPackage, callingPid, callingUid, callerInstantApp, resolvedType,
requiredPermissions, appOp, brOptions, registeredReceivers, resultTo,
resultCode, resultData, resultExtras, ordered, sticky, false, userId,
allowBackgroundActivityStarts, timeoutExempt);
if (DEBUG_BROADCAST) Slog.v(TAG_BROADCAST, "Enqueueing parallel broadcast " + r);
final boolean replaced = replacePending
&& (queue.replaceParallelBroadcastLocked(r) != null);
// Note: We assume resultTo is null for non-ordered broadcasts.
if (!replaced) {
//添加到无序广播队列
queue.enqueueParallelBroadcastLocked(r);
queue.scheduleBroadcastsLocked();
}
registeredReceivers = null;
NR = 0;
}
// Merge into one list.
int ir = 0;
if (receivers != null) {
// A special case for PACKAGE_ADDED: do not allow the package
// being added to see this broadcast. This prevents them from
// using this as a back door to get run as soon as they are
// installed. Maybe in the future we want to have a special install
// broadcast or such for apps, but we'd like to deliberately make
// this decision.
String skipPackages[] = null;
if (Intent.ACTION_PACKAGE_ADDED.equals(intent.getAction())
|| Intent.ACTION_PACKAGE_RESTARTED.equals(intent.getAction())
|| Intent.ACTION_PACKAGE_DATA_CLEARED.equals(intent.getAction())) {
Uri data = intent.getData();
if (data != null) {
String pkgName = data.getSchemeSpecificPart();
if (pkgName != null) {
skipPackages = new String[] { pkgName };
}
}
} else if (Intent.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE.equals(intent.getAction())) {
skipPackages = intent.getStringArrayExtra(Intent.EXTRA_CHANGED_PACKAGE_LIST);
}
if (skipPackages != null && (skipPackages.length > 0)) {
for (String skipPackage : skipPackages) {
if (skipPackage != null) {
int NT = receivers.size();
for (int it=0; it<NT; it++) {
ResolveInfo curt = (ResolveInfo)receivers.get(it);
if (curt.activityInfo.packageName.equals(skipPackage)) {
receivers.remove(it);
it--;
NT--;
}
}
}
}
}
int NT = receivers != null ? receivers.size() : 0;
int it = 0;
ResolveInfo curt = null;
BroadcastFilter curr = null;
//如果是无序广播，则在上面赋值了NR=0，走不进下面逻辑
//走入下面逻辑的肯定是有序广播
while (it < NT && ir < NR) {
if (curt == null) {
curt = (ResolveInfo)receivers.get(it);
}
if (curr == null) {
curr = registeredReceivers.get(ir);
}
//看这个位置，把静态注册的高优先级接收者 插到了动态注册的接收者前面
if (curr.getPriority() >= curt.priority) {
// Insert this broadcast record into the final list.
receivers.add(it, curr);
ir++;
curr = null;
it++;
NT++;
} else {
// Skip to the next ResolveInfo in the final list.
it++;
curt = null;
}
}
}
while (ir < NR) {
if (receivers == null) {
receivers = new ArrayList();
}
receivers.add(registeredReceivers.get(ir));
ir++;
}
if (isCallerSystem) {
checkBroadcastFromSystem(intent, callerApp, callerPackage, callingUid,
isProtectedBroadcast, receivers);
}
if ((receivers != null && receivers.size() > 0)
|| resultTo != null) {
//下面这段，把有序广播合成的（receivers + registeredReceivers）->receivers
//或者是无序广播的静态注册receivers
//enqueueOrderedBroadcastLocked 添加到了有序广播列表？
BroadcastQueue queue = broadcastQueueForIntent(intent);
BroadcastRecord r = new BroadcastRecord(queue, intent, callerApp,
callerPackage, callingPid, callingUid, callerInstantApp, resolvedType,
requiredPermissions, appOp, brOptions, receivers, resultTo, resultCode,
resultData, resultExtras, ordered, sticky, false, userId,
allowBackgroundActivityStarts, timeoutExempt);
if (DEBUG_BROADCAST) Slog.v(TAG_BROADCAST, "Enqueueing ordered broadcast " + r);
final BroadcastRecord oldRecord =
replacePending ? queue.replaceOrderedBroadcastLocked(r) : null;
if (oldRecord != null) {
// Replaced, fire the result-to receiver.
if (oldRecord.resultTo != null) {
final BroadcastQueue oldQueue = broadcastQueueForIntent(oldRecord.intent);
try {
oldQueue.performReceiveLocked(oldRecord.callerApp, oldRecord.resultTo,
oldRecord.intent,
Activity.RESULT_CANCELED, null, null,
false, false, oldRecord.userId);
} catch (RemoteException e) {
Slog.w(TAG, "Failure ["
+ queue.mQueueName + "] sending broadcast result of "
+ intent, e);
}
}
} else {
queue.enqueueOrderedBroadcastLocked(r);
queue.scheduleBroadcastsLocked();
}
} else {
// There was nobody interested in the broadcast, but we still want to record
// that it happened.
if (intent.getComponent() == null && intent.getPackage() == null
&& (intent.getFlags()&Intent.FLAG_RECEIVER_REGISTERED_ONLY) == 0) {
// This was an implicit broadcast... let's record it for posterity.
addBroadcastStatLocked(intent.getAction(), callerPackage, 0, 0, 0);
}
}
return ActivityManager.BROADCAST_SUCCESS;
}
那么分发逻辑的话，接着往下看：
BroadcastQueue
public void scheduleBroadcastsLocked() {
if (DEBUG_BROADCAST) Slog.v(TAG_BROADCAST, "Schedule broadcasts ["
+ mQueueName + "]: current="
+ mBroadcastsScheduled);
if (mBroadcastsScheduled) {
return;
}
mHandler.sendMessage(mHandler.obtainMessage(BROADCAST_INTENT_MSG, this));
mBroadcastsScheduled = true;
}
是BroadcastQueue的一个内部类Handler进行了处理。
BroadcastQueue
private final class BroadcastHandler extends Handler {
public BroadcastHandler(Looper looper) {
super(looper, null, true);
}
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case BROADCAST_INTENT_MSG: {
if (DEBUG_BROADCAST) Slog.v(
TAG_BROADCAST, "Received BROADCAST_INTENT_MSG ["
+ mQueueName + "]");
processNextBroadcast(true);
} break;
case BROADCAST_TIMEOUT_MSG: {
synchronized (mService) {
broadcastTimeoutLocked(true);
}
} break;
}
}
}
processNextBroadcast->processNextBroadcastLocked。这个也是一个比较长的方法。它主要的处理逻辑如下：
主要分成几个部分：
1.通过deliverToRegisteredReceiverLocked方法，把mParallelBroadcasts里动态注册的无序广播Reciver都给触发了
2.剩下的有序动态广播Reciver或是静态广播Receiver，它先判断了动态注册的Reciver，通过scheduleRegisteredReceiver调用到对应的Receiver。
3.静态广播，则通过scheduleReceiver一路调用，还是ApplicationThread->H->ActivityThread三范式操作。
可以看到，第一部分是一次处理了多条，第二和第三部分都只处理一个Receiver。那有序广播里是怎么依次执行的呢？
需要看到LoadedApk.ReceiverDispatcher.Args#sendFinished方法。调用到AMS的finishReceiver，触发了下一个Receiver执行。
.0
BroadcastQueue
final void processNextBroadcastLocked(boolean fromMsg, boolean skipOomAdj) {
BroadcastRecord r;
//这边是把所有的无序广播的动态Receiver给处理了
// First, deliver any non-serialized broadcasts right away.
while (mParallelBroadcasts.size() > 0) {
r = mParallelBroadcasts.remove(0);
r.dispatchTime = SystemClock.uptimeMillis();
r.dispatchClockTime = System.currentTimeMillis();
...
final int N = r.receivers.size();
if (DEBUG_BROADCAST_LIGHT) Slog.v(TAG_BROADCAST, "Processing parallel broadcast ["
+ mQueueName + "] " + r);
for (int i=0; i<N; i++) {
Object target = r.receivers.get(i);
if (DEBUG_BROADCAST) Slog.v(TAG_BROADCAST,
"Delivering non-ordered on [" + mQueueName + "] to registered "
+ target + ": " + r);
deliverToRegisteredReceiverLocked(r, (BroadcastFilter)target, false, i);
}
...
}
// Now take care of the next serialized one...
//等待进程拉起的Broadcast，Activity也有类似机制
...
boolean looped = false;
//这里是拿到了当前需要处理的BroadcastRecoard
//有可能是有序广播Receiver，也有可能是无序的静态广播
do {
final long now = SystemClock.uptimeMillis();
r = mDispatcher.getNextBroadcastLocked(now);
if (r == null) {
// No more broadcasts are deliverable right now, so all done!
mDispatcher.scheduleDeferralCheckLocked(false);
mService.scheduleAppGcsLocked();
if (looped) {
// If we had finished the last ordered broadcast, then
// make sure all processes have correct oom and sched
// adjustments.
mService.updateOomAdjLocked(OomAdjuster.OOM_ADJ_REASON_START_RECEIVER);
}
// when we have no more ordered broadcast on this queue, stop logging
if (mService.mUserController.mBootCompleted && mLogLatencyMetrics) {
mLogLatencyMetrics = false;
}
return;
}
boolean forceReceive = false;
// Ensure that even if something goes awry with the timeout
// detection, we catch "hung" broadcasts here, discard them,
// and continue to make progress.
//
// This is only done if the system is ready so that early-stage receivers
// don't get executed with timeouts; and of course other timeout-
// exempt broadcasts are ignored.
int numReceivers = (r.receivers != null) ? r.receivers.size() : 0;
if (mService.mProcessesReady && !r.timeoutExempt && r.dispatchTime > 0) {
if ((numReceivers > 0) &&
(now > r.dispatchTime + (2 * mConstants.TIMEOUT * numReceivers))) {
Slog.w(TAG, "Hung broadcast ["
+ mQueueName + "] discarded after timeout failure:"
+ " now=" + now
+ " dispatchTime=" + r.dispatchTime
+ " startTime=" + r.receiverTime
+ " intent=" + r.intent
+ " numReceivers=" + numReceivers
+ " nextReceiver=" + r.nextReceiver
+ " state=" + r.state);
broadcastTimeoutLocked(false); // forcibly finish this broadcast
forceReceive = true;
r.state = BroadcastRecord.IDLE;
}
}
if (r.state != BroadcastRecord.IDLE) {
if (DEBUG_BROADCAST) Slog.d(TAG_BROADCAST,
"processNextBroadcast("
+ mQueueName + ") called when not idle (state="
+ r.state + ")");
return;
}
// Is the current broadcast is done for any reason?
if (r.receivers == null || r.nextReceiver >= numReceivers
|| r.resultAbort || forceReceive) {
// Send the final result if requested
if (r.resultTo != null) {
boolean sendResult = true;
// if this was part of a split/deferral complex, update the refcount and only
// send the completion when we clear all of them
if (r.splitToken != 0) {
int newCount = mSplitRefcounts.get(r.splitToken) - 1;
if (newCount == 0) {
// done! clear out this record's bookkeeping and deliver
if (DEBUG_BROADCAST_DEFERRAL) {
Slog.i(TAG_BROADCAST,
"Sending broadcast completion for split token "
+ r.splitToken + " : " + r.intent.getAction());
}
mSplitRefcounts.delete(r.splitToken);
} else {
// still have some split broadcast records in flight; update refcount
// and hold off on the callback
if (DEBUG_BROADCAST_DEFERRAL) {
Slog.i(TAG_BROADCAST,
"Result refcount now " + newCount + " for split token "
+ r.splitToken + " : " + r.intent.getAction()
+ " - not sending completion yet");
}
sendResult = false;
mSplitRefcounts.put(r.splitToken, newCount);
}
}
if (sendResult) {
try {
if (DEBUG_BROADCAST) {
Slog.i(TAG_BROADCAST, "Finishing broadcast [" + mQueueName + "] "
+ r.intent.getAction() + " app=" + r.callerApp);
}
performReceiveLocked(r.callerApp, r.resultTo,
new Intent(r.intent), r.resultCode,
r.resultData, r.resultExtras, false, false, r.userId);
// Set this to null so that the reference
// (local and remote) isn't kept in the mBroadcastHistory.
r.resultTo = null;
} catch (RemoteException e) {
r.resultTo = null;
Slog.w(TAG, "Failure ["
+ mQueueName + "] sending broadcast result of "
+ r.intent, e);
}
}
}
if (DEBUG_BROADCAST) Slog.v(TAG_BROADCAST, "Cancelling BROADCAST_TIMEOUT_MSG");
cancelBroadcastTimeoutLocked();
if (DEBUG_BROADCAST_LIGHT) Slog.v(TAG_BROADCAST,
"Finished with ordered broadcast " + r);
// ... and on to the next...
addBroadcastToHistoryLocked(r);
if (r.intent.getComponent() == null && r.intent.getPackage() == null
&& (r.intent.getFlags()&Intent.FLAG_RECEIVER_REGISTERED_ONLY) == 0) {
// This was an implicit broadcast... let's record it for posterity.
mService.addBroadcastStatLocked(r.intent.getAction(), r.callerPackage,
r.manifestCount, r.manifestSkipCount, r.finishTime-r.dispatchTime);
}
mDispatcher.retireBroadcastLocked(r);
r = null;
looped = true;
continue;
}
// Check whether the next receiver is under deferral policy, and handle that
// accordingly. If the current broadcast was already part of deferred-delivery
// tracking, we know that it must now be deliverable as-is without re-deferral.
if (!r.deferred) {
final int receiverUid = r.getReceiverUid(r.receivers.get(r.nextReceiver));
if (mDispatcher.isDeferringLocked(receiverUid)) {
if (DEBUG_BROADCAST_DEFERRAL) {
Slog.i(TAG_BROADCAST, "Next receiver in " + r + " uid " + receiverUid
+ " at " + r.nextReceiver + " is under deferral");
}
// If this is the only (remaining) receiver in the broadcast, "splitting"
// doesn't make sense -- just defer it as-is and retire it as the
// currently active outgoing broadcast.
BroadcastRecord defer;
if (r.nextReceiver + 1 == numReceivers) {
if (DEBUG_BROADCAST_DEFERRAL) {
Slog.i(TAG_BROADCAST, "Sole receiver of " + r
+ " is under deferral; setting aside and proceeding");
}
defer = r;
mDispatcher.retireBroadcastLocked(r);
} else {
// Nontrivial case; split out 'uid's receivers to a new broadcast record
// and defer that, then loop and pick up continuing delivery of the current
// record (now absent those receivers).
// The split operation is guaranteed to match at least at 'nextReceiver'
defer = r.splitRecipientsLocked(receiverUid, r.nextReceiver);
if (DEBUG_BROADCAST_DEFERRAL) {
Slog.i(TAG_BROADCAST, "Post split:");
Slog.i(TAG_BROADCAST, "Original broadcast receivers:");
for (int i = 0; i < r.receivers.size(); i++) {
Slog.i(TAG_BROADCAST, " " + r.receivers.get(i));
}
Slog.i(TAG_BROADCAST, "Split receivers:");
for (int i = 0; i < defer.receivers.size(); i++) {
Slog.i(TAG_BROADCAST, " " + defer.receivers.get(i));
}
}
// Track completion refcount as well if relevant
if (r.resultTo != null) {
int token = r.splitToken;
if (token == 0) {
// first split of this record; refcount for 'r' and 'deferred'
r.splitToken = defer.splitToken = nextSplitTokenLocked();
mSplitRefcounts.put(r.splitToken, 2);
if (DEBUG_BROADCAST_DEFERRAL) {
Slog.i(TAG_BROADCAST,
"Broadcast needs split refcount; using new token "
+ r.splitToken);
}
} else {
// new split from an already-refcounted situation; increment count
final int curCount = mSplitRefcounts.get(token);
if (DEBUG_BROADCAST_DEFERRAL) {
if (curCount == 0) {
Slog.wtf(TAG_BROADCAST,
"Split refcount is zero with token for " + r);
}
}
mSplitRefcounts.put(token, curCount + 1);
if (DEBUG_BROADCAST_DEFERRAL) {
Slog.i(TAG_BROADCAST, "New split count for token " + token
+ " is " + (curCount + 1));
}
}
}
}
mDispatcher.addDeferredBroadcast(receiverUid, defer);
r = null;
looped = true;
continue;
}
}
} while (r == null);
// Get the next receiver...
int recIdx = r.nextReceiver++;
// Keep track of when this receiver started, and make sure there
// is a timeout message pending to kill it if need be.
r.receiverTime = SystemClock.uptimeMillis();
if (recIdx == 0) {
r.dispatchTime = r.receiverTime;
r.dispatchClockTime = System.currentTimeMillis();
if (mLogLatencyMetrics) {
StatsLog.write(
StatsLog.BROADCAST_DISPATCH_LATENCY_REPORTED,
r.dispatchClockTime - r.enqueueClockTime);
}
if (Trace.isTagEnabled(Trace.TRACE_TAG_ACTIVITY_MANAGER)) {
Trace.asyncTraceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER,
createBroadcastTraceTitle(r, BroadcastRecord.DELIVERY_PENDING),
System.identityHashCode(r));
Trace.asyncTraceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER,
createBroadcastTraceTitle(r, BroadcastRecord.DELIVERY_DELIVERED),
System.identityHashCode(r));
}
if (DEBUG_BROADCAST_LIGHT) Slog.v(TAG_BROADCAST, "Processing ordered broadcast ["
+ mQueueName + "] " + r);
}
if (! mPendingBroadcastTimeoutMessage) {
long timeoutTime = r.receiverTime + mConstants.TIMEOUT;
if (DEBUG_BROADCAST) Slog.v(TAG_BROADCAST,
"Submitting BROADCAST_TIMEOUT_MSG ["
+ mQueueName + "] for " + r + " at " + timeoutTime);
setBroadcastTimeoutLocked(timeoutTime);
}
final BroadcastOptions brOptions = r.options;
final Object nextReceiver = r.receivers.get(recIdx);
//这里走入了动态广播Receiver的逻辑
if (nextReceiver instanceof BroadcastFilter) {
// Simple case: this is a registered receiver who gets
// a direct call.
BroadcastFilter filter = (BroadcastFilter)nextReceiver;
if (DEBUG_BROADCAST) Slog.v(TAG_BROADCAST,
"Delivering ordered ["
+ mQueueName + "] to registered "
+ filter + ": " + r);
//这里也是发送给动态注册广播
deliverToRegisteredReceiverLocked(r, filter, r.ordered, recIdx);
if (r.receiver == null || !r.ordered) {
//在处理广播的过程performReceiveLocked中，如果receiver所在进程被kill，则会将r.receiver = null; r.curFilter = null;
//这里看着应该全部是有序广播？!r.ordered不知道意义何在
// The receiver has already finished, so schedule to
// process the next one.
if (DEBUG_BROADCAST) Slog.v(TAG_BROADCAST, "Quick finishing ["
+ mQueueName + "]: ordered="
+ r.ordered + " receiver=" + r.receiver);
r.state = BroadcastRecord.IDLE;
scheduleBroadcastsLocked();
} else {
if (filter.receiverList != null) {
maybeAddAllowBackgroundActivityStartsToken(filter.receiverList.app, r);
// r is guaranteed ordered at this point, so we know finishReceiverLocked()
// will get a callback and handle the activity start token lifecycle.
}
if (brOptions != null && brOptions.getTemporaryAppWhitelistDuration() > 0) {
scheduleTempWhitelistLocked(filter.owningUid,
brOptions.getTemporaryAppWhitelistDuration(), r);
}
}
return;
}
// Hard case: need to instantiate the receiver, possibly
// starting its application process to host it.
//上面都是动态Receiver，这里自然是静态Receiver
ResolveInfo info =
(ResolveInfo)nextReceiver;
ComponentName component = new ComponentName(
info.activityInfo.applicationInfo.packageName,
info.activityInfo.name);
boolean skip = false;
if (brOptions != null &&
(info.activityInfo.applicationInfo.targetSdkVersion
< brOptions.getMinManifestReceiverApiLevel() ||
info.activityInfo.applicationInfo.targetSdkVersion
> brOptions.getMaxManifestReceiverApiLevel())) {
skip = true;
}
if (!skip && !mService.validateAssociationAllowedLocked(r.callerPackage, r.callingUid,
component.getPackageName(), info.activityInfo.applicationInfo.uid)) {
Slog.w(TAG, "Association not allowed: broadcasting "
+ r.intent.toString()
+ " from " + r.callerPackage + " (pid=" + r.callingPid
+ ", uid=" + r.callingUid + ") to " + component.flattenToShortString());
skip = true;
}
if (!skip) {
skip = !mService.mIntentFirewall.checkBroadcast(r.intent, r.callingUid,
r.callingPid, r.resolvedType, info.activityInfo.applicationInfo.uid);
if (skip) {
Slog.w(TAG, "Firewall blocked: broadcasting "
+ r.intent.toString()
+ " from " + r.callerPackage + " (pid=" + r.callingPid
+ ", uid=" + r.callingUid + ") to " + component.flattenToShortString());
}
}
int perm = mService.checkComponentPermission(info.activityInfo.permission,
r.callingPid, r.callingUid, info.activityInfo.applicationInfo.uid,
info.activityInfo.exported);
if (!skip && perm != PackageManager.PERMISSION_GRANTED) {
if (!info.activityInfo.exported) {
Slog.w(TAG, "Permission Denial: broadcasting "
+ r.intent.toString()
+ " from " + r.callerPackage + " (pid=" + r.callingPid
+ ", uid=" + r.callingUid + ")"
+ " is not exported from uid " + info.activityInfo.applicationInfo.uid
+ " due to receiver " + component.flattenToShortString());
} else {
Slog.w(TAG, "Permission Denial: broadcasting "
+ r.intent.toString()
+ " from " + r.callerPackage + " (pid=" + r.callingPid
+ ", uid=" + r.callingUid + ")"
+ " requires " + info.activityInfo.permission
+ " due to receiver " + component.flattenToShortString());
}
skip = true;
} else if (!skip && info.activityInfo.permission != null) {
final int opCode = AppOpsManager.permissionToOpCode(info.activityInfo.permission);
if (opCode != AppOpsManager.OP_NONE
&& mService.mAppOpsService.noteOperation(opCode, r.callingUid,
r.callerPackage) != AppOpsManager.MODE_ALLOWED) {
Slog.w(TAG, "Appop Denial: broadcasting "
+ r.intent.toString()
+ " from " + r.callerPackage + " (pid="
+ r.callingPid + ", uid=" + r.callingUid + ")"
+ " requires appop " + AppOpsManager.permissionToOp(
info.activityInfo.permission)
+ " due to registered receiver "
+ component.flattenToShortString());
skip = true;
}
}
if (!skip && info.activityInfo.applicationInfo.uid != Process.SYSTEM_UID &&
r.requiredPermissions != null && r.requiredPermissions.length > 0) {
for (int i = 0; i < r.requiredPermissions.length; i++) {
String requiredPermission = r.requiredPermissions[i];
try {
perm = AppGlobals.getPackageManager().
checkPermission(requiredPermission,
info.activityInfo.applicationInfo.packageName,
UserHandle
.getUserId(info.activityInfo.applicationInfo.uid));
} catch (RemoteException e) {
perm = PackageManager.PERMISSION_DENIED;
}
if (perm != PackageManager.PERMISSION_GRANTED) {
Slog.w(TAG, "Permission Denial: receiving "
+ r.intent + " to "
+ component.flattenToShortString()
+ " requires " + requiredPermission
+ " due to sender " + r.callerPackage
+ " (uid " + r.callingUid + ")");
skip = true;
break;
}
int appOp = AppOpsManager.permissionToOpCode(requiredPermission);
if (appOp != AppOpsManager.OP_NONE && appOp != r.appOp
&& mService.mAppOpsService.noteOperation(appOp,
info.activityInfo.applicationInfo.uid, info.activityInfo.packageName)
!= AppOpsManager.MODE_ALLOWED) {
Slog.w(TAG, "Appop Denial: receiving "
+ r.intent + " to "
+ component.flattenToShortString()
+ " requires appop " + AppOpsManager.permissionToOp(
requiredPermission)
+ " due to sender " + r.callerPackage
+ " (uid " + r.callingUid + ")");
skip = true;
break;
}
}
}
if (!skip && r.appOp != AppOpsManager.OP_NONE
&& mService.mAppOpsService.noteOperation(r.appOp,
info.activityInfo.applicationInfo.uid, info.activityInfo.packageName)
!= AppOpsManager.MODE_ALLOWED) {
Slog.w(TAG, "Appop Denial: receiving "
+ r.intent + " to "
+ component.flattenToShortString()
+ " requires appop " + AppOpsManager.opToName(r.appOp)
+ " due to sender " + r.callerPackage
+ " (uid " + r.callingUid + ")");
skip = true;
}
boolean isSingleton = false;
try {
isSingleton = mService.isSingleton(info.activityInfo.processName,
info.activityInfo.applicationInfo,
info.activityInfo.name, info.activityInfo.flags);
} catch (SecurityException e) {
Slog.w(TAG, e.getMessage());
skip = true;
}
if ((info.activityInfo.flags&ActivityInfo.FLAG_SINGLE_USER) != 0) {
if (ActivityManager.checkUidPermission(
android.Manifest.permission.INTERACT_ACROSS_USERS,
info.activityInfo.applicationInfo.uid)
!= PackageManager.PERMISSION_GRANTED) {
Slog.w(TAG, "Permission Denial: Receiver " + component.flattenToShortString()
+ " requests FLAG_SINGLE_USER, but app does not hold "
+ android.Manifest.permission.INTERACT_ACROSS_USERS);
skip = true;
}
}
if (!skip && info.activityInfo.applicationInfo.isInstantApp()
&& r.callingUid != info.activityInfo.applicationInfo.uid) {
Slog.w(TAG, "Instant App Denial: receiving "
+ r.intent
+ " to " + component.flattenToShortString()
+ " due to sender " + r.callerPackage
+ " (uid " + r.callingUid + ")"
+ " Instant Apps do not support manifest receivers");
skip = true;
}
if (!skip && r.callerInstantApp
&& (info.activityInfo.flags & ActivityInfo.FLAG_VISIBLE_TO_INSTANT_APP) == 0
&& r.callingUid != info.activityInfo.applicationInfo.uid) {
Slog.w(TAG, "Instant App Denial: receiving "
+ r.intent
+ " to " + component.flattenToShortString()
+ " requires receiver have visibleToInstantApps set"
+ " due to sender " + r.callerPackage
+ " (uid " + r.callingUid + ")");
skip = true;
}
if (r.curApp != null && r.curApp.isCrashing()) {
// If the target process is crashing, just skip it.
Slog.w(TAG, "Skipping deliver ordered [" + mQueueName + "] " + r
+ " to " + r.curApp + ": process crashing");
skip = true;
}
if (!skip) {
boolean isAvailable = false;
try {
isAvailable = AppGlobals.getPackageManager().isPackageAvailable(
info.activityInfo.packageName,
UserHandle.getUserId(info.activityInfo.applicationInfo.uid));
} catch (Exception e) {
// all such failures mean we skip this receiver
Slog.w(TAG, "Exception getting recipient info for "
+ info.activityInfo.packageName, e);
}
if (!isAvailable) {
if (DEBUG_BROADCAST) Slog.v(TAG_BROADCAST,
"Skipping delivery to " + info.activityInfo.packageName + " / "
+ info.activityInfo.applicationInfo.uid
+ " : package no longer available");
skip = true;
}
}
// If permissions need a review before any of the app components can run, we drop
// the broadcast and if the calling app is in the foreground and the broadcast is
// explicit we launch the review UI passing it a pending intent to send the skipped
// broadcast.
if (!skip) {
if (!requestStartTargetPermissionsReviewIfNeededLocked(r,
info.activityInfo.packageName, UserHandle.getUserId(
info.activityInfo.applicationInfo.uid))) {
skip = true;
}
}
// This is safe to do even if we are skipping the broadcast, and we need
// this information now to evaluate whether it is going to be allowed to run.
final int receiverUid = info.activityInfo.applicationInfo.uid;
// If it's a singleton, it needs to be the same app or a special app
if (r.callingUid != Process.SYSTEM_UID && isSingleton
&& mService.isValidSingletonCall(r.callingUid, receiverUid)) {
info.activityInfo = mService.getActivityInfoForUser(info.activityInfo, 0);
}
String targetProcess = info.activityInfo.processName;
ProcessRecord app = mService.getProcessRecordLocked(targetProcess,
info.activityInfo.applicationInfo.uid, false);
if (!skip) {
final int allowed = mService.getAppStartModeLocked(
info.activityInfo.applicationInfo.uid, info.activityInfo.packageName,
info.activityInfo.applicationInfo.targetSdkVersion, -1, true, false, false);
if (allowed != ActivityManager.APP_START_MODE_NORMAL) {
// We won't allow this receiver to be launched if the app has been
// completely disabled from launches, or it was not explicitly sent
// to it and the app is in a state that should not receive it
// (depending on how getAppStartModeLocked has determined that).
if (allowed == ActivityManager.APP_START_MODE_DISABLED) {
Slog.w(TAG, "Background execution disabled: receiving "
+ r.intent + " to "
+ component.flattenToShortString());
skip = true;
} else if (((r.intent.getFlags()&Intent.FLAG_RECEIVER_EXCLUDE_BACKGROUND) != 0)
|| (r.intent.getComponent() == null
&& r.intent.getPackage() == null
&& ((r.intent.getFlags()
& Intent.FLAG_RECEIVER_INCLUDE_BACKGROUND) == 0)
&& !isSignaturePerm(r.requiredPermissions))) {
mService.addBackgroundCheckViolationLocked(r.intent.getAction(),
component.getPackageName());
Slog.w(TAG, "Background execution not allowed: receiving "
+ r.intent + " to "
+ component.flattenToShortString());
skip = true;
}
}
}
if (!skip && !Intent.ACTION_SHUTDOWN.equals(r.intent.getAction())
&& !mService.mUserController
.isUserRunning(UserHandle.getUserId(info.activityInfo.applicationInfo.uid),
0 /* flags */)) {
skip = true;
Slog.w(TAG,
"Skipping delivery to " + info.activityInfo.packageName + " / "
+ info.activityInfo.applicationInfo.uid + " : user is not running");
}
if (skip) {
if (DEBUG_BROADCAST) Slog.v(TAG_BROADCAST,
"Skipping delivery of ordered [" + mQueueName + "] "
+ r + " for reason described above");
r.delivery[recIdx] = BroadcastRecord.DELIVERY_SKIPPED;
r.receiver = null;
r.curFilter = null;
r.state = BroadcastRecord.IDLE;
r.manifestSkipCount++;
scheduleBroadcastsLocked();
return;
}
r.manifestCount++;
r.delivery[recIdx] = BroadcastRecord.DELIVERY_DELIVERED;
r.state = BroadcastRecord.APP_RECEIVE;
r.curComponent = component;
r.curReceiver = info.activityInfo;
if (DEBUG_MU && r.callingUid > UserHandle.PER_USER_RANGE) {
Slog.v(TAG_MU, "Updated broadcast record activity info for secondary user, "
+ info.activityInfo + ", callingUid = " + r.callingUid + ", uid = "
+ receiverUid);
}
if (brOptions != null && brOptions.getTemporaryAppWhitelistDuration() > 0) {
scheduleTempWhitelistLocked(receiverUid,
brOptions.getTemporaryAppWhitelistDuration(), r);
}
// Broadcast is being executed, its package can't be stopped.
try {
AppGlobals.getPackageManager().setPackageStoppedState(
r.curComponent.getPackageName(), false, r.userId);
} catch (RemoteException e) {
} catch (IllegalArgumentException e) {
Slog.w(TAG, "Failed trying to unstop package "
+ r.curComponent.getPackageName() + ": " + e);
}
// Is this receiver's application already running?
if (app != null && app.thread != null && !app.killed) {
try {
app.addPackage(info.activityInfo.packageName,
info.activityInfo.applicationInfo.longVersionCode, mService.mProcessStats);
maybeAddAllowBackgroundActivityStartsToken(app, r);
processCurBroadcastLocked(r, app, skipOomAdj);
return;
} catch (RemoteException e) {
Slog.w(TAG, "Exception when sending broadcast to "
+ r.curComponent, e);
} catch (RuntimeException e) {
Slog.wtf(TAG, "Failed sending broadcast to "
+ r.curComponent + " with " + r.intent, e);
// If some unexpected exception happened, just skip
// this broadcast. At this point we are not in the call
// from a client, so throwing an exception out from here
// will crash the entire system instead of just whoever
// sent the broadcast.
logBroadcastReceiverDiscardLocked(r);
finishReceiverLocked(r, r.resultCode, r.resultData,
r.resultExtras, r.resultAbort, false);
scheduleBroadcastsLocked();
// We need to reset the state if we failed to start the receiver.
r.state = BroadcastRecord.IDLE;
return;
}
// If a dead object exception was thrown -- fall through to
// restart the application.
}
//进程没启动的逻辑，这个参照Activity进程拉起逻辑
// Not running -- get it started, to be executed when the app comes up.
if (DEBUG_BROADCAST) Slog.v(TAG_BROADCAST,
"Need to start app ["
+ mQueueName + "] " + targetProcess + " for broadcast " + r);
if ((r.curApp=mService.startProcessLocked(targetProcess,
info.activityInfo.applicationInfo, true,
r.intent.getFlags() | Intent.FLAG_FROM_BACKGROUND,
new HostingRecord("broadcast", r.curComponent),
(r.intent.getFlags()&Intent.FLAG_RECEIVER_BOOT_UPGRADE) != 0, false, false))
== null) {
// Ah, this recipient is unavailable. Finish it if necessary,
// and mark the broadcast record as ready for the next.
Slog.w(TAG, "Unable to launch app "
+ info.activityInfo.applicationInfo.packageName + "/"
+ receiverUid + " for broadcast "
+ r.intent + ": process is bad");
logBroadcastReceiverDiscardLocked(r);
finishReceiverLocked(r, r.resultCode, r.resultData,
r.resultExtras, r.resultAbort, false);
scheduleBroadcastsLocked();
r.state = BroadcastRecord.IDLE;
return;
}
maybeAddAllowBackgroundActivityStartsToken(r.curApp, r);
mPendingBroadcast = r;
mPendingBroadcastRecvIndex = recIdx;
}
因为这篇代码贴得比较长，不往下继续贴代码。从代码里可以看到一般难以注意的几个细节：
- 静态注册的广播Receiver，不管是发送有序广播还是无序广播，它都是串行执行的。
- 动态注册的广播，通过InnerReceiver直接调用它的存在实例类。静态注册的广播，是反射生成的Receiver类，和Activity类似。
- 无序广播，动态注册的Reciver优先于静态注册的Receiver执行。有序广播，同优先级动态注册的Reciver优先于静态注册的Receiver执行。
参考文档：
