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通过andorid studio 下载的源码貌似有些问题

下载地址：

里面的serviceManager类

/* * Copyright (C) 2009 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * *      http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */package android.os;import java.util.Map;public final class ServiceManager {    /**     * Returns a reference to a service with the given name.     *     * @param name the name of the service to get     * @return a reference to the service, or null if the service doesn't exist     */    public static IBinder getService(String name) {        return null;    }    /**     * Is not supposed to return null, but that is fine for layoutlib.     */    public static IBinder getServiceOrThrow(String name) throws ServiceNotFoundException {        throw new ServiceNotFoundException(name);    }    /**     * Place a new @a service called @a name into the service     * manager.     *     * @param name the name of the new service     * @param service the service object     */    public static void addService(String name, IBinder service) {        // pass    }    /**     * Retrieve an existing service called @a name from the     * service manager.  Non-blocking.     */    public static IBinder checkService(String name) {        return null;    }    /**     * Return a list of all currently running services.     * @return an array of all currently running services, or null in     * case of an exception     */    public static String[] listServices() {        // actual implementation returns null sometimes, so it's ok        // to return null instead of an empty list.        return null;    }    /**     * This is only intended to be called when the process is first being brought     * up and bound by the activity manager. There is only one thread in the process     * at that time, so no locking is done.     *     * @param cache the cache of service references     * @hide     */    public static void initServiceCache(Map
   
     cache) {        // pass    }    /**     * Exception thrown when no service published for given name. This might be     * thrown early during boot before certain services have published     * themselves.     *     * @hide     */    public static class ServiceNotFoundException extends Exception {        // identical to the original implementation        public ServiceNotFoundException(String name) {            super("No service published for: " + name);        }    }}
   

可以看到，这套源码里面，serviceManager的很多方法都没有，实现

而通过

这个地址查看android.os.ServiceManager这个类可以发现是这样的

/*2 * Copyright (C) 2007 The Android Open Source Project3 *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 at7 *8 *      http://www.apache.org/licenses/LICENSE-2.09 *10 * Unless required by applicable law or agreed to in writing, software11 * 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 and14 * limitations under the License.15 */1617package android.os;1819import android.util.Log;2021import com.android.internal.annotations.GuardedBy;22import com.android.internal.os.BinderInternal;23import com.android.internal.util.StatLogger;2425import java.util.HashMap;26import java.util.Map;2728/** @hide */29public final class ServiceManager {30    private static final String TAG = "ServiceManager";31    private static final Object sLock = new Object();3233    private static IServiceManager sServiceManager;3435    /**36     * Cache for the "well known" services, such as WM and AM.37     */38    private static HashMap
   
     sCache = new HashMap
    
     ();3940    /**41     * We do the "slow log" at most once every this interval.42     */43    private static final int SLOW_LOG_INTERVAL_MS = 5000;4445    /**46     * We do the "stats log" at most once every this interval.47     */48    private static final int STATS_LOG_INTERVAL_MS = 5000;4950    /**51     * Threshold in uS for a "slow" call, used on core UIDs. We use a more relax value to52     * avoid logspam.53     */54    private static final long GET_SERVICE_SLOW_THRESHOLD_US_CORE =55            SystemProperties.getInt("debug.servicemanager.slow_call_core_ms", 10) * 1000;5657    /**58     * Threshold in uS for a "slow" call, used on non-core UIDs. We use a more relax value to59     * avoid logspam.60     */61    private static final long GET_SERVICE_SLOW_THRESHOLD_US_NON_CORE =62            SystemProperties.getInt("debug.servicemanager.slow_call_ms", 50) * 1000;6364    /**65     * We log stats logging ever this many getService() calls.66     */67    private static final int GET_SERVICE_LOG_EVERY_CALLS_CORE =68            SystemProperties.getInt("debug.servicemanager.log_calls_core", 100);6970    /**71     * We log stats logging ever this many getService() calls.72     */73    private static final int GET_SERVICE_LOG_EVERY_CALLS_NON_CORE =74            SystemProperties.getInt("debug.servicemanager.log_calls", 200);7576    @GuardedBy("sLock")77    private static int sGetServiceAccumulatedUs;7879    @GuardedBy("sLock")80    private static int sGetServiceAccumulatedCallCount;8182    @GuardedBy("sLock")83    private static long sLastStatsLogUptime;8485    @GuardedBy("sLock")86    private static long sLastSlowLogUptime;8788    @GuardedBy("sLock")89    private static long sLastSlowLogActualTime;9091    interface Stats {92        int GET_SERVICE = 0;9394        int COUNT = GET_SERVICE + 1;95    }9697    public static final StatLogger sStatLogger = new StatLogger(new String[] {98            "getService()",99    });100101    private static IServiceManager getIServiceManager() {102        if (sServiceManager != null) {103            return sServiceManager;104        }105106        // Find the service manager107        sServiceManager = ServiceManagerNative108                .asInterface(Binder.allowBlocking(BinderInternal.getContextObject()));109        return sServiceManager;110    }111112    /**113     * Returns a reference to a service with the given name.114     *115     * @param name the name of the service to get116     * @return a reference to the service, or 
     null if the service doesn't exist117     */118    public static IBinder getService(String name) {119        try {120            IBinder service = sCache.get(name);121            if (service != null) {122                return service;123            } else {124                return Binder.allowBlocking(rawGetService(name));125            }126        } catch (RemoteException e) {127            Log.e(TAG, "error in getService", e);128        }129        return null;130    }131132    /**133     * Returns a reference to a service with the given name, or throws134     * {@link NullPointerException} if none is found.135     *136     * @hide137     */138    public static IBinder getServiceOrThrow(String name) throws ServiceNotFoundException {139        final IBinder binder = getService(name);140        if (binder != null) {141            return binder;142        } else {143            throw new ServiceNotFoundException(name);144        }145    }146147    /**148     * Place a new @a service called @a name into the service149     * manager.150     *151     * @param name the name of the new service152     * @param service the service object153     */154    public static void addService(String name, IBinder service) {155        addService(name, service, false, IServiceManager.DUMP_FLAG_PRIORITY_DEFAULT);156    }157158    /**159     * Place a new @a service called @a name into the service160     * manager.161     *162     * @param name the name of the new service163     * @param service the service object164     * @param allowIsolated set to true to allow isolated sandboxed processes165     * to access this service166     */167    public static void addService(String name, IBinder service, boolean allowIsolated) {168        addService(name, service, allowIsolated, IServiceManager.DUMP_FLAG_PRIORITY_DEFAULT);169    }170171    /**172     * Place a new @a service called @a name into the service173     * manager.174     *175     * @param name the name of the new service176     * @param service the service object177     * @param allowIsolated set to true to allow isolated sandboxed processes178     * @param dumpPriority supported dump priority levels as a bitmask179     * to access this service180     */181    public static void addService(String name, IBinder service, boolean allowIsolated,182            int dumpPriority) {183        try {184            getIServiceManager().addService(name, service, allowIsolated, dumpPriority);185        } catch (RemoteException e) {186            Log.e(TAG, "error in addService", e);187        }188    }189190    /**191     * Retrieve an existing service called @a name from the192     * service manager.  Non-blocking.193     */194    public static IBinder checkService(String name) {195        try {196            IBinder service = sCache.get(name);197            if (service != null) {198                return service;199            } else {200                return Binder.allowBlocking(getIServiceManager().checkService(name));201            }202        } catch (RemoteException e) {203            Log.e(TAG, "error in checkService", e);204            return null;205        }206    }207208    /**209     * Return a list of all currently running services.210     * @return an array of all currently running services, or 
     null in211     * case of an exception212     */213    public static String[] listServices() {214        try {215            return getIServiceManager().listServices(IServiceManager.DUMP_FLAG_PRIORITY_ALL);216        } catch (RemoteException e) {217            Log.e(TAG, "error in listServices", e);218            return null;219        }220    }221222    /**223     * This is only intended to be called when the process is first being brought224     * up and bound by the activity manager. There is only one thread in the process225     * at that time, so no locking is done.226     *227     * @param cache the cache of service references228     * @hide229     */230    public static void initServiceCache(Map
     
       cache) {231        if (sCache.size() != 0) {232            throw new IllegalStateException("setServiceCache may only be called once");233        }234        sCache.putAll(cache);235    }236237    /**238     * Exception thrown when no service published for given name. This might be239     * thrown early during boot before certain services have published240     * themselves.241     *242     * @hide243     */244    public static class ServiceNotFoundException extends Exception {245        public ServiceNotFoundException(String name) {246            super("No service published for: " + name);247        }248    }249250    private static IBinder rawGetService(String name) throws RemoteException {251        final long start = sStatLogger.getTime();252253        final IBinder binder = getIServiceManager().getService(name);254255        final int time = (int) sStatLogger.logDurationStat(Stats.GET_SERVICE, start);256257        final int myUid = Process.myUid();258        final boolean isCore = UserHandle.isCore(myUid);259260        final long slowThreshold = isCore261                ? GET_SERVICE_SLOW_THRESHOLD_US_CORE262                : GET_SERVICE_SLOW_THRESHOLD_US_NON_CORE;263264        synchronized (sLock) {265            sGetServiceAccumulatedUs += time;266            sGetServiceAccumulatedCallCount++;267268            final long nowUptime = SystemClock.uptimeMillis();269270            // Was a slow call?271            if (time >= slowThreshold) {272                // We do a slow log:273                // - At most once in every SLOW_LOG_INTERVAL_MS274                // - OR it was slower than the previously logged slow call.275                if ((nowUptime > (sLastSlowLogUptime + SLOW_LOG_INTERVAL_MS))276                        || (sLastSlowLogActualTime < time)) {277                    EventLogTags.writeServiceManagerSlow(time / 1000, name);278279                    sLastSlowLogUptime = nowUptime;280                    sLastSlowLogActualTime = time;281                }282            }283284            // Every GET_SERVICE_LOG_EVERY_CALLS calls, log the total time spent in getService().285286            final int logInterval = isCore287                    ? GET_SERVICE_LOG_EVERY_CALLS_CORE288                    : GET_SERVICE_LOG_EVERY_CALLS_NON_CORE;289290            if ((sGetServiceAccumulatedCallCount >= logInterval)291                    && (nowUptime >= (sLastStatsLogUptime + STATS_LOG_INTERVAL_MS))) {292293                EventLogTags.writeServiceManagerStats(294                        sGetServiceAccumulatedCallCount, // Total # of getService() calls.295                        sGetServiceAccumulatedUs / 1000, // Total time spent in getService() calls.296                        (int) (nowUptime - sLastStatsLogUptime)); // Uptime duration since last log.297                sGetServiceAccumulatedCallCount = 0;298                sGetServiceAccumulatedUs = 0;299                sLastStatsLogUptime = nowUptime;300            }301        }302        return binder;303    }304}305
     
    
   

这r3版本的源码，serviceManager里面的东西就都实现了。。。

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那么，serviceManager这个类主要是用来干嘛的呢，其实这个类是系统中的ServiceManager在java端的一个代理

看下SystemServiceRegister类中它干了什么就知道了，如下，很多service的代理都可以通过它得到

registerService(Context.CONNECTIVITY_SERVICE, ConnectivityManager.class,                new StaticApplicationContextServiceFetcher
   
    () {            @Override            public ConnectivityManager createService(Context context) throws ServiceNotFoundException {                IBinder b = ServiceManager.getServiceOrThrow(Context.CONNECTIVITY_SERVICE);                IConnectivityManager service = IConnectivityManager.Stub.asInterface(b);                return new ConnectivityManager(context, service);            }});        registerService(Context.IPSEC_SERVICE, IpSecManager.class,                new CachedServiceFetcher
    
     () {            @Override            public IpSecManager createService(ContextImpl ctx) throws ServiceNotFoundException {                IBinder b = ServiceManager.getService(Context.IPSEC_SERVICE);                IIpSecService service = IIpSecService.Stub.asInterface(b);                return new IpSecManager(ctx, service);            }});        registerService(Context.COUNTRY_DETECTOR, CountryDetector.class,                new StaticServiceFetcher
     
      () {            @Override            public CountryDetector createService() throws ServiceNotFoundException {                IBinder b = ServiceManager.getServiceOrThrow(Context.COUNTRY_DETECTOR);                return new CountryDetector(ICountryDetector.Stub.asInterface(b));            }});        registerService(Context.DEVICE_POLICY_SERVICE, DevicePolicyManager.class,                new CachedServiceFetcher
      
       () {            @Override            public DevicePolicyManager createService(ContextImpl ctx) throws ServiceNotFoundException {                IBinder b = ServiceManager.getServiceOrThrow(Context.DEVICE_POLICY_SERVICE);                return new DevicePolicyManager(ctx, IDevicePolicyManager.Stub.asInterface(b));            }});
      
     
    
   

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