AMS 启动应用程序进程

    private String bringUpServiceLocked(ServiceRecord r, int intentFlags, boolean execInFg,
            boolean whileRestarting, boolean permissionsReviewRequired)
            throws TransactionTooLargeException {
        if (r.app != null && r.app.thread != null) {
            sendServiceArgsLocked(r, execInFg, false);
            return null;
        }
 
        if (!whileRestarting && mRestartingServices.contains(r)) {
            // If waiting for a restart, then do nothing.
            return null;
        }
 
        if (DEBUG_SERVICE) {
            Slog.v(TAG_SERVICE, "Bringing up " + r + " " + r.intent + " fg=" + r.fgRequired);
        }
 
        // We are now bringing the service up, so no longer in the
        // restarting state.
        if (mRestartingServices.remove(r)) {
            clearRestartingIfNeededLocked(r);
        }
 
        // Make sure this service is no longer considered delayed, we are starting it now.
        if (r.delayed) {
            if (DEBUG_DELAYED_STARTS) Slog.v(TAG_SERVICE, "REM FR DELAY LIST (bring up): " + r);
            getServiceMapLocked(r.userId).mDelayedStartList.remove(r);
            r.delayed = false;
        }
 
        // Make sure that the user who owns this service is started.  If not,
        // we don't want to allow it to run.
        if (!mAm.mUserController.hasStartedUserState(r.userId)) {
            String msg = "Unable to launch app "
                    + r.appInfo.packageName + "/"
                    + r.appInfo.uid + " for service "
                    + r.intent.getIntent() + ": user " + r.userId + " is stopped";
            Slog.w(TAG, msg);
            bringDownServiceLocked(r);
            return msg;
        }
        // Service is now being launched, its package can't be stopped.
        try {
            AppGlobals.getPackageManager().setPackageStoppedState(
                    r.packageName, false, r.userId);
        } catch (RemoteException e) {
        } catch (IllegalArgumentException e) {
            Slog.w(TAG, "Failed trying to unstop package "
                    + r.packageName + ": " + e);
        }
 
        final boolean isolated = (r.serviceInfo.flags&ServiceInfo.FLAG_ISOLATED_PROCESS) != 0;
得到ServiceRecord的processName的值赋值给procName ，其中ServiceRecord用来描述Service的android:process属性。
        final String procName = r.processName;
        HostingRecord hostingRecord = new HostingRecord("service", r.instanceName);
        ProcessRecord app;
 
        if (!isolated) {
将procName和Service的uid传入到AMS的getProcessRecordLocked方法中，来查询是否存在一个与Service对应的ProcessRecord类型的对象app，ProcessRecord主要用来记录运行的应用程序进程的信息。
            app = mAm.getProcessRecordLocked(procName, r.appInfo.uid, false);
            if (DEBUG_MU) Slog.v(TAG_MU, "bringUpServiceLocked: appInfo.uid=" + r.appInfo.uid
                        + " app=" + app);
            if (app != null && app.thread != null) {
                try {
 
                    app.addPackage(r.appInfo.packageName, r.appInfo.longVersionCode, mAm.mProcessStats);
                    realStartServiceLocked(r, app, execInFg);
                    return null;
                } catch (TransactionTooLargeException e) {
                    throw e;
                } catch (RemoteException e) {
                    Slog.w(TAG, "Exception when starting service " + r.shortInstanceName, e);
                }
 
                // If a dead object exception was thrown -- fall through to
                // restart the application.
            }
        } else {
            // If this service runs in an isolated process, then each time
            // we call startProcessLocked() we will get a new isolated
            // process, starting another process if we are currently waiting
            // for a previous process to come up.  To deal with this, we store
            // in the service any current isolated process it is running in or
            // waiting to have come up.
            app = r.isolatedProc;
            if (WebViewZygote.isMultiprocessEnabled()
                    && r.serviceInfo.packageName.equals(WebViewZygote.getPackageName())) {
                hostingRecord = HostingRecord.byWebviewZygote(r.instanceName);
            }
            if ((r.serviceInfo.flags & ServiceInfo.FLAG_USE_APP_ZYGOTE) != 0) {
                hostingRecord = HostingRecord.byAppZygote(r.instanceName, r.definingPackageName,
                        r.definingUid);
            }
        }
 
        // Not running -- get it started, and enqueue this service record
        // to be executed when the app comes up.
判断Service对应的app为null则说明用来运行Service的应用程序进程不存在
        if (app == null && !permissionsReviewRequired) {
            // TODO (chriswailes): Change the Zygote policy flags based on if the launch-for-service
            //  was initiated from a notification tap or not.
startProcessLocked方法来创建对应的应用程序进程
            if ((app=mAm.startProcessLocked(procName, r.appInfo, true, intentFlags,
                    hostingRecord, ZYGOTE_POLICY_FLAG_EMPTY, false, isolated, false)) == null) {
                String msg = "Unable to launch app "
                        + r.appInfo.packageName + "/"
                        + r.appInfo.uid + " for service "
                        + r.intent.getIntent() + ": process is bad";
                Slog.w(TAG, msg);
                bringDownServiceLocked(r);
                return msg;
            }
            if (isolated) {
                r.isolatedProc = app;
            }
        }
 
        if (r.fgRequired) {
            if (DEBUG_FOREGROUND_SERVICE) {
                Slog.v(TAG, "Whitelisting " + UserHandle.formatUid(r.appInfo.uid)
                        + " for fg-service launch");
            }
            mAm.tempWhitelistUidLocked(r.appInfo.uid,
                    SERVICE_START_FOREGROUND_TIMEOUT, "fg-service-launch");
        }
 
        if (!mPendingServices.contains(r)) {
            mPendingServices.add(r);
        }
 
        if (r.delayedStop) {
            // Oh and hey we've already been asked to stop!
            r.delayedStop = false;
            if (r.startRequested) {
                if (DEBUG_DELAYED_STARTS) Slog.v(TAG_SERVICE,
                        "Applying delayed stop (in bring up): " + r);
                stopServiceLocked(r);
            }
        }
        return null;
    }