信息会话Thread_id异常处理(MMS草稿修改收件人，SMS新信息丢失thread数据)

protected void onReceiveWithPrivilege(Context context, Intent intent, boolean privileged) {
        String action = intent.getAction();
        // If ‘privileged‘ is false, it means that the intent was delivered to the base
        // no-permissions receiver class.  If we get an SMS_RECEIVED message that way, it
        // means someone has tried to spoof the message by delivering it outside the normal
        // permission-checked route, so we just ignore it.
        if (!privileged && (Intents.SMS_DELIVER_ACTION.equals(action) ||
                "android.cellbroadcastreceiver.CB_AREA_INFO_RECEIVED".equals(action))) {
            return;
        }

        intent.setClass(context, SmsReceiverService.class);
        intent.putExtra("result", getResultCode());
        beginStartingService(context, intent);
    }

public static void beginStartingService(Context context, Intent intent) {
        synchronized (mStartingServiceSync) {
            if (mStartingService == null) {
                PowerManager pm =
                    (PowerManager)context.getSystemService(Context.POWER_SERVICE);
                mStartingService = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK,
                        "StartingAlertService");
                mStartingService.setReferenceCounted(false);
            }
            mStartingService.acquire();//使用PowerManager.WakeLock保证Service在灭屏状态下依然可以运行
            context.startService(intent);
        }
    }

if (((threadId == null) || (threadId == 0)) && (address != null)) {
            threadId = Conversation.getOrCreateThreadId(context, address);
            values.put(Sms.THREAD_ID, threadId);
}

ContentResolver resolver = context.getContentResolver();

Uri insertedUri = SqliteWrapper.insert(context, resolver, Inbox.CONTENT_URI, values);//数据库更新

// Now make sure we‘re not over the limit in stored messages
Recycler.getSmsRecycler().deleteOldMessagesByThreadId(context, threadId);
MmsWidgetProvider.notifyDatasetChanged(context);

return insertedUri;

case URI_UNREAD_AND_LOST_THREADS: { //自定义一个查询类型，对于unread Sms进行thread_id判断过滤
                String unreadSmsQuery = "SELECT _id, thread_id, address "
                        + "FROM sms "
                        + "WHERE sms.read = 0 AND thread_id NOT IN( SELECT _id FROM threads)";
                        
                cursor = mOpenHelper.getReadableDatabase().rawQuery(unreadSmsQuery, EMPTY_STRING_ARRAY);
                if(cursor!=null && cursor.getCount()>0){
                    //should repair the lost data in thread table, but I have no good idea now, so just leave it
                    Log.e("antoon", "MmsSmsProvider, have lost thread sms : "+cursor.getCount());
                }
        return cursor;
}

private void asyncUpdateDraftMmsMessage(final Conversation conv, final boolean isStopping) {
        if (Log.isLoggable(LogTag.APP, Log.VERBOSE)) {
            LogTag.debug("asyncUpdateDraftMmsMessage conv=%s mMessageUri=%s", conv, mMessageUri);
        }
        final HashMap<Uri, InputStream> preOpenedFiles =
                mSlideshow.openPartFiles(mContentResolver);

        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    DraftCache.getInstance().setSavingDraft(true);

                    final PduPersister persister = PduPersister.getPduPersister(mActivity);
                    final SendReq sendReq = makeSendReq(conv, mSubject);
                    persister.setMmsDraftThreadId(mOldMmsDraftThreadId);//add by antoon, send old thread_id to pdu
                    
                    if (mMessageUri == null) {
                        mMessageUri = createDraftMmsMessage(persister, sendReq, mSlideshow, null,
                                mActivity, preOpenedFiles);//对于MMS保存，thread_id会在pdu保存时创建
                    } else {
                        updateDraftMmsMessage(mMessageUri, persister, mSlideshow, sendReq,
                                preOpenedFiles);//修改之前保存的MMS后，pdu更新数据，这里会根据收件人getOrCreateThreadId,所以修改收件人会导致创建新的thread
                    }
                    ensureThreadIdIfNeeded(conv, isStopping);//这里确认thread_id创建或获取成功，否则再次执行getOrCreateThreadId
                    conv.setDraftState(true);
                    if (Log.isLoggable(LogTag.APP, Log.VERBOSE)) {
                        LogTag.debug("asyncUpdateDraftMmsMessage conv: " + conv +
                                " uri: " + mMessageUri);
                    }

                    // Be paranoid and delete any SMS drafts that might be lying around. Must do
                    // this after ensureThreadId so conv has the correct thread id.
                    asyncDeleteDraftSmsMessage(conv);
                } finally {
                    DraftCache.getInstance().setSavingDraft(false);
                    closePreOpenedFiles(preOpenedFiles);
                }
            }
        }, "WorkingMessage.asyncUpdateDraftMmsMessage").start();
    }

private void ensureThreadIdIfNeeded(final Conversation conv, final boolean isStopping) {
        if (isStopping && conv.getMessageCount() == 0) {
            // We need to save the drafts in an unorphaned thread id. When the user goes
            // back to ConversationList while we‘re saving a draft from CMA‘s.onStop,
            // ConversationList will delete all threads from the thread table that
            // don‘t have associated sms or pdu entries. In case our thread got deleted,
            // well call clearThreadId() so ensureThreadId will query the db for the new
            // thread.
            conv.clearThreadId();   // force us to get the updated thread id
        }
        if (!conv.getRecipients().isEmpty()) {
            conv.ensureThreadId();
        }
    }

public synchronized void clearThreadId() {
        // remove ourself from the cache
        if (Log.isLoggable(LogTag.APP, Log.VERBOSE)) {
            LogTag.debug("clearThreadId old threadId was: " + mThreadId + " now zero");
        }
        Cache.remove(mThreadId);

        mThreadId = 0;
}

public synchronized long ensureThreadId() {
        if (DEBUG || DELETEDEBUG) {
            LogTag.debug("ensureThreadId before: " + mThreadId);
        }
        if (mThreadId <= 0) {
            if (mIsGroupChat && mGroupChat != null) {
                HashSet<String> numbers = new HashSet<String>();
                numbers.add(String.valueOf(mGroupChat.getThreadId()));
                ContactList groupRecip = ContactList.getByNumbers(numbers, false);
                mThreadId = getOrCreateThreadId(mContext, groupRecip, mIsGroupChat);
            } else {
                mThreadId = getOrCreateThreadId(mContext, mRecipients, mIsGroupChat);
            }
        }
        if (DEBUG || DELETEDEBUG) {
            LogTag.debug("ensureThreadId after: " + mThreadId);
        }

        return mThreadId;
}