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      1 /*
      2  * Copyright (C) 2017 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 #ifndef HWUI_THREADBASE_H
     18 #define HWUI_THREADBASE_H
     19 
     20 #include "WorkQueue.h"
     21 #include "utils/Macros.h"
     22 
     23 #include <utils/Looper.h>
     24 #include <utils/Thread.h>
     25 
     26 #include <algorithm>
     27 
     28 namespace android::uirenderer {
     29 
     30 class ThreadBase : public Thread {
     31     PREVENT_COPY_AND_ASSIGN(ThreadBase);
     32 
     33 public:
     34     ThreadBase()
     35             : Thread(false)
     36             , mLooper(new Looper(false))
     37             , mQueue([this]() { mLooper->wake(); }, mLock) {}
     38 
     39     WorkQueue& queue() { return mQueue; }
     40 
     41     void requestExit() {
     42         Thread::requestExit();
     43         mLooper->wake();
     44     }
     45 
     46     void start(const char* name = "ThreadBase") { Thread::run(name); }
     47 
     48     void join() { Thread::join(); }
     49 
     50     bool isRunning() const { return Thread::isRunning(); }
     51 
     52 protected:
     53     void waitForWork() {
     54         nsecs_t nextWakeup;
     55         {
     56             std::unique_lock lock{mLock};
     57             nextWakeup = mQueue.nextWakeup(lock);
     58         }
     59         int timeout = -1;
     60         if (nextWakeup < std::numeric_limits<nsecs_t>::max()) {
     61             timeout = ns2ms(nextWakeup - WorkQueue::clock::now());
     62             if (timeout < 0) timeout = 0;
     63         }
     64         int result = mLooper->pollOnce(timeout);
     65         LOG_ALWAYS_FATAL_IF(result == Looper::POLL_ERROR, "RenderThread Looper POLL_ERROR!");
     66     }
     67 
     68     void processQueue() { mQueue.process(); }
     69 
     70     virtual bool threadLoop() override {
     71         Looper::setForThread(mLooper);
     72         while (!exitPending()) {
     73             waitForWork();
     74             processQueue();
     75         }
     76         Looper::setForThread(nullptr);
     77         return false;
     78     }
     79 
     80     sp<Looper> mLooper;
     81 
     82 private:
     83     WorkQueue mQueue;
     84     std::mutex mLock;
     85 };
     86 
     87 }  // namespace android::uirenderer
     88 
     89 #endif  // HWUI_THREADBASE_H
     90