ProcessState实例化过程讲解

1.ProcessState实例化过程

类图

时序图

<1>.new ProcessState();

<2>.ProcessState::self()->startThreadPool()

2.程序例子

1)RefBase基类和智能指针StrongPointer关系

make()函数用法在StrongPointer.h里.
system/core/libutils/include/utils/StrongPointer.h
class sp {
 template <typename T>
 template <typename... Args>
 sp<T> sp<T>::make(Args&&... args) {
    T* t = new T(std::forward<Args>(args)...);
    sp<T> result;
    result.m_ptr = t;
    t->incStrong(t);  // bypass check_not_on_stack for heap allocation
    return result;
 }
};
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2).其实RefBase.h里引用了utils/StrongPointer.h,即使用了智能指针,如下所示：

system/core/libutils/include/utils/RefBase.h
#include **
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<1>.Android.mk

```Makefile
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE_TAGS := optional
LOCAL_MODULE := sppointer
LOCAL_SRC_FILES := strong_pointer.cpp
LOCAL_SHARED_LIBRARIES := libcutils libutils
include $(BUILD_EXECUTABLE)

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<2>.strong_pointer.cpp

#include 
#include 
#include 
using namespace android;

class Bigclass : public RefBase{
public:
  Bigclass(String8 name): mDriverName(name){
    printf("Bigclass::mDriverName = %s\n",mDriverName.c_str());
  }

  String8 getDriverName() {
    return mDriverName;
  }
  
private:
  String8 mDriverName;
};

int main(){
  const char *driver = "/dev/binder";
  static sp<Bigclass>  bC;

  //bC = = new Bigclass(String8(driver));
  //Or  
  //注意：此处make(String8(driver))等价于类实例化new Bigclass(String8(driver));
  bC = sp<Bigclass>::make(String8(driver));
  printf("xxx------> driverName = %s\n",bC->getDriverName().c_str());
  return 0;
}

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