Binder C + + class

Binder

Binder as a mechanism for IPC in Android, is used everywhere in Android. Contains three layers (Java, c++/c, driver).
The purpose of binder is to implement communication between multiple processes, with data passed between the basic data type, binder type, and this wrapper in parcel.
In the C + + tier, use multiple classes to encapsulate:

The main classes are:

1. RefBaseAbout reference counting
2. ParcelThis is the data container for the transfer and also supports the ##### #IBinder对象 ##### #的引用.
3. IBinderBinder object interface with transact pure virtual function
4. BpBinderBinder Reference Object, present BpRefBase in, generated by binder driver
5. BBinderBinder's Entity Object
6. IInterfaceInterface
7. BnInterfaceTemplate class, inherited by Ixx and Bbinder
8. BpInterfaceTemplate class, inherited by Ixx and Bprefbase
9. IPCThreadState
10. ProcessStateAfter the class is generated, the binder driver opens.

In C + + to write binder applications, to have a client code and server-side code, one of my applications, the main code is:

Client

  
 

   
  

  
int main(int argc, char** argv) 
   
  

  
 { 
   
  

  
 LOGI("binderclient"); 
   
  

  
 printf("binderclient --\n"); 
   
  

  
 int sum = 0; 
   
  

  
 sp mTestBinserService; 
   
  

  
 if (mTestBinserService.get() == 0) { 
   
  

  
 sp sm = defaultServiceManager(); 
   
  

  
 sp binder; 
   
  

  
 do { 
   
  

  
 binder = sm->getService(String16("my.test.binder")); 
   
  

  
 if (binder != 0) 
   
  

  
 break; 
   
  

  
 LOGI("getService fail"); 
   
  

  
 usleep(500000); // 0.5 s 
   
  

  
 } while (true); 
   
  

  
 mTestBinserService = interface_cast (binder); 
   
  

  
 LOGE_IF(mTestBinserService == 0, "no ITestBinserService!?"); 
   
  

  
 } 
   
  

  
 sum = mTestBinserService->add(3, 4); 
   
  

  
 LOGI("sum = %d", sum); 
   
  

  
 return 0; 
   
  

  

   
  

  
}
  
 

Service side

  
 

   
  

  
int main(int argc, char** argv) 
   
  

  
 { 
   
  

  

   
  

  
 sp proc(ProcessState::self()); 
   
  

  
 sp sm = defaultServiceManager(); 
   
  

  
 LOGI("TestBinderService before"); 
   
  

  
 //TestBinderService::instantiate(); 
   
  

  
 sm->addService(String16("my.test.binder", new TestBinderService());//TestBinderService继承于B你Interface, 也就是继承于ITestBinderService和BBinder.
   
  

  
 LOGI("TestBinderService End"); 
   
  

  
 ProcessState::self()->startThreadPool(); 
   
  

  
 IPCThreadState::self()->joinThreadPool(); 
   
  

  
 LOGI("TestBinderService End"); 
   
  

  
 return 0; 
   
  

  

   
  

  
}
  
 

Inter-process callbacks

Using binders allows you to implement callbacks between processes. The IBinder interface is available as a function parameter.

From for notes (Wiz)

Binder C + + class