Android Binder机制（一） ------- 整体框架
1. Binder基本介绍
Binder主要用于android系统进程间的通讯。数据在进程间传递只需要拷贝一次数据。由Binder内核层、Native核心层、C++/JAVA应用层组成。
2. Binder框架图
graph BT
A(Linux Binder Driver) --> B(ProcessState IPCThreadState)
B --> A
B --> C(Binder Client)
C --> B
B --> D(Binder Server)
D --> B
- Binder驱动属于内核层，进程与内核打交道，最终实现进程间通信
- ProcessState/IPCThreadState属于Native核心层，操作Binder设备文件，对上提供内核层Binder接口的封装
- 客户端、服务端属于应用层，主要是具体服务的实现及调用，进程间通讯体现在这一层次。
3. Binder类图
@startuml
interface IBinder {
virtual sp queryLocalInterface(const String16& descriptor);
virtual const String16& getInterfaceDescriptor() const = 0;
virtual status_t dump(int fd, const Vector& args) = 0;
virtual status_t transact(uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags = 0) = 0;
virtual status_t linkToDeath(const sp& recipient, void* cookie = NULL, uint32_t flags = 0) = 0;
}
class BBinder {
virtual status_t onTransact( uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags = 0);
}
IBinder <|.. BBinder
class BpRefBase {
IBinder* const mRemote;
}
IBinder <|.. BpRefBase
class BpBinder {
const int32_t mHandle;
}
IBinder <|.. BpBinder
class ISurfaceComposer {
}
class BnInterface {
}
BBinder <|-- BnInterface
ISurfaceComposer <|-- BnInterface
class BpInterface {
}
BpRefBase <|-- BpInterface
ISurfaceComposer <|-- BpInterface
@enduml
