前言：

Android 在native层(c/c++)提供了一种 IPC 机制 —— Binder，Binder的底层是通过共享内存来实现的，共享内存的 wrapper IMemory 也在 Binder 的工程里，而且是可以复用的，即如果想在 Android的 native 层使用共享内存，那么可以使用 IMemory 体系。

源码路径：\frameworks\native\libs\binder

Binder同时提供了 ndk 和 aidl ，因此同时存在 java 和 c++ 的api 。

native头文件路径：#include <binder/xxx> , \frameworks\native\libs\binder\include\binder

工程结构：

核心工程 libbinder 

cc_library_shared {name: "libbinder",...srcs: ["ActivityManager.cpp","AppOpsManager.cpp","Binder.cpp","BpBinder.cpp","BufferedTextOutput.cpp","Debug.cpp","IActivityManager.cpp","IAppOpsCallback.cpp","IAppOpsService.cpp","IBatteryStats.cpp","IInterface.cpp","IMediaResourceMonitor.cpp","IMemory.cpp","IPCThreadState.cpp","IPermissionController.cpp","IProcessInfoService.cpp","IResultReceiver.cpp","IServiceManager.cpp","IShellCallback.cpp","IUidObserver.cpp","MemoryBase.cpp","MemoryDealer.cpp","MemoryHeapBase.cpp","Parcel.cpp","ParcelFileDescriptor.cpp","PermissionCache.cpp","PermissionController.cpp","PersistableBundle.cpp","ProcessInfoService.cpp","ProcessState.cpp","Static.cpp","Status.cpp","TextOutput.cpp","IpPrefix.cpp","Value.cpp",":libbinder_aidl",],...}

ndk 工程 libbinder_ndk 

cc_library {name: "libbinder_ndk",
...srcs: ["ibinder.cpp","ibinder_jni.cpp","parcel.cpp","process.cpp","status.cpp","service_manager.cpp",],shared_libs: ["libandroid_runtime_lazy","libbase","libbinder","libutils",],...}ndk_library {name: "libbinder_ndk",symbol_file: "libbinder_ndk.map.txt",first_version: "29",
}

核心内容：

头文件：\frameworks\native\libs\binder\include\binder\*

源文件：\frameworks\native\libs\binder\*.cpp