目錄
Fuchsia IPC Architecture Overview
概述
Fuchsia使用Fuchsia Interface Definition Language (FIDL) 作爲進程IPC的接口描述語言,本文旨在詳細分析基於FIDL的IPC原理
Fuchsia IPC Architecture Overview
- 通過FIDL描述IPC接口Interface
- Client 進程使用InterfacePtr<Interface>來調用Interface中的接口獲得服務
- Service進程實現Interface中的接口來提供服務
- 爲了描述更具體清晰,本文使用view_provider.fidl 作爲Interface的具體例子來分析IPC的原理和過程
[Discoverable]
interface ViewProvider {
// Creates a new View under the control of the ViewProvider.
//
// |token| is one half of the shared eventpair which will bind the new View
// to its associated ViewHolder. The ViewProvider will use |token| to
// create its internal View representation. The caller is expected to use
// its half to create corresponding ViewHolder object.
//
// |incoming_services| allows clients to request services from the
// ViewProvider implementation. |outgoing_services| allows clients to
// provide services of their own to the ViewProvider implementation.
//
// Clients can embed a ViewHolder (and by proxy the paired View) into their
// scene graph by using |Node.AddChild()|. The ViewHolder cannot itself
// have any children. A ViewProvider implementation can nest scene objects
// within its View by using |View.AddChild()|. The View itself
// cannot be a child of anything.
//
// Modules can use these mechanisms to establish a distributed,
// inter-process scene graph.
CreateView(handle<eventpair> token,
request<fuchsia.sys.ServiceProvider>? incoming_services,
fuchsia.sys.ServiceProvider? outgoing_services);
};
FIDL IPC 詳解
FIDL IPC中涉及的Class大致可以分爲4種
- Client端使用的Class
- Service端使用的Class
- FIDL自動代碼生成的Class
- Client和Service都會使用到的Class(包括訪問Zircon微內核channel的Class)
下面依然以FIDL view_provider.fidl 中定義的interface ViewProvider作爲具體的例子說明Client與Service的IPC時序
Tips
- Fuchsia FIDL文件的位置: fuchsia/garnet/public/fidl/<fuchsia.package.name>
- 編譯FIDL後自動生成的代碼位置:fuchsia/out/arm64/fidling/gen/fuchsia/<package>/<name>