Symbian OS中的Client/Server机制分析

核心提示：RSessionBase::CreateSession() variants that take a server handle.@return The handle to the server.*/inline RServer2 Server() const { return iServer; }protected:

RSessionBase::CreateSession() variants that take a server handle.

@return The handle to the server.

*/

inline RServer2 Server() const { return iServer; }

protected:

inline const RMessage2& Message() const;

IMPORT_C CServer2(TInt aPriority, TServerType aType=EUnsharableSessions);

IMPORT_C void DoCancel();

IMPORT_C void RunL();

IMPORT_C TInt RunError(TInt aError);

private:

/**

Creates a server-side session object.

The session represents a communication link between a client and a server, and its creation is initiated by the client through a call to one of the RSessionBase::CreateSession() variants.

A server must provide an implementation, which as a minimum should:

- check that the version of the server is compatible with the client by comparing the client supplied version number against the server's version number; it should leave if there is incompatibility.

- construct and return the server side client session object.

@param aVersion The version information supplied by the client.

@param aMessage Represents the details of the client request that is requesting the creation of the session.

@return A pointer to the newly created server-side session object.

@see User::QueryVersionSupported()

*/

IMPORT_C virtual CSession2* NewSessionL(const TVersion& aVersion,const RMessage2& aMessage) const =0;

...

...

};

有两个API需要我们注意一下：

IMPORT_C void StartL(const TDesC& aName);

SDK 中描述是把指定名称的Server加入到AS中，并且触发一个请求。一般这个函数会在我们自己写的类的ConstructL()中调用。因为 CServer2是从CActive派生的，所以我们可以猜测在StartL中，会触发一个请求，然后调用CActive的方法SetActive来表明 AO启动了请求。