aoexampleengine.h

Active Object实现动画

/*
* ==============================================================================
*  Name     : CAOExampleEngine from AOExampleEngine.h
*  Part of  : AOExample
*  Created  : 3.5.2004
*  Description:
*  Version  :
*  Copyright: Nokia
* ==============================================================================
*/

#ifndef AOEXAMPLEENGINE_H
#define AOEXAMPLEENGINE_H

#include <e32base.h>
#include <in_sock.h>
#include "Debug.h"

/**
 * Instance of this class is used to fetch a document from a HTTP server.
 * This is an example implementation that uses a socket connection to the
 * server and fetches the document by using simple HTTP 1.0 request.
 *
 * The implementation is based on active object framework so the file
 * fetching
 */
class CAOExampleEngine : public CActive
    {
    public:
        enum TStates
        {
            ENotConnected,
            ELookingUpIP,
            EConnecting,
            EWriting,
            EReading,
        };

        /**
        * Class implementing this observer interface is called by the
        * engine when and events occurs and when the requested
        * document is fetched.
        */
        class MEngineObserver
            {
            public:
                /**
                * Called when the requested document is fetched.
                * @param aContent content of the fetched document
                */
                virtual void FileFetched(CBufBase* aContent)=0;

                /**
                * Called when the file fetching fails for some
                * reason and is cancelled.
                * @param aReason an explanation what went wrong.
                */
                virtual void Cancelled(const TDesC& aReason)=0;

                /**
                * Called when the progress of document fetching
                * goes to a next step.
                */
                virtual void ToState(TStates aState)=0;
            };

	public: // methods

        /**
        * Factory method to be used to create an instance of engine
        * object.
        */
		static CAOExampleEngine* NewLC();

        /**
        * Constructor.
        */
        CAOExampleEngine();

        /**
        * Two phase constructor.
        */
        void ConstructL();

        /**
        * Destructor.
        */
        CAOExampleEngine::~CAOExampleEngine();

        /**
        * Fetches a document from the HTTP server asynchronously.
        * @param anURL an URL, for example:
        *        "http://www.myserver.com:81/docs/doc.html"
        * @param aBuffer dynamic buffer where the document
        *        content is stored.
        * @param anObserver is notified when the file download
        *        has completed or it has been cancelled.
        */
        void FetchFileL( const TDesC& anURL,
                         CBufBase* aBuffer,
                         MEngineObserver* anObserver );

        /**
        * Helper function that parses server name, port and document
        * part from http url string.
        */
        static void ParseURLL( const TDesC& anURL,
                               MEngineObserver& anObserver,
                               TDes& aServerName,
                               TInt& aPort,
                               TDes& aDocument );

    private: // methods

        /**
        * Checks the IP address of server. iServerName must be set
        * before calling. This makes an asynchronous call and sets
        * this active object to wait until address is resolved. RunL
        * is then called.
        */
        void ResolveIP();

        /**
        * Open socket connection to given address. This makes an
        * asychronous call. RunL is called when request completes.
        */
        void Connect(TInetAddr& aInetAddr);

        /**
        * Writes a HTTP request to the open socket. This is an
        * asynchronous call. RunL is called when data is sent.
        */
        void CAOExampleEngine::MakeHTTPRequest();

        /**
        * Writes a HTTP request to the open socket. This is an
        * asynchronous call. RunL is called when data is sent.
        * @param aContinue, whether or not to make a new read
        *        request to the server
        */
        void ReadHTTPResponse(TBool aContinue);

        /**
         * Reset the state of this object to state like it would
         * just have been constructed. Any outstanding request is
         * cancelled.
         */
        void Reset();

    private: // from CActive

		virtual void RunL();
		virtual void DoCancel();

	private: // attributes
        TInt             iState; // don't mess to CActive::iStatus
        TBuf<64>         iServerName;
        TInt             iPort;
        TBuf<128>        iDocument;
        MEngineObserver* iObserver;
        CBufBase*        iOutputBuffer;
        TBuf<512>        iMsgBuf; // buffer for messages
        TBuf8<256>       iSocketBuf;

	    RSocketServ      iSocketServ;
        RSocket          iSocket;
	    RHostResolver    iHostResolver;
        TNameEntry       iNameEntry;

        TSockXfrLength   iStupid;

DEBUG
(
    public:
        /**
        * Debug given string witn file logger.
        */
        void Log(const TDesC& msg);

        CFileLogger*     iFileLogger;
);

    };

#endif