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 #ifndef __XRDSSIREQUEST_HH__
 #define __XRDSSIREQUEST_HH__
 /******************************************************************************/
 /*                                                                            */
 /*                      X r d S s i R e q u e s t . h h                       */
 /*                                                                            */
 /* (c) 2013 by the Board of Trustees of the Leland Stanford, Jr., University  */
 /*   Produced by Andrew Hanushevsky for Stanford University under contract    */
 /*              DE-AC02-76-SFO0515 with the Department of Energy              */
 /*                                                                            */
 /* This file is part of the XRootD software suite.                            */
 /*                                                                            */
 /* XRootD is free software: you can redistribute it and/or modify it under    */
 /* the terms of the GNU Lesser General Public License as published by the     */
 /* Free Software Foundation, either version 3 of the License, or (at your     */
 /* option) any later version.                                                 */
 /*                                                                            */
 /* XRootD is distributed in the hope that it will be useful, but WITHOUT      */
 /* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or      */
 /* FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public       */
 /* License for more details.                                                  */
 /*                                                                            */
 /* You should have received a copy of the GNU Lesser General Public License   */
 /* along with XRootD in a file called COPYING.LESSER (LGPL license) and file  */
 /* COPYING (GPL license).  If not, see <http://www.gnu.org/licenses/>.        */
 /*                                                                            */
 /* The copyright holder's institutional names and contributor's names may not */
 /* be used to endorse or promote products derived from this software without  */
 /* specific prior written permission of the institution or contributor.       */
 /******************************************************************************/
 
 #include <cstdint>
 #include <cstdlib>
 #include <cstring>
 
 #include "XrdSsi/XrdSsiAtomics.hh"
 #include "XrdSsi/XrdSsiErrInfo.hh"
 #include "XrdSsi/XrdSsiRespInfo.hh"
 
 //-----------------------------------------------------------------------------
 //! The XrdSsiRequest class describes a client request and is used to effect a
 //! response to the request via a companion object described by XrdSsiResponder.
 //! Client-Side: Use this object to encapsulate your request and hand it off
 //!              to XrdSsiService::Execute() either use GetResponseData() or
 //!              the actual response structure to get the response data once the
 //!              ProcessResponse() callback is invoked.
 //!
 //! Server-side: XrdSsiService::ProcessRequest() is called with this object.
 //!              Use the XrdSsiResponder object to post a response.
 //!
 //! In either case, the client must invoke XrdSsiRequest::Finished() after the
 //! client-server exchange is complete in order to revert ownership of this
 //! object to the object's creator to allow it to be deleted or reused.
 //!
 //! This is an abstract class and several methods need to be implemented:
 //!
 //! Alert()               Optional, allows receiving of server alerts.
 //! GetRequest()          Mandatory to supply the buffer holding the request
 //!                       along with its length.
 //! RelRequestBuffer()    Optional, allows memory optimization.
 //! ProcessResponse()     Initial response: Mandatory
 //! ProcessResponseData() Data    response: Mandatory only if response data is
 //!                                         asynchronously received.
 //!
 //! All callbacks are invoked with no locks outstanding unless otherwise noted.
 //-----------------------------------------------------------------------------
 
 class XrdSsiResponder;
 
 class XrdSsiRequest
 {
 public:
 friend class XrdSsiResponder;
 friend class XrdSsiRRAgent;
 
 //-----------------------------------------------------------------------------
 //! Indicate that request processing has been finished. This method calls
 //! XrdSsiResponder::Finished() on the associated responder object.
 //!
 //! Note: This method locks the object's recursive mutex.
 //!
 //! @param  cancel False -> the request/response sequence completed normally.
 //!                True  -> the request/response sequence aborted because of an
 //!                         error or the client cancelled the request.
 //!
 //! @return true   Finish accepted. Request object may be reclaimed.
 //! @return false  Finish cannot be accepted because this request object is
 //!                not bound to a responder. This indicates a logic error.
 //-----------------------------------------------------------------------------
 
         bool    Finished(bool cancel=false);
 
 //-----------------------------------------------------------------------------
 //! Obtain the detached request time to live value. If the value is non-zero,
 //! the request is detached. Otherwise, it is an attached request and requires a
 //! live TCP connection during it execution.
 //!
 //! @return The detached time to live value in seconds.
 //-----------------------------------------------------------------------------
 
 inline uint32_t GetDetachTTL() {return detTTL;}
 
 //-----------------------------------------------------------------------------
 //! Obtain the endpoint host name.
 //!
 //! @return A string containing the endpoint host name. If a null string is
 //!         returned, the endpoint has not yet been determined. Generally, the
 //!         endpoint is available on the first callback to this object.
 //-----------------------------------------------------------------------------
 
 std::string     GetEndPoint();
 
 //-----------------------------------------------------------------------------
 //! Obtain the metadata associated with a response.
 //!
 //!
 //! Note: This method locks the object's recursive mutex.
 //!
 //! @param  dlen  holds the length of the metadata after the call.
 //!
 //! @return =0    No metadata available, dlen has been set to zero.
 //! @return !0    Pointer to the buffer holding the metadata, dlen has the length
 //-----------------------------------------------------------------------------
 
 const char     *GetMetadata(int &dlen);
 
 //-----------------------------------------------------------------------------
 //! Obtain the request data sent by a client.
 //!
 //! This method is duplicated in XrdSsiResponder to allow calling consistency.
 //!
 //! @param  dlen  holds the length of the request after the call.
 //!
 //! @return =0    No request data available, dlen has been set to zero.
 //! @return !0    Pointer to the buffer holding the request, dlen has the length
 //-----------------------------------------------------------------------------
 
 virtual char   *GetRequest(int &dlen) = 0;
 
 //-----------------------------------------------------------------------------
 //! Get the request ID established at object creation time.
 //!
 //! @return Pointer to the request ID or nil if there is none.
 //-----------------------------------------------------------------------------
 
 inline
 const   char   *GetRequestID() {return reqID;}
 
 //-----------------------------------------------------------------------------
 //! Asynchronously obtain response data. This is a helper method that allows a
 //! client to deal with a passive stream response. This method also handles
 //! data response, albeit inefficiently by copying the data response. However,
 //! this allows for uniform response processing regardless of response type.
 //!
 //! @param  buff  pointer to the buffer to receive the data. The buffer must
 //!               remain valid until ProcessResponseData() is called.
 //! @param  blen  the length of the buffer (i.e. maximum that can be returned).
 //-----------------------------------------------------------------------------
 
         void    GetResponseData(char *buff, int  blen);
 
 //-----------------------------------------------------------------------------
 //! Get timeout for initiating the request.
 //!
 //! @return The timeout value.
 //-----------------------------------------------------------------------------
 
         uint16_t GetTimeOut() {return tOut;}
 
 //-----------------------------------------------------------------------------
 //! Notify request that a response is ready to be processed. This method must
 //! be supplied by the request object's implementation.
 //!
 //! @param  eInfo Error information. You can check if an error occurred using
 //!               eInfo.hasError() or eInfo.isOK().
 //! @param  rInfo Raw response information.
 //!
 //! @return true  Response processed.
 //! @return false Response could not be processed, the request is not active.
 //-----------------------------------------------------------------------------
 
 virtual bool    ProcessResponse(const XrdSsiErrInfo  &eInfo,
                                 const XrdSsiRespInfo &rInfo)=0;
 
 //-----------------------------------------------------------------------------
 //! Handle incoming async stream data or error. This method is called by a
 //! stream object after a successful GetResponseData() or an asynchronous
 //! stream SetBuff() call.
 //!
 //! @param  eInfo Error information. You can check if an error occurred using
 //!               eInfo.hasError() or eInfo.isOK().
 //! @param  buff  Pointer to the buffer given to XrdSsiStream::SetBuff().
 //! @param  blen  The number of bytes in buff or an error indication if blen < 0.
 //! @param  last  true  This is the last stream segment, no more data remains.
 //!               false More data may remain in the stream.
 //-----------------------------------------------------------------------------
 
 virtual void ProcessResponseData(const XrdSsiErrInfo  &eInfo, char *buff,
                                  int blen, bool last) {}
 
 //-----------------------------------------------------------------------------
 //! Release the request buffer of the request bound to this object. This method
 //! duplicates the protected method RelRequestBuffer() and exists here for
 //! calling safety and consistency relative to the responder.
 //-----------------------------------------------------------------------------
 
         void   ReleaseRequestBuffer();
 
 //-----------------------------------------------------------------------------
 //! Constructor
 //!
 //! @param reqid   Pointer to a request ID that can be used to group requests.
 //!                See ProcessResponseData() and RestartDataReponse(). If reqid
 //!                is nil then held responses are placed in the global queue.
 //!                The pointer must be valid for the life of this object.
 //!
 //! @param tmo     The request initiation timeout value 0 equals default).
 //-----------------------------------------------------------------------------
 
                 XrdSsiRequest(const char *reqid=0, uint16_t tmo=0);
 
 protected:
 
 //-----------------------------------------------------------------------------
 //! @brief Send or receive a server generated alert.
 //!
 //! The Alert() method is used server-side to send one or more alerts before a
 //! response is posted (alerts afterwards are ignored). To avoid race conditions,
 //! server-side alerts should be sent via the Responder's Alert() method.
 //! Clients must implement this method in order to receive alerts.
 //!
 //! @param  aMsg   Reference to the message object containing the alert message.
 //!                Non-positive alert lengths cause the alert call to be
 //!                ignored. You should call the message RecycleMsg() method
 //!                once you have consumed the message to release its resources.
 //-----------------------------------------------------------------------------
 
 virtual void    Alert(XrdSsiRespInfoMsg &aMsg) {aMsg.RecycleMsg(false);}
 
 //-----------------------------------------------------------------------------
 //! Release the request buffer. Use this method to optimize storage use; this
 //! is especially relevant for long-running requests. If the request buffer
 //! has been consumed and is no longer needed, early return of the buffer will
 //! minimize memory usage. This method is also invoked via XrdSsiResponder.
 //!
 //!
 //! Note: This method is called with the object's recursive mutex locked when
 //!       it is invoked via XrdSsiResponder's ReleaseRequestBuffer().
 //-----------------------------------------------------------------------------
 
 virtual void    RelRequestBuffer() {}
 
 //-----------------------------------------------------------------------------
 //! @brief Set the detached request time to live value.
 //!
 //! By default, requests are executed in the foreground (i.e. during its
 //! execution, if the TCP connection drops, the request is automatically
 //! cancelled. When a non-zero time to live is set, the request is executed in
 //! the background (i.e. detached) and no persistent TCP connection is required.
 //! You must use the XrdSsiService::Attach() method to foreground such a
 //! request within the number of seconds specified for dttl or the request is
 //! automatically cancelled. The value must be set before passing the request
 //! to XrdSsiService::ProcessRequest(). Once the request is started, a request
 //! handle is returned which can be passed to XrdSsiService::Attach().
 //!
 //! @param  dttl The detach time to live value.
 //-----------------------------------------------------------------------------
 
 inline void     SetDetachTTL(uint32_t dttl) {detTTL = dttl;}
 
 //-----------------------------------------------------------------------------
 //! Set request retry notification. If a non-default value is desired, it must
 //! be set prior to calling XrdSsiService::ProcessRequest(). This is a one-time
 //! request and retry mode is turned off in the request object afterwards.
 //!
 //! @param onoff   True to turn retry on and false to turn it off.
 //-----------------------------------------------------------------------------
 
        void     SetRetry(bool onoff);
 
 //-----------------------------------------------------------------------------
 //! Set timeout for initiating the request. If a non-default value is desired,
 //! it must be set prior to calling XrdSsiService::ProcessRequest().
 //!
 //! @param tmo     The timeout value.
 //-----------------------------------------------------------------------------
 
        void     SetTimeOut(uint16_t tmo) {tOut = tmo;}
 
 //-----------------------------------------------------------------------------
 //! Destructor. This object can only be deleted by the object creator. Once the
 //! object is passed to XrdSsiService::ProcessRequest() it may only be deleted
 //! after Finished() is called to allow the service to reclaim any resources
 //! allocated for the request object.
 //-----------------------------------------------------------------------------
 
 virtual        ~XrdSsiRequest() {}
 
 private:
 virtual void     BindDone() {}
         void     CleanUp();
         bool     CopyData(char *buff, int blen);
 virtual void     Dispose() {}
 
 const char      *reqID;
 XrdSsiMutex     *rrMutex;
 XrdSsiResponder *theRespond; // Set via XrdSsiResponder::BindRequest()
 XrdSsiRespInfo   Resp;       // Set via XrdSsiResponder::SetResponse()
 XrdSsiErrInfo    errInfo;
 long long        rsvd1;
 const char      *epNode;
 uint32_t         detTTL;
 uint16_t         tOut;
 bool             onClient;
 char             flags;
 static const int isaRetry = 1;
 };
 #endif

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