#ifndef __CURL_MULTI_H
#define __CURL_MULTI_H
/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) 1998 - 2004, Daniel Stenberg, <daniel@haxx.se>, et al.
 *
 * This software is licensed as described in the file COPYING, which
 * you should have received as part of this distribution. The terms
 * are also available at http://curl.haxx.se/docs/copyright.html.
 *
 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
 * copies of the Software, and permit persons to whom the Software is
 * furnished to do so, under the terms of the COPYING file.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 * $Id: multi.h,v 1.20 2004/09/30 19:50:36 bagder Exp $
 ***************************************************************************/
/*
  This is meant to be the "external" header file. Don't give away any
  internals here!

  This document presents a mixture of ideas from at least:
  - Daniel Stenberg
  - Steve Dekorte
  - Sterling Hughes
  - Ben Greear

  -------------------------------------------
  GOALS

  o Enable a "pull" interface. The application that uses libcurl decides where
	and when to ask libcurl to get/send data.

  o Enable multiple simultaneous transfers in the same thread without making it
	complicated for the application.

  o Enable the application to select() on its own file descriptors and curl's
	file descriptors simultaneous easily.

*/
#if defined( _WIN32 ) && !defined( WIN32 )
/* Chris Lewis mentioned that he doesn't get WIN32 defined, only _WIN32 so we
   make this adjustment to catch this. */
#define WIN32 1
#endif

#if defined( WIN32 ) && !defined( __GNUC__ ) || defined( __MINGW32__ )
#if !( defined( _WINSOCKAPI_ ) || defined( _WINSOCK_H ) )
/* The check above prevents the winsock2 inclusion if winsock.h already was
   included, since they can't co-exist without problems */
#include <winsock2.h>
#endif
#else

/* HP-UX systems version 9, 10 and 11 lack sys/select.h and so does oldish
   libc5-based Linux systems. Only include it on system that are known to
   require it! */
#if defined( _AIX ) || defined( NETWARE )
#include <sys/select.h>
#endif

#include <sys/socket.h>
#include <sys/time.h>
#include <sys/types.h>
#endif

#include "curl.h"

#ifdef  __cplusplus
extern "C" {
#endif

typedef void CURLM;

typedef enum {
	CURLM_CALL_MULTI_PERFORM = -1, /* please call curl_multi_perform() soon */
	CURLM_OK,
	CURLM_BAD_HANDLE,    /* the passed-in handle is not a valid CURLM handle */
	CURLM_BAD_EASY_HANDLE, /* an easy handle was not good/valid */
	CURLM_OUT_OF_MEMORY, /* if you ever get this, you're in deep sh*t */
	CURLM_INTERNAL_ERROR, /* this is a libcurl bug */
	CURLM_LAST
} CURLMcode;

typedef enum {
	CURLMSG_NONE, /* first, not used */
	CURLMSG_DONE, /* This easy handle has completed. 'result' contains
				   the CURLcode of the transfer */
	CURLMSG_LAST /* last, not used */
} CURLMSG;

struct CURLMsg {
	CURLMSG msg;     /* what this message means */
	CURL *easy_handle; /* the handle it concerns */
	union {
		void *whatever; /* message-specific data */
		CURLcode result; /* return code for transfer */
	} data;
};
typedef struct CURLMsg CURLMsg;

/*
 * Name:    curl_multi_init()
 *
 * Desc:    inititalize multi-style curl usage
 * Returns: a new CURLM handle to use in all 'curl_multi' functions.
 */
CURLM *curl_multi_init( void );

/*
 * Name:    curl_multi_add_handle()
 *
 * Desc:    add a standard curl handle to the multi stack
 * Returns: CURLMcode type, general multi error code.
 */
CURLMcode curl_multi_add_handle( CURLM *multi_handle,
								 CURL *curl_handle );

/*
 * Name:    curl_multi_remove_handle()
 *
 * Desc:    removes a curl handle from the multi stack again
 * Returns: CURLMcode type, general multi error code.
 */
CURLMcode curl_multi_remove_handle( CURLM *multi_handle,
									CURL *curl_handle );

/*
 * Name:    curl_multi_fdset()
 *
 * Desc:    Ask curl for its fd_set sets. The app can use these to select() or
 *          poll() on. We want curl_multi_perform() called as soon as one of
 *          them are ready.
 * Returns: CURLMcode type, general multi error code.
 */
CURLMcode curl_multi_fdset( CURLM *multi_handle,
							fd_set *read_fd_set,
							fd_set *write_fd_set,
							fd_set *exc_fd_set,
							int *max_fd );

/*
 * Name:    curl_multi_perform()
 *
 * Desc:    When the app thinks there's data available for curl it calls this
 *          function to read/write whatever there is right now. This returns
 *          as soon as the reads and writes are done. This function does not
 *          require that there actually is data available for reading or that
 *          data can be written, it can be called just in case. It returns
 *          the number of handles that still transfer data in the second
 *          argument's integer-pointer.
 *
 * Returns: CURLMcode type, general multi error code. *NOTE* that this only
 *          returns errors etc regarding the whole multi stack. There might
 *          still have occurred problems on invidual transfers even when this
 *          returns OK.
 */
CURLMcode curl_multi_perform( CURLM *multi_handle,
							  int *running_handles );

/*
 * Name:    curl_multi_cleanup()
 *
 * Desc:    Cleans up and removes a whole multi stack. It does not free or
 *          touch any individual easy handles in any way. We need to define
 *          in what state those handles will be if this function is called
 *          in the middle of a transfer.
 * Returns: CURLMcode type, general multi error code.
 */
CURLMcode curl_multi_cleanup( CURLM *multi_handle );

/*
 * Name:    curl_multi_info_read()
 *
 * Desc:    Ask the multi handle if there's any messages/informationals from
 *          the individual transfers. Messages include informationals such as
 *          error code from the transfer or just the fact that a transfer is
 *          completed. More details on these should be written down as well.
 *
 *          Repeated calls to this function will return a new struct each
 *          time, until a special "end of msgs" struct is returned as a signal
 *          that there is no more to get at this point.
 *
 *          The data the returned pointer points to will not survive calling
 *          curl_multi_cleanup().
 *
 *          The 'CURLMsg' struct is meant to be very simple and only contain
 *          very basic informations. If more involved information is wanted,
 *          we will provide the particular "transfer handle" in that struct
 *          and that should/could/would be used in subsequent
 *          curl_easy_getinfo() calls (or similar). The point being that we
 *          must never expose complex structs to applications, as then we'll
 *          undoubtably get backwards compatibility problems in the future.
 *
 * Returns: A pointer to a filled-in struct, or NULL if it failed or ran out
 *          of structs. It also writes the number of messages left in the
 *          queue (after this read) in the integer the second argument points
 *          to.
 */
CURLMsg *curl_multi_info_read( CURLM *multi_handle,
							   int *msgs_in_queue );

/*
 * NAME curl_multi_strerror()
 *
 * DESCRIPTION
 *
 * The curl_multi_strerror function may be used to turn a CURLMcode value
 * into the equivalent human readable error string.  This is useful
 * for printing meaningful error messages.
 */
const char *curl_multi_strerror( CURLMcode );

#ifdef __cplusplus
} /* end of extern "C" */
#endif

#endif
