mingw/include/curl/multi.h

   1 #ifndef __CURL_MULTI_H
   2 #define __CURL_MULTI_H
   3 /***************************************************************************
   4  *                                  _   _ ____  _
   5  *  Project                     ___| | | |  _ \| |
   6  *                             / __| | | | |_) | |
   7  *                            | (__| |_| |  _ <| |___
   8  *                             \___|\___/|_| \_\_____|
   9  *
  10  * Copyright (C) 1998 - 2012, Daniel Stenberg, <daniel@haxx.se>, et al.
  11  *
  12  * This software is licensed as described in the file COPYING, which
  13  * you should have received as part of this distribution. The terms
  14  * are also available at http://curl.haxx.se/docs/copyright.html.
  15  *
  16  * You may opt to use, copy, modify, merge, publish, distribute and/or sell
  17  * copies of the Software, and permit persons to whom the Software is
  18  * furnished to do so, under the terms of the COPYING file.
  19  *
  20  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  21  * KIND, either express or implied.
  22  *
  23  ***************************************************************************/
  24 /*
  25   This is an "external" header file. Don't give away any internals here!
  26
  27   GOALS
  28
  29   o Enable a "pull" interface. The application that uses libcurl decides where
  30     and when to ask libcurl to get/send data.
  31
  32   o Enable multiple simultaneous transfers in the same thread without making it
  33     complicated for the application.
  34
  35   o Enable the application to select() on its own file descriptors and curl's
  36     file descriptors simultaneous easily.
  37
  38 */
  39
  40 /*
  41  * This header file should not really need to include "curl.h" since curl.h
  42  * itself includes this file and we expect user applications to do #include
  43  * <curl/curl.h> without the need for especially including multi.h.
  44  *
  45  * For some reason we added this include here at one point, and rather than to
  46  * break existing (wrongly written) libcurl applications, we leave it as-is
  47  * but with this warning attached.
  48  */
  49 #include "curl.h"
  50
  51 #ifdef  __cplusplus
  52 extern "C" {
  53 #endif
  54
  55 typedef void CURLM;
  56
  57 typedef enum {
  58   CURLM_CALL_MULTI_PERFORM = -1, /* please call curl_multi_perform() or
  59                                     curl_multi_socket*() soon */
  60   CURLM_OK,
  61   CURLM_BAD_HANDLE,      /* the passed-in handle is not a valid CURLM handle */
  62   CURLM_BAD_EASY_HANDLE, /* an easy handle was not good/valid */
  63   CURLM_OUT_OF_MEMORY,   /* if you ever get this, you're in deep sh*t */
  64   CURLM_INTERNAL_ERROR,  /* this is a libcurl bug */
  65   CURLM_BAD_SOCKET,      /* the passed in socket argument did not match */
  66   CURLM_UNKNOWN_OPTION,  /* curl_multi_setopt() with unsupported option */
  67   CURLM_LAST
  68 } CURLMcode;
  69
  70 /* just to make code nicer when using curl_multi_socket() you can now check
  71    for CURLM_CALL_MULTI_SOCKET too in the same style it works for
  72    curl_multi_perform() and CURLM_CALL_MULTI_PERFORM */
  73 #define CURLM_CALL_MULTI_SOCKET CURLM_CALL_MULTI_PERFORM
  74
  75 typedef enum {
  76   CURLMSG_NONE, /* first, not used */
  77   CURLMSG_DONE, /* This easy handle has completed. 'result' contains
  78                    the CURLcode of the transfer */
  79   CURLMSG_LAST /* last, not used */
  80 } CURLMSG;
  81
  82 struct CURLMsg {
  83   CURLMSG msg;       /* what this message means */
  84   CURL *easy_handle; /* the handle it concerns */
  85   union {
  86     void *whatever;    /* message-specific data */
  87     CURLcode result;   /* return code for transfer */
  88   } data;
  89 };
  90 typedef struct CURLMsg CURLMsg;
  91
  92 /* Based on poll(2) structure and values.
  93  * We don't use pollfd and POLL* constants explicitly
  94  * to cover platforms without poll(). */
  95 #define CURL_WAIT_POLLIN    0x0001
  96 #define CURL_WAIT_POLLPRI   0x0002
  97 #define CURL_WAIT_POLLOUT   0x0004
  98
  99 struct curl_waitfd {
 100   curl_socket_t fd;
 101   short events;
 102   short revents; /* not supported yet */
 103 };
 104
 105 /*
 106  * Name:    curl_multi_init()
 107  *
 108  * Desc:    inititalize multi-style curl usage
 109  *
 110  * Returns: a new CURLM handle to use in all 'curl_multi' functions.
 111  */
 112 CURL_EXTERN CURLM *curl_multi_init(void);
 113
 114 /*
 115  * Name:    curl_multi_add_handle()
 116  *
 117  * Desc:    add a standard curl handle to the multi stack
 118  *
 119  * Returns: CURLMcode type, general multi error code.
 120  */
 121 CURL_EXTERN CURLMcode curl_multi_add_handle(CURLM *multi_handle,
 122                                             CURL *curl_handle);
 123
 124  /*
 125   * Name:    curl_multi_remove_handle()
 126   *
 127   * Desc:    removes a curl handle from the multi stack again
 128   *
 129   * Returns: CURLMcode type, general multi error code.
 130   */
 131 CURL_EXTERN CURLMcode curl_multi_remove_handle(CURLM *multi_handle,
 132                                                CURL *curl_handle);
 133
 134  /*
 135   * Name:    curl_multi_fdset()
 136   *
 137   * Desc:    Ask curl for its fd_set sets. The app can use these to select() or
 138   *          poll() on. We want curl_multi_perform() called as soon as one of
 139   *          them are ready.
 140   *
 141   * Returns: CURLMcode type, general multi error code.
 142   */
 143 CURL_EXTERN CURLMcode curl_multi_fdset(CURLM *multi_handle,
 144                                        fd_set *read_fd_set,
 145                                        fd_set *write_fd_set,
 146                                        fd_set *exc_fd_set,
 147                                        int *max_fd);
 148
 149 /*
 150  * Name:     curl_multi_wait()
 151  *
 152  * Desc:     Poll on all fds within a CURLM set as well as any
 153  *           additional fds passed to the function.
 154  *
 155  * Returns:  CURLMcode type, general multi error code.
 156  */
 157 CURL_EXTERN CURLMcode curl_multi_wait(CURLM *multi_handle,
 158                                       struct curl_waitfd extra_fds[],
 159                                       unsigned int extra_nfds,
 160                                       int timeout_ms,
 161                                       int *ret);
 162
 163  /*
 164   * Name:    curl_multi_perform()
 165   *
 166   * Desc:    When the app thinks there's data available for curl it calls this
 167   *          function to read/write whatever there is right now. This returns
 168   *          as soon as the reads and writes are done. This function does not
 169   *          require that there actually is data available for reading or that
 170   *          data can be written, it can be called just in case. It returns
 171   *          the number of handles that still transfer data in the second
 172   *          argument's integer-pointer.
 173   *
 174   * Returns: CURLMcode type, general multi error code. *NOTE* that this only
 175   *          returns errors etc regarding the whole multi stack. There might
 176   *          still have occurred problems on invidual transfers even when this
 177   *          returns OK.
 178   */
 179 CURL_EXTERN CURLMcode curl_multi_perform(CURLM *multi_handle,
 180                                          int *running_handles);
 181
 182  /*
 183   * Name:    curl_multi_cleanup()
 184   *
 185   * Desc:    Cleans up and removes a whole multi stack. It does not free or
 186   *          touch any individual easy handles in any way. We need to define
 187   *          in what state those handles will be if this function is called
 188   *          in the middle of a transfer.
 189   *
 190   * Returns: CURLMcode type, general multi error code.
 191   */
 192 CURL_EXTERN CURLMcode curl_multi_cleanup(CURLM *multi_handle);
 193
 194 /*
 195  * Name:    curl_multi_info_read()
 196  *
 197  * Desc:    Ask the multi handle if there's any messages/informationals from
 198  *          the individual transfers. Messages include informationals such as
 199  *          error code from the transfer or just the fact that a transfer is
 200  *          completed. More details on these should be written down as well.
 201  *
 202  *          Repeated calls to this function will return a new struct each
 203  *          time, until a special "end of msgs" struct is returned as a signal
 204  *          that there is no more to get at this point.
 205  *
 206  *          The data the returned pointer points to will not survive calling
 207  *          curl_multi_cleanup().
 208  *
 209  *          The 'CURLMsg' struct is meant to be very simple and only contain
 210  *          very basic informations. If more involved information is wanted,
 211  *          we will provide the particular "transfer handle" in that struct
 212  *          and that should/could/would be used in subsequent
 213  *          curl_easy_getinfo() calls (or similar). The point being that we
 214  *          must never expose complex structs to applications, as then we'll
 215  *          undoubtably get backwards compatibility problems in the future.
 216  *
 217  * Returns: A pointer to a filled-in struct, or NULL if it failed or ran out
 218  *          of structs. It also writes the number of messages left in the
 219  *          queue (after this read) in the integer the second argument points
 220  *          to.
 221  */
 222 CURL_EXTERN CURLMsg *curl_multi_info_read(CURLM *multi_handle,
 223                                           int *msgs_in_queue);
 224
 225 /*
 226  * Name:    curl_multi_strerror()
 227  *
 228  * Desc:    The curl_multi_strerror function may be used to turn a CURLMcode
 229  *          value into the equivalent human readable error string.  This is
 230  *          useful for printing meaningful error messages.
 231  *
 232  * Returns: A pointer to a zero-terminated error message.
 233  */
 234 CURL_EXTERN const char *curl_multi_strerror(CURLMcode);
 235
 236 /*
 237  * Name:    curl_multi_socket() and
 238  *          curl_multi_socket_all()
 239  *
 240  * Desc:    An alternative version of curl_multi_perform() that allows the
 241  *          application to pass in one of the file descriptors that have been
 242  *          detected to have "action" on them and let libcurl perform.
 243  *          See man page for details.
 244  */
 245 #define CURL_POLL_NONE   0
 246 #define CURL_POLL_IN     1
 247 #define CURL_POLL_OUT    2
 248 #define CURL_POLL_INOUT  3
 249 #define CURL_POLL_REMOVE 4
 250
 251 #define CURL_SOCKET_TIMEOUT CURL_SOCKET_BAD
 252
 253 #define CURL_CSELECT_IN   0x01
 254 #define CURL_CSELECT_OUT  0x02
 255 #define CURL_CSELECT_ERR  0x04
 256
 257 typedef int (*curl_socket_callback)(CURL *easy,      /* easy handle */
 258                                     curl_socket_t s, /* socket */
 259                                     int what,        /* see above */
 260                                     void *userp,     /* private callback
 261                                                         pointer */
 262                                     void *socketp);  /* private socket
 263                                                         pointer */
 264 /*
 265  * Name:    curl_multi_timer_callback
 266  *
 267  * Desc:    Called by libcurl whenever the library detects a change in the
 268  *          maximum number of milliseconds the app is allowed to wait before
 269  *          curl_multi_socket() or curl_multi_perform() must be called
 270  *          (to allow libcurl's timed events to take place).
 271  *
 272  * Returns: The callback should return zero.
 273  */
 274 typedef int (*curl_multi_timer_callback)(CURLM *multi,    /* multi handle */
 275                                          long timeout_ms, /* see above */
 276                                          void *userp);    /* private callback
 277                                                              pointer */
 278
 279 CURL_EXTERN CURLMcode curl_multi_socket(CURLM *multi_handle, curl_socket_t s,
 280                                         int *running_handles);
 281
 282 CURL_EXTERN CURLMcode curl_multi_socket_action(CURLM *multi_handle,
 283                                                curl_socket_t s,
 284                                                int ev_bitmask,
 285                                                int *running_handles);
 286
 287 CURL_EXTERN CURLMcode curl_multi_socket_all(CURLM *multi_handle,
 288                                             int *running_handles);
 289
 290 #ifndef CURL_ALLOW_OLD_MULTI_SOCKET
 291 /* This macro below was added in 7.16.3 to push users who recompile to use
 292    the new curl_multi_socket_action() instead of the old curl_multi_socket()
 293 */
 294 #define curl_multi_socket(x,y,z) curl_multi_socket_action(x,y,0,z)
 295 #endif
 296
 297 /*
 298  * Name:    curl_multi_timeout()
 299  *
 300  * Desc:    Returns the maximum number of milliseconds the app is allowed to
 301  *          wait before curl_multi_socket() or curl_multi_perform() must be
 302  *          called (to allow libcurl's timed events to take place).
 303  *
 304  * Returns: CURLM error code.
 305  */
 306 CURL_EXTERN CURLMcode curl_multi_timeout(CURLM *multi_handle,
 307                                          long *milliseconds);
 308
 309 #undef CINIT /* re-using the same name as in curl.h */
 310
 311 #ifdef CURL_ISOCPP
 312 #define CINIT(name,type,num) CURLMOPT_ ## name = CURLOPTTYPE_ ## type + num
 313 #else
 314 /* The macro "##" is ISO C, we assume pre-ISO C doesn't support it. */
 315 #define LONG          CURLOPTTYPE_LONG
 316 #define OBJECTPOINT   CURLOPTTYPE_OBJECTPOINT
 317 #define FUNCTIONPOINT CURLOPTTYPE_FUNCTIONPOINT
 318 #define OFF_T         CURLOPTTYPE_OFF_T
 319 #define CINIT(name,type,number) CURLMOPT_/**/name = type + number
 320 #endif
 321
 322 typedef enum {
 323   /* This is the socket callback function pointer */
 324   CINIT(SOCKETFUNCTION, FUNCTIONPOINT, 1),
 325
 326   /* This is the argument passed to the socket callback */
 327   CINIT(SOCKETDATA, OBJECTPOINT, 2),
 328
 329     /* set to 1 to enable pipelining for this multi handle */
 330   CINIT(PIPELINING, LONG, 3),
 331
 332    /* This is the timer callback function pointer */
 333   CINIT(TIMERFUNCTION, FUNCTIONPOINT, 4),
 334
 335   /* This is the argument passed to the timer callback */
 336   CINIT(TIMERDATA, OBJECTPOINT, 5),
 337
 338   /* maximum number of entries in the connection cache */
 339   CINIT(MAXCONNECTS, LONG, 6),
 340
 341   CURLMOPT_LASTENTRY /* the last unused */
 342 } CURLMoption;
 343
 344
 345 /*
 346  * Name:    curl_multi_setopt()
 347  *
 348  * Desc:    Sets options for the multi handle.
 349  *
 350  * Returns: CURLM error code.
 351  */
 352 CURL_EXTERN CURLMcode curl_multi_setopt(CURLM *multi_handle,
 353                                         CURLMoption option, ...);
 354
 355
 356 /*
 357  * Name:    curl_multi_assign()
 358  *
 359  * Desc:    This function sets an association in the multi handle between the
 360  *          given socket and a private pointer of the application. This is
 361  *          (only) useful for curl_multi_socket uses.
 362  *
 363  * Returns: CURLM error code.
 364  */
 365 CURL_EXTERN CURLMcode curl_multi_assign(CURLM *multi_handle,
 366                                         curl_socket_t sockfd, void *sockp);
 367
 368 #ifdef __cplusplus
 369 } /* end of extern "C" */
 370 #endif
 371
 372 #endif