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 - 2007, 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 /*
  93  * Name:    curl_multi_init()
  94  *
  95  * Desc:    inititalize multi-style curl usage
  96  *
  97  * Returns: a new CURLM handle to use in all 'curl_multi' functions.
  98  */
  99 CURL_EXTERN CURLM *curl_multi_init(void);
 100
 101 /*
 102  * Name:    curl_multi_add_handle()
 103  *
 104  * Desc:    add a standard curl handle to the multi stack
 105  *
 106  * Returns: CURLMcode type, general multi error code.
 107  */
 108 CURL_EXTERN CURLMcode curl_multi_add_handle(CURLM *multi_handle,
 109                                             CURL *curl_handle);
 110
 111  /*
 112   * Name:    curl_multi_remove_handle()
 113   *
 114   * Desc:    removes a curl handle from the multi stack again
 115   *
 116   * Returns: CURLMcode type, general multi error code.
 117   */
 118 CURL_EXTERN CURLMcode curl_multi_remove_handle(CURLM *multi_handle,
 119                                                CURL *curl_handle);
 120
 121  /*
 122   * Name:    curl_multi_fdset()
 123   *
 124   * Desc:    Ask curl for its fd_set sets. The app can use these to select() or
 125   *          poll() on. We want curl_multi_perform() called as soon as one of
 126   *          them are ready.
 127   *
 128   * Returns: CURLMcode type, general multi error code.
 129   */
 130 CURL_EXTERN CURLMcode curl_multi_fdset(CURLM *multi_handle,
 131                                        fd_set *read_fd_set,
 132                                        fd_set *write_fd_set,
 133                                        fd_set *exc_fd_set,
 134                                        int *max_fd);
 135
 136  /*
 137   * Name:    curl_multi_perform()
 138   *
 139   * Desc:    When the app thinks there's data available for curl it calls this
 140   *          function to read/write whatever there is right now. This returns
 141   *          as soon as the reads and writes are done. This function does not
 142   *          require that there actually is data available for reading or that
 143   *          data can be written, it can be called just in case. It returns
 144   *          the number of handles that still transfer data in the second
 145   *          argument's integer-pointer.
 146   *
 147   * Returns: CURLMcode type, general multi error code. *NOTE* that this only
 148   *          returns errors etc regarding the whole multi stack. There might
 149   *          still have occurred problems on invidual transfers even when this
 150   *          returns OK.
 151   */
 152 CURL_EXTERN CURLMcode curl_multi_perform(CURLM *multi_handle,
 153                                          int *running_handles);
 154
 155  /*
 156   * Name:    curl_multi_cleanup()
 157   *
 158   * Desc:    Cleans up and removes a whole multi stack. It does not free or
 159   *          touch any individual easy handles in any way. We need to define
 160   *          in what state those handles will be if this function is called
 161   *          in the middle of a transfer.
 162   *
 163   * Returns: CURLMcode type, general multi error code.
 164   */
 165 CURL_EXTERN CURLMcode curl_multi_cleanup(CURLM *multi_handle);
 166
 167 /*
 168  * Name:    curl_multi_info_read()
 169  *
 170  * Desc:    Ask the multi handle if there's any messages/informationals from
 171  *          the individual transfers. Messages include informationals such as
 172  *          error code from the transfer or just the fact that a transfer is
 173  *          completed. More details on these should be written down as well.
 174  *
 175  *          Repeated calls to this function will return a new struct each
 176  *          time, until a special "end of msgs" struct is returned as a signal
 177  *          that there is no more to get at this point.
 178  *
 179  *          The data the returned pointer points to will not survive calling
 180  *          curl_multi_cleanup().
 181  *
 182  *          The 'CURLMsg' struct is meant to be very simple and only contain
 183  *          very basic informations. If more involved information is wanted,
 184  *          we will provide the particular "transfer handle" in that struct
 185  *          and that should/could/would be used in subsequent
 186  *          curl_easy_getinfo() calls (or similar). The point being that we
 187  *          must never expose complex structs to applications, as then we'll
 188  *          undoubtably get backwards compatibility problems in the future.
 189  *
 190  * Returns: A pointer to a filled-in struct, or NULL if it failed or ran out
 191  *          of structs. It also writes the number of messages left in the
 192  *          queue (after this read) in the integer the second argument points
 193  *          to.
 194  */
 195 CURL_EXTERN CURLMsg *curl_multi_info_read(CURLM *multi_handle,
 196                                           int *msgs_in_queue);
 197
 198 /*
 199  * Name:    curl_multi_strerror()
 200  *
 201  * Desc:    The curl_multi_strerror function may be used to turn a CURLMcode
 202  *          value into the equivalent human readable error string.  This is
 203  *          useful for printing meaningful error messages.
 204  *
 205  * Returns: A pointer to a zero-terminated error message.
 206  */
 207 CURL_EXTERN const char *curl_multi_strerror(CURLMcode);
 208
 209 /*
 210  * Name:    curl_multi_socket() and
 211  *          curl_multi_socket_all()
 212  *
 213  * Desc:    An alternative version of curl_multi_perform() that allows the
 214  *          application to pass in one of the file descriptors that have been
 215  *          detected to have "action" on them and let libcurl perform.
 216  *          See man page for details.
 217  */
 218 #define CURL_POLL_NONE   0
 219 #define CURL_POLL_IN     1
 220 #define CURL_POLL_OUT    2
 221 #define CURL_POLL_INOUT  3
 222 #define CURL_POLL_REMOVE 4
 223
 224 #define CURL_SOCKET_TIMEOUT CURL_SOCKET_BAD
 225
 226 #define CURL_CSELECT_IN   0x01
 227 #define CURL_CSELECT_OUT  0x02
 228 #define CURL_CSELECT_ERR  0x04
 229
 230 typedef int (*curl_socket_callback)(CURL *easy,      /* easy handle */
 231                                     curl_socket_t s, /* socket */
 232                                     int what,        /* see above */
 233                                     void *userp,     /* private callback
 234                                                         pointer */
 235                                     void *socketp);  /* private socket
 236                                                         pointer */
 237 /*
 238  * Name:    curl_multi_timer_callback
 239  *
 240  * Desc:    Called by libcurl whenever the library detects a change in the
 241  *          maximum number of milliseconds the app is allowed to wait before
 242  *          curl_multi_socket() or curl_multi_perform() must be called
 243  *          (to allow libcurl's timed events to take place).
 244  *
 245  * Returns: The callback should return zero.
 246  */
 247 typedef int (*curl_multi_timer_callback)(CURLM *multi,    /* multi handle */
 248                                          long timeout_ms, /* see above */
 249                                          void *userp);    /* private callback
 250                                                              pointer */
 251
 252 CURL_EXTERN CURLMcode curl_multi_socket(CURLM *multi_handle, curl_socket_t s,
 253                                         int *running_handles);
 254
 255 CURL_EXTERN CURLMcode curl_multi_socket_action(CURLM *multi_handle,
 256                                                curl_socket_t s,
 257                                                int ev_bitmask,
 258                                                int *running_handles);
 259
 260 CURL_EXTERN CURLMcode curl_multi_socket_all(CURLM *multi_handle,
 261                                             int *running_handles);
 262
 263 #ifndef CURL_ALLOW_OLD_MULTI_SOCKET
 264 /* This macro below was added in 7.16.3 to push users who recompile to use
 265    the new curl_multi_socket_action() instead of the old curl_multi_socket()
 266 */
 267 #define curl_multi_socket(x,y,z) curl_multi_socket_action(x,y,0,z)
 268 #endif
 269
 270 /*
 271  * Name:    curl_multi_timeout()
 272  *
 273  * Desc:    Returns the maximum number of milliseconds the app is allowed to
 274  *          wait before curl_multi_socket() or curl_multi_perform() must be
 275  *          called (to allow libcurl's timed events to take place).
 276  *
 277  * Returns: CURLM error code.
 278  */
 279 CURL_EXTERN CURLMcode curl_multi_timeout(CURLM *multi_handle,
 280                                          long *milliseconds);
 281
 282 #undef CINIT /* re-using the same name as in curl.h */
 283
 284 #ifdef CURL_ISOCPP
 285 #define CINIT(name,type,num) CURLMOPT_ ## name = CURLOPTTYPE_ ## type + num
 286 #else
 287 /* The macro "##" is ISO C, we assume pre-ISO C doesn't support it. */
 288 #define LONG          CURLOPTTYPE_LONG
 289 #define OBJECTPOINT   CURLOPTTYPE_OBJECTPOINT
 290 #define FUNCTIONPOINT CURLOPTTYPE_FUNCTIONPOINT
 291 #define OFF_T         CURLOPTTYPE_OFF_T
 292 #define CINIT(name,type,number) CURLMOPT_/**/name = type + number
 293 #endif
 294
 295 typedef enum {
 296   /* This is the socket callback function pointer */
 297   CINIT(SOCKETFUNCTION, FUNCTIONPOINT, 1),
 298
 299   /* This is the argument passed to the socket callback */
 300   CINIT(SOCKETDATA, OBJECTPOINT, 2),
 301
 302     /* set to 1 to enable pipelining for this multi handle */
 303   CINIT(PIPELINING, LONG, 3),
 304
 305    /* This is the timer callback function pointer */
 306   CINIT(TIMERFUNCTION, FUNCTIONPOINT, 4),
 307
 308   /* This is the argument passed to the timer callback */
 309   CINIT(TIMERDATA, OBJECTPOINT, 5),
 310
 311   /* maximum number of entries in the connection cache */
 312   CINIT(MAXCONNECTS, LONG, 6),
 313
 314   CURLMOPT_LASTENTRY /* the last unused */
 315 } CURLMoption;
 316
 317
 318 /*
 319  * Name:    curl_multi_setopt()
 320  *
 321  * Desc:    Sets options for the multi handle.
 322  *
 323  * Returns: CURLM error code.
 324  */
 325 CURL_EXTERN CURLMcode curl_multi_setopt(CURLM *multi_handle,
 326                                         CURLMoption option, ...);
 327
 328
 329 /*
 330  * Name:    curl_multi_assign()
 331  *
 332  * Desc:    This function sets an association in the multi handle between the
 333  *          given socket and a private pointer of the application. This is
 334  *          (only) useful for curl_multi_socket uses.
 335  *
 336  * Returns: CURLM error code.
 337  */
 338 CURL_EXTERN CURLMcode curl_multi_assign(CURLM *multi_handle,
 339                                         curl_socket_t sockfd, void *sockp);
 340
 341 #ifdef __cplusplus
 342 } /* end of extern "C" */
 343 #endif
 344
 345 #endif