multi.h 16 KB

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  1. #ifndef __CURL_MULTI_H
  2. #define __CURL_MULTI_H
  3. /***************************************************************************
  4. * _ _ ____ _
  5. * Project ___| | | | _ \| |
  6. * / __| | | | |_) | |
  7. * | (__| |_| | _ <| |___
  8. * \___|\___/|_| \_\_____|
  9. *
  10. * Copyright (C) 1998 - 2017, 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 https://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. GOALS
  27. o Enable a "pull" interface. The application that uses libcurl decides where
  28. and when to ask libcurl to get/send data.
  29. o Enable multiple simultaneous transfers in the same thread without making it
  30. complicated for the application.
  31. o Enable the application to select() on its own file descriptors and curl's
  32. file descriptors simultaneous easily.
  33. */
  34. /*
  35. * This header file should not really need to include "curl.h" since curl.h
  36. * itself includes this file and we expect user applications to do #include
  37. * <curl/curl.h> without the need for especially including multi.h.
  38. *
  39. * For some reason we added this include here at one point, and rather than to
  40. * break existing (wrongly written) libcurl applications, we leave it as-is
  41. * but with this warning attached.
  42. */
  43. #include "curl.h"
  44. #ifdef __cplusplus
  45. extern "C" {
  46. #endif
  47. #if defined(BUILDING_LIBCURL) || defined(CURL_STRICTER)
  48. typedef struct Curl_multi CURLM;
  49. #else
  50. typedef void CURLM;
  51. #endif
  52. typedef enum {
  53. CURLM_CALL_MULTI_PERFORM = -1, /* please call curl_multi_perform() or
  54. curl_multi_socket*() soon */
  55. CURLM_OK,
  56. CURLM_BAD_HANDLE, /* the passed-in handle is not a valid CURLM handle */
  57. CURLM_BAD_EASY_HANDLE, /* an easy handle was not good/valid */
  58. CURLM_OUT_OF_MEMORY, /* if you ever get this, you're in deep sh*t */
  59. CURLM_INTERNAL_ERROR, /* this is a libcurl bug */
  60. CURLM_BAD_SOCKET, /* the passed in socket argument did not match */
  61. CURLM_UNKNOWN_OPTION, /* curl_multi_setopt() with unsupported option */
  62. CURLM_ADDED_ALREADY, /* an easy handle already added to a multi handle was
  63. attempted to get added - again */
  64. CURLM_LAST
  65. } CURLMcode;
  66. /* just to make code nicer when using curl_multi_socket() you can now check
  67. for CURLM_CALL_MULTI_SOCKET too in the same style it works for
  68. curl_multi_perform() and CURLM_CALL_MULTI_PERFORM */
  69. #define CURLM_CALL_MULTI_SOCKET CURLM_CALL_MULTI_PERFORM
  70. /* bitmask bits for CURLMOPT_PIPELINING */
  71. #define CURLPIPE_NOTHING 0L
  72. #define CURLPIPE_HTTP1 1L
  73. #define CURLPIPE_MULTIPLEX 2L
  74. typedef enum {
  75. CURLMSG_NONE, /* first, not used */
  76. CURLMSG_DONE, /* This easy handle has completed. 'result' contains
  77. the CURLcode of the transfer */
  78. CURLMSG_LAST /* last, not used */
  79. } CURLMSG;
  80. struct CURLMsg {
  81. CURLMSG msg; /* what this message means */
  82. CURL *easy_handle; /* the handle it concerns */
  83. union {
  84. void *whatever; /* message-specific data */
  85. CURLcode result; /* return code for transfer */
  86. } data;
  87. };
  88. typedef struct CURLMsg CURLMsg;
  89. /* Based on poll(2) structure and values.
  90. * We don't use pollfd and POLL* constants explicitly
  91. * to cover platforms without poll(). */
  92. #define CURL_WAIT_POLLIN 0x0001
  93. #define CURL_WAIT_POLLPRI 0x0002
  94. #define CURL_WAIT_POLLOUT 0x0004
  95. struct curl_waitfd {
  96. curl_socket_t fd;
  97. short events;
  98. short revents; /* not supported yet */
  99. };
  100. /*
  101. * Name: curl_multi_init()
  102. *
  103. * Desc: inititalize multi-style curl usage
  104. *
  105. * Returns: a new CURLM handle to use in all 'curl_multi' functions.
  106. */
  107. CURL_EXTERN CURLM *curl_multi_init(void);
  108. /*
  109. * Name: curl_multi_add_handle()
  110. *
  111. * Desc: add a standard curl handle to the multi stack
  112. *
  113. * Returns: CURLMcode type, general multi error code.
  114. */
  115. CURL_EXTERN CURLMcode curl_multi_add_handle(CURLM *multi_handle,
  116. CURL *curl_handle);
  117. /*
  118. * Name: curl_multi_remove_handle()
  119. *
  120. * Desc: removes a curl handle from the multi stack again
  121. *
  122. * Returns: CURLMcode type, general multi error code.
  123. */
  124. CURL_EXTERN CURLMcode curl_multi_remove_handle(CURLM *multi_handle,
  125. CURL *curl_handle);
  126. /*
  127. * Name: curl_multi_fdset()
  128. *
  129. * Desc: Ask curl for its fd_set sets. The app can use these to select() or
  130. * poll() on. We want curl_multi_perform() called as soon as one of
  131. * them are ready.
  132. *
  133. * Returns: CURLMcode type, general multi error code.
  134. */
  135. CURL_EXTERN CURLMcode curl_multi_fdset(CURLM *multi_handle,
  136. fd_set *read_fd_set,
  137. fd_set *write_fd_set,
  138. fd_set *exc_fd_set,
  139. int *max_fd);
  140. /*
  141. * Name: curl_multi_wait()
  142. *
  143. * Desc: Poll on all fds within a CURLM set as well as any
  144. * additional fds passed to the function.
  145. *
  146. * Returns: CURLMcode type, general multi error code.
  147. */
  148. CURL_EXTERN CURLMcode curl_multi_wait(CURLM *multi_handle,
  149. struct curl_waitfd extra_fds[],
  150. unsigned int extra_nfds,
  151. int timeout_ms,
  152. int *ret);
  153. /*
  154. * Name: curl_multi_perform()
  155. *
  156. * Desc: When the app thinks there's data available for curl it calls this
  157. * function to read/write whatever there is right now. This returns
  158. * as soon as the reads and writes are done. This function does not
  159. * require that there actually is data available for reading or that
  160. * data can be written, it can be called just in case. It returns
  161. * the number of handles that still transfer data in the second
  162. * argument's integer-pointer.
  163. *
  164. * Returns: CURLMcode type, general multi error code. *NOTE* that this only
  165. * returns errors etc regarding the whole multi stack. There might
  166. * still have occurred problems on invidual transfers even when this
  167. * returns OK.
  168. */
  169. CURL_EXTERN CURLMcode curl_multi_perform(CURLM *multi_handle,
  170. int *running_handles);
  171. /*
  172. * Name: curl_multi_cleanup()
  173. *
  174. * Desc: Cleans up and removes a whole multi stack. It does not free or
  175. * touch any individual easy handles in any way. We need to define
  176. * in what state those handles will be if this function is called
  177. * in the middle of a transfer.
  178. *
  179. * Returns: CURLMcode type, general multi error code.
  180. */
  181. CURL_EXTERN CURLMcode curl_multi_cleanup(CURLM *multi_handle);
  182. /*
  183. * Name: curl_multi_info_read()
  184. *
  185. * Desc: Ask the multi handle if there's any messages/informationals from
  186. * the individual transfers. Messages include informationals such as
  187. * error code from the transfer or just the fact that a transfer is
  188. * completed. More details on these should be written down as well.
  189. *
  190. * Repeated calls to this function will return a new struct each
  191. * time, until a special "end of msgs" struct is returned as a signal
  192. * that there is no more to get at this point.
  193. *
  194. * The data the returned pointer points to will not survive calling
  195. * curl_multi_cleanup().
  196. *
  197. * The 'CURLMsg' struct is meant to be very simple and only contain
  198. * very basic information. If more involved information is wanted,
  199. * we will provide the particular "transfer handle" in that struct
  200. * and that should/could/would be used in subsequent
  201. * curl_easy_getinfo() calls (or similar). The point being that we
  202. * must never expose complex structs to applications, as then we'll
  203. * undoubtably get backwards compatibility problems in the future.
  204. *
  205. * Returns: A pointer to a filled-in struct, or NULL if it failed or ran out
  206. * of structs. It also writes the number of messages left in the
  207. * queue (after this read) in the integer the second argument points
  208. * to.
  209. */
  210. CURL_EXTERN CURLMsg *curl_multi_info_read(CURLM *multi_handle,
  211. int *msgs_in_queue);
  212. /*
  213. * Name: curl_multi_strerror()
  214. *
  215. * Desc: The curl_multi_strerror function may be used to turn a CURLMcode
  216. * value into the equivalent human readable error string. This is
  217. * useful for printing meaningful error messages.
  218. *
  219. * Returns: A pointer to a zero-terminated error message.
  220. */
  221. CURL_EXTERN const char *curl_multi_strerror(CURLMcode);
  222. /*
  223. * Name: curl_multi_socket() and
  224. * curl_multi_socket_all()
  225. *
  226. * Desc: An alternative version of curl_multi_perform() that allows the
  227. * application to pass in one of the file descriptors that have been
  228. * detected to have "action" on them and let libcurl perform.
  229. * See man page for details.
  230. */
  231. #define CURL_POLL_NONE 0
  232. #define CURL_POLL_IN 1
  233. #define CURL_POLL_OUT 2
  234. #define CURL_POLL_INOUT 3
  235. #define CURL_POLL_REMOVE 4
  236. #define CURL_SOCKET_TIMEOUT CURL_SOCKET_BAD
  237. #define CURL_CSELECT_IN 0x01
  238. #define CURL_CSELECT_OUT 0x02
  239. #define CURL_CSELECT_ERR 0x04
  240. typedef int (*curl_socket_callback)(CURL *easy, /* easy handle */
  241. curl_socket_t s, /* socket */
  242. int what, /* see above */
  243. void *userp, /* private callback
  244. pointer */
  245. void *socketp); /* private socket
  246. pointer */
  247. /*
  248. * Name: curl_multi_timer_callback
  249. *
  250. * Desc: Called by libcurl whenever the library detects a change in the
  251. * maximum number of milliseconds the app is allowed to wait before
  252. * curl_multi_socket() or curl_multi_perform() must be called
  253. * (to allow libcurl's timed events to take place).
  254. *
  255. * Returns: The callback should return zero.
  256. */
  257. typedef int (*curl_multi_timer_callback)(CURLM *multi, /* multi handle */
  258. long timeout_ms, /* see above */
  259. void *userp); /* private callback
  260. pointer */
  261. CURL_EXTERN CURLMcode curl_multi_socket(CURLM *multi_handle, curl_socket_t s,
  262. int *running_handles);
  263. CURL_EXTERN CURLMcode curl_multi_socket_action(CURLM *multi_handle,
  264. curl_socket_t s,
  265. int ev_bitmask,
  266. int *running_handles);
  267. CURL_EXTERN CURLMcode curl_multi_socket_all(CURLM *multi_handle,
  268. int *running_handles);
  269. #ifndef CURL_ALLOW_OLD_MULTI_SOCKET
  270. /* This macro below was added in 7.16.3 to push users who recompile to use
  271. the new curl_multi_socket_action() instead of the old curl_multi_socket()
  272. */
  273. #define curl_multi_socket(x,y,z) curl_multi_socket_action(x,y,0,z)
  274. #endif
  275. /*
  276. * Name: curl_multi_timeout()
  277. *
  278. * Desc: Returns the maximum number of milliseconds the app is allowed to
  279. * wait before curl_multi_socket() or curl_multi_perform() must be
  280. * called (to allow libcurl's timed events to take place).
  281. *
  282. * Returns: CURLM error code.
  283. */
  284. CURL_EXTERN CURLMcode curl_multi_timeout(CURLM *multi_handle,
  285. long *milliseconds);
  286. #undef CINIT /* re-using the same name as in curl.h */
  287. #ifdef CURL_ISOCPP
  288. #define CINIT(name,type,num) CURLMOPT_ ## name = CURLOPTTYPE_ ## type + num
  289. #else
  290. /* The macro "##" is ISO C, we assume pre-ISO C doesn't support it. */
  291. #define LONG CURLOPTTYPE_LONG
  292. #define OBJECTPOINT CURLOPTTYPE_OBJECTPOINT
  293. #define FUNCTIONPOINT CURLOPTTYPE_FUNCTIONPOINT
  294. #define OFF_T CURLOPTTYPE_OFF_T
  295. #define CINIT(name,type,number) CURLMOPT_/**/name = type + number
  296. #endif
  297. typedef enum {
  298. /* This is the socket callback function pointer */
  299. CINIT(SOCKETFUNCTION, FUNCTIONPOINT, 1),
  300. /* This is the argument passed to the socket callback */
  301. CINIT(SOCKETDATA, OBJECTPOINT, 2),
  302. /* set to 1 to enable pipelining for this multi handle */
  303. CINIT(PIPELINING, LONG, 3),
  304. /* This is the timer callback function pointer */
  305. CINIT(TIMERFUNCTION, FUNCTIONPOINT, 4),
  306. /* This is the argument passed to the timer callback */
  307. CINIT(TIMERDATA, OBJECTPOINT, 5),
  308. /* maximum number of entries in the connection cache */
  309. CINIT(MAXCONNECTS, LONG, 6),
  310. /* maximum number of (pipelining) connections to one host */
  311. CINIT(MAX_HOST_CONNECTIONS, LONG, 7),
  312. /* maximum number of requests in a pipeline */
  313. CINIT(MAX_PIPELINE_LENGTH, LONG, 8),
  314. /* a connection with a content-length longer than this
  315. will not be considered for pipelining */
  316. CINIT(CONTENT_LENGTH_PENALTY_SIZE, OFF_T, 9),
  317. /* a connection with a chunk length longer than this
  318. will not be considered for pipelining */
  319. CINIT(CHUNK_LENGTH_PENALTY_SIZE, OFF_T, 10),
  320. /* a list of site names(+port) that are blacklisted from
  321. pipelining */
  322. CINIT(PIPELINING_SITE_BL, OBJECTPOINT, 11),
  323. /* a list of server types that are blacklisted from
  324. pipelining */
  325. CINIT(PIPELINING_SERVER_BL, OBJECTPOINT, 12),
  326. /* maximum number of open connections in total */
  327. CINIT(MAX_TOTAL_CONNECTIONS, LONG, 13),
  328. /* This is the server push callback function pointer */
  329. CINIT(PUSHFUNCTION, FUNCTIONPOINT, 14),
  330. /* This is the argument passed to the server push callback */
  331. CINIT(PUSHDATA, OBJECTPOINT, 15),
  332. CURLMOPT_LASTENTRY /* the last unused */
  333. } CURLMoption;
  334. /*
  335. * Name: curl_multi_setopt()
  336. *
  337. * Desc: Sets options for the multi handle.
  338. *
  339. * Returns: CURLM error code.
  340. */
  341. CURL_EXTERN CURLMcode curl_multi_setopt(CURLM *multi_handle,
  342. CURLMoption option, ...);
  343. /*
  344. * Name: curl_multi_assign()
  345. *
  346. * Desc: This function sets an association in the multi handle between the
  347. * given socket and a private pointer of the application. This is
  348. * (only) useful for curl_multi_socket uses.
  349. *
  350. * Returns: CURLM error code.
  351. */
  352. CURL_EXTERN CURLMcode curl_multi_assign(CURLM *multi_handle,
  353. curl_socket_t sockfd, void *sockp);
  354. /*
  355. * Name: curl_push_callback
  356. *
  357. * Desc: This callback gets called when a new stream is being pushed by the
  358. * server. It approves or denies the new stream.
  359. *
  360. * Returns: CURL_PUSH_OK or CURL_PUSH_DENY.
  361. */
  362. #define CURL_PUSH_OK 0
  363. #define CURL_PUSH_DENY 1
  364. struct curl_pushheaders; /* forward declaration only */
  365. CURL_EXTERN char *curl_pushheader_bynum(struct curl_pushheaders *h,
  366. size_t num);
  367. CURL_EXTERN char *curl_pushheader_byname(struct curl_pushheaders *h,
  368. const char *name);
  369. typedef int (*curl_push_callback)(CURL *parent,
  370. CURL *easy,
  371. size_t num_headers,
  372. struct curl_pushheaders *headers,
  373. void *userp);
  374. #ifdef __cplusplus
  375. } /* end of extern "C" */
  376. #endif
  377. #endif