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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 
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 #if defined(BUILDING_LIBCURL) || defined(CURL_STRICTER)
56 typedef struct Curl_multi CURLM;
57 #else
58 typedef void CURLM;
59 #endif
60 
61 typedef enum {
62   CURLM_CALL_MULTI_PERFORM = -1, /* please call curl_multi_perform() or
63                                     curl_multi_socket*() soon */
64   CURLM_OK,
65   CURLM_BAD_HANDLE,      /* the passed-in handle is not a valid CURLM handle */
66   CURLM_BAD_EASY_HANDLE, /* an easy handle was not good/valid */
67   CURLM_OUT_OF_MEMORY,   /* if you ever get this, you're in deep sh*t */
68   CURLM_INTERNAL_ERROR,  /* this is a libcurl bug */
69   CURLM_BAD_SOCKET,      /* the passed in socket argument did not match */
70   CURLM_UNKNOWN_OPTION,  /* curl_multi_setopt() with unsupported option */
71   CURLM_ADDED_ALREADY,   /* an easy handle already added to a multi handle was
72                             attempted to get added - again */
73   CURLM_RECURSIVE_API_CALL, /* an api function was called from inside a
74                                callback */
75   CURLM_LAST
76 } CURLMcode;
77 
78 /* just to make code nicer when using curl_multi_socket() you can now check
79    for CURLM_CALL_MULTI_SOCKET too in the same style it works for
80    curl_multi_perform() and CURLM_CALL_MULTI_PERFORM */
81 #define CURLM_CALL_MULTI_SOCKET CURLM_CALL_MULTI_PERFORM
82 
83 /* bitmask bits for CURLMOPT_PIPELINING */
84 #define CURLPIPE_NOTHING   0L
85 #define CURLPIPE_HTTP1     1L
86 #define CURLPIPE_MULTIPLEX 2L
87 
88 typedef enum {
89   CURLMSG_NONE, /* first, not used */
90   CURLMSG_DONE, /* This easy handle has completed. 'result' contains
91                    the CURLcode of the transfer */
92   CURLMSG_LAST /* last, not used */
93 } CURLMSG;
94 
95 struct CURLMsg {
96   CURLMSG msg;       /* what this message means */
97   CURL *easy_handle; /* the handle it concerns */
98   union {
99     void *whatever;    /* message-specific data */
100     CURLcode result;   /* return code for transfer */
101   } data;
102 };
103 typedef struct CURLMsg CURLMsg;
104 
105 /* Based on poll(2) structure and values.
106  * We don't use pollfd and POLL* constants explicitly
107  * to cover platforms without poll(). */
108 #define CURL_WAIT_POLLIN    0x0001
109 #define CURL_WAIT_POLLPRI   0x0002
110 #define CURL_WAIT_POLLOUT   0x0004
111 
112 struct curl_waitfd {
113   curl_socket_t fd;
114   short events;
115   short revents; /* not supported yet */
116 };
117 
118 /*
119  * Name:    curl_multi_init()
120  *
121  * Desc:    inititalize multi-style curl usage
122  *
123  * Returns: a new CURLM handle to use in all 'curl_multi' functions.
124  */
125 CURL_EXTERN CURLM *curl_multi_init(void);
126 
127 /*
128  * Name:    curl_multi_add_handle()
129  *
130  * Desc:    add a standard curl handle to the multi stack
131  *
132  * Returns: CURLMcode type, general multi error code.
133  */
134 CURL_EXTERN CURLMcode curl_multi_add_handle(CURLM *multi_handle,
135                                             CURL *curl_handle);
136 
137  /*
138   * Name:    curl_multi_remove_handle()
139   *
140   * Desc:    removes a curl handle from the multi stack again
141   *
142   * Returns: CURLMcode type, general multi error code.
143   */
144 CURL_EXTERN CURLMcode curl_multi_remove_handle(CURLM *multi_handle,
145                                                CURL *curl_handle);
146 
147  /*
148   * Name:    curl_multi_fdset()
149   *
150   * Desc:    Ask curl for its fd_set sets. The app can use these to select() or
151   *          poll() on. We want curl_multi_perform() called as soon as one of
152   *          them are ready.
153   *
154   * Returns: CURLMcode type, general multi error code.
155   */
156 CURL_EXTERN CURLMcode curl_multi_fdset(CURLM *multi_handle,
157                                        fd_set *read_fd_set,
158                                        fd_set *write_fd_set,
159                                        fd_set *exc_fd_set,
160                                        int *max_fd);
161 
162 /*
163  * Name:     curl_multi_wait()
164  *
165  * Desc:     Poll on all fds within a CURLM set as well as any
166  *           additional fds passed to the function.
167  *
168  * Returns:  CURLMcode type, general multi error code.
169  */
170 CURL_EXTERN CURLMcode curl_multi_wait(CURLM *multi_handle,
171                                       struct curl_waitfd extra_fds[],
172                                       unsigned int extra_nfds,
173                                       int timeout_ms,
174                                       int *ret);
175 
176  /*
177   * Name:    curl_multi_perform()
178   *
179   * Desc:    When the app thinks there's data available for curl it calls this
180   *          function to read/write whatever there is right now. This returns
181   *          as soon as the reads and writes are done. This function does not
182   *          require that there actually is data available for reading or that
183   *          data can be written, it can be called just in case. It returns
184   *          the number of handles that still transfer data in the second
185   *          argument's integer-pointer.
186   *
187   * Returns: CURLMcode type, general multi error code. *NOTE* that this only
188   *          returns errors etc regarding the whole multi stack. There might
189   *          still have occurred problems on individual transfers even when
190   *          this returns OK.
191   */
192 CURL_EXTERN CURLMcode curl_multi_perform(CURLM *multi_handle,
193                                          int *running_handles);
194 
195  /*
196   * Name:    curl_multi_cleanup()
197   *
198   * Desc:    Cleans up and removes a whole multi stack. It does not free or
199   *          touch any individual easy handles in any way. We need to define
200   *          in what state those handles will be if this function is called
201   *          in the middle of a transfer.
202   *
203   * Returns: CURLMcode type, general multi error code.
204   */
205 CURL_EXTERN CURLMcode curl_multi_cleanup(CURLM *multi_handle);
206 
207 /*
208  * Name:    curl_multi_info_read()
209  *
210  * Desc:    Ask the multi handle if there's any messages/informationals from
211  *          the individual transfers. Messages include informationals such as
212  *          error code from the transfer or just the fact that a transfer is
213  *          completed. More details on these should be written down as well.
214  *
215  *          Repeated calls to this function will return a new struct each
216  *          time, until a special "end of msgs" struct is returned as a signal
217  *          that there is no more to get at this point.
218  *
219  *          The data the returned pointer points to will not survive calling
220  *          curl_multi_cleanup().
221  *
222  *          The 'CURLMsg' struct is meant to be very simple and only contain
223  *          very basic information. If more involved information is wanted,
224  *          we will provide the particular "transfer handle" in that struct
225  *          and that should/could/would be used in subsequent
226  *          curl_easy_getinfo() calls (or similar). The point being that we
227  *          must never expose complex structs to applications, as then we'll
228  *          undoubtably get backwards compatibility problems in the future.
229  *
230  * Returns: A pointer to a filled-in struct, or NULL if it failed or ran out
231  *          of structs. It also writes the number of messages left in the
232  *          queue (after this read) in the integer the second argument points
233  *          to.
234  */
235 CURL_EXTERN CURLMsg *curl_multi_info_read(CURLM *multi_handle,
236                                           int *msgs_in_queue);
237 
238 /*
239  * Name:    curl_multi_strerror()
240  *
241  * Desc:    The curl_multi_strerror function may be used to turn a CURLMcode
242  *          value into the equivalent human readable error string.  This is
243  *          useful for printing meaningful error messages.
244  *
245  * Returns: A pointer to a zero-terminated error message.
246  */
247 CURL_EXTERN const char *curl_multi_strerror(CURLMcode);
248 
249 /*
250  * Name:    curl_multi_socket() and
251  *          curl_multi_socket_all()
252  *
253  * Desc:    An alternative version of curl_multi_perform() that allows the
254  *          application to pass in one of the file descriptors that have been
255  *          detected to have "action" on them and let libcurl perform.
256  *          See man page for details.
257  */
258 #define CURL_POLL_NONE   0
259 #define CURL_POLL_IN     1
260 #define CURL_POLL_OUT    2
261 #define CURL_POLL_INOUT  3
262 #define CURL_POLL_REMOVE 4
263 
264 #define CURL_SOCKET_TIMEOUT CURL_SOCKET_BAD
265 
266 #define CURL_CSELECT_IN   0x01
267 #define CURL_CSELECT_OUT  0x02
268 #define CURL_CSELECT_ERR  0x04
269 
270 typedef int (*curl_socket_callback)(CURL *easy,      /* easy handle */
271                                     curl_socket_t s, /* socket */
272                                     int what,        /* see above */
273                                     void *userp,     /* private callback
274                                                         pointer */
275                                     void *socketp);  /* private socket
276                                                         pointer */
277 /*
278  * Name:    curl_multi_timer_callback
279  *
280  * Desc:    Called by libcurl whenever the library detects a change in the
281  *          maximum number of milliseconds the app is allowed to wait before
282  *          curl_multi_socket() or curl_multi_perform() must be called
283  *          (to allow libcurl's timed events to take place).
284  *
285  * Returns: The callback should return zero.
286  */
287 typedef int (*curl_multi_timer_callback)(CURLM *multi,    /* multi handle */
288                                          long timeout_ms, /* see above */
289                                          void *userp);    /* private callback
290                                                              pointer */
291 
292 CURL_EXTERN CURLMcode curl_multi_socket(CURLM *multi_handle, curl_socket_t s,
293                                         int *running_handles);
294 
295 CURL_EXTERN CURLMcode curl_multi_socket_action(CURLM *multi_handle,
296                                                curl_socket_t s,
297                                                int ev_bitmask,
298                                                int *running_handles);
299 
300 CURL_EXTERN CURLMcode curl_multi_socket_all(CURLM *multi_handle,
301                                             int *running_handles);
302 
303 #ifndef CURL_ALLOW_OLD_MULTI_SOCKET
304 /* This macro below was added in 7.16.3 to push users who recompile to use
305    the new curl_multi_socket_action() instead of the old curl_multi_socket()
306 */
307 #define curl_multi_socket(x,y,z) curl_multi_socket_action(x,y,0,z)
308 #endif
309 
310 /*
311  * Name:    curl_multi_timeout()
312  *
313  * Desc:    Returns the maximum number of milliseconds the app is allowed to
314  *          wait before curl_multi_socket() or curl_multi_perform() must be
315  *          called (to allow libcurl's timed events to take place).
316  *
317  * Returns: CURLM error code.
318  */
319 CURL_EXTERN CURLMcode curl_multi_timeout(CURLM *multi_handle,
320                                          long *milliseconds);
321 
322 #undef CINIT /* re-using the same name as in curl.h */
323 
324 #ifdef CURL_ISOCPP
325 #define CINIT(name,type,num) CURLMOPT_ ## name = CURLOPTTYPE_ ## type + num
326 #else
327 /* The macro "##" is ISO C, we assume pre-ISO C doesn't support it. */
328 #define LONG          CURLOPTTYPE_LONG
329 #define OBJECTPOINT   CURLOPTTYPE_OBJECTPOINT
330 #define FUNCTIONPOINT CURLOPTTYPE_FUNCTIONPOINT
331 #define OFF_T         CURLOPTTYPE_OFF_T
332 #define CINIT(name,type,number) CURLMOPT_/**/name = type + number
333 #endif
334 
335 typedef enum {
336   /* This is the socket callback function pointer */
337   CINIT(SOCKETFUNCTION, FUNCTIONPOINT, 1),
338 
339   /* This is the argument passed to the socket callback */
340   CINIT(SOCKETDATA, OBJECTPOINT, 2),
341 
342     /* set to 1 to enable pipelining for this multi handle */
343   CINIT(PIPELINING, LONG, 3),
344 
345    /* This is the timer callback function pointer */
346   CINIT(TIMERFUNCTION, FUNCTIONPOINT, 4),
347 
348   /* This is the argument passed to the timer callback */
349   CINIT(TIMERDATA, OBJECTPOINT, 5),
350 
351   /* maximum number of entries in the connection cache */
352   CINIT(MAXCONNECTS, LONG, 6),
353 
354   /* maximum number of (pipelining) connections to one host */
355   CINIT(MAX_HOST_CONNECTIONS, LONG, 7),
356 
357   /* maximum number of requests in a pipeline */
358   CINIT(MAX_PIPELINE_LENGTH, LONG, 8),
359 
360   /* a connection with a content-length longer than this
361      will not be considered for pipelining */
362   CINIT(CONTENT_LENGTH_PENALTY_SIZE, OFF_T, 9),
363 
364   /* a connection with a chunk length longer than this
365      will not be considered for pipelining */
366   CINIT(CHUNK_LENGTH_PENALTY_SIZE, OFF_T, 10),
367 
368   /* a list of site names(+port) that are blacklisted from
369      pipelining */
370   CINIT(PIPELINING_SITE_BL, OBJECTPOINT, 11),
371 
372   /* a list of server types that are blacklisted from
373      pipelining */
374   CINIT(PIPELINING_SERVER_BL, OBJECTPOINT, 12),
375 
376   /* maximum number of open connections in total */
377   CINIT(MAX_TOTAL_CONNECTIONS, LONG, 13),
378 
379    /* This is the server push callback function pointer */
380   CINIT(PUSHFUNCTION, FUNCTIONPOINT, 14),
381 
382   /* This is the argument passed to the server push callback */
383   CINIT(PUSHDATA, OBJECTPOINT, 15),
384 
385   CURLMOPT_LASTENTRY /* the last unused */
386 } CURLMoption;
387 
388 
389 /*
390  * Name:    curl_multi_setopt()
391  *
392  * Desc:    Sets options for the multi handle.
393  *
394  * Returns: CURLM error code.
395  */
396 CURL_EXTERN CURLMcode curl_multi_setopt(CURLM *multi_handle,
397                                         CURLMoption option, ...);
398 
399 
400 /*
401  * Name:    curl_multi_assign()
402  *
403  * Desc:    This function sets an association in the multi handle between the
404  *          given socket and a private pointer of the application. This is
405  *          (only) useful for curl_multi_socket uses.
406  *
407  * Returns: CURLM error code.
408  */
409 CURL_EXTERN CURLMcode curl_multi_assign(CURLM *multi_handle,
410                                         curl_socket_t sockfd, void *sockp);
411 
412 
413 /*
414  * Name: curl_push_callback
415  *
416  * Desc: This callback gets called when a new stream is being pushed by the
417  *       server. It approves or denies the new stream.
418  *
419  * Returns: CURL_PUSH_OK or CURL_PUSH_DENY.
420  */
421 #define CURL_PUSH_OK   0
422 #define CURL_PUSH_DENY 1
423 
424 struct curl_pushheaders;  /* forward declaration only */
425 
426 CURL_EXTERN char *curl_pushheader_bynum(struct curl_pushheaders *h,
427                                         size_t num);
428 CURL_EXTERN char *curl_pushheader_byname(struct curl_pushheaders *h,
429                                          const char *name);
430 
431 typedef int (*curl_push_callback)(CURL *parent,
432                                   CURL *easy,
433                                   size_t num_headers,
434                                   struct curl_pushheaders *headers,
435                                   void *userp);
436 
437 #ifdef __cplusplus
438 } /* end of extern "C" */
439 #endif
440 
441 #endif
442