multi.h revision d9d863e153d12532fc85bd8b44bc47f079ed064c 
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 * $Id: multi.h,v 1.45 2008-05-20 10:21:50 patrickm Exp $
24 ***************************************************************************/
25/*
26  This is an "external" header file. Don't give away any internals here!
27
28  GOALS
29
30  o Enable a "pull" interface. The application that uses libcurl decides where
31    and when to ask libcurl to get/send data.
32
33  o Enable multiple simultaneous transfers in the same thread without making it
34    complicated for the application.
35
36  o Enable the application to select() on its own file descriptors and curl's
37    file descriptors simultaneous easily.
38
39*/
40
41/*
42 * This header file should not really need to include "curl.h" since curl.h
43 * itself includes this file and we expect user applications to do #include
44 * <curl/curl.h> without the need for especially including multi.h.
45 *
46 * For some reason we added this include here at one point, and rather than to
47 * break existing (wrongly written) libcurl applications, we leave it as-is
48 * but with this warning attached.
49 */
50#include "curl.h"
51
52#ifdef  __cplusplus
53extern "C" {
54#endif
55
56typedef void CURLM;
57
58typedef enum {
59  CURLM_CALL_MULTI_PERFORM = -1, /* please call curl_multi_perform() or
60                                    curl_multi_socket*() soon */
61  CURLM_OK,
62  CURLM_BAD_HANDLE,      /* the passed-in handle is not a valid CURLM handle */
63  CURLM_BAD_EASY_HANDLE, /* an easy handle was not good/valid */
64  CURLM_OUT_OF_MEMORY,   /* if you ever get this, you're in deep sh*t */
65  CURLM_INTERNAL_ERROR,  /* this is a libcurl bug */
66  CURLM_BAD_SOCKET,      /* the passed in socket argument did not match */
67  CURLM_UNKNOWN_OPTION,  /* curl_multi_setopt() with unsupported option */
68  CURLM_LAST
69} CURLMcode;
70
71/* just to make code nicer when using curl_multi_socket() you can now check
72   for CURLM_CALL_MULTI_SOCKET too in the same style it works for
73   curl_multi_perform() and CURLM_CALL_MULTI_PERFORM */
74#define CURLM_CALL_MULTI_SOCKET CURLM_CALL_MULTI_PERFORM
75
76typedef enum {
77  CURLMSG_NONE, /* first, not used */
78  CURLMSG_DONE, /* This easy handle has completed. 'result' contains
79                   the CURLcode of the transfer */
80  CURLMSG_LAST /* last, not used */
81} CURLMSG;
82
83struct CURLMsg {
84  CURLMSG msg;       /* what this message means */
85  CURL *easy_handle; /* the handle it concerns */
86  union {
87    void *whatever;    /* message-specific data */
88    CURLcode result;   /* return code for transfer */
89  } data;
90};
91typedef struct CURLMsg CURLMsg;
92
93/*
94 * Name:    curl_multi_init()
95 *
96 * Desc:    inititalize multi-style curl usage
97 *
98 * Returns: a new CURLM handle to use in all 'curl_multi' functions.
99 */
100CURL_EXTERN CURLM *curl_multi_init(void);
101
102/*
103 * Name:    curl_multi_add_handle()
104 *
105 * Desc:    add a standard curl handle to the multi stack
106 *
107 * Returns: CURLMcode type, general multi error code.
108 */
109CURL_EXTERN CURLMcode curl_multi_add_handle(CURLM *multi_handle,
110                                            CURL *curl_handle);
111
112 /*
113  * Name:    curl_multi_remove_handle()
114  *
115  * Desc:    removes a curl handle from the multi stack again
116  *
117  * Returns: CURLMcode type, general multi error code.
118  */
119CURL_EXTERN CURLMcode curl_multi_remove_handle(CURLM *multi_handle,
120                                               CURL *curl_handle);
121
122 /*
123  * Name:    curl_multi_fdset()
124  *
125  * Desc:    Ask curl for its fd_set sets. The app can use these to select() or
126  *          poll() on. We want curl_multi_perform() called as soon as one of
127  *          them are ready.
128  *
129  * Returns: CURLMcode type, general multi error code.
130  */
131CURL_EXTERN CURLMcode curl_multi_fdset(CURLM *multi_handle,
132                                       fd_set *read_fd_set,
133                                       fd_set *write_fd_set,
134                                       fd_set *exc_fd_set,
135                                       int *max_fd);
136
137 /*
138  * Name:    curl_multi_perform()
139  *
140  * Desc:    When the app thinks there's data available for curl it calls this
141  *          function to read/write whatever there is right now. This returns
142  *          as soon as the reads and writes are done. This function does not
143  *          require that there actually is data available for reading or that
144  *          data can be written, it can be called just in case. It returns
145  *          the number of handles that still transfer data in the second
146  *          argument's integer-pointer.
147  *
148  * Returns: CURLMcode type, general multi error code. *NOTE* that this only
149  *          returns errors etc regarding the whole multi stack. There might
150  *          still have occurred problems on invidual transfers even when this
151  *          returns OK.
152  */
153CURL_EXTERN CURLMcode curl_multi_perform(CURLM *multi_handle,
154                                         int *running_handles);
155
156 /*
157  * Name:    curl_multi_cleanup()
158  *
159  * Desc:    Cleans up and removes a whole multi stack. It does not free or
160  *          touch any individual easy handles in any way. We need to define
161  *          in what state those handles will be if this function is called
162  *          in the middle of a transfer.
163  *
164  * Returns: CURLMcode type, general multi error code.
165  */
166CURL_EXTERN CURLMcode curl_multi_cleanup(CURLM *multi_handle);
167
168/*
169 * Name:    curl_multi_info_read()
170 *
171 * Desc:    Ask the multi handle if there's any messages/informationals from
172 *          the individual transfers. Messages include informationals such as
173 *          error code from the transfer or just the fact that a transfer is
174 *          completed. More details on these should be written down as well.
175 *
176 *          Repeated calls to this function will return a new struct each
177 *          time, until a special "end of msgs" struct is returned as a signal
178 *          that there is no more to get at this point.
179 *
180 *          The data the returned pointer points to will not survive calling
181 *          curl_multi_cleanup().
182 *
183 *          The 'CURLMsg' struct is meant to be very simple and only contain
184 *          very basic informations. If more involved information is wanted,
185 *          we will provide the particular "transfer handle" in that struct
186 *          and that should/could/would be used in subsequent
187 *          curl_easy_getinfo() calls (or similar). The point being that we
188 *          must never expose complex structs to applications, as then we'll
189 *          undoubtably get backwards compatibility problems in the future.
190 *
191 * Returns: A pointer to a filled-in struct, or NULL if it failed or ran out
192 *          of structs. It also writes the number of messages left in the
193 *          queue (after this read) in the integer the second argument points
194 *          to.
195 */
196CURL_EXTERN CURLMsg *curl_multi_info_read(CURLM *multi_handle,
197                                          int *msgs_in_queue);
198
199/*
200 * Name:    curl_multi_strerror()
201 *
202 * Desc:    The curl_multi_strerror function may be used to turn a CURLMcode
203 *          value into the equivalent human readable error string.  This is
204 *          useful for printing meaningful error messages.
205 *
206 * Returns: A pointer to a zero-terminated error message.
207 */
208CURL_EXTERN const char *curl_multi_strerror(CURLMcode);
209
210/*
211 * Name:    curl_multi_socket() and
212 *          curl_multi_socket_all()
213 *
214 * Desc:    An alternative version of curl_multi_perform() that allows the
215 *          application to pass in one of the file descriptors that have been
216 *          detected to have "action" on them and let libcurl perform.
217 *          See man page for details.
218 */
219#define CURL_POLL_NONE   0
220#define CURL_POLL_IN     1
221#define CURL_POLL_OUT    2
222#define CURL_POLL_INOUT  3
223#define CURL_POLL_REMOVE 4
224
225#define CURL_SOCKET_TIMEOUT CURL_SOCKET_BAD
226
227#define CURL_CSELECT_IN   0x01
228#define CURL_CSELECT_OUT  0x02
229#define CURL_CSELECT_ERR  0x04
230
231typedef int (*curl_socket_callback)(CURL *easy,      /* easy handle */
232                                    curl_socket_t s, /* socket */
233                                    int what,        /* see above */
234                                    void *userp,     /* private callback
235                                                        pointer */
236                                    void *socketp);  /* private socket
237                                                        pointer */
238/*
239 * Name:    curl_multi_timer_callback
240 *
241 * Desc:    Called by libcurl whenever the library detects a change in the
242 *          maximum number of milliseconds the app is allowed to wait before
243 *          curl_multi_socket() or curl_multi_perform() must be called
244 *          (to allow libcurl's timed events to take place).
245 *
246 * Returns: The callback should return zero.
247 */
248typedef int (*curl_multi_timer_callback)(CURLM *multi,    /* multi handle */
249                                         long timeout_ms, /* see above */
250                                         void *userp);    /* private callback
251                                                             pointer */
252
253CURL_EXTERN CURLMcode curl_multi_socket(CURLM *multi_handle, curl_socket_t s,
254                                        int *running_handles);
255
256CURL_EXTERN CURLMcode curl_multi_socket_action(CURLM *multi_handle,
257                                               curl_socket_t s,
258                                               int ev_bitmask,
259                                               int *running_handles);
260
261CURL_EXTERN CURLMcode curl_multi_socket_all(CURLM *multi_handle,
262                                            int *running_handles);
263
264#ifndef CURL_ALLOW_OLD_MULTI_SOCKET
265/* This macro below was added in 7.16.3 to push users who recompile to use
266   the new curl_multi_socket_action() instead of the old curl_multi_socket()
267*/
268#define curl_multi_socket(x,y,z) curl_multi_socket_action(x,y,0,z)
269#endif
270
271/*
272 * Name:    curl_multi_timeout()
273 *
274 * Desc:    Returns the maximum number of milliseconds the app is allowed to
275 *          wait before curl_multi_socket() or curl_multi_perform() must be
276 *          called (to allow libcurl's timed events to take place).
277 *
278 * Returns: CURLM error code.
279 */
280CURL_EXTERN CURLMcode curl_multi_timeout(CURLM *multi_handle,
281                                         long *milliseconds);
282
283#undef CINIT /* re-using the same name as in curl.h */
284
285#ifdef CURL_ISOCPP
286#define CINIT(name,type,num) CURLMOPT_ ## name = CURLOPTTYPE_ ## type + num
287#else
288/* The macro "##" is ISO C, we assume pre-ISO C doesn't support it. */
289#define LONG          CURLOPTTYPE_LONG
290#define OBJECTPOINT   CURLOPTTYPE_OBJECTPOINT
291#define FUNCTIONPOINT CURLOPTTYPE_FUNCTIONPOINT
292#define OFF_T         CURLOPTTYPE_OFF_T
293#define CINIT(name,type,number) CURLMOPT_/**/name = type + number
294#endif
295
296typedef enum {
297  /* This is the socket callback function pointer */
298  CINIT(SOCKETFUNCTION, FUNCTIONPOINT, 1),
299
300  /* This is the argument passed to the socket callback */
301  CINIT(SOCKETDATA, OBJECTPOINT, 2),
302
303    /* set to 1 to enable pipelining for this multi handle */
304  CINIT(PIPELINING, LONG, 3),
305
306   /* This is the timer callback function pointer */
307  CINIT(TIMERFUNCTION, FUNCTIONPOINT, 4),
308
309  /* This is the argument passed to the timer callback */
310  CINIT(TIMERDATA, OBJECTPOINT, 5),
311
312  /* maximum number of entries in the connection cache */
313  CINIT(MAXCONNECTS, LONG, 6),
314
315  CURLMOPT_LASTENTRY /* the last unused */
316} CURLMoption;
317
318
319/*
320 * Name:    curl_multi_setopt()
321 *
322 * Desc:    Sets options for the multi handle.
323 *
324 * Returns: CURLM error code.
325 */
326CURL_EXTERN CURLMcode curl_multi_setopt(CURLM *multi_handle,
327                                        CURLMoption option, ...);
328
329
330/*
331 * Name:    curl_multi_assign()
332 *
333 * Desc:    This function sets an association in the multi handle between the
334 *          given socket and a private pointer of the application. This is
335 *          (only) useful for curl_multi_socket uses.
336 *
337 * Returns: CURLM error code.
338 */
339CURL_EXTERN CURLMcode curl_multi_assign(CURLM *multi_handle,
340                                        curl_socket_t sockfd, void *sockp);
341
342#ifdef __cplusplus
343} /* end of extern "C" */
344#endif
345
346#endif
347