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authorDaniel Stenberg <daniel@haxx.se>2001-11-28 11:09:18 +0000
committerDaniel Stenberg <daniel@haxx.se>2001-11-28 11:09:18 +0000
commit15a56b42d6203603eadfe54f2b58f51de73fdac8 (patch)
tree817922ad58f1249528954e71f03d8ef11794cb00 /lib/multi.h
parentd3706814e981fcaaf922ab8a05394bcbb8448575 (diff)
used in the new multi interface, not yet actually part of libcurl but
added to CVS to make them available to others
Diffstat (limited to 'lib/multi.h')
-rw-r--r--lib/multi.h200
1 files changed, 200 insertions, 0 deletions
diff --git a/lib/multi.h b/lib/multi.h
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+++ b/lib/multi.h
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+#ifndef __CURL_MULTI_H
+#define __CURL_MULTI_H
+/*****************************************************************************
+ * _ _ ____ _
+ * Project ___| | | | _ \| |
+ * / __| | | | |_) | |
+ * | (__| |_| | _ <| |___
+ * \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 2001, Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * In order to be useful for every potential user, curl and libcurl are
+ * dual-licensed under the MPL and the MIT/X-derivate licenses.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the MPL or the MIT/X-derivate
+ * licenses. You may pick one of these licenses.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ * $Id$
+ *****************************************************************************/
+/*
+ This is meant to be the "external" header file. Don't give away any
+ internals here!
+
+ This document presents a mixture of ideas from at least:
+ - Daniel Stenberg
+ - Steve Dekorte
+ - Sterling Hughes
+ - Ben Greear
+
+ -------------------------------------------
+ GOALS
+
+ o Enable a "pull" interface. The application that uses libcurl decides where
+ and when to ask libcurl to get/send data.
+
+ o Enable multiple simultaneous transfers without using threads or making it
+ very complicated for the application.
+
+ o Enable the application to select() on its own file descriptors and curl's
+ file descriptors simultaneous easily.
+
+ Example source using this interface: http://curl.haxx.se/dev/multi-app.c
+
+*/
+#ifdef HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+#include <curl/types.h>
+
+typedef void CURLM;
+
+typedef enum {
+ CURLM_OK,
+ CURLM_BAD_HANDLE, /* the passed-in handle is not a valid CURLM handle */
+ CURLM_BAD_EASY_HANDLE, /* an easy handle was not good/valid */
+ CURLM_OUT_OF_MEMORY, /* if you ever get this, you're in deep sh*t */
+ CURLM_LAST
+} CURLMcode;
+
+struct CURLMsg {
+ CURL *easy_handle;
+ void *whatever;
+};
+typedef struct CURLMsg CURLMsg;
+
+typedef void * CURLMinfo;
+
+/*
+ * Desc: inititalize multi-style curl usage
+ * Name: curl_multi_init()
+ * Returns: a new CURLM handle to use in all 'curl_multi' functions.
+ */
+CURLM *curl_multi_init(void);
+
+/*
+ * Desc: add a standard curl handle to the multi stack
+ * Name: curl_multi_add_handle()
+ * Returns: CURLMcode type, general error code.
+ */
+CURLMcode curl_multi_add_handle(CURLM *multi_handle,
+ CURL *curl_handle);
+
+ /*
+ * Desc: removes a curl handle from the multi stack again
+ * Name: curl_multi_remove_handle()
+ * Returns: CURLMcode type, general error code.
+ */
+CURLMcode curl_multi_remove_handle(CURLM *multi_handle,
+ CURL *curl_handle);
+
+ /*
+ * Desc: Ask curl for its fd_set sets. The app can use these to select() or
+ * poll() on. We want curl_multi_perform() called as soon as one of
+ * them are ready.
+ * Name: curl_multi_fdset()
+ * Returns: CURLMcode type, general error code.
+ */
+CURLMcode curl_multi_fdset(CURLM *multi_handle,
+ fd_set *read_fd_set, fd_set *write_fd_set,
+ fd_set *exc_fd_set, int *max_fd);
+
+ /*
+ * Desc: When the app thinks there's data available for curl it calls this
+ * function to read/write whatever there is right now. This returns
+ * as soon as the reads and writes are done. This function does not
+ * require that there actually is data available for reading or that
+ * data can be written, it can be called just in case. It returns
+ * the number of handles that still transfer data in the second
+ * argument's integer-pointer.
+ * Name: curl_multi_fdset()
+ * Returns: CURLMcode type, general error code. *NOTE* that this only returns
+ * errors etc regardin the whole multi stack. There might still have
+ * occurred problems on invidual transfers even when this returns OK.
+ */
+
+CURLMcode curl_multi_perform(CURLM *multi_handle, int *running_handles);
+
+ /*
+ * Desc: Cleans up and removes a whole multi stack.
+ * Name: curl_multi_cleanup()
+ * Returns: CURLMcode type, general error code.
+ */
+CURLMcode curl_multi_cleanup(CURLM *multi_handle);
+
+/* ---------------------------------------------------------------------- */
+/*
+ * I suggest an fopen style system to get information from the multi layer.
+ * I've named these functions "curl_multi_info*" something to make it apparent
+ * that they belong together.
+ *
+ * I expect that the curl_multi_info_open will be used fairly often after
+ * calls to curl_multi_perform(), but there's nothing in this design that
+ * forces the application to invoke it at that particular time. In fact, many
+ * applications will do good without using it at all. */
+
+/*
+ * Desc: Ask the multi handle if there's any messages/informationals from
+ * the individual transfers. We pass a pointer to a 'CURLMinfo' that
+ * can be used as input in a subsequent call to curl_multi_info_read.
+ *
+ * Messages include informationals such as error code from the
+ * transfer or just the fact that a transfer is completed. More
+ * details on these should be written down as well.
+ *
+ * Name: curl_multi_info_open()
+ * Returns: The number of transfers that have information stored that can be
+ * read. If zero is returned, there's no need to call
+ * curl_multi_info_close() on the returned handle, but there's no
+ * harm in doing so.
+ */
+int curl_multi_info_open(CURLM *multi_handle, CURLMinfo *info_handle);
+
+/*
+ * Desc: Returns a pointer to a filled-in struct with information.
+ *
+ * Repeated calls to this function will return a new struct each
+ * time, until a special "end of msgs" struct is returned as a signal
+ * that there is no more to get at this point.
+ *
+ * curl_multi_info_close() should be called when the last info has
+ * been read. In fact, it must be called if curl_multi_info_open()
+ * was called.
+ *
+ * The data the returned pointer points to will not survive calling
+ * curl_multi_cleanup().
+ *
+ * The 'CURLMsg' struct is meant to be very simple and only contain
+ * very basic informations. If more involved information is wanted,
+ * we will provide the particular "transfer handle" in that struct
+ * and that should/could/would be used in subsequent
+ * curl_easy_getinfo() calls (or similar). The point being that we
+ * must never expose complex structs to applications, as then we'll
+ * undoubtably get backwards compatibility problems in the future.
+ *
+ * Name: curl_multi_info_read()
+ *
+ * Returns: A pointer to a struct, or NULL if it failed or ran out of structs.
+ * Note that if you continue reading until you get a NULL, you did
+ * read at least one too many times!
+ */
+CURLMsg *curl_multi_info_read(CURLMinfo *info_handle);
+
+/*
+ * Desc: Terminates an info reading "session".
+ *
+ * Name: curl_multi_info_close()
+ *
+ * Returns: When we've read all the info we want from the info_handle, we
+ * signal this to the multi system by calling this function.
+ * After this call, the info_handle can no longer be used.
+ *
+ */
+void curl_multi_info_close(CURLMinfo *info_handle);
+
+#endif