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curl/lib/multihandle.h
Linus Nielsen Feltzing 0f147887b0 Multiple pipelines and limiting the number of connections.
Introducing a number of options to the multi interface that
allows for multiple pipelines to the same host, in order to
optimize the balance between the penalty for opening new
connections and the potential pipelining latency.

Two new options for limiting the number of connections:

CURLMOPT_MAX_HOST_CONNECTIONS - Limits the number of running connections
to the same host. When adding a handle that exceeds this limit,
that handle will be put in a pending state until another handle is
finished, so we can reuse the connection.

CURLMOPT_MAX_TOTAL_CONNECTIONS - Limits the number of connections in total.
When adding a handle that exceeds this limit,
that handle will be put in a pending state until another handle is
finished. The free connection will then be reused, if possible, or
closed if the pending handle can't reuse it.

Several new options for pipelining:

CURLMOPT_MAX_PIPELINE_LENGTH - Limits the pipeling length. If a
pipeline is "full" when a connection is to be reused, a new connection
will be opened if the CURLMOPT_MAX_xxx_CONNECTIONS limits allow it.
If not, the handle will be put in a pending state until a connection is
ready (either free or a pipe got shorter).

CURLMOPT_CONTENT_LENGTH_PENALTY_SIZE - A pipelined connection will not
be reused if it is currently processing a transfer with a content
length that is larger than this.

CURLMOPT_CHUNK_LENGTH_PENALTY_SIZE - A pipelined connection will not
be reused if it is currently processing a chunk larger than this.

CURLMOPT_PIPELINING_SITE_BL - A blacklist of hosts that don't allow
pipelining.

CURLMOPT_PIPELINING_SERVER_BL - A blacklist of server types that don't allow
pipelining.

See the curl_multi_setopt() man page for details.
2013-03-13 23:55:24 +01:00

160 lines
6.6 KiB
C

#ifndef HEADER_CURL_MULTIHANDLE_H
#define HEADER_CURL_MULTIHANDLE_H
/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2013, Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at http://curl.haxx.se/docs/copyright.html.
*
* 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 COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
***************************************************************************/
struct Curl_message {
/* the 'CURLMsg' is the part that is visible to the external user */
struct CURLMsg extmsg;
};
/* NOTE: if you add a state here, add the name to the statename[] array as
well!
*/
typedef enum {
CURLM_STATE_INIT, /* 0 - start in this state */
CURLM_STATE_CONNECT_PEND, /* 1 - no connections, waiting for one */
CURLM_STATE_CONNECT, /* 2 - resolve/connect has been sent off */
CURLM_STATE_WAITRESOLVE, /* 3 - awaiting the resolve to finalize */
CURLM_STATE_WAITCONNECT, /* 4 - awaiting the connect to finalize */
CURLM_STATE_WAITPROXYCONNECT, /* 5 - awaiting proxy CONNECT to finalize */
CURLM_STATE_PROTOCONNECT, /* 6 - completing the protocol-specific connect
phase */
CURLM_STATE_WAITDO, /* 7 - wait for our turn to send the request */
CURLM_STATE_DO, /* 8 - start send off the request (part 1) */
CURLM_STATE_DOING, /* 9 - sending off the request (part 1) */
CURLM_STATE_DO_MORE, /* 10 - send off the request (part 2) */
CURLM_STATE_DO_DONE, /* 11 - done sending off request */
CURLM_STATE_WAITPERFORM, /* 12 - wait for our turn to read the response */
CURLM_STATE_PERFORM, /* 13 - transfer data */
CURLM_STATE_TOOFAST, /* 14 - wait because limit-rate exceeded */
CURLM_STATE_DONE, /* 15 - post data transfer operation */
CURLM_STATE_COMPLETED, /* 16 - operation complete */
CURLM_STATE_MSGSENT, /* 17 - the operation complete message is sent */
CURLM_STATE_LAST /* 18 - not a true state, never use this */
} CURLMstate;
/* we support N sockets per easy handle. Set the corresponding bit to what
action we should wait for */
#define MAX_SOCKSPEREASYHANDLE 5
#define GETSOCK_READABLE (0x00ff)
#define GETSOCK_WRITABLE (0xff00)
struct Curl_one_easy {
/* first, two fields for the linked list of these */
struct Curl_one_easy *next;
struct Curl_one_easy *prev;
struct SessionHandle *easy_handle; /* the easy handle for this unit */
struct connectdata *easy_conn; /* the "unit's" connection */
CURLMstate state; /* the handle's state */
CURLcode result; /* previous result */
struct Curl_message msg; /* A single posted message. */
/* Array with the plain socket numbers this handle takes care of, in no
particular order. Note that all sockets are added to the sockhash, where
the state etc are also kept. This array is mostly used to detect when a
socket is to be removed from the hash. See singlesocket(). */
curl_socket_t sockets[MAX_SOCKSPEREASYHANDLE];
int numsocks;
};
/* This is the struct known as CURLM on the outside */
struct Curl_multi {
/* First a simple identifier to easier detect if a user mix up
this multi handle with an easy handle. Set this to CURL_MULTI_HANDLE. */
long type;
/* We have a doubly-linked circular list with easy handles */
struct Curl_one_easy easy;
int num_easy; /* amount of entries in the linked list above. */
int num_alive; /* amount of easy handles that are added but have not yet
reached COMPLETE state */
struct curl_llist *msglist; /* a list of messages from completed transfers */
/* callback function and user data pointer for the *socket() API */
curl_socket_callback socket_cb;
void *socket_userp;
/* Hostname cache */
struct curl_hash *hostcache;
/* timetree points to the splay-tree of time nodes to figure out expire
times of all currently set timers */
struct Curl_tree *timetree;
/* 'sockhash' is the lookup hash for socket descriptor => easy handles (note
the pluralis form, there can be more than one easy handle waiting on the
same actual socket) */
struct curl_hash *sockhash;
/* Whether pipelining is enabled for this multi handle */
bool pipelining_enabled;
/* Shared connection cache (bundles)*/
struct conncache *conn_cache;
/* This handle will be used for closing the cached connections in
curl_multi_cleanup() */
struct SessionHandle *closure_handle;
long maxconnects; /* if >0, a fixed limit of the maximum number of entries
we're allowed to grow the connection cache to */
long max_host_connections; /* if >0, a fixed limit of the maximum number
of connections per host */
long max_total_connections; /* if >0, a fixed limit of the maximum number
of connections in total */
long max_pipeline_length; /* if >0, maximum number of requests in a
pipeline */
long content_length_penalty_size; /* a connection with a
content-length bigger than
this is not considered
for pipelining */
long chunk_length_penalty_size; /* a connection with a chunk length
bigger than this is not
considered for pipelining */
struct curl_llist *pipelining_site_bl; /* List of sites that are blacklisted
from pipelining */
struct curl_llist *pipelining_server_bl; /* List of server types that are
blacklisted from pipelining */
/* timer callback and user data pointer for the *socket() API */
curl_multi_timer_callback timer_cb;
void *timer_userp;
struct timeval timer_lastcall; /* the fixed time for the timeout for the
previous callback */
};
#endif /* HEADER_CURL_MULTIHANDLE_H */