Commit d021f2e8 authored by Linus Nielsen's avatar Linus Nielsen Committed by Daniel Stenberg
Browse files

Introducing a new persistent connection caching system using "bundles". 

A bundle is a list of all persistent connections to the same host.
The connection cache consists of a hash of bundles, with the
hostname as the key.
The benefits may not be obvious, but they are two:

1) Faster search for connections to reuse, since the hash
   lookup only finds connections to the host in question.
2) It lays out the groundworks for an upcoming patch,
   which will introduce multiple HTTP pipelines.

This patch also removes the awkward list of "closure handles",
which were needed to send QUIT commands to the FTP server
when closing a connection.
Now we allocate a separate closure handle and use that
one to close all connections.

This has been tested in a live system for a few weeks, and of
course passes the test suite.
parent ca5f4e21

lib/Makefile.inc

+4 −3
Original line number Diff line number Diff line
@@ -24,7 +24,8 @@ CSOURCES = file.c timeval.c base64.c hostip.c progress.c formdata.c \ 
  idn_win32.c http_negotiate_sspi.c cyassl.c http_proxy.c non-ascii.c	\

  asyn-ares.c asyn-thread.c curl_gssapi.c curl_ntlm.c curl_ntlm_wb.c	\

  curl_ntlm_core.c curl_ntlm_msgs.c curl_sasl.c curl_schannel.c	        \

  curl_multibyte.c curl_darwinssl.c hostcheck.c

  curl_multibyte.c curl_darwinssl.c hostcheck.c                         \

  bundles.c conncache.c



HHEADERS = arpa_telnet.h netrc.h file.h timeval.h qssl.h hostip.h	\

  progress.h formdata.h cookie.h http.h sendf.h ftp.h url.h dict.h	\
@@ -42,4 +43,4 @@ HHEADERS = arpa_telnet.h netrc.h file.h timeval.h qssl.h hostip.h \ 
  gopher.h axtls.h cyassl.h http_proxy.h non-ascii.h asyn.h curl_ntlm.h	\

  curl_gssapi.h curl_ntlm_wb.h curl_ntlm_core.h curl_ntlm_msgs.h	\

  curl_sasl.h curl_schannel.h curl_multibyte.h curl_darwinssl.h	\

  hostcheck.h
 
  hostcheck.h bundles.h conncache.h

lib/bundles.c

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/***************************************************************************

 *                                  _   _ ____  _

 *  Project                     ___| | | |  _ \| |

 *                             / __| | | | |_) | |

 *                            | (__| |_| |  _ <| |___

 *                             \___|\___/|_| \_\_____|

 *

 * Copyright (C) 2012, Linus Nielsen Feltzing, <linus@haxx.se>

 *

 * 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.

 *

 ***************************************************************************/



#include "setup.h"



#include <curl/curl.h>



#include "urldata.h"

#include "url.h"

#include "progress.h"

#include "multiif.h"

#include "bundles.h"

#include "sendf.h"

#include "rawstr.h"



#include "curl_memory.h"

/* The last #include file should be: */

#include "memdebug.h"



static void conn_llist_dtor(void *user, void *element)

{

  struct connectdata *data = element;

  (void)user;



  data->bundle = NULL;

}



CURLcode Curl_bundle_create(struct SessionHandle *data,

                            struct connectbundle **cb_ptr)

{

  (void)data;

  *cb_ptr = malloc(sizeof(struct connectbundle));

  if(!*cb_ptr)

    return CURLE_OUT_OF_MEMORY;



  (*cb_ptr)->num_connections = 0;

  (*cb_ptr)->server_supports_pipelining = FALSE;



  (*cb_ptr)->conn_list = Curl_llist_alloc((curl_llist_dtor) conn_llist_dtor);

  if(!(*cb_ptr)->conn_list)

    return CURLE_OUT_OF_MEMORY;

  return CURLE_OK;

}



void Curl_bundle_destroy(struct connectbundle *cb_ptr)

{

  if(cb_ptr->conn_list)

    Curl_llist_destroy(cb_ptr->conn_list, NULL);

  Curl_safefree(cb_ptr);

}



/* Add a connection to a bundle */

CURLcode Curl_bundle_add_conn(struct connectbundle *cb_ptr,

                              struct connectdata *conn)

{

  if(!Curl_llist_insert_next(cb_ptr->conn_list, cb_ptr->conn_list->tail, conn))

    return CURLE_OUT_OF_MEMORY;



  conn->bundle = cb_ptr;



  cb_ptr->num_connections++;

  return CURLE_OK;

}



/* Remove a connection from a bundle */

int Curl_bundle_remove_conn(struct connectbundle *cb_ptr,

                            struct connectdata *conn)

{

  struct curl_llist_element *curr;



  curr = cb_ptr->conn_list->head;

  while(curr) {

    if(curr->ptr == conn) {

      Curl_llist_remove(cb_ptr->conn_list, curr, NULL);

      cb_ptr->num_connections--;

      conn->bundle = NULL;

      return 1; /* we removed a handle */

    }

    curr = curr->next;

  }

  return 0;

}

lib/bundles.h

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Original line number Diff line number Diff line 
#ifndef __BUNDLES_H

#define __BUNDLES_H

/***************************************************************************

 *                                  _   _ ____  _

 *  Project                     ___| | | |  _ \| |

 *                             / __| | | | |_) | |

 *                            | (__| |_| |  _ <| |___

 *                             \___|\___/|_| \_\_____|

 *

 * Copyright (C) 2012, Linus Nielsen Feltzing, <linus@haxx.se>

 *

 * 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 connectbundle {

  bool server_supports_pipelining; /* TRUE if server supports pipelining,

                                      set after first response */

  size_t num_connections;       /* Number of connections in the bundle */

  struct curl_llist *conn_list; /* The connectdata members of the bundle */

};



CURLcode Curl_bundle_create(struct SessionHandle *data,

                            struct connectbundle **cb_ptr);



void Curl_bundle_destroy(struct connectbundle *cb_ptr);



CURLcode Curl_bundle_add_conn(struct connectbundle *cb_ptr,

                              struct connectdata *conn);



int Curl_bundle_remove_conn(struct connectbundle *cb_ptr,

                            struct connectdata *conn);





#endif /* __BUNDLES_H */

lib/conncache.c

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+270 −0
Original line number Diff line number Diff line 
/***************************************************************************

 *                                  _   _ ____  _

 *  Project                     ___| | | |  _ \| |

 *                             / __| | | | |_) | |

 *                            | (__| |_| |  _ <| |___

 *                             \___|\___/|_| \_\_____|

 *

 * Copyright (C) 2012, Linus Nielsen Feltzing, <linus@haxx.se>

 *

 * 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.

 *

 ***************************************************************************/



#include "setup.h"



#include <curl/curl.h>



#include "urldata.h"

#include "url.h"

#include "progress.h"

#include "multiif.h"

#include "sendf.h"

#include "rawstr.h"

#include "bundles.h"

#include "conncache.h"



#include "curl_memory.h"

/* The last #include file should be: */

#include "memdebug.h"



#define CONNECTION_HASH_SIZE 97



static void free_bundle_hash_entry(void *freethis)

{

  struct connectbundle *b = (struct connectbundle *) freethis;



  Curl_bundle_destroy(b);

}



struct conncache *Curl_conncache_init(int type)

{

  struct conncache *connc;



  connc = calloc(1, sizeof(struct conncache));

  if(!connc)

    return NULL;



  connc->hash = Curl_hash_alloc(CONNECTION_HASH_SIZE, Curl_hash_str,

                                Curl_str_key_compare, free_bundle_hash_entry);



  if(!connc->hash) {

    free(connc);

    return NULL;

  }



  connc->type = type;

  connc->num_connections = 0;



  return connc;

}



void Curl_conncache_destroy(struct conncache *connc)

{

  Curl_hash_destroy(connc->hash);

  free(connc);

}



struct connectbundle *Curl_conncache_find_bundle(struct conncache *connc,

                                                 char *hostname)

{

  struct connectbundle *bundle = NULL;



  if(connc)

    bundle = Curl_hash_pick(connc->hash, hostname, strlen(hostname)+1);



  return bundle;

}



static bool conncache_add_bundle(struct conncache *connc,

                                 char *hostname,

                                 struct connectbundle *bundle)

{

  void *p;



  p = Curl_hash_add(connc->hash, hostname, strlen(hostname)+1, bundle);



  return p?TRUE:FALSE;

}



static void conncache_remove_bundle(struct conncache *connc,

                                    struct connectbundle *bundle)

{

  struct curl_hash_iterator iter;

  struct curl_hash_element *he;



  if(!connc)

    return;



  Curl_hash_start_iterate(connc->hash, &iter);



  he = Curl_hash_next_element(&iter);

  while(he) {

    if(he->ptr == bundle) {

      /* The bundle is destroyed by the hash destructor function,

         free_bundle_hash_entry() */

      Curl_hash_delete(connc->hash, he->key, he->key_len);

      return;

    }



    he = Curl_hash_next_element(&iter);

  }

}



CURLcode Curl_conncache_add_conn(struct conncache *connc,

                                 struct connectdata *conn)

{

  CURLcode result;

  struct connectbundle *bundle;

  struct SessionHandle *data = conn->data;



  bundle = Curl_conncache_find_bundle(data->state.conn_cache,

                                      conn->host.name);

  if(!bundle) {

    result = Curl_bundle_create(data, &bundle);

    if(result != CURLE_OK)

      return result;



    if(!conncache_add_bundle(data->state.conn_cache,

                             conn->host.name, bundle))

      return CURLE_OUT_OF_MEMORY;

  }



  result = Curl_bundle_add_conn(bundle, conn);

  if(result != CURLE_OK)

    return result;



  connc->num_connections++;



  return CURLE_OK;

}



void Curl_conncache_remove_conn(struct conncache *connc,

                                struct connectdata *conn)

{

  struct connectbundle *bundle = conn->bundle;



  /* The bundle pointer can be NULL, since this function can be called

     due to a failed connection attempt, before being added to a bundle */

  if(bundle) {

    Curl_bundle_remove_conn(bundle, conn);

    if(bundle->num_connections == 0) {

      conncache_remove_bundle(connc, bundle);

    }

    connc->num_connections--;



    DEBUGF(infof(conn->data, "The cache now contains %d members\n",

                 connc->num_connections));

  }

}



/* This function iterates the entire connection cache and calls the

   function func() with the connection pointer as the first argument

   and the supplied 'param' argument as the other */

void Curl_conncache_foreach(struct conncache *connc,

                            void *param,

                            void (*func)(void *conn, void *param))

{

  struct curl_hash_iterator iter;

  struct curl_llist_element *curr;

  struct curl_hash_element *he;



  if(!connc)

    return;



  Curl_hash_start_iterate(connc->hash, &iter);



  he = Curl_hash_next_element(&iter);

  while(he) {

    struct connectbundle *bundle;

    struct connectdata *conn;



    bundle = he->ptr;



    curr = bundle->conn_list->head;

    while(curr) {

      /* Yes, we need to update curr before calling func(), because func()

         might decide to remove the connection */

      conn = curr->ptr;

      curr = curr->next;



      func(conn, param);

    }



    he = Curl_hash_next_element(&iter);

  }

}



/* Return the first connection found in the cache. Used when closing all

   connections */

struct connectdata *

Curl_conncache_find_first_connection(struct conncache *connc)

{

  struct curl_hash_iterator iter;

  struct curl_llist_element *curr;

  struct curl_hash_element *he;

  struct connectbundle *bundle;



  Curl_hash_start_iterate(connc->hash, &iter);



  he = Curl_hash_next_element(&iter);

  while(he) {

    bundle = he->ptr;



    curr = bundle->conn_list->head;

    if(curr) {

      return curr->ptr;

    }



    he = Curl_hash_next_element(&iter);

  }



  return NULL;

}





#if 0

/* Useful for debugging the connection cache */

void Curl_conncache_print(struct conncache *connc)

{

  struct curl_hash_iterator iter;

  struct curl_llist_element *curr;

  struct curl_hash_element *he;



  if(!connc)

    return;



  fprintf(stderr, "=Bundle cache=\n");



  Curl_hash_start_iterate(connc->hash, &iter);



  he = Curl_hash_next_element(&iter);

  while(he) {

    struct connectbundle *bundle;

    struct connectdata *conn;



    bundle = he->ptr;



    fprintf(stderr, "%s -", he->key);

    curr = bundle->conn_list->head;

    while(curr) {

      conn = curr->ptr;



      fprintf(stderr, " [%p %d]", (void *)conn, conn->inuse);

      curr = curr->next;

    }

    fprintf(stderr, "\n");



    he = Curl_hash_next_element(&iter);

  }

}

#endif

lib/conncache.h

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Original line number Diff line number Diff line 
#ifndef __CONNCACHE_H

#define __CONNCACHE_H

/***************************************************************************

 *                                  _   _ ____  _

 *  Project                     ___| | | |  _ \| |

 *                             / __| | | | |_) | |

 *                            | (__| |_| |  _ <| |___

 *                             \___|\___/|_| \_\_____|

 *

 * Copyright (C) 2012, Linus Nielsen Feltzing, <linus@haxx.se>

 *

 * 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 conncache {

  struct curl_hash *hash;

  enum {

    CONNCACHE_PRIVATE, /* used for an easy handle alone */

    CONNCACHE_MULTI    /* shared within a multi handle */

  } type;

  size_t num_connections;

};



struct conncache *Curl_conncache_init(int type);



void Curl_conncache_destroy(struct conncache *connc);



struct connectbundle *Curl_conncache_find_bundle(struct conncache *connc,

                                                 char *hostname);



CURLcode Curl_conncache_add_conn(struct conncache *connc,

                                 struct connectdata *conn);



void Curl_conncache_remove_conn(struct conncache *connc,

                                struct connectdata *conn);



void Curl_conncache_foreach(struct conncache *connc,

                            void *param,

                            void (*func)(void *, void *));



struct connectdata *

Curl_conncache_find_first_connection(struct conncache *connc);



void Curl_conncache_print(struct conncache *connc);



#endif /* __CONNCACHE_H */