src/httpfetch.cpp

   1 /*
   2 Minetest
   3 Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>
   4
   5 This program is free software; you can redistribute it and/or modify
   6 it under the terms of the GNU Lesser General Public License as published by
   7 the Free Software Foundation; either version 2.1 of the License, or
   8 (at your option) any later version.
   9
  10 This program is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU Lesser General Public License for more details.
  14
  15 You should have received a copy of the GNU Lesser General Public License along
  16 with this program; if not, write to the Free Software Foundation, Inc.,
  17 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18 */
  19
  20 #include "socket.h" // for select()
  21 #include "porting.h" // for sleep_ms()
  22 #include "httpfetch.h"
  23 #include <iostream>
  24 #include <sstream>
  25 #include <list>
  26 #include <map>
  27 #include <errno.h>
  28 #include "jthread/jevent.h"
  29 #include "config.h"
  30 #include "exceptions.h"
  31 #include "debug.h"
  32 #include "log.h"
  33 #include "util/container.h"
  34 #include "util/thread.h"
  35
  36 JMutex g_httpfetch_mutex;
  37 std::map<unsigned long, std::list<HTTPFetchResult> > g_httpfetch_results;
  38
  39 static void httpfetch_deliver_result(const HTTPFetchResult &fetchresult)
  40 {
  41         unsigned long caller = fetchresult.caller;
  42         if (caller != HTTPFETCH_DISCARD) {
  43                 JMutexAutoLock lock(g_httpfetch_mutex);
  44                 g_httpfetch_results[caller].push_back(fetchresult);
  45         }
  46 }
  47
  48 static void httpfetch_request_clear(unsigned long caller);
  49
  50 unsigned long httpfetch_caller_alloc()
  51 {
  52         JMutexAutoLock lock(g_httpfetch_mutex);
  53
  54         // Check each caller ID except HTTPFETCH_DISCARD
  55         const unsigned long discard = HTTPFETCH_DISCARD;
  56         for (unsigned long caller = discard + 1; caller != discard; ++caller) {
  57                 std::map<unsigned long, std::list<HTTPFetchResult> >::iterator
  58                         it = g_httpfetch_results.find(caller);
  59                 if (it == g_httpfetch_results.end()) {
  60                         verbosestream<<"httpfetch_caller_alloc: allocating "
  61                                         <<caller<<std::endl;
  62                         // Access element to create it
  63                         g_httpfetch_results[caller];
  64                         return caller;
  65                 }
  66         }
  67
  68         assert("httpfetch_caller_alloc: ran out of caller IDs" == 0);
  69         return discard;
  70 }
  71
  72 void httpfetch_caller_free(unsigned long caller)
  73 {
  74         verbosestream<<"httpfetch_caller_free: freeing "
  75                         <<caller<<std::endl;
  76
  77         httpfetch_request_clear(caller);
  78         if (caller != HTTPFETCH_DISCARD) {
  79                 JMutexAutoLock lock(g_httpfetch_mutex);
  80                 g_httpfetch_results.erase(caller);
  81         }
  82 }
  83
  84 bool httpfetch_async_get(unsigned long caller, HTTPFetchResult &fetchresult)
  85 {
  86         JMutexAutoLock lock(g_httpfetch_mutex);
  87
  88         // Check that caller exists
  89         std::map<unsigned long, std::list<HTTPFetchResult> >::iterator
  90                 it = g_httpfetch_results.find(caller);
  91         if (it == g_httpfetch_results.end())
  92                 return false;
  93
  94         // Check that result queue is nonempty
  95         std::list<HTTPFetchResult> &callerresults = it->second;
  96         if (callerresults.empty())
  97                 return false;
  98
  99         // Pop first result
 100         fetchresult = callerresults.front();
 101         callerresults.pop_front();
 102         return true;
 103 }
 104
 105 #if USE_CURL
 106 #include <curl/curl.h>
 107
 108 /*
 109         USE_CURL is on: use cURL based httpfetch implementation
 110 */
 111
 112 static size_t httpfetch_writefunction(
 113                 char *ptr, size_t size, size_t nmemb, void *userdata)
 114 {
 115         std::ostringstream *stream = (std::ostringstream*)userdata;
 116         size_t count = size * nmemb;
 117         stream->write(ptr, count);
 118         return count;
 119 }
 120
 121 static size_t httpfetch_discardfunction(
 122                 char *ptr, size_t size, size_t nmemb, void *userdata)
 123 {
 124         return size * nmemb;
 125 }
 126
 127 class CurlHandlePool
 128 {
 129         std::list<CURL*> handles;
 130
 131 public:
 132         CurlHandlePool() {}
 133         ~CurlHandlePool()
 134         {
 135                 for (std::list<CURL*>::iterator it = handles.begin();
 136                                 it != handles.end(); ++it) {
 137                         curl_easy_cleanup(*it);
 138                 }
 139         }
 140         CURL * alloc()
 141         {
 142                 CURL *curl;
 143                 if (handles.empty()) {
 144                         curl = curl_easy_init();
 145                         if (curl == NULL) {
 146                                 errorstream<<"curl_easy_init returned NULL"<<std::endl;
 147                         }
 148                 }
 149                 else {
 150                         curl = handles.front();
 151                         handles.pop_front();
 152                 }
 153                 return curl;
 154         }
 155         void free(CURL *handle)
 156         {
 157                 if (handle)
 158                         handles.push_back(handle);
 159         }
 160 };
 161
 162 struct HTTPFetchOngoing
 163 {
 164         CurlHandlePool *pool;
 165         CURL *curl;
 166         CURLM *multi;
 167         HTTPFetchRequest request;
 168         HTTPFetchResult result;
 169         std::ostringstream oss;
 170         char *post_fields;
 171         struct curl_slist *httpheader;
 172
 173         HTTPFetchOngoing(HTTPFetchRequest request_, CurlHandlePool *pool_):
 174                 pool(pool_),
 175                 curl(NULL),
 176                 multi(NULL),
 177                 request(request_),
 178                 result(request_),
 179                 oss(std::ios::binary),
 180                 httpheader(NULL)
 181         {
 182                 curl = pool->alloc();
 183                 if (curl != NULL) {
 184                         // Set static cURL options
 185                         curl_easy_setopt(curl, CURLOPT_NOSIGNAL, 1);
 186                         curl_easy_setopt(curl, CURLOPT_FAILONERROR, 1);
 187                         curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1);
 188                         curl_easy_setopt(curl, CURLOPT_MAXREDIRS, 1);
 189
 190 #if LIBCURL_VERSION_NUM >= 0x071304
 191                         // Restrict protocols so that curl vulnerabilities in
 192                         // other protocols don't affect us.
 193                         // These settings were introduced in curl 7.19.4.
 194                         long protocols =
 195                                 CURLPROTO_HTTP |
 196                                 CURLPROTO_HTTPS |
 197                                 CURLPROTO_FTP |
 198                                 CURLPROTO_FTPS;
 199                         curl_easy_setopt(curl, CURLOPT_PROTOCOLS, protocols);
 200                         curl_easy_setopt(curl, CURLOPT_REDIR_PROTOCOLS, protocols);
 201 #endif
 202
 203                         // Set cURL options based on HTTPFetchRequest
 204                         curl_easy_setopt(curl, CURLOPT_URL,
 205                                         request.url.c_str());
 206                         curl_easy_setopt(curl, CURLOPT_TIMEOUT_MS,
 207                                         request.timeout);
 208                         curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT_MS,
 209                                         request.connect_timeout);
 210
 211                         if (request.useragent != "")
 212                                 curl_easy_setopt(curl, CURLOPT_USERAGENT, request.useragent.c_str());
 213
 214                         // Set up a write callback that writes to the
 215                         // ostringstream ongoing->oss, unless the data
 216                         // is to be discarded
 217                         if (request.caller == HTTPFETCH_DISCARD) {
 218                                 curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION,
 219                                                 httpfetch_discardfunction);
 220                                 curl_easy_setopt(curl, CURLOPT_WRITEDATA, NULL);
 221                         }
 222                         else {
 223                                 curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION,
 224                                                 httpfetch_writefunction);
 225                                 curl_easy_setopt(curl, CURLOPT_WRITEDATA, &oss);
 226                         }
 227                         // Set POST (or GET) data
 228                         if (request.post_fields.empty()) {
 229                                 curl_easy_setopt(curl, CURLOPT_HTTPGET, 1);
 230                         }
 231                         else {
 232                                 curl_easy_setopt(curl, CURLOPT_POST, 1);
 233                                 curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE,
 234                                                 request.post_fields.size());
 235                                 curl_easy_setopt(curl, CURLOPT_POSTFIELDS,
 236                                                 request.post_fields.c_str());
 237                                 // request.post_fields must now *never* be
 238                                 // modified until CURLOPT_POSTFIELDS is cleared
 239                         }
 240                         // Set additional HTTP headers
 241                         for (size_t i = 0; i < request.extra_headers.size(); ++i) {
 242                                 httpheader = curl_slist_append(
 243                                         httpheader,
 244                                         request.extra_headers[i].c_str());
 245                         }
 246                         curl_easy_setopt(curl, CURLOPT_HTTPHEADER, httpheader);
 247                 }
 248         }
 249
 250         CURLcode start(CURLM *multi_)
 251         {
 252                 if (curl == NULL)
 253                         return CURLE_FAILED_INIT;
 254
 255                 if (multi_) {
 256                         // Multi interface (async)
 257                         CURLMcode mres = curl_multi_add_handle(multi_, curl);
 258                         if (mres != CURLM_OK) {
 259                                 errorstream<<"curl_multi_add_handle"
 260                                         <<" returned error code "<<mres
 261                                         <<std::endl;
 262                                 return CURLE_FAILED_INIT;
 263                         }
 264                         multi = multi_; // store for curl_multi_remove_handle
 265                         return CURLE_OK;
 266                 }
 267                 else {
 268                         // Easy interface (sync)
 269                         return curl_easy_perform(curl);
 270                 }
 271         }
 272
 273         void complete(CURLcode res)
 274         {
 275                 result.succeeded = (res == CURLE_OK);
 276                 result.timeout = (res == CURLE_OPERATION_TIMEDOUT);
 277                 result.data = oss.str();
 278
 279                 // Get HTTP/FTP response code
 280                 result.response_code = 0;
 281                 if (curl != NULL) {
 282                         if (curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE,
 283                                         &result.response_code) != CURLE_OK) {
 284                                 //we failed to get a return code make sure it is still 0
 285                                 result.response_code = 0;
 286                         }
 287                 }
 288
 289                 if (res != CURLE_OK) {
 290                         infostream<<request.url<<" not found ("
 291                                 <<curl_easy_strerror(res)<<")"
 292                                 <<" (response code "<<result.response_code<<")"
 293                                 <<std::endl;
 294                 }
 295         }
 296
 297         ~HTTPFetchOngoing()
 298         {
 299                 if (multi != NULL) {
 300                         CURLMcode mres = curl_multi_remove_handle(multi, curl);
 301                         if (mres != CURLM_OK) {
 302                                 errorstream<<"curl_multi_remove_handle"
 303                                         <<" returned error code "<<mres
 304                                         <<std::endl;
 305                         }
 306                 }
 307
 308                 // Set safe options for the reusable cURL handle
 309                 curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION,
 310                                 httpfetch_discardfunction);
 311                 curl_easy_setopt(curl, CURLOPT_WRITEDATA, NULL);
 312                 curl_easy_setopt(curl, CURLOPT_POSTFIELDS, NULL);
 313                 if (httpheader != NULL) {
 314                         curl_easy_setopt(curl, CURLOPT_HTTPHEADER, NULL);
 315                         curl_slist_free_all(httpheader);
 316                 }
 317
 318                 // Store the cURL handle for reuse
 319                 pool->free(curl);
 320         }
 321 };
 322
 323 class CurlFetchThread : public JThread
 324 {
 325 protected:
 326         enum RequestType {
 327                 RT_FETCH,
 328                 RT_CLEAR,
 329                 RT_WAKEUP,
 330         };
 331
 332         struct Request {
 333                 RequestType type;
 334                 HTTPFetchRequest fetchrequest;
 335                 Event *event;
 336         };
 337
 338         CURLM *m_multi;
 339         MutexedQueue<Request> m_requests;
 340         size_t m_parallel_limit;
 341
 342         // Variables exclusively used within thread
 343         std::vector<HTTPFetchOngoing*> m_all_ongoing;
 344         std::list<HTTPFetchRequest> m_queued_fetches;
 345
 346 public:
 347         CurlFetchThread(int parallel_limit)
 348         {
 349                 if (parallel_limit >= 1)
 350                         m_parallel_limit = parallel_limit;
 351                 else
 352                         m_parallel_limit = 1;
 353         }
 354
 355         void requestFetch(const HTTPFetchRequest &fetchrequest)
 356         {
 357                 Request req;
 358                 req.type = RT_FETCH;
 359                 req.fetchrequest = fetchrequest;
 360                 req.event = NULL;
 361                 m_requests.push_back(req);
 362         }
 363
 364         void requestClear(unsigned long caller, Event *event)
 365         {
 366                 Request req;
 367                 req.type = RT_CLEAR;
 368                 req.fetchrequest.caller = caller;
 369                 req.event = event;
 370                 m_requests.push_back(req);
 371         }
 372
 373         void requestWakeUp()
 374         {
 375                 Request req;
 376                 req.type = RT_WAKEUP;
 377                 req.event = NULL;
 378                 m_requests.push_back(req);
 379         }
 380
 381 protected:
 382         // Handle a request from some other thread
 383         // E.g. new fetch; clear fetches for one caller; wake up
 384         void processRequest(const Request &req)
 385         {
 386                 if (req.type == RT_FETCH) {
 387                         // New fetch, queue until there are less
 388                         // than m_parallel_limit ongoing fetches
 389                         m_queued_fetches.push_back(req.fetchrequest);
 390
 391                         // see processQueued() for what happens next
 392
 393                 }
 394                 else if (req.type == RT_CLEAR) {
 395                         unsigned long caller = req.fetchrequest.caller;
 396
 397                         // Abort all ongoing fetches for the caller
 398                         for (std::vector<HTTPFetchOngoing*>::iterator
 399                                         it = m_all_ongoing.begin();
 400                                         it != m_all_ongoing.end();) {
 401                                 if ((*it)->request.caller == caller) {
 402                                         delete (*it);
 403                                         it = m_all_ongoing.erase(it);
 404                                 }
 405                                 else
 406                                         ++it;
 407                         }
 408
 409                         // Also abort all queued fetches for the caller
 410                         for (std::list<HTTPFetchRequest>::iterator
 411                                         it = m_queued_fetches.begin();
 412                                         it != m_queued_fetches.end();) {
 413                                 if ((*it).caller == caller)
 414                                         it = m_queued_fetches.erase(it);
 415                                 else
 416                                         ++it;
 417                         }
 418                 }
 419                 else if (req.type == RT_WAKEUP) {
 420                         // Wakeup: Nothing to do, thread is awake at this point
 421                 }
 422
 423                 if (req.event != NULL)
 424                         req.event->signal();
 425         }
 426
 427         // Start new ongoing fetches if m_parallel_limit allows
 428         void processQueued(CurlHandlePool *pool)
 429         {
 430                 while (m_all_ongoing.size() < m_parallel_limit &&
 431                                 !m_queued_fetches.empty()) {
 432                         HTTPFetchRequest request = m_queued_fetches.front();
 433                         m_queued_fetches.pop_front();
 434
 435                         // Create ongoing fetch data and make a cURL handle
 436                         // Set cURL options based on HTTPFetchRequest
 437                         HTTPFetchOngoing *ongoing =
 438                                 new HTTPFetchOngoing(request, pool);
 439
 440                         // Initiate the connection (curl_multi_add_handle)
 441                         CURLcode res = ongoing->start(m_multi);
 442                         if (res == CURLE_OK) {
 443                                 m_all_ongoing.push_back(ongoing);
 444                         }
 445                         else {
 446                                 ongoing->complete(res);
 447                                 httpfetch_deliver_result(ongoing->result);
 448                                 delete ongoing;
 449                         }
 450                 }
 451         }
 452
 453         // Process CURLMsg (indicates completion of a fetch)
 454         void processCurlMessage(CURLMsg *msg)
 455         {
 456                 // Determine which ongoing fetch the message pertains to
 457                 size_t i = 0;
 458                 bool found = false;
 459                 for (i = 0; i < m_all_ongoing.size(); ++i) {
 460                         if (m_all_ongoing[i]->curl == msg->easy_handle) {
 461                                 found = true;
 462                                 break;
 463                         }
 464                 }
 465                 if (msg->msg == CURLMSG_DONE && found) {
 466                         // m_all_ongoing[i] succeeded or failed.
 467                         HTTPFetchOngoing *ongoing = m_all_ongoing[i];
 468                         ongoing->complete(msg->data.result);
 469                         httpfetch_deliver_result(ongoing->result);
 470                         delete ongoing;
 471                         m_all_ongoing.erase(m_all_ongoing.begin() + i);
 472                 }
 473         }
 474
 475         // Wait for a request from another thread, or timeout elapses
 476         void waitForRequest(long timeout)
 477         {
 478                 if (m_queued_fetches.empty()) {
 479                         try {
 480                                 Request req = m_requests.pop_front(timeout);
 481                                 processRequest(req);
 482                         }
 483                         catch (ItemNotFoundException &e) {}
 484                 }
 485         }
 486
 487         // Wait until some IO happens, or timeout elapses
 488         void waitForIO(long timeout)
 489         {
 490                 fd_set read_fd_set;
 491                 fd_set write_fd_set;
 492                 fd_set exc_fd_set;
 493                 int max_fd;
 494                 long select_timeout = -1;
 495                 struct timeval select_tv;
 496                 CURLMcode mres;
 497
 498                 FD_ZERO(&read_fd_set);
 499                 FD_ZERO(&write_fd_set);
 500                 FD_ZERO(&exc_fd_set);
 501
 502                 mres = curl_multi_fdset(m_multi, &read_fd_set,
 503                                 &write_fd_set, &exc_fd_set, &max_fd);
 504                 if (mres != CURLM_OK) {
 505                         errorstream<<"curl_multi_fdset"
 506                                 <<" returned error code "<<mres
 507                                 <<std::endl;
 508                         select_timeout = 0;
 509                 }
 510
 511                 mres = curl_multi_timeout(m_multi, &select_timeout);
 512                 if (mres != CURLM_OK) {
 513                         errorstream<<"curl_multi_timeout"
 514                                 <<" returned error code "<<mres
 515                                 <<std::endl;
 516                         select_timeout = 0;
 517                 }
 518
 519                 // Limit timeout so new requests get through
 520                 if (select_timeout < 0 || select_timeout > timeout)
 521                         select_timeout = timeout;
 522
 523                 if (select_timeout > 0) {
 524                         // in Winsock it is forbidden to pass three empty
 525                         // fd_sets to select(), so in that case use sleep_ms
 526                         if (max_fd == -1) {
 527                                 select_tv.tv_sec = select_timeout / 1000;
 528                                 select_tv.tv_usec = (select_timeout % 1000) * 1000;
 529                                 int retval = select(max_fd + 1, &read_fd_set,
 530                                                 &write_fd_set, &exc_fd_set,
 531                                                 &select_tv);
 532                                 if (retval == -1) {
 533                                         #ifdef _WIN32
 534                                         errorstream<<"select returned error code "
 535                                                 <<WSAGetLastError()<<std::endl;
 536                                         #else
 537                                         errorstream<<"select returned error code "
 538                                                 <<errno<<std::endl;
 539                                         #endif
 540                                 }
 541                         }
 542                         else {
 543                                 sleep_ms(select_timeout);
 544                         }
 545                 }
 546         }
 547
 548         void * Thread()
 549         {
 550                 ThreadStarted();
 551                 log_register_thread("CurlFetchThread");
 552                 DSTACK(__FUNCTION_NAME);
 553
 554                 CurlHandlePool pool;
 555
 556                 m_multi = curl_multi_init();
 557                 if (m_multi == NULL) {
 558                         errorstream<<"curl_multi_init returned NULL\n";
 559                         return NULL;
 560                 }
 561
 562                 assert(m_all_ongoing.empty());
 563
 564                 while (!StopRequested()) {
 565                         BEGIN_DEBUG_EXCEPTION_HANDLER
 566
 567                         /*
 568                                 Handle new async requests
 569                         */
 570
 571                         while (!m_requests.empty()) {
 572                                 Request req = m_requests.pop_front();
 573                                 processRequest(req);
 574                         }
 575                         processQueued(&pool);
 576
 577                         /*
 578                                 Handle ongoing async requests
 579                         */
 580
 581                         int still_ongoing = 0;
 582                         while (curl_multi_perform(m_multi, &still_ongoing) ==
 583                                         CURLM_CALL_MULTI_PERFORM)
 584                                 /* noop */;
 585
 586                         /*
 587                                 Handle completed async requests
 588                         */
 589                         if (still_ongoing < (int) m_all_ongoing.size()) {
 590                                 CURLMsg *msg;
 591                                 int msgs_in_queue;
 592                                 msg = curl_multi_info_read(m_multi, &msgs_in_queue);
 593                                 while (msg != NULL) {
 594                                         processCurlMessage(msg);
 595                                         msg = curl_multi_info_read(m_multi, &msgs_in_queue);
 596                                 }
 597                         }
 598
 599                         /*
 600                                 If there are ongoing requests, wait for data
 601                                 (with a timeout of 100ms so that new requests
 602                                 can be processed).
 603
 604                                 If no ongoing requests, wait for a new request.
 605                                 (Possibly an empty request that signals
 606                                 that the thread should be stopped.)
 607                         */
 608                         if (m_all_ongoing.empty())
 609                                 waitForRequest(100000000);
 610                         else
 611                                 waitForIO(100);
 612
 613                         END_DEBUG_EXCEPTION_HANDLER(errorstream)
 614                 }
 615
 616                 // Call curl_multi_remove_handle and cleanup easy handles
 617                 for (size_t i = 0; i < m_all_ongoing.size(); ++i) {
 618                         delete m_all_ongoing[i];
 619                 }
 620                 m_all_ongoing.clear();
 621
 622                 m_queued_fetches.clear();
 623
 624                 CURLMcode mres = curl_multi_cleanup(m_multi);
 625                 if (mres != CURLM_OK) {
 626                         errorstream<<"curl_multi_cleanup"
 627                                 <<" returned error code "<<mres
 628                                 <<std::endl;
 629                 }
 630
 631                 return NULL;
 632         }
 633 };
 634
 635 CurlFetchThread *g_httpfetch_thread = NULL;
 636
 637 void httpfetch_init(int parallel_limit)
 638 {
 639         verbosestream<<"httpfetch_init: parallel_limit="<<parallel_limit
 640                         <<std::endl;
 641
 642         CURLcode res = curl_global_init(CURL_GLOBAL_DEFAULT);
 643         assert(res == CURLE_OK);
 644
 645         g_httpfetch_thread = new CurlFetchThread(parallel_limit);
 646 }
 647
 648 void httpfetch_cleanup()
 649 {
 650         verbosestream<<"httpfetch_cleanup: cleaning up"<<std::endl;
 651
 652         g_httpfetch_thread->Stop();
 653         g_httpfetch_thread->requestWakeUp();
 654         g_httpfetch_thread->Wait();
 655         delete g_httpfetch_thread;
 656
 657         curl_global_cleanup();
 658 }
 659
 660 void httpfetch_async(const HTTPFetchRequest &fetchrequest)
 661 {
 662         g_httpfetch_thread->requestFetch(fetchrequest);
 663         if (!g_httpfetch_thread->IsRunning())
 664                 g_httpfetch_thread->Start();
 665 }
 666
 667 static void httpfetch_request_clear(unsigned long caller)
 668 {
 669         if (g_httpfetch_thread->IsRunning()) {
 670                 Event event;
 671                 g_httpfetch_thread->requestClear(caller, &event);
 672                 event.wait();
 673         }
 674         else {
 675                 g_httpfetch_thread->requestClear(caller, NULL);
 676         }
 677 }
 678
 679 void httpfetch_sync(const HTTPFetchRequest &fetchrequest,
 680                 HTTPFetchResult &fetchresult)
 681 {
 682         // Create ongoing fetch data and make a cURL handle
 683         // Set cURL options based on HTTPFetchRequest
 684         CurlHandlePool pool;
 685         HTTPFetchOngoing ongoing(fetchrequest, &pool);
 686         // Do the fetch (curl_easy_perform)
 687         CURLcode res = ongoing.start(NULL);
 688         // Update fetchresult
 689         ongoing.complete(res);
 690         fetchresult = ongoing.result;
 691 }
 692
 693 #else  // USE_CURL
 694
 695 /*
 696         USE_CURL is off:
 697
 698         Dummy httpfetch implementation that always returns an error.
 699 */
 700
 701 void httpfetch_init(int parallel_limit)
 702 {
 703 }
 704
 705 void httpfetch_cleanup()
 706 {
 707 }
 708
 709 void httpfetch_async(const HTTPFetchRequest &fetchrequest)
 710 {
 711         errorstream<<"httpfetch_async: unable to fetch "<<fetchrequest.url
 712                         <<" because USE_CURL=0"<<std::endl;
 713
 714         HTTPFetchResult fetchresult(fetchrequest); // sets succeeded = false etc.
 715         httpfetch_deliver_result(fetchresult);
 716 }
 717
 718 static void httpfetch_request_clear(unsigned long caller)
 719 {
 720 }
 721
 722 void httpfetch_sync(const HTTPFetchRequest &fetchrequest,
 723                 HTTPFetchResult &fetchresult)
 724 {
 725         errorstream<<"httpfetch_sync: unable to fetch "<<fetchrequest.url
 726                         <<" because USE_CURL=0"<<std::endl;
 727
 728         fetchresult = HTTPFetchResult(fetchrequest); // sets succeeded = false etc.
 729 }
 730
 731 #endif  // USE_CURL