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