diff options
Diffstat (limited to 'common/curl_request.cpp')
| -rw-r--r-- | common/curl_request.cpp | 383 |
1 files changed, 383 insertions, 0 deletions
diff --git a/common/curl_request.cpp b/common/curl_request.cpp new file mode 100644 index 0000000000..3370c0a859 --- /dev/null +++ b/common/curl_request.cpp @@ -0,0 +1,383 @@ + +#include <mbgl/platform/platform.hpp> +#include <mbgl/platform/request.hpp> +#include <mbgl/util/uv_detail.hpp> +#include <mbgl/util/std.hpp> + +#include <queue> +#include <boost/lockfree/queue.hpp> + +#include <curl/curl.h> + +// This file contains code from http://curl.haxx.se/libcurl/c/multi-uv.html: + +/*************************************************************************** + * _ _ ____ _ + * 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. + * + ***************************************************************************/ + +/* Example application code using the multi socket interface to download + multiple files at once, but instead of using curl_multi_perform and + curl_multi_wait, which uses select(), we use libuv. + It supports epoll, kqueue, etc. on unixes and fast IO completion ports on + Windows, which means, it should be very fast on all platforms.. + + Written by Clemens Gruber, based on an outdated example from uvbook and + some tests from libuv. + + Requires libuv and (of course) libcurl. + + See http://nikhilm.github.com/uvbook/ for more information on libuv. +*/ + +namespace mbgl { +namespace platform { +namespace request { + +struct curl_context { + uv_poll_t poll_handle; + curl_socket_t sockfd; +}; + +// Handles the request thread + messaging to the thread. +static uv_thread_t thread; +static uv::once init_thread_once; +static uv_loop_t *loop = nullptr; +static uv_async_t async_add; +static uv_async_t async_cancel; + +// Stores pointers (!) to shared_ptrs. We use shared_ptrs so that request objects don't get +// auto-destructed while they're in progress. The TileData object retains a weak_ptr to this +// request, so we have to use a shared_ptr here to ensure that this object stays alive. +static boost::lockfree::queue<std::shared_ptr<mbgl::platform::Request> *> add_queue(8); +static boost::lockfree::queue<std::shared_ptr<mbgl::platform::Request> *> cancel_queue(8); + +// Used as the CURL timer function to periodically check for socket updates. +static uv_timer_t timeout; + +// CURL multi handle that we use to request multiple URLs at the same time, without having to block +// and spawn threads. +static CURLM *curl_multi = nullptr; + +// CURL share handles are used for sharing session state (e.g.) +static uv::mutex curl_share_mutex; +static CURLSH *curl_share = nullptr; + +// A queue that we use for storing resuable CURL easy handles to avoid creating and destroying them +// all the time. +static std::queue<CURL *> curl_handle_cache; + + +class CURLRequest : public mbgl::platform::Request { +public: + CURLRequest(const std::string &url, + std::function<void(mbgl::platform::Response *)> callback, + std::shared_ptr<uv::loop> loop) + : Request(url, callback, loop) {} + + CURL *curl = nullptr; +}; + + +// Implementation starts here. + +// Locks the CURL share handle +void curl_share_lock(CURL *, curl_lock_data, curl_lock_access, void *) { curl_share_mutex.lock(); } + +// Unlocks the CURL share handle +void curl_share_unlock(CURL *, curl_lock_data, void *) { curl_share_mutex.unlock(); } + +curl_context *create_curl_context(curl_socket_t sockfd) { + curl_context *context = new curl_context; + context->sockfd = sockfd; + + uv_poll_init_socket(loop, &context->poll_handle, sockfd); + context->poll_handle.data = context; + + return context; +} + +void curl_close_cb(uv_handle_t *handle) { + curl_context *context = (curl_context *)handle->data; + free(context); +} + +void destroy_curl_context(curl_context *context) { + uv_close((uv_handle_t *)&context->poll_handle, curl_close_cb); +} + +void remove_curl_handle(CURL *handle) { + CURLMcode error = curl_multi_remove_handle(curl_multi, handle); + if (error != CURLM_OK) { + throw std::runtime_error(std::string("CURL multi error: ") + curl_multi_strerror(error)); + } + + curl_easy_reset(handle); + curl_handle_cache.push(handle); +} + +void curl_perform(uv_poll_t *req, int /*status*/, int events) { + int running_handles; + int flags = 0; + curl_context *context; + CURLMsg *message; + int pending; + + uv_timer_stop(&timeout); + + if (events & UV_READABLE) + flags |= CURL_CSELECT_IN; + if (events & UV_WRITABLE) + flags |= CURL_CSELECT_OUT; + + context = (curl_context *)req; + + curl_multi_socket_action(curl_multi, context->sockfd, flags, &running_handles); + + while ((message = curl_multi_info_read(curl_multi, &pending))) { + switch (message->msg) { + case CURLMSG_DONE: { + std::shared_ptr<Request> *req = nullptr; + curl_easy_getinfo(message->easy_handle, CURLINFO_PRIVATE, (char *)&req); + + // Add human-readable error code + if (message->data.result != CURLE_OK) { + (*req)->res->error_message = curl_easy_strerror(message->data.result); + (*req)->res->code = -1; + } else { + curl_easy_getinfo(message->easy_handle, CURLINFO_RESPONSE_CODE, &(*req)->res->code); + } + + // We're currently in the CURL request thread. We're going to schedule a uv_work request + // that executes the background function in a threadpool, and tell it to call the + // after callback back in the main uv loop. + (*req)->complete(); + + CURL *handle = message->easy_handle; + remove_curl_handle(handle); + + // We're setting this to NULL because there might still be shared_ptrs around that could + // be cancelled. + ((CURLRequest *)req->get())->curl = nullptr; + + // Delete the shared_ptr pointer we created earlier. + delete req; + break; + } + + default: + // This should never happen, because there are no other message types. + throw std::runtime_error("CURLMSG returned unknown message type"); + } + } +} + +int handle_socket(CURL * /*easy*/, curl_socket_t s, int action, void * /*userp*/, void *socketp) { + curl_context *context = nullptr; + + if (socketp) { + context = (curl_context *)socketp; + } else if (action != CURL_POLL_REMOVE) { + context = create_curl_context(s); + } + + if (context) { + curl_multi_assign(curl_multi, s, (void *)context); + if (action == CURL_POLL_IN || action == CURL_POLL_INOUT) { + uv_poll_start(&context->poll_handle, UV_READABLE, curl_perform); + } + if (action == CURL_POLL_OUT || action == CURL_POLL_INOUT) { + uv_poll_start(&context->poll_handle, UV_WRITABLE, curl_perform); + } + if (action == CURL_POLL_REMOVE && socketp) { + uv_poll_stop(&context->poll_handle); + destroy_curl_context(context); + curl_multi_assign(curl_multi, s, NULL); + } + } + + return 0; +} + +void on_timeout(uv_timer_t *, int status /*req*/) { + int running_handles; + CURLMcode error = + curl_multi_socket_action(curl_multi, CURL_SOCKET_TIMEOUT, 0, &running_handles); + if (error != CURLM_OK) { + throw std::runtime_error(std::string("CURL multi error: ") + curl_multi_strerror(error)); + } +} + +void start_timeout(CURLM * /*multi*/, long timeout_ms, void * /*userp*/) { + if (timeout_ms <= 0) { + on_timeout(&timeout, -1); + } else { + uv_timer_start(&timeout, &on_timeout, timeout_ms, 0); + } +} + +// This function is the first function called in the request thread. It sets up the CURL share/multi +// handles and runs the thread loop. +void thread_init(void * /*ptr*/) { + uv_timer_init(loop, &timeout); + + CURLSHcode share_error; + curl_share = curl_share_init(); + + share_error = curl_share_setopt(curl_share, CURLSHOPT_LOCKFUNC, curl_share_lock); + if (share_error != CURLSHE_OK) { + throw std::runtime_error(std::string("CURL share error: ") + curl_share_strerror(share_error)); + } + + share_error = curl_share_setopt(curl_share, CURLSHOPT_UNLOCKFUNC, curl_share_unlock); + if (share_error != CURLSHE_OK) { + throw std::runtime_error(std::string("CURL share error: ") + curl_share_strerror(share_error)); + } + + CURLMcode multi_error; + curl_multi = curl_multi_init(); + + multi_error = curl_multi_setopt(curl_multi, CURLMOPT_SOCKETFUNCTION, handle_socket); + if (multi_error != CURLM_OK) { + throw std::runtime_error(std::string("CURL multi error: ") + curl_multi_strerror(multi_error)); + } + multi_error = curl_multi_setopt(curl_multi, CURLMOPT_TIMERFUNCTION, start_timeout); + if (multi_error != CURLM_OK) { + throw std::runtime_error(std::string("CURL multi error: ") + curl_multi_strerror(multi_error)); + + } + + // Main event loop. This will not return until the request loop is terminated. + uv_run(loop, UV_RUN_DEFAULT); + + curl_multi_cleanup(curl_multi); + curl_multi = nullptr; + curl_share_cleanup(curl_share); + curl_share = nullptr; + + // Clean up all the CURL easy handles that we kept around for potential future reuse. + while (!curl_handle_cache.empty()) { + curl_easy_cleanup(curl_handle_cache.front()); + curl_handle_cache.pop(); + } +} + +// This function is called when we have new data for a request. We just append it to the string +// containing the previous data. +size_t curl_write_cb(void *contents, size_t size, size_t nmemb, void *userp) { + ((std::string *)userp)->append((char *)contents, size * nmemb); + return size * nmemb; +} + +// This callback is called in the request event loop (on the request thread). +// It initializes newly queued up download requests and adds them to the CURL +// multi handle. +void async_add_cb(uv_async_t *, int status /*async*/) { + std::shared_ptr<Request> *req = nullptr; + while (add_queue.pop(req)) { + // Make sure that we're not starting requests that have been cancelled + // already by async_cancel_cb. + if ((*req)->cancelled) { + delete req; + continue; + } + + // Obtain a curl handle (and try to reuse existing handles before creating new ones). + CURL *handle = nullptr; + if (!curl_handle_cache.empty()) { + handle = curl_handle_cache.front(); + curl_handle_cache.pop(); + } else { + handle = curl_easy_init(); + } + + ((CURLRequest *)req->get())->curl = handle; + + curl_easy_setopt(handle, CURLOPT_PRIVATE, req); + curl_easy_setopt(handle, CURLOPT_CAINFO, "ca-bundle.crt"); + curl_easy_setopt(handle, CURLOPT_URL, (*req)->url.c_str()); + curl_easy_setopt(handle, CURLOPT_WRITEFUNCTION, curl_write_cb); + curl_easy_setopt(handle, CURLOPT_WRITEDATA, &(*req)->res->body); + curl_easy_setopt(handle, CURLOPT_ACCEPT_ENCODING, "gzip, deflate"); + curl_easy_setopt(handle, CURLOPT_SHARE, curl_share); + curl_multi_add_handle(curl_multi, handle); + } +} + +void async_cancel_cb(uv_async_t *, int status /*async*/) { + std::shared_ptr<Request> *req = nullptr; + while (cancel_queue.pop(req)) { + // It is possible that the request has not yet been started, but that it already has been + // added to the queue for scheduling new requests. In this case, the CURL handle is invalid + // and we manually mark the Request as cancelled. + CURL *handle = ((CURLRequest *)req->get())->curl; + if (handle && !(*req)->cancelled) { + remove_curl_handle(handle); + ((CURLRequest *)req->get())->curl = nullptr; + } + (*req)->cancelled = true; + + delete req; + req = nullptr; + } +} + +void thread_init_cb() { + curl_global_init(CURL_GLOBAL_ALL); + + loop = uv_loop_new(); + uv_async_init(loop, &async_add, &async_add_cb); + uv_async_init(loop, &async_cancel, &async_cancel_cb); + uv_thread_create(&thread, thread_init, nullptr); +} +} // end namespace request +} // end namespace platform + + +std::shared_ptr<platform::Request> +platform::request_http(const std::string &url, + std::function<void(Response *)> callback, + std::shared_ptr<uv::loop> loop) { + using namespace request; + init_thread_once(thread_init_cb); + std::shared_ptr<CURLRequest> req = std::make_shared<CURLRequest>(url, callback, loop); + + // Note that we are creating a new shared_ptr pointer(!) because the lockless queue can't store + // objects with nontrivial destructors. We have to make absolutely sure that we manually delete + // the shared_ptr when we pop it from the queue. + add_queue.push(new std::shared_ptr<Request>(req)); + uv_async_send(&async_add); + + return req; +} + +// Cancels an HTTP request. +void platform::cancel_request_http(const std::shared_ptr<Request> &req) { + if (req) { + using namespace request; + + // Note that we are creating a new shared_ptr pointer(!) because the lockless queue can't + // store objects with nontrivial destructors. We have to make absolutely shure that we + // manually delete the shared_ptr when we pop it from the queue. + cancel_queue.push(new std::shared_ptr<Request>(req)); + uv_async_send(&async_cancel); + } +} +} // end namespace mbgl |