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Diffstat (limited to 'indra/llcorehttp/_httpservice.h')
| -rw-r--r-- | indra/llcorehttp/_httpservice.h | 224 |
1 files changed, 224 insertions, 0 deletions
diff --git a/indra/llcorehttp/_httpservice.h b/indra/llcorehttp/_httpservice.h new file mode 100644 index 0000000000..ffe0349d4d --- /dev/null +++ b/indra/llcorehttp/_httpservice.h @@ -0,0 +1,224 @@ +/** + * @file _httpservice.h + * @brief Declarations for internal class providing HTTP service. + * + * $LicenseInfo:firstyear=2012&license=viewerlgpl$ + * Second Life Viewer Source Code + * Copyright (C) 2012, Linden Research, Inc. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; + * version 2.1 of the License only. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + * + * Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA + * $/LicenseInfo$ + */ + +#ifndef _LLCORE_HTTP_SERVICE_H_ +#define _LLCORE_HTTP_SERVICE_H_ + + +#include <vector> + +#include "linden_common.h" +#include "llapr.h" +#include "httpcommon.h" +#include "httprequest.h" +#include "_httppolicyglobal.h" +#include "_httppolicyclass.h" + + +namespace LLCoreInt +{ + +class HttpThread; + +} + + +namespace LLCore +{ + + +class HttpRequestQueue; +class HttpPolicy; +class HttpLibcurl; + + +/// The HttpService class does the work behind the request queue. It +/// oversees the HTTP workflow carrying out a number of tasks: +/// - Pulling requests from the global request queue +/// - Executing 'immediate' requests directly +/// - Prioritizing and re-queuing on internal queues the slower requests +/// - Providing cpu cycles to the libcurl plumbing +/// - Overseeing retry operations +/// +/// Note that the service object doesn't have a pointer to any +/// reply queue. These are kept by HttpRequest and HttpOperation +/// only. +/// +/// Service, Policy and Transport +/// +/// HttpService could have been a monolithic class combining a request +/// queue servicer, request policy manager and network transport. +/// Instead, to prevent monolithic growth and allow for easier +/// replacement, it was developed as three separate classes: HttpService, +/// HttpPolicy and HttpLibcurl (transport). These always exist in a +/// 1:1:1 relationship with HttpService managing instances of the other +/// two. So, these classes do not use reference counting to refer +/// to one another, their lifecycles are always managed together. + +class HttpService +{ +protected: + HttpService(); + virtual ~HttpService(); + +private: + HttpService(const HttpService &); // Not defined + void operator=(const HttpService &); // Not defined + +public: + enum EState + { + NOT_INITIALIZED = -1, + INITIALIZED, ///< init() has been called + RUNNING, ///< thread created and running + STOPPED ///< thread has committed to exiting + }; + + // Ordered enumeration of idling strategies available to + // threadRun's loop. Ordered so that std::min on values + // produces the most conservative result of multiple + // requests. + enum ELoopSpeed + { + NORMAL, ///< continuous polling of request, ready, active queues + REQUEST_SLEEP ///< can sleep indefinitely waiting for request queue write + }; + + static void init(HttpRequestQueue *); + static void term(); + + /// Threading: callable by any thread once inited. + inline static HttpService * instanceOf() + { + return sInstance; + } + + /// Return the state of the worker thread. Note that the + /// transition from RUNNING to STOPPED is performed by the + /// worker thread itself. This has two weaknesses: + /// - race where the thread hasn't really stopped but will + /// - data ordering between threads where a non-worker thread + /// may see a stale RUNNING status. + /// + /// This transition is generally of interest only to unit tests + /// and these weaknesses shouldn't be any real burden. + /// + /// Threading: callable by any thread with above exceptions. + static EState getState() + { + return sState; + } + + /// Threading: callable by any thread but uses @see getState() and + /// acquires its weaknesses. + static bool isStopped(); + + /// Threading: callable by consumer thread *once*. + void startThread(); + + /// Threading: callable by worker thread. + void stopRequested(); + + /// Threading: callable by worker thread. + void shutdown(); + + /// Try to find the given request handle on any of the request + /// queues and reset the priority (and queue position) of the + /// request if found. + /// + /// @return True if the request was found somewhere. + /// + /// Threading: callable by worker thread. + bool changePriority(HttpHandle handle, HttpRequest::priority_t priority); + + /// Try to find the given request handle on any of the request + /// queues and cancel the operation. + /// + /// @return True if the request was found and canceled. + /// + /// Threading: callable by worker thread. + bool cancel(HttpHandle handle); + + /// Threading: callable by worker thread. + HttpPolicy & getPolicy() + { + return *mPolicy; + } + + /// Threading: callable by worker thread. + HttpLibcurl & getTransport() + { + return *mTransport; + } + + /// Threading: callable by worker thread. + HttpRequestQueue & getRequestQueue() + { + return *mRequestQueue; + } + + /// Threading: callable by consumer thread. + HttpPolicyGlobal & getGlobalOptions() + { + return mPolicyGlobal; + } + + /// Threading: callable by consumer thread. + HttpRequest::policy_t createPolicyClass(); + + /// Threading: callable by consumer thread. + HttpPolicyClass & getClassOptions(HttpRequest::policy_t policy_class) + { + llassert(policy_class >= 0 && policy_class < mPolicyClasses.size()); + return mPolicyClasses[policy_class]; + } + +protected: + void threadRun(LLCoreInt::HttpThread * thread); + + ELoopSpeed processRequestQueue(ELoopSpeed loop); + +protected: + static HttpService * sInstance; + + // === shared data === + static volatile EState sState; + HttpRequestQueue * mRequestQueue; // Refcounted + LLAtomicU32 mExitRequested; + LLCoreInt::HttpThread * mThread; + + // === consumer-thread-only data === + HttpPolicyGlobal mPolicyGlobal; + std::vector<HttpPolicyClass> mPolicyClasses; + + // === working-thread-only data === + HttpPolicy * mPolicy; // Simple pointer, has ownership + HttpLibcurl * mTransport; // Simple pointer, has ownership +}; // end class HttpService + +} // end namespace LLCore + +#endif // _LLCORE_HTTP_SERVICE_H_ |