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authorMonty Brandenberg <monty@lindenlab.com>2012-04-23 16:19:39 -0400
committerMonty Brandenberg <monty@lindenlab.com>2012-04-23 16:19:39 -0400
commit5611cb6d476540e6a1c654c1f9acdce2787b3505 (patch)
treee35afc4aa33ae00e71679ba3ccfead0de563843d /indra/llcorehttp/_httpservice.h
parentb187aeb8f177bd76e792652e773617beff18b47b (diff)
Okay, imported the core-http library and got it compiling suspiciously easily.
The unit/integration tests don't work yet as I'm still battling cmake/autobuild as usual but first milestone passed.
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+/**
+ * @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_
+
+
+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
+ };
+
+ 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 application thread *once*.
+ void startThread();
+
+ /// Threading: callable by worker thread.
+ void stopRequested();
+
+ /// Threading: callable by worker thread.
+ void shutdown();
+
+ HttpPolicy * getPolicy()
+ {
+ return mPolicy;
+ }
+
+ HttpLibcurl * getTransport()
+ {
+ return mTransport;
+ }
+
+protected:
+ void threadRun(LLCoreInt::HttpThread * thread);
+
+ void processRequestQueue();
+
+protected:
+ static HttpService * sInstance;
+
+ // === shared data ===
+ static volatile EState sState;
+ HttpRequestQueue * mRequestQueue;
+ volatile bool mExitRequested;
+
+ // === calling-thread-only data ===
+ LLCoreInt::HttpThread * mThread;
+
+ // === working-thread-only data ===
+ HttpPolicy * mPolicy;
+ HttpLibcurl * mTransport;
+
+}; // end class HttpService
+
+} // end namespace LLCore
+
+#endif // _LLCORE_HTTP_SERVICE_H_