merge changes for DRTVWR-209

1 files changed, 224 insertions, 0 deletions

diff --git a/indra/llcorehttp/_httpservice.h b/indra/llcorehttp/_httpservice.h
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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_
+
+
+#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_