Initial AISv3 merge. New HTTP messages not plugged in yet.

indra/newview/llhttpretrypolicy.h

@@ -0,0 +1,88 @@
+/** 
+ * @file file llhttpretrypolicy.h
+ * @brief declarations for http retry policy class.
+ *
+ * $LicenseInfo:firstyear=2013&license=viewerlgpl$
+ * Second Life Viewer Source Code
+ * Copyright (C) 2013, 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 LL_RETRYPOLICY_H
+#define LL_RETRYPOLICY_H
+
+#include "lltimer.h"
+#include "llthread.h"
+
+class AIHTTPReceivedHeaders;
+
+// This is intended for use with HTTP Clients/Responders, but is not
+// specifically coupled with those classes.
+class LLHTTPRetryPolicy: public LLThreadSafeRefCount
+{
+public:
+	LLHTTPRetryPolicy() {}
+
+	virtual ~LLHTTPRetryPolicy() {}
+	// Call after a sucess to reset retry state.
+
+	virtual void onSuccess() = 0;
+	// Call once after an HTTP failure to update state.
+	virtual void onFailure(S32 status, const AIHTTPReceivedHeaders& headers) = 0;
+
+	virtual bool shouldRetry(F32& seconds_to_wait) const = 0;
+
+	virtual void reset() = 0;
+};
+
+// Very general policy with geometric back-off after failures,
+// up to a maximum delay, and maximum number of retries.
+class LLAdaptiveRetryPolicy: public LLHTTPRetryPolicy
+{
+public:
+	LLAdaptiveRetryPolicy(F32 min_delay, F32 max_delay, F32 backoff_factor, U32 max_retries, bool retry_on_4xx = false);
+
+	// virtual
+	void onSuccess();
+
+	void reset();
+	
+	// virtual
+	void onFailure(S32 status, const AIHTTPReceivedHeaders& headers);
+	// virtual
+	bool shouldRetry(F32& seconds_to_wait) const;
+
+protected:
+	void init();
+	bool getRetryAfter(const AIHTTPReceivedHeaders& headers, F32& retry_header_time);
+	void onFailureCommon(S32 status, bool has_retry_header_time, F32 retry_header_time);
+
+private:
+	F32 mMinDelay; // delay never less than this value
+	F32 mMaxDelay; // delay never exceeds this value
+	F32 mBackoffFactor; // delay increases by this factor after each retry, up to mMaxDelay.
+	U32 mMaxRetries; // maximum number of times shouldRetry will return true.
+	F32 mDelay; // current delay.
+	U32 mRetryCount; // number of times shouldRetry has been called.
+	LLTimer mRetryTimer; // time until next retry.
+	bool mShouldRetry; // Becomes false after too many retries, or the wrong sort of status received, etc.
+	bool mRetryOn4xx; // Normally only retry on 5xx server errors.
+};
+
+#endif