89 lines
2.9 KiB
C++
89 lines
2.9 KiB
C++
/**
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* @file file llhttpretrypolicy.h
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* @brief declarations for http retry policy class.
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*
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* $LicenseInfo:firstyear=2013&license=viewerlgpl$
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* Second Life Viewer Source Code
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* Copyright (C) 2013, Linden Research, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation;
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* version 2.1 of the License only.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
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* $/LicenseInfo$
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*/
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#ifndef LL_RETRYPOLICY_H
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#define LL_RETRYPOLICY_H
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#include "lltimer.h"
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#include "llthread.h"
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class AIHTTPReceivedHeaders;
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// This is intended for use with HTTP Clients/Responders, but is not
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// specifically coupled with those classes.
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class LLHTTPRetryPolicy: public LLThreadSafeRefCount
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{
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public:
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LLHTTPRetryPolicy() {}
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virtual ~LLHTTPRetryPolicy() {}
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// Call after a sucess to reset retry state.
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virtual void onSuccess() = 0;
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// Call once after an HTTP failure to update state.
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virtual void onFailure(S32 status, const AIHTTPReceivedHeaders& headers) = 0;
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virtual bool shouldRetry(F32& seconds_to_wait) const = 0;
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virtual void reset() = 0;
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};
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// Very general policy with geometric back-off after failures,
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// up to a maximum delay, and maximum number of retries.
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class LLAdaptiveRetryPolicy: public LLHTTPRetryPolicy
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{
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public:
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LLAdaptiveRetryPolicy(F32 min_delay, F32 max_delay, F32 backoff_factor, U32 max_retries, bool retry_on_4xx = false);
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// virtual
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void onSuccess();
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void reset();
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// virtual
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void onFailure(S32 status, const AIHTTPReceivedHeaders& headers);
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// virtual
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bool shouldRetry(F32& seconds_to_wait) const;
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protected:
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void init();
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bool getRetryAfter(const AIHTTPReceivedHeaders& headers, F32& retry_header_time);
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void onFailureCommon(S32 status, bool has_retry_header_time, F32 retry_header_time);
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private:
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F32 mMinDelay; // delay never less than this value
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F32 mMaxDelay; // delay never exceeds this value
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F32 mBackoffFactor; // delay increases by this factor after each retry, up to mMaxDelay.
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U32 mMaxRetries; // maximum number of times shouldRetry will return true.
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F32 mDelay; // current delay.
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U32 mRetryCount; // number of times shouldRetry has been called.
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LLTimer mRetryTimer; // time until next retry.
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bool mShouldRetry; // Becomes false after too many retries, or the wrong sort of status received, etc.
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bool mRetryOn4xx; // Normally only retry on 5xx server errors.
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};
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#endif
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