1 files changed, 492 insertions, 0 deletions
diff --git a/indra/llcorehttp/_httppolicy.cpp b/indra/llcorehttp/_httppolicy.cpp
new file mode 100755
index 0000000000..e5d6321401
--- /dev/null
+++ b/indra/llcorehttp/_httppolicy.cpp
@@ -0,0 +1,492 @@
+/**
+ * @file _httppolicy.cpp
+ * @brief Internal definitions of the Http policy thread
+ *
+ * $LicenseInfo:firstyear=2012&license=viewerlgpl$
+ * Second Life Viewer Source Code
+ * Copyright (C) 2012-2014, 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
+ * $/LicenseInfo$
+ */
+
+#include "linden_common.h"
+
+#include "_httppolicy.h"
+
+#include "_httpoprequest.h"
+#include "_httpservice.h"
+#include "_httplibcurl.h"
+#include "_httppolicyclass.h"
+
+#include "lltimer.h"
+
+namespace
+{
+
+static const char * const LOG_CORE("CoreHttp");
+
+} // end anonymous namespace
+
+
+namespace LLCore
+{
+
+
+// Per-policy-class data for a running system.
+// Collection of queues, options and other data
+// for a single policy class.
+//
+// Threading:  accessed only by worker thread
+struct HttpPolicy::ClassState
+{
+public:
+	ClassState()
+		: mThrottleEnd(0),
+		  mThrottleLeft(0L),
+		  mRequestCount(0L),
+		  mStallStaging(false)
+		{}
+	
+	HttpReadyQueue		mReadyQueue;
+	HttpRetryQueue		mRetryQueue;
+
+	HttpPolicyClass		mOptions;
+	HttpTime			mThrottleEnd;
+	long				mThrottleLeft;
+	long				mRequestCount;
+	bool				mStallStaging;
+};
+
+
+HttpPolicy::HttpPolicy(HttpService * service)
+	: mService(service)
+{
+	// Create default class
+	mClasses.push_back(new ClassState());
+}
+
+
+HttpPolicy::~HttpPolicy()
+{
+	shutdown();
+
+	for (class_list_t::iterator it(mClasses.begin()); it != mClasses.end(); ++it)
+	{
+		delete (*it);
+	}
+	mClasses.clear();
+	
+	mService = NULL;
+}
+
+
+HttpRequest::policy_t HttpPolicy::createPolicyClass()
+{
+	const HttpRequest::policy_t policy_class(mClasses.size());
+	if (policy_class >= HTTP_POLICY_CLASS_LIMIT)
+	{
+		return HttpRequest::INVALID_POLICY_ID;
+	}
+	mClasses.push_back(new ClassState());
+	return policy_class;
+}
+
+
+void HttpPolicy::shutdown()
+{
+	for (int policy_class(0); policy_class < mClasses.size(); ++policy_class)
+	{
+		ClassState & state(*mClasses[policy_class]);
+		
+		HttpRetryQueue & retryq(state.mRetryQueue);
+		while (! retryq.empty())
+		{
+			HttpOpRequest * op(retryq.top());
+			retryq.pop();
+		
+			op->cancel();
+			op->release();
+		}
+
+		HttpReadyQueue & readyq(state.mReadyQueue);
+		while (! readyq.empty())
+		{
+			HttpOpRequest * op(readyq.top());
+			readyq.pop();
+		
+			op->cancel();
+			op->release();
+		}
+	}
+}
+
+
+void HttpPolicy::start()
+{
+}
+
+
+void HttpPolicy::addOp(HttpOpRequest * op)
+{
+	const int policy_class(op->mReqPolicy);
+	
+	op->mPolicyRetries = 0;
+	op->mPolicy503Retries = 0;
+	mClasses[policy_class]->mReadyQueue.push(op);
+}
+
+
+void HttpPolicy::retryOp(HttpOpRequest * op)
+{
+	static const HttpTime retry_deltas[] =
+		{
+			 250000,			// 1st retry in 0.25 S, etc...
+			 500000,
+			1000000,
+			2000000,
+			5000000				// ... to every 5.0 S.
+		};
+	static const int delta_max(int(LL_ARRAY_SIZE(retry_deltas)) - 1);
+	static const HttpStatus error_503(503);
+
+	const HttpTime now(totalTime());
+	const int policy_class(op->mReqPolicy);
+	HttpTime delta(retry_deltas[llclamp(op->mPolicyRetries, 0, delta_max)]);
+	bool external_delta(false);
+
+	if (op->mReplyRetryAfter > 0 && op->mReplyRetryAfter < 30)
+	{
+		delta = op->mReplyRetryAfter * U64L(1000000);
+		external_delta = true;
+	}
+	op->mPolicyRetryAt = now + delta;
+	++op->mPolicyRetries;
+	if (error_503 == op->mStatus)
+	{
+		++op->mPolicy503Retries;
+	}
+	LL_DEBUGS(LOG_CORE) << "HTTP request " << static_cast<HttpHandle>(op)
+						<< " retry " << op->mPolicyRetries
+						<< " scheduled in " << (delta / HttpTime(1000))
+						<< " mS (" << (external_delta ? "external" : "internal")
+						<< ").  Status:  " << op->mStatus.toTerseString()
+						<< LL_ENDL;
+	if (op->mTracing > HTTP_TRACE_OFF)
+	{
+		LL_INFOS(LOG_CORE) << "TRACE, ToRetryQueue, Handle:  "
+						   << static_cast<HttpHandle>(op)
+						   << ", Delta:  " << (delta / HttpTime(1000))
+						   << ", Retries:  " << op->mPolicyRetries
+						   << LL_ENDL;
+	}
+	mClasses[policy_class]->mRetryQueue.push(op);
+}
+
+
+// Attempt to deliver requests to the transport layer.
+//
+// Tries to find HTTP requests for each policy class with
+// available capacity.  Starts with the retry queue first
+// looking for requests that have waited long enough then
+// moves on to the ready queue.
+//
+// If all queues are empty, will return an indication that
+// the worker thread may sleep hard otherwise will ask for
+// normal polling frequency.
+//
+// Implements a client-side request rate throttle as well.
+// This is intended to mimic and predict throttling behavior
+// of grid services but that is difficult to do with different
+// time bases.  This also represents a rigid coupling between
+// viewer and server that makes it hard to change parameters
+// and I hope we can make this go away with pipelining.
+//
+HttpService::ELoopSpeed HttpPolicy::processReadyQueue()
+{
+	const HttpTime now(totalTime());
+	HttpService::ELoopSpeed result(HttpService::REQUEST_SLEEP);
+	HttpLibcurl & transport(mService->getTransport());
+	
+	for (int policy_class(0); policy_class < mClasses.size(); ++policy_class)
+	{
+		ClassState & state(*mClasses[policy_class]);
+		HttpRetryQueue & retryq(state.mRetryQueue);
+		HttpReadyQueue & readyq(state.mReadyQueue);
+
+		if (state.mStallStaging)
+		{
+			// Stalling but don't sleep.  Need to complete operations
+			// and get back to servicing queues.  Do this test before
+			// the retryq/readyq test or you'll get stalls until you
+			// click a setting or an asset request comes in.
+			result = HttpService::NORMAL;
+			continue;
+		}
+		if (retryq.empty() && readyq.empty())
+		{
+			continue;
+		}
+		
+		const bool throttle_enabled(state.mOptions.mThrottleRate > 0L);
+		const bool throttle_current(throttle_enabled && now < state.mThrottleEnd);
+
+		if (throttle_current && state.mThrottleLeft <= 0)
+		{
+			// Throttled condition, don't serve this class but don't sleep hard.
+			result = HttpService::NORMAL;
+			continue;
+		}
+
+		int active(transport.getActiveCountInClass(policy_class));
+		int active_limit(state.mOptions.mPipelining > 1L
+						 ? (state.mOptions.mPerHostConnectionLimit
+							* state.mOptions.mPipelining)
+						 : state.mOptions.mConnectionLimit);
+		int needed(active_limit - active);		// Expect negatives here
+
+		if (needed > 0)
+		{
+			// First see if we have any retries...
+			while (needed > 0 && ! retryq.empty())
+			{
+				HttpOpRequest * op(retryq.top());
+				if (op->mPolicyRetryAt > now)
+					break;
+			
+				retryq.pop();
+				
+				op->stageFromReady(mService);
+				op->release();
+
+				++state.mRequestCount;
+				--needed;
+				if (throttle_enabled)
+				{
+					if (now >= state.mThrottleEnd)
+					{
+						// Throttle expired, move to next window
+						LL_DEBUGS(LOG_CORE) << "Throttle expired with " << state.mThrottleLeft
+											<< " requests to go and " << state.mRequestCount
+											<< " requests issued." << LL_ENDL;
+						state.mThrottleLeft = state.mOptions.mThrottleRate;
+						state.mThrottleEnd = now + HttpTime(1000000);
+					}
+					if (--state.mThrottleLeft <= 0)
+					{
+						goto throttle_on;
+					}
+				}
+			}
+			
+			// Now go on to the new requests...
+			while (needed > 0 && ! readyq.empty())
+			{
+				HttpOpRequest * op(readyq.top());
+				readyq.pop();
+
+				op->stageFromReady(mService);
+				op->release();
+					
+				++state.mRequestCount;
+				--needed;
+				if (throttle_enabled)
+				{
+					if (now >= state.mThrottleEnd)
+					{
+						// Throttle expired, move to next window
+						LL_DEBUGS(LOG_CORE) << "Throttle expired with " << state.mThrottleLeft
+											<< " requests to go and " << state.mRequestCount
+											<< " requests issued." << LL_ENDL;
+						state.mThrottleLeft = state.mOptions.mThrottleRate;
+						state.mThrottleEnd = now + HttpTime(1000000);
+					}
+					if (--state.mThrottleLeft <= 0)
+					{
+						goto throttle_on;
+					}
+				}
+			}
+		}
+
+	throttle_on:
+		
+		if (! readyq.empty() || ! retryq.empty())
+		{
+			// If anything is ready, continue looping...
+			result = HttpService::NORMAL;
+		}
+	} // end foreach policy_class
+
+	return result;
+}
+
+
+bool HttpPolicy::changePriority(HttpHandle handle, HttpRequest::priority_t priority)
+{
+	for (int policy_class(0); policy_class < mClasses.size(); ++policy_class)
+	{
+		ClassState & state(*mClasses[policy_class]);
+		// We don't scan retry queue because a priority change there
+		// is meaningless.  The request will be issued based on retry
+		// intervals not priority value, which is now moot.
+		
+		// Scan ready queue for requests that match policy
+		HttpReadyQueue::container_type & c(state.mReadyQueue.get_container());
+		for (HttpReadyQueue::container_type::iterator iter(c.begin()); c.end() != iter;)
+		{
+			HttpReadyQueue::container_type::iterator cur(iter++);
+
+			if (static_cast<HttpHandle>(*cur) == handle)
+			{
+				HttpOpRequest * op(*cur);
+				c.erase(cur);									// All iterators are now invalidated
+				op->mReqPriority = priority;
+				state.mReadyQueue.push(op);						// Re-insert using adapter class
+				return true;
+			}
+		}
+	}
+	
+	return false;
+}
+
+
+bool HttpPolicy::cancel(HttpHandle handle)
+{
+	for (int policy_class(0); policy_class < mClasses.size(); ++policy_class)
+	{
+		ClassState & state(*mClasses[policy_class]);
+
+		// Scan retry queue
+		HttpRetryQueue::container_type & c1(state.mRetryQueue.get_container());
+		for (HttpRetryQueue::container_type::iterator iter(c1.begin()); c1.end() != iter;)
+		{
+			HttpRetryQueue::container_type::iterator cur(iter++);
+
+			if (static_cast<HttpHandle>(*cur) == handle)
+			{
+				HttpOpRequest * op(*cur);
+				c1.erase(cur);									// All iterators are now invalidated
+				op->cancel();
+				op->release();
+				return true;
+			}
+		}
+		
+		// Scan ready queue
+		HttpReadyQueue::container_type & c2(state.mReadyQueue.get_container());
+		for (HttpReadyQueue::container_type::iterator iter(c2.begin()); c2.end() != iter;)
+		{
+			HttpReadyQueue::container_type::iterator cur(iter++);
+
+			if (static_cast<HttpHandle>(*cur) == handle)
+			{
+				HttpOpRequest * op(*cur);
+				c2.erase(cur);									// All iterators are now invalidated
+				op->cancel();
+				op->release();
+				return true;
+			}
+		}
+	}
+	
+	return false;
+}
+
+
+bool HttpPolicy::stageAfterCompletion(HttpOpRequest * op)
+{
+	// Retry or finalize
+	if (! op->mStatus)
+	{
+		// *DEBUG:  For "[curl:bugs] #1420" tests.  This will interfere
+		// with unit tests due to allocation retention by logging code.
+		// But you won't be checking this in enabled.
+#if 0
+		if (op->mStatus == HttpStatus(HttpStatus::EXT_CURL_EASY, CURLE_OPERATION_TIMEDOUT))
+		{
+			LL_WARNS(LOG_CORE) << "HTTP request " << static_cast<HttpHandle>(op)
+							   << " timed out."
+							   << LL_ENDL;
+		}
+#endif
+		
+		// If this failed, we might want to retry.
+		if (op->mPolicyRetries < op->mPolicyRetryLimit && op->mStatus.isRetryable())
+		{
+			// Okay, worth a retry.
+			retryOp(op);
+			return true;				// still active/ready
+		}
+	}
+
+	// This op is done, finalize it delivering it to the reply queue...
+	if (! op->mStatus)
+	{
+		LL_WARNS(LOG_CORE) << "HTTP request " << static_cast<HttpHandle>(op)
+						   << " failed after " << op->mPolicyRetries
+						   << " retries.  Reason:  " << op->mStatus.toString()
+						   << " (" << op->mStatus.toTerseString() << ")"
+						   << LL_ENDL;
+	}
+	else if (op->mPolicyRetries)
+	{
+		LL_DEBUGS(LOG_CORE) << "HTTP request " << static_cast<HttpHandle>(op)
+							<< " succeeded on retry " << op->mPolicyRetries << "."
+							<< LL_ENDL;
+	}
+
+	op->stageFromActive(mService);
+	op->release();
+	return false;						// not active
+}
+
+	
+HttpPolicyClass & HttpPolicy::getClassOptions(HttpRequest::policy_t pclass)
+{
+	llassert_always(pclass >= 0 && pclass < mClasses.size());
+	
+	return mClasses[pclass]->mOptions;
+}
+
+
+int HttpPolicy::getReadyCount(HttpRequest::policy_t policy_class) const
+{
+	if (policy_class < mClasses.size())
+	{
+		return (mClasses[policy_class]->mReadyQueue.size()
+				+ mClasses[policy_class]->mRetryQueue.size());
+	}
+	return 0;
+}
+
+
+bool HttpPolicy::stallPolicy(HttpRequest::policy_t policy_class, bool stall)
+{
+	bool ret(false);
+	
+	if (policy_class < mClasses.size())
+	{
+		ret = mClasses[policy_class]->mStallStaging;
+		mClasses[policy_class]->mStallStaging = stall;
+	}
+	return ret;
+}
+
+
+}  // end namespace LLCore