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Diffstat (limited to 'indra/llcorehttp/_httpinternal.h')
| -rwxr-xr-x | indra/llcorehttp/_httpinternal.h | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/indra/llcorehttp/_httpinternal.h b/indra/llcorehttp/_httpinternal.h new file mode 100755 index 0000000000..008e4fd95c --- /dev/null +++ b/indra/llcorehttp/_httpinternal.h @@ -0,0 +1,151 @@ +/** + * @file _httpinternal.h + * @brief Implementation constants and magic numbers + * + * $LicenseInfo:firstyear=2012&license=viewerlgpl$ + * 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_INTERNAL_H_ +#define _LLCORE_HTTP_INTERNAL_H_ + + +// If you find this included in a public interface header, +// something wrong is probably happening. + + +// -------------------------------------------------------------------- +// General library to-do list +// +// - Implement policy classes. Structure is mostly there just didn't +// need it for the first consumer. +// - Consider Removing 'priority' from the request interface. Its use +// in an always active class can lead to starvation of low-priority +// requests. Requires coodination of priority values across all +// components that share a class. Changing priority across threads +// is slightly expensive (relative to gain) and hasn't been completely +// implemented. And the major user of priority, texture fetches, +// may not really need it. +// - Set/get for global policy and policy classes is clumsy. Rework +// it heading in a direction that allows for more dynamic behavior. +// - Move HttpOpRequest::prepareRequest() to HttpLibcurl for the +// pedantic. +// - Update downloader and other long-duration services are going to +// need a progress notification. Initial idea is to introduce a +// 'repeating request' which can piggyback on another request and +// persist until canceled or carrier completes. Current queue +// structures allow an HttpOperation object to be enqueued +// repeatedly, so... +// - Investigate making c-ares' re-implementation of a resolver library +// more resilient or more intelligent on Mac. Part of the DNS failure +// lies in here. The mechanism also looks a little less dynamic +// than needed in an environments where networking is changing. +// - Global optimizations: 'borrowing' connections from other classes, +// HTTP pipelining. +// - Dynamic/control system stuff: detect problems and self-adjust. +// This won't help in the face of the router problems we've looked +// at, however. Detect starvation due to UDP activity and provide +// feedback to it. +// +// Integration to-do list +// - LLTextureFetch still needs a major refactor. The use of +// LLQueuedThread makes it hard to inspect workers and do the +// resource waiting we're now doing. Rebuild along simpler lines +// some of which are suggested in new commentary at the top of +// the main source file. +// - Expand areas of usage eventually leading to the removal of LLCurl. +// Rough order of expansion: +// . Mesh fetch +// . Avatar names +// . Group membership lists +// . Caps access in general +// . 'The rest' +// - Adapt texture cache, image decode and other image consumers to +// the BufferArray model to reduce data copying. Alternatively, +// adapt this library to something else. +// +// -------------------------------------------------------------------- + + +// If '1', internal ready queues will not order ready +// requests by priority, instead it's first-come-first-served. +// Reprioritization requests have the side-effect of then +// putting the modified request at the back of the ready queue. + +#define LLCORE_HTTP_READY_QUEUE_IGNORES_PRIORITY 1 + + +namespace LLCore +{ + +// Maxium number of policy classes that can be defined. +// *TODO: Currently limited to the default class, extend. +const int HTTP_POLICY_CLASS_LIMIT = 1; + +// Debug/informational tracing. Used both +// as a global option and in per-request traces. +const int HTTP_TRACE_OFF = 0; +const int HTTP_TRACE_LOW = 1; +const int HTTP_TRACE_CURL_HEADERS = 2; +const int HTTP_TRACE_CURL_BODIES = 3; + +const int HTTP_TRACE_MIN = HTTP_TRACE_OFF; +const int HTTP_TRACE_MAX = HTTP_TRACE_CURL_BODIES; + +// Request retry limits +// +// At a minimum, retries need to extend past any throttling +// window we're expecting from central services. In the case +// of Linden services running through the caps routers, there's +// a five-second or so window for throttling with some spillover. +// We want to span a few windows to allow transport to slow +// after onset of the throttles and then recover without a final +// failure. Other systems may need other constants. +const int HTTP_RETRY_COUNT_DEFAULT = 8; +const int HTTP_RETRY_COUNT_MIN = 0; +const int HTTP_RETRY_COUNT_MAX = 100; + +const int HTTP_REDIRECTS_DEFAULT = 10; + +// Timeout value used for both connect and protocol exchange. +// Retries and time-on-queue are not included and aren't +// accounted for. +const long HTTP_REQUEST_TIMEOUT_DEFAULT = 30L; +const long HTTP_REQUEST_TIMEOUT_MIN = 0L; +const long HTTP_REQUEST_TIMEOUT_MAX = 3600L; + +// Limits on connection counts +const int HTTP_CONNECTION_LIMIT_DEFAULT = 8; +const int HTTP_CONNECTION_LIMIT_MIN = 1; +const int HTTP_CONNECTION_LIMIT_MAX = 256; + +// Tuning parameters + +// Time worker thread sleeps after a pass through the +// request, ready and active queues. +const int HTTP_SERVICE_LOOP_SLEEP_NORMAL_MS = 2; + +// Block allocation size (a tuning parameter) is found +// in bufferarray.h. + +} // end namespace LLCore + +#endif // _LLCORE_HTTP_INTERNAL_H_ |