143 lines
4.6 KiB
C++
143 lines
4.6 KiB
C++
/* -*-c++-*- */
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/* osgEarth - Geospatial SDK for OpenSceneGraph
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* Copyright 2020 Pelican Mapping
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* http://osgearth.org
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*
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* osgEarth is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>
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*/
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#ifndef OSGEARTH_CACHE_POLICY_H
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#define OSGEARTH_CACHE_POLICY_H 1
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#include <osgEarth/Common>
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#include <osgEarth/Config>
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#include <osgEarth/DateTime>
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#include <osgDB/Options>
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namespace osgEarth
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{
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/**
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* Policy for cache usage.
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*/
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class OSGEARTH_EXPORT CachePolicy
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{
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public:
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enum Usage
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{
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USAGE_READ_WRITE = 0, // read/write to the cache if one exists.
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USAGE_CACHE_ONLY = 1, // treat the cache as the ONLY source of data.
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USAGE_READ_ONLY = 2, // read from the cache, but don't write new data to it.
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USAGE_NO_CACHE = 3 // neither read from or write to the cache
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};
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/** default cache policy (READ_WRITE) */
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static CachePolicy DEFAULT;
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/* policy indicating to never use a cache */
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static CachePolicy NO_CACHE;
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/** policy indicating to only use a cache */
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static CachePolicy CACHE_ONLY;
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public:
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/** constructs an invalid CachePolicy. */
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CachePolicy();
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/** copy ctor */
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CachePolicy(const CachePolicy& rhs);
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/** constructs a caching policy. */
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CachePolicy( const Usage& usage );
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/** constructs a CachePolicy from a config options */
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CachePolicy( const Config& conf );
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/** Merges any set properties in another CP into this one, override existing values. */
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void mergeAndOverride(const CachePolicy& rhs);
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void mergeAndOverride(const optional<CachePolicy>& rhs);
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/** Gets the oldest timestamp for which to accept a cache record */
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TimeStamp getMinAcceptTime() const;
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/** Whether the given timestamp is considered to be expired based on this CachePolicy */
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bool isExpired(TimeStamp lastModified) const;
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/** dtor */
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virtual ~CachePolicy() { }
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/** Gets the usage policy */
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optional<Usage>& usage() { return _usage; }
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const optional<Usage>& usage() const { return _usage; }
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/** Gets the age limit for a cache record (in seconds) */
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optional<TimeSpan>& maxAge() { return _maxAge; }
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const optional<TimeSpan>& maxAge() const { return _maxAge; }
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/** Gets the age limit for a cache record (as an absolute timestamp) */
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optional<TimeStamp>& minTime() { return _minTime; }
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const optional<TimeStamp>& minTime() const { return _minTime; }
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/** Whether any of the fields are set */
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bool empty() const;
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public: // convenience functions.
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bool isCacheEnabled() const {
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return isCacheReadable() || isCacheWriteable();
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}
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bool isCacheDisabled() const {
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return !isCacheEnabled();
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}
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bool isCacheReadable() const {
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return *_usage == USAGE_READ_WRITE || *_usage == USAGE_CACHE_ONLY || *_usage == USAGE_READ_ONLY;
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}
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bool isCacheWriteable() const {
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return *_usage == USAGE_READ_WRITE;
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}
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bool isCacheOnly() const {
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return *_usage == USAGE_CACHE_ONLY;
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}
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bool operator == ( const CachePolicy& rhs ) const;
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bool operator != ( const CachePolicy& rhs ) const {
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return ! operator==(rhs);
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}
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CachePolicy& operator = ( const CachePolicy& rhs );
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// returns a readable string describing usage
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std::string usageString() const;
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public: // config
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Config getConfig() const;
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void fromConfig( const Config& conf );
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private:
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optional<Usage> _usage;
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optional<TimeSpan> _maxAge;
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optional<TimeStamp> _minTime;
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};
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}
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OSGEARTH_SPECIALIZE_CONFIG(osgEarth::CachePolicy);
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#endif // OSGEARTH_CACHE_POLICY_H
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