ossim::CurlHeaderCache Class Reference

#include <CurlHeaderCache.h>

Public Types
typedef std::shared_ptr< CurlHeaderCacheNode >	Node_t
typedef std::string	Key_t
typedef ossim_int64	TimeIndex_t
typedef std::map< Key_t, Node_t >	CacheType
typedef std::map< TimeIndex_t, Key_t >	CacheTimeIndexType

Public Member Functions
	CurlHeaderCache ()
virtual	~CurlHeaderCache ()
bool	getCachedFilesize (const Key_t &key, ossim_int64 &filesize) const
void	addHeader (const Key_t &key, Node_t &node)
void	setMaxCacheEntries (ossim_int64 maxEntries)
void	touchEntry (const Key_t &key)

Static Public Member Functions
static std::shared_ptr< CurlHeaderCache >	instance ()

Protected Member Functions
void	shrinkEntries ()
void	touchEntryProtected (const Key_t &key)

Protected Attributes
std::mutex	m_mutex
CacheType	m_cache
CacheTimeIndexType	m_cacheTime
ossim_int64	m_maxCacheEntries

Static Protected Attributes
static std::shared_ptr< CurlHeaderCache >	m_instance

Detailed Description

Definition at line 27 of file CurlHeaderCache.h.

Member Typedef Documentation

CacheTimeIndexType

typedef std::map<TimeIndex_t, Key_t > ossim::CurlHeaderCache::CacheTimeIndexType

Definition at line 34 of file CurlHeaderCache.h.

CacheType

typedef std::map<Key_t, Node_t > ossim::CurlHeaderCache::CacheType

Definition at line 33 of file CurlHeaderCache.h.

Key_t

typedef std::string ossim::CurlHeaderCache::Key_t

Definition at line 31 of file CurlHeaderCache.h.

Node_t

typedef std::shared_ptr<CurlHeaderCacheNode> ossim::CurlHeaderCache::Node_t

Definition at line 30 of file CurlHeaderCache.h.

TimeIndex_t

typedef ossim_int64 ossim::CurlHeaderCache::TimeIndex_t

Definition at line 32 of file CurlHeaderCache.h.

Constructor & Destructor Documentation

CurlHeaderCache()

ossim::CurlHeaderCache::CurlHeaderCache

(

)

Definition at line 7 of file CurlHeaderCache.cpp.

:m_maxCacheEntries(ossim::CurlStreamDefaults::m_nReadCacheHeaders)
{

}

~CurlHeaderCache()

ossim::CurlHeaderCache::~CurlHeaderCache ( )

virtual

Definition at line 13 of file CurlHeaderCache.cpp.

{
   m_cache.clear();
}

Member Function Documentation

addHeader()

void ossim::CurlHeaderCache::addHeader	(	const Key_t &	key,
		Node_t &	node
	)

Definition at line 49 of file CurlHeaderCache.cpp.

References ossimTimer::instance(), and ossimTimer::tick().

{
   std::unique_lock<std::mutex> lock(m_mutex);
   if(m_maxCacheEntries<=0) return;
   CacheType::const_iterator iter = m_cache.find(key);
   if(iter != m_cache.end())
   {
      iter->second->m_filesize = node->m_filesize;
      touchEntryProtected(key);
   }  
   else
   {
      if(m_cache.size() >= m_maxCacheEntries)
      {
         shrinkEntries();
      }
      node->m_timestamp = ossimTimer::instance()->tick();
      m_cache.insert( std::make_pair(key, node) );
      m_cacheTime.insert( std::make_pair(node->m_timestamp, key) );
   } 
}

getCachedFilesize()

bool ossim::CurlHeaderCache::getCachedFilesize	(	const Key_t &	key,
		ossim_int64 &	filesize
	)		const

Definition at line 28 of file CurlHeaderCache.cpp.

References touchEntryProtected().

{
   std::unique_lock<std::mutex> lock(m_mutex);
   bool result = false;
   if(m_maxCacheEntries<=0) return result;
   CacheType::const_iterator iter = m_cache.find(key);

   if(iter != m_cache.end())
   {
      filesize = iter->second->m_filesize;
      result = true;
   }
   if(result)
   {
      ossim::CurlHeaderCache* curlHeaderConstPtr = const_cast<ossim::CurlHeaderCache*>(this);
      curlHeaderConstPtr->touchEntryProtected(key);
   }

   return result;
}

instance()

std::shared_ptr< ossim::CurlHeaderCache > ossim::CurlHeaderCache::instance ( )

static

Definition at line 18 of file CurlHeaderCache.cpp.

{
   if(!m_instance)
   {
      m_instance = std::make_shared<CurlHeaderCache>();
   }

   return m_instance;
}

setMaxCacheEntries()

void ossim::CurlHeaderCache::setMaxCacheEntries

(

ossim_int64

maxEntries

)

shrinkEntries()

void ossim::CurlHeaderCache::shrinkEntries ( )

protected

Definition at line 96 of file CurlHeaderCache.cpp.

{
   ossim_int64 targetSize = static_cast<ossim_int64>(0.2*m_maxCacheEntries);

   if(m_cacheTime.empty()) return;
   if(targetSize >= m_cache.size())
   {
      m_cache.clear();
      m_cacheTime.clear();
      return;
   }

   CacheTimeIndexType::iterator iter = m_cacheTime.begin();

   while(targetSize > 0)
   {
      m_cache.erase(iter->second);
      iter = m_cacheTime.erase(iter);
      --targetSize;
   }
}

touchEntry()

void ossim::CurlHeaderCache::touchEntry

(

const Key_t &

key

)

Definition at line 71 of file CurlHeaderCache.cpp.

{
   // I think unique lock is recursive but need to test first
   // So for now we will wrap with a touchEntryProtected that does not lock
   // so all public methods are locking.
   //
   std::unique_lock<std::mutex> lock(m_mutex);
   touchEntryProtected(key);
}

touchEntryProtected()

void ossim::CurlHeaderCache::touchEntryProtected ( const Key_t &  key )

protected

Definition at line 81 of file CurlHeaderCache.cpp.

References ossimTimer::instance(), and ossimTimer::tick().

Referenced by getCachedFilesize().

{
   CacheType::iterator iter = m_cache.find(key);
   if(iter!=m_cache.end())
   {
      CacheTimeIndexType::iterator cacheTimeIter = m_cacheTime.find(iter->second->m_timestamp);
      if(cacheTimeIter!=m_cacheTime.end())
      {
         m_cacheTime.erase(cacheTimeIter);
         iter->second->m_timestamp = ossimTimer::instance()->tick();
         m_cacheTime.insert( std::make_pair(iter->second->m_timestamp, key) );
      }
   }
}

Member Data Documentation

m_cache

CacheType ossim::CurlHeaderCache::m_cache

protected

Definition at line 52 of file CurlHeaderCache.h.

m_cacheTime

CacheTimeIndexType ossim::CurlHeaderCache::m_cacheTime

protected

Definition at line 53 of file CurlHeaderCache.h.

m_instance

std::shared_ptr< ossim::CurlHeaderCache > ossim::CurlHeaderCache::m_instance

staticprotected

Definition at line 49 of file CurlHeaderCache.h.

m_maxCacheEntries

ossim_int64 ossim::CurlHeaderCache::m_maxCacheEntries

protected

Definition at line 54 of file CurlHeaderCache.h.

m_mutex

std::mutex ossim::CurlHeaderCache::m_mutex

mutableprotected

Definition at line 50 of file CurlHeaderCache.h.

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The documentation for this class was generated from the following files:

• CurlHeaderCache.h
• CurlHeaderCache.cpp