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UT_LocalDiskCache Class Reference

A disk cache to store expensive data on a local disk. More...

#include <UT_LocalDiskCache.h>

Public Member Functions

 UT_LocalDiskCache (const char *cache_name, int64 max_item_size, int64 max_item_count)
 ~UT_LocalDiskCache ()
void clearCache (bool reset_file=true)
bool extractFromCache (const UT_LocalDiskCacheKey &key, void *buffer, int64 &buffer_size, bool remove_from_cache=true)
void storeInCache (const UT_LocalDiskCacheKey &key, const void *buffer, int64 buffer_size)
 Store in the cache. More...
int64 getMemoryUsed () const
 Get memory used. More...
int64 getFileSize () const
 Get the file size. More...
template<typename T >
void traverseCache (T &task)
 Traverse the cache. More...
const UT_CappedCachegetCache () const
 Const access to the cache. More...

Detailed Description

A disk cache to store expensive data on a local disk.

In some cases, accessing data can be expensive:

  • Loading over a saturated network
  • An expensive computation This cache provides a means to store this data on disk. The disk file is automatically cleaned up when the program completes.

This cache makes a reasonable secondary cache.

Definition at line 51 of file UT_LocalDiskCache.h.

Constructor & Destructor Documentation

UT_LocalDiskCache::UT_LocalDiskCache ( const char *  cache_name,
int64  max_item_size,
int64  max_item_count 

The cache is used to store data in a temporary disk file max_item_size is the maximum size for each item put into the cache max_item_count is the maximum number of items to be stored in the cache It's fairly obvious that the maximum size for the disk file will be max_item_size*max_item_count.

UT_LocalDiskCache::~UT_LocalDiskCache ( )

Member Function Documentation

void UT_LocalDiskCache::clearCache ( bool  reset_file = true)

Clear entire disk cache. This is not thread safe and should only be called when the cache isn't under contention.

bool UT_LocalDiskCache::extractFromCache ( const UT_LocalDiskCacheKey key,
void buffer,
int64 buffer_size,
bool  remove_from_cache = true 

Extract from the disk cache. Once extracted, the item will no longer exist in the cache.

The flag determines whether the object will be removed from the disk cache after extraction. Since this cache is usually used as a secondary cache, it's usually the primary cache which extracts the data from the disk cache (keeping the object in the primary cache after).

const UT_CappedCache& UT_LocalDiskCache::getCache ( ) const

Const access to the cache.

Definition at line 101 of file UT_LocalDiskCache.h.

int64 UT_LocalDiskCache::getFileSize ( ) const

Get the file size.

Definition at line 92 of file UT_LocalDiskCache.h.

int64 UT_LocalDiskCache::getMemoryUsed ( ) const

Get memory used.

void UT_LocalDiskCache::storeInCache ( const UT_LocalDiskCacheKey key,
const void buffer,
int64  buffer_size 

Store in the cache.

template<typename T >
void UT_LocalDiskCache::traverseCache ( T task)

Traverse the cache.

Definition at line 95 of file UT_LocalDiskCache.h.

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