sp_cache.h

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/* -*- C++ -*- */
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#ifndef _SP_CACHE_H_
#define _SP_CACHE_H_
 
#include <sys/types.h>
 
#include "my_inttypes.h"
 
/*
  Stored procedures/functions cache. This is used as follows:
   * Each thread has its own cache.
   * Each sp_head object is put into its thread cache before it is used, and
     then remains in the cache until deleted.
*/
 
class sp_cache;
class sp_head;
class sp_name;
 
/*
  Cache usage scenarios:
  1. SP execution in thread:
  1.1 While holding sp_head* pointers:
 
    // look up a routine in the cache (no checks if it is up to date or not)
    sp_cache_lookup();
 
    sp_cache_insert();
    sp_cache_invalidate();
 
  1.2 When not holding any sp_head* pointers:
    sp_cache_flush_obsolete();
 
  2. Before thread exit:
    sp_cache_clear();
*/
 
void sp_cache_clear(sp_cache **cp);
void sp_cache_insert(sp_cache **cp, sp_head *sp);
sp_head *sp_cache_lookup(sp_cache **cp, const sp_name *name);
void sp_cache_invalidate();
void sp_cache_flush_obsolete(sp_cache **cp, sp_head **sp);
int64 sp_cache_version();
void sp_cache_enforce_limit(sp_cache *cp, ulong upper_limit_for_elements);
 
/**
 * @brief Check if the sp_cache contains the specified stored program.
 *
 * @note If the sp is part of a recursion, check if the first instance is part
 * of the sp_cache
 *
 * @param[in] cp - the sp_cache that is to be checked.
 * @param[in] sp - the stored program that needs to be part of that cache.
 * @return true if the element is in the cache.
 * @return false if not.
 */
bool sp_cache_has(sp_cache *cp, sp_head *sp);
 
#endif /* _SP_CACHE_H_ */