thodg/libgit2/src/cache.h

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• Hash : 335d6c99
  Author :
  Date : 2011-05-17T01:46:07
  

  cache: Drop cuckoo hashing
  
  Now we use a simple closed-addressing cache. Cuckoo hashing was creating
  too many issues with race conditions. Fuck that.
  
  Let's see what happens performance wise, we may have to roll back or
  come up with another way to implement an efficient multi-threaded cache.
  

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• src/cache.h

• #ifndef INCLUDE_cache_h__
  #define INCLUDE_cache_h__
  
  #include "git2/common.h"
  #include "git2/oid.h"
  #include "git2/odb.h"
  
  #include "thread-utils.h"
  
  #define GIT_DEFAULT_CACHE_SIZE 128
  
  typedef void (*git_cached_obj_freeptr)(void *);
  
  typedef struct {
  	git_oid oid;
  	git_atomic refcount;
  } git_cached_obj;
  
  typedef struct {
  	git_cached_obj *ptr;
  	git_mutex lock;
  } cache_node;
  
  typedef struct {
  	cache_node *nodes;
  
  	unsigned int lru_count;
  	size_t size_mask;
  	git_cached_obj_freeptr free_obj;
  } git_cache;
  
  
  int git_cache_init(git_cache *cache, size_t size, git_cached_obj_freeptr free_ptr);
  void git_cache_free(git_cache *cache);
  
  void *git_cache_try_store(git_cache *cache, void *entry);
  void *git_cache_get(git_cache *cache, const git_oid *oid);
  
  
  GIT_INLINE(int) git_cached_obj_compare(git_cached_obj *obj, const git_oid *oid)
  {
  	return git_oid_cmp(&obj->oid, oid);
  }
  
  GIT_INLINE(void) git_cached_obj_incref(git_cached_obj *obj)
  {
  	git_atomic_inc(&obj->refcount);
  }
  
  GIT_INLINE(void) git_cached_obj_decref(git_cached_obj *obj, git_cached_obj_freeptr free_obj)
  {
  	if (git_atomic_dec(&obj->refcount) == 0)
  		free_obj(obj);
  }
  
  
  
  #endif
  

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