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![Linus Torvalds](/assets/img/avatar_default.png)
This shrinks "struct object" to the absolutely minimal size possible. It now contains /only/ the object flags and the SHA1 hash name of the object. The "refs" field, which is really needed only for fsck, is maintained in a separate hashed lookup-table, allowing all normal users to totally ignore it. This helps memory usage, although not as much as I hoped: it looks like the allocation overhead of malloc (and the alignment constraints in particular) means that while the structure size shrinks, the actual allocation overhead mostly does not. [ That said: memory usage is actually down, but not as much as it should be: I suspect just one of the object types actually ended up shrinking its effective allocation size. To get to the next level, we probably need specialized allocators that don't pad the allocation more than necessary. ] The separation makes for some code cleanup, though, and makes the ref tracking that fsck wants a clearly separate thing. Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
76 lines
1.9 KiB
C
76 lines
1.9 KiB
C
#ifndef OBJECT_H
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#define OBJECT_H
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struct object_list {
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struct object *item;
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struct object_list *next;
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const char *name;
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};
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struct object_refs {
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unsigned count;
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struct object *base;
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struct object *ref[FLEX_ARRAY]; /* more */
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};
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#define TYPE_BITS 3
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#define FLAG_BITS 27
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#define TYPE_NONE 0
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#define TYPE_BLOB 1
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#define TYPE_TREE 2
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#define TYPE_COMMIT 3
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#define TYPE_TAG 4
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#define TYPE_BAD 5
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struct object {
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unsigned parsed : 1;
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unsigned used : 1;
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unsigned type : TYPE_BITS;
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unsigned flags : FLAG_BITS;
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unsigned char sha1[20];
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};
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extern int track_object_refs;
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extern int obj_allocs;
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extern struct object **objs;
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extern const char *type_names[];
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static inline const char *typename(unsigned int type)
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{
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return type_names[type > TYPE_TAG ? TYPE_BAD : type];
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}
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extern struct object_refs *lookup_object_refs(struct object *);
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/** Internal only **/
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struct object *lookup_object(const unsigned char *sha1);
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/** Returns the object, having looked it up as being the given type. **/
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struct object *lookup_object_type(const unsigned char *sha1, const char *type);
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void created_object(const unsigned char *sha1, struct object *obj);
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/** Returns the object, having parsed it to find out what it is. **/
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struct object *parse_object(const unsigned char *sha1);
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/** Returns the object, with potentially excess memory allocated. **/
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struct object *lookup_unknown_object(const unsigned char *sha1);
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struct object_refs *alloc_object_refs(unsigned count);
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void set_object_refs(struct object *obj, struct object_refs *refs);
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void mark_reachable(struct object *obj, unsigned int mask);
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struct object_list *object_list_insert(struct object *item,
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struct object_list **list_p);
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void object_list_append(struct object *item,
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struct object_list **list_p);
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unsigned object_list_length(struct object_list *list);
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int object_list_contains(struct object_list *list, struct object *obj);
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#endif /* OBJECT_H */
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