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![Linus Torvalds](/assets/img/avatar_default.png)
We've had this notion of a "object_list" for a long time, which eventually grew a "name" member because some users (notably git-rev-list) wanted to name each object as it is generated. That object_list is great for some things, but it isn't all that wonderful for others, and the "name" member is generally not used by everybody. This patch splits the users of the object_list array up into two: the traditional list users, who want the list-like format, and who don't actually use or want the name. And another class of users that really used the list as an extensible array, and generally wanted to name the objects. The patch is fairly straightforward, but it's also biggish. Most of it really just cleans things up: switching the revision parsing and listing over to the array makes things like the builtin-diff usage much simpler (we now see exactly how many members the array has, and we don't get the objects reversed from the order they were on the command line). One of the main reasons for doing this at all is that the malloc overhead of the simple object list was actually pretty high, and the array is just a lot denser. So this patch brings down memory usage by git-rev-list by just under 3% (on top of all the other memory use optimizations) on the mozilla archive. It does add more lines than it removes, and more importantly, it adds a whole new infrastructure for maintaining lists of objects, but on the other hand, the new dynamic array code is pretty obvious. The change to builtin-diff-tree.c shows a fairly good example of why an array interface is sometimes more natural, and just much simpler for everybody. Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
87 lines
2.1 KiB
C
87 lines
2.1 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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};
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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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struct object_array {
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unsigned int nr;
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unsigned int alloc;
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struct object_array_entry {
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struct object *item;
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const char *name;
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} *objects;
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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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/* Object array handling .. */
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void add_object_array(struct object *obj, const char *name, struct object_array *array);
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#endif /* OBJECT_H */
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