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1 | /* | |
2 | * alloc.c - specialized allocator for internal objects | |
3 | * | |
4 | * Copyright (C) 2006 Linus Torvalds | |
5 | * | |
6 | * The standard malloc/free wastes too much space for objects, partly because | |
7 | * it maintains all the allocation infrastructure, but even more because it ends | |
8 | * up with maximal alignment because it doesn't know what the object alignment | |
9 | * for the new allocation is. | |
10 | */ | |
11 | #include "git-compat-util.h" | |
12 | #include "object.h" | |
13 | #include "blob.h" | |
14 | #include "tree.h" | |
15 | #include "commit.h" | |
16 | #include "repository.h" | |
17 | #include "tag.h" | |
18 | #include "alloc.h" | |
19 | ||
20 | #define BLOCKING 1024 | |
21 | ||
22 | union any_object { | |
23 | struct object object; | |
24 | struct blob blob; | |
25 | struct tree tree; | |
26 | struct commit commit; | |
27 | struct tag tag; | |
28 | }; | |
29 | ||
30 | struct alloc_state { | |
31 | int nr; /* number of nodes left in current allocation */ | |
32 | void *p; /* first free node in current allocation */ | |
33 | ||
34 | /* bookkeeping of allocations */ | |
35 | void **slabs; | |
36 | int slab_nr, slab_alloc; | |
37 | }; | |
38 | ||
39 | struct alloc_state *allocate_alloc_state(void) | |
40 | { | |
41 | return xcalloc(1, sizeof(struct alloc_state)); | |
42 | } | |
43 | ||
44 | void clear_alloc_state(struct alloc_state *s) | |
45 | { | |
46 | while (s->slab_nr > 0) { | |
47 | s->slab_nr--; | |
48 | free(s->slabs[s->slab_nr]); | |
49 | } | |
50 | ||
51 | FREE_AND_NULL(s->slabs); | |
52 | } | |
53 | ||
54 | static inline void *alloc_node(struct alloc_state *s, size_t node_size) | |
55 | { | |
56 | void *ret; | |
57 | ||
58 | if (!s->nr) { | |
59 | s->nr = BLOCKING; | |
60 | s->p = xmalloc(BLOCKING * node_size); | |
61 | ||
62 | ALLOC_GROW(s->slabs, s->slab_nr + 1, s->slab_alloc); | |
63 | s->slabs[s->slab_nr++] = s->p; | |
64 | } | |
65 | s->nr--; | |
66 | ret = s->p; | |
67 | s->p = (char *)s->p + node_size; | |
68 | memset(ret, 0, node_size); | |
69 | ||
70 | return ret; | |
71 | } | |
72 | ||
73 | void *alloc_blob_node(struct repository *r) | |
74 | { | |
75 | struct blob *b = alloc_node(r->parsed_objects->blob_state, sizeof(struct blob)); | |
76 | b->object.type = OBJ_BLOB; | |
77 | return b; | |
78 | } | |
79 | ||
80 | void *alloc_tree_node(struct repository *r) | |
81 | { | |
82 | struct tree *t = alloc_node(r->parsed_objects->tree_state, sizeof(struct tree)); | |
83 | t->object.type = OBJ_TREE; | |
84 | return t; | |
85 | } | |
86 | ||
87 | void *alloc_tag_node(struct repository *r) | |
88 | { | |
89 | struct tag *t = alloc_node(r->parsed_objects->tag_state, sizeof(struct tag)); | |
90 | t->object.type = OBJ_TAG; | |
91 | return t; | |
92 | } | |
93 | ||
94 | void *alloc_object_node(struct repository *r) | |
95 | { | |
96 | struct object *obj = alloc_node(r->parsed_objects->object_state, sizeof(union any_object)); | |
97 | obj->type = OBJ_NONE; | |
98 | return obj; | |
99 | } | |
100 | ||
101 | /* | |
102 | * The returned count is to be used as an index into commit slabs, | |
103 | * that are *NOT* maintained per repository, and that is why a single | |
104 | * global counter is used. | |
105 | */ | |
106 | static unsigned int alloc_commit_index(void) | |
107 | { | |
108 | static unsigned int parsed_commits_count; | |
109 | return parsed_commits_count++; | |
110 | } | |
111 | ||
112 | void init_commit_node(struct commit *c) | |
113 | { | |
114 | c->object.type = OBJ_COMMIT; | |
115 | c->index = alloc_commit_index(); | |
116 | } | |
117 | ||
118 | void *alloc_commit_node(struct repository *r) | |
119 | { | |
120 | struct commit *c = alloc_node(r->parsed_objects->commit_state, sizeof(struct commit)); | |
121 | init_commit_node(c); | |
122 | return c; | |
123 | } |